feat(maestro): port preview mode to React (#251)

Extends layoutStore with previewSession/commitPreview, mirroring
multiview.ts's preview controller: a throwaway tab for a session no pane
holds, byte-for-byte restore on end, and every real layout-changing action
drops an active preview first. Never schedules a save while a preview is up.

Adds usePreview, wrapping the store actions with previewSchedule.ts's
120ms leading-edge throttle, plus a touch guard and an immediate `end()`
for real changes. MultiView/TabBar render the preview hue on the pane
titlebar, canvas ring/chip, and the throwaway tab (dashed, unclickable).

.claude/settings.local.json

@@ -0,0 +1,18 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(git add:*)",
+      "Bash(git commit:*)",
+      "Bash(git fetch:*)",
+      "Bash(git merge:*)",
+      "Bash(npx tsc:*)",
+      "Bash(npm run build:*)",
+      "Bash(npm install:*)",
+      "Bash(./node_modules/.bin/tsc:*)",
+      "Bash(npm test:*)",
+      "Bash(cargo check:*)",
+      "Bash(cargo clippy:*)",
+      "Bash(cargo test:*)"
+    ]
+  }
+}

CLAUDE.md

@@ -92,6 +92,12 @@ clients — how it opens, the sigils, the key model, the match-and-rank algorith
 the two matchers must agree on, and the fixture table they are tested against.
 Read it before changing either bar or either matcher.
 
+`docs/STRUCTURED-VIEW.md` is the contract for a structured session (an agent
+run as a daemon child over ACP instead of in a tmux pane) — the eight
+transcript row kinds, the two projections and their cursor/replay semantics,
+the handshake and declined capabilities, and the approval nonce rules. Read
+it before changing anything that renders a structured session.
+
 `nix run .#dev` (or `just dev`) brings up the whole local stack under
 process-compose: a debug daemon on 127.0.0.1:7071, then Vite on :5173 once the
 daemon answers `/api/info`. The SPA proxies `/api/*` back to the daemon, so only

Cargo.lock

@@ -1467,6 +1467,7 @@ dependencies = [
  "maestro-cli",
  "maestro-daemon",
  "maestro-tui",
+ "tempfile",
  "tokio",
  "tracing-subscriber",
 ]
@@ -1477,6 +1478,7 @@ version = "0.1.0"
 dependencies = [
  "agent-client-protocol",
  "libc",
+ "serde",
  "serde_json",
  "tempfile",
  "thiserror 1.0.69",
@@ -1644,6 +1646,7 @@ dependencies = [
  "tokio",
  "tokio-tungstenite 0.21.0",
  "tracing",
+ "unicode-width",
  "uuid",
  "vt100",
 ]

Cargo.toml

@@ -44,6 +44,7 @@ tokio-util = { version = "0.7", features = ["compat"] }
 toml = "0.8"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+unicode-width = "0.1"
 uuid = { version = "1", features = ["v4", "serde"] }
 ratatui = "0.28"
 vt100 = "0.15"

crates/maestro-acp/Cargo.toml

@@ -5,11 +5,12 @@ edition.workspace = true
 license.workspace = true
 repository.workspace = true
 publish.workspace = true
-description = "ACP client role: one claude-code-acp child per structured session"
+description = "ACP client role: one provider adapter child per structured session"
 
 [dependencies]
 agent-client-protocol.workspace = true
 libc.workspace = true
+serde.workspace = true
 serde_json.workspace = true
 thiserror.workspace = true
 tokio.workspace = true

crates/maestro-acp/src/lib.rs

@@ -1,5 +1,5 @@
-//! ACP client role for the daemon (#134): one `claude-code-acp` child per
-//! structured session.
+//! ACP client role for the daemon: one provider adapter child per structured
+//! session.
 //!
 //! The daemon is the client; the adapter is the agent. [`spawn`] starts the
 //! adapter as a child process with stdio pipes, in the session's `cwd` with
@@ -9,10 +9,10 @@
 //!
 //! **The handshake declares almost nothing.** `initialize` reports
 //! `fs.readTextFile`, `fs.writeTextFile` and `terminal` as `false`, so the
-//! adapter uses Claude Code's own Read / Write / Bash instead of asking the
-//! daemon to act on its behalf — exactly what already happens in the
-//! terminal view. `session/request_permission` is the one client method that
-//! gets a real implementation, in #139; here it is a stub that declines.
+//! adapter uses the provider's own file and command tools instead of asking
+//! the daemon to act on its behalf — exactly what already happens in the
+//! terminal view. `session/request_permission` is the one client method with
+//! a real implementation.
 //!
 //! Every `session/update` notification the adapter sends lands on an
 //! unbounded channel the session owns ([`AcpSession::take_updates`]). Nothing
@@ -42,30 +42,62 @@ use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
 use agent_client_protocol::schema::v1::{
-    CancelNotification, ClientCapabilities, ContentBlock, FileSystemCapabilities, Implementation,
-    InitializeRequest, LoadSessionRequest, NewSessionRequest, PromptRequest,
-    RequestPermissionOutcome, RequestPermissionRequest, RequestPermissionResponse, SessionId,
-    SessionNotification,
+    CancelNotification, ClientCapabilities, ConfigOptionUpdate, ContentBlock, CurrentModeUpdate,
+    FileSystemCapabilities, Implementation, InitializeRequest, PromptRequest,
+    RequestPermissionOutcome, RequestPermissionRequest, RequestPermissionResponse,
+    SessionConfigKind, SessionConfigOption, SessionConfigOptionCategory, SessionConfigOptionValue,
+    SessionConfigSelectOption, SessionId, SessionModeState, SessionNotification, SessionUpdate,
+    SetSessionConfigOptionRequest, SetSessionModeRequest,
 };
 use agent_client_protocol::schema::ProtocolVersion;
-use agent_client_protocol::{ByteStreams, Client};
+use agent_client_protocol::{ByteStreams, Client, JsonRpcRequest, JsonRpcResponse};
+use serde::{Deserialize, Serialize};
 use tokio::io::AsyncBufReadExt;
 use tokio::sync::{mpsc, oneshot, watch};
 use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
 
 pub use agent_client_protocol::schema::v1 as schema;
 
-/// The adapter binary, resolved on `PATH`.
-pub const ADAPTER_BIN: &str = "claude-code-acp";
+/// ACP adapter selected from the structured session's resolved command.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AcpAdapter {
+    ClaudeCode,
+    Codex,
+}
 
-/// How to install the adapter when it is missing. Named in the error so an
-/// operator staring at a failed session knows what to run.
+impl AcpAdapter {
+    pub const fn binary(self) -> &'static str {
+        match self {
+            Self::ClaudeCode => "claude-code-acp",
+            Self::Codex => "codex-acp",
+        }
+    }
+
+    pub const fn install_command(self) -> &'static str {
+        match self {
+            Self::ClaudeCode => "npm install -g --prefix ~/.local @zed-industries/claude-code-acp",
+            Self::Codex => "npm install -g --prefix ~/.local @agentclientprotocol/codex-acp",
+        }
+    }
+}
+
+impl std::fmt::Display for AcpAdapter {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::ClaudeCode => "Claude Code",
+            Self::Codex => "Codex",
+        })
+    }
+}
+
+/// Compatibility aliases for Claude Code callers.
+pub const ADAPTER_BIN: &str = "claude-code-acp";
 pub const INSTALL_COMMAND: &str =
     "npm install -g --prefix ~/.local @zed-industries/claude-code-acp";
 
 /// How long `initialize` + `session/new` may take before the spawn is
-/// declared failed. The real adapter boots a node process and the Claude
-/// Code SDK behind it; a slow machine takes seconds, never a minute.
+/// declared failed. The real adapters boot a node process and their provider
+/// client behind it; a slow machine takes seconds, never a minute.
 pub const HANDSHAKE_TIMEOUT: Duration = Duration::from_secs(60);
 
 /// How long [`AcpSession::terminate`] waits after `session/cancel` before
@@ -78,6 +110,75 @@ pub const TERM_GRACE: Duration = Duration::from_secs(2);
 
 /// Bytes of the child's stderr kept for the failure message.
 const STDERR_TAIL_BYTES: usize = 4096;
+const LEGACY_MODEL_CONFIG_ID: &str = "__maestro_legacy_model";
+const LEGACY_MODE_CONFIG_ID: &str = "__maestro_legacy_mode";
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcRequest)]
+#[request(method = "session/new", response = ExtendedNewSessionResponse)]
+#[serde(rename_all = "camelCase")]
+struct ExtendedNewSessionRequest {
+    cwd: PathBuf,
+    mcp_servers: Vec<serde_json::Value>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcResponse)]
+#[serde(rename_all = "camelCase")]
+struct ExtendedNewSessionResponse {
+    session_id: SessionId,
+    #[serde(default)]
+    modes: Option<SessionModeState>,
+    #[serde(default)]
+    config_options: Option<Vec<SessionConfigOption>>,
+    #[serde(default)]
+    models: Option<LegacyModelState>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcRequest)]
+#[request(method = "session/load", response = ExtendedLoadSessionResponse)]
+#[serde(rename_all = "camelCase")]
+struct ExtendedLoadSessionRequest {
+    session_id: SessionId,
+    cwd: PathBuf,
+    mcp_servers: Vec<serde_json::Value>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcResponse)]
+#[serde(rename_all = "camelCase")]
+struct ExtendedLoadSessionResponse {
+    #[serde(default)]
+    modes: Option<SessionModeState>,
+    #[serde(default)]
+    config_options: Option<Vec<SessionConfigOption>>,
+    #[serde(default)]
+    models: Option<LegacyModelState>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct LegacyModelState {
+    current_model_id: String,
+    available_models: Vec<LegacyModel>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct LegacyModel {
+    model_id: String,
+    name: String,
+    #[serde(default)]
+    description: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcRequest)]
+#[request(method = "session/set_model", response = LegacySetModelResponse)]
+#[serde(rename_all = "camelCase")]
+struct LegacySetModelRequest {
+    session_id: SessionId,
+    model_id: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, JsonRpcResponse)]
+struct LegacySetModelResponse {}
 
 /// What [`spawn`] needs to start one adapter.
 #[derive(Debug, Clone)]
@@ -94,6 +195,8 @@ pub struct SpawnConfig {
     /// instead of opening a fresh one. The adapter must advertise
     /// `loadSession`; the handshake fails otherwise.
     pub load_session: Option<String>,
+    /// The provider-specific adapter to launch.
+    pub adapter: AcpAdapter,
 }
 
 impl SpawnConfig {
@@ -103,6 +206,7 @@ impl SpawnConfig {
             env,
             handshake_timeout: HANDSHAKE_TIMEOUT,
             load_session: None,
+            adapter: AcpAdapter::ClaudeCode,
         }
     }
 
@@ -111,6 +215,11 @@ impl SpawnConfig {
         self.load_session = Some(session_id.into());
         self
     }
+
+    pub fn adapter(mut self, adapter: AcpAdapter) -> Self {
+        self.adapter = adapter;
+        self
+    }
 }
 
 /// A blocked ACP permission request delivered to the daemon.
@@ -126,31 +235,39 @@ pub struct PermissionRequest {
 pub enum AcpError {
     /// The adapter is not on `PATH`. The message names the install command
     /// so the failed session is actionable rather than silently dead.
-    #[error("{ADAPTER_BIN} not found on PATH; install it with: {INSTALL_COMMAND}")]
-    AdapterMissing,
-    #[error("failed to start {ADAPTER_BIN}: {0}")]
-    Spawn(#[source] std::io::Error),
+    #[error("{adapter} ACP adapter ({bin}) not found on PATH; install it with: {install_command}", bin = adapter.binary(), install_command = adapter.install_command())]
+    AdapterMissing { adapter: AcpAdapter },
+    #[error("failed to start {adapter} ACP adapter ({bin}): {source}", bin = adapter.binary())]
+    Spawn {
+        adapter: AcpAdapter,
+        #[source]
+        source: std::io::Error,
+    },
     /// The adapter answered the handshake with an error.
     #[error("ACP handshake failed: {0}")]
     Handshake(String),
     /// The adapter went away before the handshake finished. Carries the
     /// tail of its stderr, which is where a missing Claude login shows up.
-    #[error("{ADAPTER_BIN} exited during the ACP handshake ({status}){stderr}")]
-    ExitedEarly { status: String, stderr: String },
+    #[error("{adapter} ACP adapter ({bin}) exited during the ACP handshake ({status}){stderr}", bin = adapter.binary())]
+    ExitedEarly {
+        adapter: AcpAdapter,
+        status: String,
+        stderr: String,
+    },
     #[error("ACP handshake timed out after {0:?}")]
     HandshakeTimeout(Duration),
 }
 
 /// Resolve [`ADAPTER_BIN`] against the `PATH` the child would run with: the
 /// session env's `PATH` when it sets one, the daemon's own otherwise.
-pub fn resolve_adapter(env: &HashMap<String, String>) -> Option<PathBuf> {
+pub fn resolve_adapter(adapter: AcpAdapter, env: &HashMap<String, String>) -> Option<PathBuf> {
     let path: OsString = match env.get("PATH") {
         Some(p) => OsString::from(p),
         None => std::env::var_os("PATH")?,
     };
     std::env::split_paths(&path)
         .filter(|dir| !dir.as_os_str().is_empty())
-        .map(|dir| dir.join(ADAPTER_BIN))
+        .map(|dir| dir.join(adapter.binary()))
         .find(|candidate| is_executable(candidate))
 }
 
@@ -168,9 +285,20 @@ enum Command {
         turn: u64,
         done: oneshot::Sender<Result<(), String>>,
     },
+    SetConfig {
+        config_id: String,
+        value: SessionConfigOptionValue,
+        done: oneshot::Sender<Result<(), String>>,
+    },
     Close,
 }
 
+struct ConnectionConfig {
+    cwd: PathBuf,
+    load_session: Option<String>,
+    adapter: AcpAdapter,
+}
+
 enum ChildCommand {
     Signal(libc::c_int),
     Reap(oneshot::Sender<bool>),
@@ -301,6 +429,23 @@ impl AcpSession {
         Ok(done_rx)
     }
 
+    /// Change one option advertised by the ACP agent.
+    pub fn set_config(
+        &self,
+        config_id: String,
+        value: SessionConfigOptionValue,
+    ) -> Result<oneshot::Receiver<Result<(), String>>, String> {
+        let (done_tx, done_rx) = oneshot::channel();
+        self.commands
+            .send(Command::SetConfig {
+                config_id,
+                value,
+                done: done_tx,
+            })
+            .map_err(|_| "ACP connection is closed".to_string())?;
+        Ok(done_rx)
+    }
+
     /// End the child: `session/cancel`, wait `cancel_grace`, `SIGTERM`, wait
     /// `term_grace`, `SIGKILL`. Returns once the child has been reaped.
     pub async fn terminate(&self, cancel_grace: Duration, term_grace: Duration) {
@@ -341,7 +486,9 @@ impl Drop for AcpSession {
 /// Fails without a running child: on any error the process is already
 /// signalled, so a failed session never leaves a stray adapter behind.
 pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
-    let adapter = resolve_adapter(&config.env).ok_or(AcpError::AdapterMissing)?;
+    let provider = config.adapter;
+    let adapter = resolve_adapter(provider, &config.env)
+        .ok_or(AcpError::AdapterMissing { adapter: provider })?;
 
     let mut cmd = tokio::process::Command::new(&adapter);
     cmd.current_dir(&config.cwd)
@@ -369,18 +516,27 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
             });
         }
     }
-    let mut child = cmd.spawn().map_err(AcpError::Spawn)?;
+    let mut child = cmd.spawn().map_err(|source| AcpError::Spawn {
+        adapter: provider,
+        source,
+    })?;
     let pid = child.id().expect("child pid is known before wait");
     let stdin = child.stdin.take().expect("piped stdin");
     let stdout = child.stdout.take().expect("piped stdout");
     let stderr = child.stderr.take().expect("piped stderr");
 
     let stderr_tail = Arc::new(Mutex::new(VecDeque::<u8>::new()));
-    tokio::spawn(drain_stderr(stderr, pid, stderr_tail.clone()));
+    tokio::spawn(drain_stderr(stderr, pid, stderr_tail.clone(), provider));
 
     let (exit_tx, exit_rx) = watch::channel(None);
     let (child_commands_tx, child_commands_rx) = mpsc::unbounded_channel();
-    tokio::spawn(supervise_child(child, pid, child_commands_rx, exit_tx));
+    tokio::spawn(supervise_child(
+        child,
+        pid,
+        child_commands_rx,
+        exit_tx,
+        provider,
+    ));
 
     let (updates_tx, updates_rx) = mpsc::unbounded_channel();
     let (permission_tx, permission_rx) = mpsc::unbounded_channel();
@@ -389,8 +545,11 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
     let transport = ByteStreams::new(stdin.compat_write(), stdout.compat());
     tokio::spawn(run_connection(
         transport,
-        config.cwd.clone(),
-        config.load_session.clone(),
+        ConnectionConfig {
+            cwd: config.cwd.clone(),
+            load_session: config.load_session.clone(),
+            adapter: provider,
+        },
         updates_tx,
         permission_tx,
         commands_rx,
@@ -423,6 +582,7 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
                     .to_string()
             };
             AcpError::ExitedEarly {
+                adapter: provider,
                 status: status.map_or_else(|| "unknown status".into(), |s| s.to_string()),
                 stderr: if stderr.is_empty() {
                     String::new()
@@ -457,12 +617,13 @@ async fn supervise_child(
     pid: u32,
     mut commands: mpsc::UnboundedReceiver<ChildCommand>,
     exit_tx: watch::Sender<Option<ExitStatus>>,
+    adapter: AcpAdapter,
 ) {
     loop {
         tokio::select! {
             status = child.wait() => {
                 let status = status.ok();
-                tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                 let _ = exit_tx.send(status);
                 return;
             }
@@ -476,7 +637,7 @@ async fn supervise_child(
                 Some(ChildCommand::Reap(done)) => match child.try_wait() {
                     Ok(Some(status)) => {
                         let _ = done.send(true);
-                        tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                        tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                         let _ = exit_tx.send(Some(status));
                         return;
                     }
@@ -484,7 +645,7 @@ async fn supervise_child(
                         let _ = done.send(false);
                     }
                     Err(error) => {
-                        tracing::warn!(pid, %error, "could not reap {ADAPTER_BIN}");
+                        tracing::warn!(pid, %error, provider = %adapter, "could not reap ACP adapter");
                         let _ = done.send(false);
                     }
                 },
@@ -494,7 +655,7 @@ async fn supervise_child(
                     // a reused PID.
                     unsafe { libc::kill(pid as libc::pid_t, libc::SIGTERM) };
                     let status = child.wait().await.ok();
-                    tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                    tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                     let _ = exit_tx.send(status);
                     return;
                 }
@@ -513,10 +674,104 @@ fn client_capabilities() -> ClientCapabilities {
         .terminal(false)
 }
 
+fn advertised_config_options(
+    mut options: Vec<SessionConfigOption>,
+    modes: Option<&SessionModeState>,
+    models: Option<&LegacyModelState>,
+) -> Vec<SessionConfigOption> {
+    let has_model = options
+        .iter()
+        .any(|option| matches!(option.category, Some(SessionConfigOptionCategory::Model)));
+    let has_mode = options
+        .iter()
+        .any(|option| matches!(option.category, Some(SessionConfigOptionCategory::Mode)));
+    if let Some(models) = models.filter(|_| !has_model) {
+        let mut choices = models
+            .available_models
+            .iter()
+            .map(|model| {
+                let mut option =
+                    SessionConfigSelectOption::new(model.model_id.clone(), &model.name);
+                if model.model_id == "default" {
+                    option.name = "Opus (default)".into();
+                }
+                option.description.clone_from(&model.description);
+                option
+            })
+            .collect::<Vec<_>>();
+        if !models
+            .available_models
+            .iter()
+            .any(|model| model.model_id == "fable")
+        {
+            choices.push(SessionConfigSelectOption::new("fable", "Fable"));
+        }
+        options.push(
+            SessionConfigOption::select(
+                LEGACY_MODEL_CONFIG_ID,
+                "Model",
+                models.current_model_id.clone(),
+                choices,
+            )
+            .category(SessionConfigOptionCategory::Model),
+        );
+    }
+    if let Some(modes) = modes.filter(|_| !has_mode) {
+        let choices = modes
+            .available_modes
+            .iter()
+            .map(|mode| {
+                let mut option = SessionConfigSelectOption::new(mode.id.0.clone(), &mode.name);
+                option.description.clone_from(&mode.description);
+                option
+            })
+            .collect::<Vec<_>>();
+        options.push(
+            SessionConfigOption::select(
+                LEGACY_MODE_CONFIG_ID,
+                "Mode",
+                modes.current_mode_id.0.clone(),
+                choices,
+            )
+            .category(SessionConfigOptionCategory::Mode),
+        );
+    }
+    options
+}
+
+fn replace_config_value(
+    options: &Arc<Mutex<Vec<SessionConfigOption>>>,
+    config_id: &str,
+    value: &SessionConfigOptionValue,
+) -> Vec<SessionConfigOption> {
+    let mut options = options.lock().expect("config options");
+    if let Some(option) = options
+        .iter_mut()
+        .find(|option| option.id.0.as_ref() == config_id)
+    {
+        match (&mut option.kind, value) {
+            (SessionConfigKind::Select(select), SessionConfigOptionValue::ValueId { value }) => {
+                select.current_value = value.clone();
+            }
+            (SessionConfigKind::Boolean(boolean), SessionConfigOptionValue::Boolean { value }) => {
+                boolean.current_value = *value;
+            }
+            _ => {}
+        }
+    }
+    options.clone()
+}
+
+fn config_notification(session_id: &str, options: Vec<SessionConfigOption>) -> SessionNotification {
+    SessionNotification::new(
+        SessionId::new(session_id),
+        SessionUpdate::ConfigOptionUpdate(ConfigOptionUpdate::new(options)),
+    )
+}
+
 async fn run_connection<T>(
     transport: T,
-    cwd: PathBuf,
-    load_session: Option<String>,
+    config: ConnectionConfig,
     updates_tx: mpsc::UnboundedSender<SessionNotification>,
     permission_requests: mpsc::UnboundedSender<PermissionRequest>,
     mut commands_rx: mpsc::UnboundedReceiver<Command>,
@@ -534,6 +789,7 @@ async fn run_connection<T>(
     // until a cancelled prompt settles, so this active turn is unambiguous.
     let permission_turn = Arc::new(Mutex::new(PermissionTurnState::default()));
     let permission_turn_seen = permission_turn.clone();
+    let received_updates = updates_tx.clone();
     let result = Client
         .builder()
         .name("maestro")
@@ -544,7 +800,7 @@ async fn run_connection<T>(
                     return Ok(());
                 }
                 // A dropped receiver only means nobody wants updates any more.
-                let _ = updates_tx.send(notification);
+                let _ = received_updates.send(notification);
                 Ok(())
             },
             agent_client_protocol::on_receive_notification!(),
@@ -589,11 +845,13 @@ async fn run_connection<T>(
                     return Ok(());
                 }
             };
-            let session_id = match load_session {
+            let (session_id, modes, initial_options, models) = match config.load_session {
                 Some(existing) => {
                     if !initialized.agent_capabilities.load_session {
                         let _ = ready_tx.send(Err(ReadyError::Handshake(format!(
-                            "{ADAPTER_BIN} does not advertise loadSession; cannot resume session {existing}"
+                            "{} ACP adapter ({}) does not advertise loadSession; cannot resume session {existing}",
+                            config.adapter,
+                            config.adapter.binary()
                         ))));
                         return Ok(());
                     }
@@ -601,7 +859,11 @@ async fn run_connection<T>(
                     let (loaded_tx, loaded_rx) = oneshot::channel();
                     let replaying_done = replaying.clone();
                     if let Err(e) = cx
-                        .send_request(LoadSessionRequest::new(existing.clone(), cwd))
+                        .send_request(ExtendedLoadSessionRequest {
+                            session_id: SessionId::new(existing.as_str()),
+                            cwd: config.cwd,
+                            mcp_servers: vec![],
+                        })
                         .on_receiving_result(move |result| {
                             replaying_done.store(false, Ordering::SeqCst);
                             async move {
@@ -613,8 +875,8 @@ async fn run_connection<T>(
                         let _ = ready_tx.send(Err(ready_error(e)));
                         return Ok(());
                     }
-                    match loaded_rx.await {
-                        Ok(Ok(_)) => {}
+                    let loaded = match loaded_rx.await {
+                        Ok(Ok(loaded)) => loaded,
                         Ok(Err(e)) => {
                             let _ = ready_tx.send(Err(ready_error(e)));
                             return Ok(());
@@ -625,21 +887,48 @@ async fn run_connection<T>(
                             )));
                             return Ok(());
                         }
-                    }
-                    existing
+                    };
+                    (existing, loaded.modes, loaded.config_options.unwrap_or_default(), loaded.models)
                 }
                 None => match cx
-                    .send_request(NewSessionRequest::new(cwd))
+                    .send_request(ExtendedNewSessionRequest {
+                        cwd: config.cwd,
+                        mcp_servers: vec![],
+                    })
                     .block_task()
                     .await
                 {
-                    Ok(created) => created.session_id.0.to_string(),
+                    Ok(created) => (
+                        created.session_id.0.to_string(),
+                        created.modes,
+                        created.config_options.unwrap_or_default(),
+                        created.models,
+                    ),
                     Err(e) => {
                         let _ = ready_tx.send(Err(ready_error(e)));
                         return Ok(());
                     }
                 },
             };
+            let config_options = Arc::new(Mutex::new(advertised_config_options(
+                initial_options,
+                modes.as_ref(),
+                models.as_ref(),
+            )));
+            if let Some(modes) = &modes {
+                let _ = updates_tx.send(SessionNotification::new(
+                    SessionId::new(session_id.as_str()),
+                    SessionUpdate::CurrentModeUpdate(CurrentModeUpdate::new(
+                        modes.current_mode_id.clone(),
+                    )),
+                ));
+            }
+            if !config_options.lock().expect("config options").is_empty() {
+                let _ = updates_tx.send(config_notification(
+                    &session_id,
+                    config_options.lock().expect("config options").clone(),
+                ));
+            }
             let _ = ready_tx.send(Ok(session_id.clone()));
 
             loop {
@@ -689,6 +978,83 @@ async fn run_connection<T>(
                                 }
                             }
                         }
+                        Some(Command::SetConfig { config_id, value, done }) => {
+                            let done = Arc::new(Mutex::new(Some(done)));
+                            let callback_done = done.clone();
+                            let callback_options = config_options.clone();
+                            let callback_updates = updates_tx.clone();
+                            let callback_session = session_id.clone();
+                            let callback_config_id = config_id.clone();
+                            let callback_value = value.clone();
+                            let sent = if config_id == LEGACY_MODEL_CONFIG_ID {
+                                let Some(model_id) = value.as_value_id() else {
+                                    let _ = done.lock().expect("config sender").take()
+                                        .map(|done| done.send(Err("model must be a string value".into())));
+                                    continue;
+                                };
+                                cx.send_request(LegacySetModelRequest {
+                                    session_id: SessionId::new(session_id.as_str()),
+                                    model_id: model_id.0.to_string(),
+                                }).on_receiving_result(move |result| async move {
+                                    if result.is_ok() {
+                                        let options = replace_config_value(&callback_options, &callback_config_id, &callback_value);
+                                        let _ = callback_updates.send(config_notification(&callback_session, options));
+                                    }
+                                    if let Some(done) = callback_done.lock().expect("config sender").take() {
+                                        let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));
+                                    }
+                                    Ok(())
+                                })
+                            } else if config_id == LEGACY_MODE_CONFIG_ID {
+                                let Some(mode_id) = value.as_value_id() else {
+                                    let _ = done.lock().expect("config sender").take()
+                                        .map(|done| done.send(Err("mode must be a string value".into())));
+                                    continue;
+                                };
+                                cx.send_request(SetSessionModeRequest::new(
+                                    SessionId::new(session_id.as_str()),
+                                    mode_id.0.to_string(),
+                                )).on_receiving_result(move |result| async move {
+                                    if result.is_ok() {
+                                        let options = replace_config_value(&callback_options, &callback_config_id, &callback_value);
+                                        let _ = callback_updates.send(config_notification(&callback_session, options));
+                                        let _ = callback_updates.send(SessionNotification::new(
+                                            SessionId::new(callback_session.as_str()),
+                                            SessionUpdate::CurrentModeUpdate(CurrentModeUpdate::new(
+                                                callback_value.as_value_id().expect("checked mode value").0.clone(),
+                                            )),
+                                        ));
+                                    }
+                                    if let Some(done) = callback_done.lock().expect("config sender").take() {
+                                        let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));
+                                    }
+                                    Ok(())
+                                })
+                            } else {
+                                cx.send_request(SetSessionConfigOptionRequest::new(
+                                    SessionId::new(session_id.as_str()),
+                                    config_id,
+                                    value,
+                                ))
+                                    .on_receiving_result(move |result| async move {
+                                        if let Ok(response) = &result {
+                                            let mut current = callback_options.lock().expect("config options");
+                                            current.retain(|option| option.id.0.as_ref().starts_with("__maestro_legacy_"));
+                                            current.extend(response.config_options.clone());
+                                            let _ = callback_updates.send(config_notification(&callback_session, current.clone()));
+                                        }
+                                        if let Some(done) = callback_done.lock().expect("config sender").take() {
+                                            let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));
+                                        }
+                                        Ok(())
+                                    })
+                            };
+                            if let Err(error) = sent {
+                                if let Some(done) = done.lock().expect("config sender").take() {
+                                    let _ = done.send(Err(error.to_string()));
+                                }
+                            }
+                        }
                         Some(Command::Close) | None => break,
                     },
                     _ = cx.incoming_closed() => break,
@@ -706,10 +1072,11 @@ async fn drain_stderr(
     stderr: tokio::process::ChildStderr,
     pid: u32,
     tail: Arc<Mutex<VecDeque<u8>>>,
+    adapter: AcpAdapter,
 ) {
     let mut lines = tokio::io::BufReader::new(stderr).lines();
     while let Ok(Some(line)) = lines.next_line().await {
-        tracing::debug!(pid, "{ADAPTER_BIN}: {line}");
+        tracing::debug!(pid, provider = %adapter, "ACP adapter: {line}");
         let mut tail = tail.lock().expect("stderr tail");
         tail.extend(line.as_bytes());
         tail.push_back(b'\n');

crates/maestro-acp/tests/fake_acp_agent.py

@@ -19,6 +19,8 @@ Environment knobs, all optional:
   FAKE_ACP_INIT_FAIL=1    answer `initialize` with a JSON-RPC error
   FAKE_ACP_DELAY_SESSION_NEW_MS=n  wait n milliseconds before answering
                              `session/new`
+  FAKE_ACP_SESSION_NEW_GATE=path  wait for `path` to exist before answering
+                             `session/new`
   FAKE_ACP_EXIT_AFTER_NEW=1  exit 0 right after answering `session/new`
   FAKE_ACP_EXIT_ON_CANCEL=1  exit 0 on `session/cancel` (default: keep running
                              so the SIGTERM path is exercised)
@@ -34,6 +36,7 @@ Environment knobs, all optional:
   FAKE_ACP_PROMPT_FAIL=1  answer every `session/prompt` with a JSON-RPC error
   FAKE_ACP_PROMPT_FAIL_ONCE=1  answer only the first `session/prompt` with a
                              JSON-RPC error
+  FAKE_ACP_SETTINGS=1      advertise legacy model/mode and modern effort options
   FAKE_ACP_PERMISSION_AFTER_CANCEL=1  defer the first prompt's permission
                              callback until a later prompt
 
@@ -76,6 +79,41 @@ prompt_failures = 0
 pending_prompt_id = None
 pending_permission_id = None
 delayed_permission = False
+current_model = "opus"
+current_mode = "default"
+current_effort = "high"
+
+
+def settings_response(include_session=False):
+    result = {}
+    if include_session:
+        result["sessionId"] = session_id
+    if os.environ.get("FAKE_ACP_SETTINGS") == "1":
+        result.update({
+            "models": {
+                "currentModelId": current_model,
+                "availableModels": [
+                    {"modelId": "opus", "name": "Opus"},
+                    {"modelId": "sonnet", "name": "Sonnet"},
+                ],
+            },
+            "modes": {
+                "currentModeId": current_mode,
+                "availableModes": [
+                    {"id": "default", "name": "Default"},
+                    {"id": "plan", "name": "Plan"},
+                ],
+            },
+            "configOptions": [{
+                "id": "effort", "name": "Effort", "category": "thought_level",
+                "type": "select", "currentValue": current_effort,
+                "options": [
+                    {"value": "low", "name": "Low"},
+                    {"value": "high", "name": "High"},
+                ],
+            }],
+        })
+    return result
 
 
 def chunk(text):
@@ -133,8 +171,11 @@ for raw in sys.stdin:
             "authMethods": [],
         }})
     elif method == "session/new":
+        gate = os.environ.get("FAKE_ACP_SESSION_NEW_GATE")
+        while gate and not os.path.exists(gate):
+            time.sleep(0.01)
         time.sleep(int(os.environ.get("FAKE_ACP_DELAY_SESSION_NEW_MS", "0")) / 1000)
-        send({"jsonrpc": "2.0", "id": rid, "result": {"sessionId": session_id}})
+        send({"jsonrpc": "2.0", "id": rid, "result": settings_response(True)})
         send(chunk("hello from fake"))
         if os.environ.get("FAKE_ACP_EXIT_AFTER_NEW") == "1":
             sys.exit(0)
@@ -147,8 +188,18 @@ for raw in sys.stdin:
             continue
         for i in range(int(os.environ.get("FAKE_ACP_LOAD_REPLAY", "0"))):
             send(chunk(f"replayed {i + 1}"))
-        send({"jsonrpc": "2.0", "id": rid, "result": {}})
+        send({"jsonrpc": "2.0", "id": rid, "result": settings_response()})
         send(chunk("hello after load"))
+    elif method == "session/set_model":
+        current_model = params.get("modelId")
+        send({"jsonrpc": "2.0", "id": rid, "result": {}})
+    elif method == "session/set_mode":
+        current_mode = params.get("modeId")
+        send({"jsonrpc": "2.0", "id": rid, "result": {}})
+    elif method == "session/set_config_option":
+        current_effort = params.get("value")
+        send({"jsonrpc": "2.0", "id": rid, "result": {
+            "configOptions": settings_response()["configOptions"]}})
     elif method == "session/cancel":
         if os.environ.get("FAKE_ACP_EMIT_ON_CANCEL") == "1":
             send(chunk("final on cancel"))

crates/maestro-acp/tests/spawn.rs

@@ -1,12 +1,12 @@
 //! `maestro-acp` against the fake adapter in `tests/fake_acp_agent.py`, plus
-//! one ignored test against the real `claude-code-acp`.
+//! ignored smoke tests against each maintained adapter.
 
 use std::collections::HashMap;
 use std::path::{Path, PathBuf};
 use std::time::{Duration, Instant};
 
 use maestro_acp::schema::{ContentBlock, SessionUpdate};
-use maestro_acp::{AcpError, SpawnConfig, ADAPTER_BIN, INSTALL_COMMAND};
+use maestro_acp::{AcpAdapter, AcpError, SpawnConfig, ADAPTER_BIN, INSTALL_COMMAND};
 use tempfile::TempDir;
 
 fn fake_agent() -> PathBuf {
@@ -25,6 +25,7 @@ impl Fake {
         let bin = dir.path().join("bin");
         std::fs::create_dir_all(&bin).unwrap();
         std::fs::copy(fake_agent(), bin.join(ADAPTER_BIN)).unwrap();
+        std::fs::copy(fake_agent(), bin.join(AcpAdapter::Codex.binary())).unwrap();
         Self { dir }
     }
 
@@ -146,12 +147,38 @@ async fn missing_adapter_names_the_install_command() {
     let err = maestro_acp::spawn(SpawnConfig::new(cwd.path(), env))
         .await
         .expect_err("no adapter on PATH");
-    assert!(matches!(err, AcpError::AdapterMissing));
+    assert!(matches!(
+        err,
+        AcpError::AdapterMissing {
+            adapter: AcpAdapter::ClaudeCode
+        }
+    ));
     let msg = err.to_string();
     assert!(msg.contains(ADAPTER_BIN), "{msg}");
     assert!(msg.contains(INSTALL_COMMAND), "{msg}");
 }
 
+#[test]
+fn codex_adapter_has_its_own_binary_and_install_guidance() {
+    assert_eq!(AcpAdapter::Codex.binary(), "codex-acp");
+    assert!(AcpAdapter::Codex
+        .install_command()
+        .contains("@agentclientprotocol/codex-acp"));
+}
+
+#[tokio::test]
+async fn spawn_selects_the_codex_adapter() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let session = maestro_acp::spawn(fake.config(cwd.path()).adapter(AcpAdapter::Codex))
+        .await
+        .expect("spawn Codex adapter");
+    assert!(fake.log().contains("recv session/new"));
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .await;
+}
+
 #[tokio::test]
 async fn session_updates_reach_the_taken_receiver() {
     let fake = Fake::new();
@@ -180,11 +207,68 @@ async fn session_updates_reach_the_taken_receiver() {
         .await;
 }
 
+#[tokio::test]
+async fn advertised_settings_are_normalized_and_mutable() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut config = fake.config(cwd.path());
+    config.env.insert("FAKE_ACP_SETTINGS".into(), "1".into());
+    let session = maestro_acp::spawn(config).await.expect("spawn");
+    let mut updates = session.take_updates().expect("updates");
+
+    let initial = loop {
+        let update = tokio::time::timeout(Duration::from_secs(5), updates.recv())
+            .await
+            .expect("settings update")
+            .expect("channel open");
+        if let SessionUpdate::ConfigOptionUpdate(options) = update.update {
+            break options.config_options;
+        }
+    };
+    assert_eq!(initial.len(), 3);
+    assert!(initial
+        .iter()
+        .any(|option| option.id.0.as_ref() == "effort"));
+    assert!(initial
+        .iter()
+        .any(|option| option.id.0.as_ref() == "__maestro_legacy_model"));
+    assert!(initial
+        .iter()
+        .any(|option| option.id.0.as_ref() == "__maestro_legacy_mode"));
+    let model = initial
+        .iter()
+        .find(|option| option.id.0.as_ref() == "__maestro_legacy_model")
+        .expect("legacy model option");
+    let model = serde_json::to_value(model).unwrap();
+    assert_eq!(model["options"][0]["name"], "Opus");
+    assert!(model["options"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .any(|option| option["value"] == "fable"));
+
+    let changed = session
+        .set_config(
+            "__maestro_legacy_model".into(),
+            maestro_acp::schema::SessionConfigOptionValue::value_id("sonnet"),
+        )
+        .expect("queue model change");
+    changed
+        .await
+        .expect("response delivered")
+        .expect("model changed");
+    fake.wait_for_log("recv session/set_model").await;
+
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .await;
+}
+
 #[tokio::test]
 async fn terminate_sends_cancel_then_sigterm() {
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let session = maestro_acp::spawn(fake.config(cwd.path()))
+    let session = maestro_acp::spawn(fake.config(cwd.path()).adapter(AcpAdapter::Codex))
         .await
         .expect("spawn");
     let pid = session.pid();
@@ -225,7 +309,7 @@ async fn terminate_is_satisfied_by_an_exit_on_cancel() {
 async fn handshake_error_fails_the_spawn_and_reaps_the_child() {
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let mut config = fake.config(cwd.path());
+    let mut config = fake.config(cwd.path()).adapter(AcpAdapter::Codex);
     config.env.insert("FAKE_ACP_INIT_FAIL".into(), "1".into());
 
     let err = maestro_acp::spawn(config).await.expect_err("init fails");
@@ -284,7 +368,7 @@ async fn child_exit_before_handshake_reports_exited_early() {
 
     let err = maestro_acp::spawn(config).await.expect_err("child died");
     match &err {
-        AcpError::ExitedEarly { status, stderr } => {
+        AcpError::ExitedEarly { status, stderr, .. } => {
             assert!(status.contains('3'), "{status}");
             assert!(stderr.contains("not logged in"), "{stderr}");
         }
@@ -320,7 +404,10 @@ fn chunk_text(n: &maestro_acp::schema::SessionNotification) -> String {
 async fn load_session_resumes_the_stored_id_and_drops_the_replay() {
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let mut config = fake.config(cwd.path()).load_session("fake-old");
+    let mut config = fake
+        .config(cwd.path())
+        .adapter(AcpAdapter::Codex)
+        .load_session("fake-old");
     config.env.insert("FAKE_ACP_LOAD_REPLAY".into(), "3".into());
 
     let session = maestro_acp::spawn(config).await.expect("spawn");
@@ -353,7 +440,10 @@ async fn load_session_resumes_the_stored_id_and_drops_the_replay() {
 async fn load_session_requires_the_load_capability() {
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let mut config = fake.config(cwd.path()).load_session("fake-old");
+    let mut config = fake
+        .config(cwd.path())
+        .adapter(AcpAdapter::Codex)
+        .load_session("fake-old");
     config.env.insert("FAKE_ACP_NO_LOAD".into(), "1".into());
 
     let err = maestro_acp::spawn(config)
@@ -368,7 +458,10 @@ async fn load_session_requires_the_load_capability() {
 async fn load_session_error_fails_the_spawn() {
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let mut config = fake.config(cwd.path()).load_session("fake-old");
+    let mut config = fake
+        .config(cwd.path())
+        .adapter(AcpAdapter::Codex)
+        .load_session("fake-old");
     config.env.insert("FAKE_ACP_LOAD_FAIL".into(), "1".into());
 
     let err = maestro_acp::spawn(config).await.expect_err("load fails");
@@ -392,3 +485,21 @@ async fn real_adapter_handshake() {
         .await;
     assert!(session.has_exited());
 }
+
+/// End to end against the maintained Codex adapter. It needs a locally
+/// authenticated Codex CLI, so CI runs it only when explicitly requested.
+#[tokio::test]
+#[ignore]
+async fn real_codex_adapter_handshake() {
+    let cwd = TempDir::new().unwrap();
+    let session =
+        maestro_acp::spawn(SpawnConfig::new(cwd.path(), HashMap::new()).adapter(AcpAdapter::Codex))
+            .await
+            .expect("real codex-acp handshake");
+    assert!(!session.session_id().is_empty());
+    assert!(pid_alive(session.pid()));
+    session
+        .terminate(maestro_acp::CANCEL_GRACE, maestro_acp::TERM_GRACE)
+        .await;
+    assert!(session.has_exited());
+}

crates/maestro-cli/src/attach.rs

@@ -19,6 +19,12 @@ use tokio_tungstenite::tungstenite::Message;
 pub enum AttachError {
     #[error("ws: {0}")]
     WebSocket(#[from] tokio_tungstenite::tungstenite::Error),
+    #[error("daemon returned {status} ({code}): {message}")]
+    Rejected {
+        status: String,
+        code: String,
+        message: String,
+    },
     #[error("io: {0}")]
     Io(#[from] io::Error),
     #[error("termios: {0}")]
@@ -32,6 +38,21 @@ pub enum AttachError {
 }
 
 impl AttachError {
+    fn from_websocket(error: tokio_tungstenite::tungstenite::Error) -> Self {
+        if let tokio_tungstenite::tungstenite::Error::Http(response) = &error {
+            if let Some(body) = response.body().as_deref() {
+                if let Ok(error_body) = serde_json::from_slice::<maestro_protocol::ApiError>(body) {
+                    return Self::Rejected {
+                        status: response.status().to_string(),
+                        code: error_body.error.code,
+                        message: error_body.error.message,
+                    };
+                }
+            }
+        }
+        Self::WebSocket(error)
+    }
+
     /// True when the failure was an inability to reach the WS endpoint at the
     /// transport level (connection refused), as opposed to an HTTP-level
     /// rejection from a daemon that did answer.
@@ -111,7 +132,9 @@ fn current_winsize() -> Option<(u16, u16)> {
 /// byte that exits cleanly without killing the session.
 #[allow(clippy::result_large_err)]
 pub async fn run_attach_url(url: &str, detach_byte: u8) -> Result<(), AttachError> {
-    let (ws, _resp) = tokio_tungstenite::connect_async(url).await?;
+    let (ws, _resp) = tokio_tungstenite::connect_async(url)
+        .await
+        .map_err(AttachError::from_websocket)?;
     let (mut sink, mut stream) = ws.split();
 
     let raw = RawTty::enable()?;
@@ -233,4 +256,25 @@ mod tests {
             Err(AttachError::InvalidDetachKey(_))
         ));
     }
+
+    #[test]
+    fn attach_surfaces_structured_handshake_errors() {
+        let body = serde_json::to_vec(&maestro_protocol::ApiError::new(
+            "not_terminal",
+            "session is not a terminal session",
+        ))
+        .unwrap();
+        let response = tokio_tungstenite::tungstenite::http::Response::builder()
+            .status(409)
+            .body(Some(body))
+            .unwrap();
+
+        let error =
+            AttachError::from_websocket(tokio_tungstenite::tungstenite::Error::Http(response));
+
+        assert_eq!(
+            error.to_string(),
+            "daemon returned 409 Conflict (not_terminal): session is not a terminal session"
+        );
+    }
 }

crates/maestro-cli/src/cli.rs

@@ -41,8 +41,8 @@ pub enum Command {
     Attach(AttachArgs),
     /// Kill a session by ID.
     Kill(KillArgs),
-    /// Type text into a running session, as if it had been typed on an
-    /// attached terminal.
+    /// Send text to a running session. Terminal sessions receive raw
+    /// keystrokes; structured sessions receive an ACP prompt.
     Send(SendArgs),
     /// Install or update the agent activity hook (#106).
     Hooks(HooksArgs),
@@ -92,6 +92,14 @@ pub struct SpawnArgs {
     /// there.
     #[arg(long)]
     pub existing_branch: bool,
+    /// Run a Claude Code or Codex session in a plain terminal instead of the
+    /// structured (ACP) view it otherwise gets by default.
+    #[arg(long, conflicts_with = "structured")]
+    pub terminal: bool,
+    /// Ask for the structured (ACP) view explicitly. Only Claude Code and
+    /// Codex commands have an adapter; the daemon refuses anything else.
+    #[arg(long)]
+    pub structured: bool,
     /// After spawning, attach immediately.
     #[arg(long, short = 'a')]
     pub attach: bool,

crates/maestro-cli/src/sessions.rs

@@ -3,10 +3,10 @@
 use std::collections::HashMap;
 use std::io::Write;
 
-use maestro_protocol::display::abbreviate_dir;
+use maestro_protocol::display::{abbreviate_dir, supports_structured_view};
 use maestro_protocol::{
     ActivityState, ClientError, CreateSessionRequest, DaemonClient, DaemonInfo, SendInputRequest,
-    Session, SessionStatus, WorktreeSpec,
+    Session, SessionStatus, SessionView, WorktreeSpec,
 };
 use serde_json::Value;
 
@@ -51,16 +51,33 @@ pub async fn run_spawn(client: &DaemonClient, args: SpawnArgs) -> Result<Session
     };
 
     let body = CreateSessionRequest {
-        view: Default::default(),
+        view: spawn_view(&args),
         cwd: args.cwd.clone(),
         command: args.command.clone(),
         env,
         metadata,
         worktree,
+        auto_approve: false,
     };
     client.create_session(&body).await
 }
 
+/// The view a `maestro spawn` asks for: structured whenever the command
+/// resolves to an agent with an ACP adapter, since that is the richer session
+/// and the one both other clients now default to. `--terminal` opts out;
+/// `--structured` forces the request through even for a command this side
+/// does not recognise, leaving the refusal to the daemon.
+fn spawn_view(args: &SpawnArgs) -> SessionView {
+    if args.terminal {
+        return SessionView::Terminal;
+    }
+    if args.structured || supports_structured_view(&args.command) {
+        SessionView::Structured
+    } else {
+        SessionView::Terminal
+    }
+}
+
 /// `maestro kill`. A forced kill (#81) retains the guarded worktree instead
 /// of removing it; the outcome names what was kept so dispatch can say where
 /// the work went.
@@ -113,9 +130,12 @@ pub fn resolve_session(sessions: &[Session], needle: &str) -> Result<uuid::Uuid,
 /// `maestro send`. Answers with the session that was typed into, so the
 /// caller can name it once the daemon has accepted the text.
 ///
-/// A bare ID skips the catalog fetch; anything else needs the list to match
-/// against. Text comes from the arguments, or from stdin when there is none —
-/// the shape a heredoc or a pipe wants.
+/// Terminal sessions get raw keystrokes via `send_input`; structured sessions
+/// get an ACP prompt via `send_structured_prompt` (`--no-enter` is ignored
+/// there — ACP prompts are always complete messages).
+///
+/// Text comes from the arguments, or from stdin when there is none — the
+/// shape a heredoc or a pipe wants.
 #[allow(clippy::result_large_err)]
 pub async fn run_send(
     client: &DaemonClient,
@@ -138,19 +158,28 @@ pub async fn run_send(
         return Err(CliError::NothingToSend);
     }
 
-    let id = match uuid::Uuid::parse_str(args.session.trim()) {
-        Ok(id) => id,
-        Err(_) => {
-            let sessions = client.list_sessions().await?;
-            resolve_session(&sessions, &args.session)?
-        }
-    };
+    // We always need the session list: even a bare UUID needs the view field
+    // to decide which endpoint to hit.
+    let sessions = client.list_sessions().await?;
+    let id = resolve_session(&sessions, &args.session)?;
+    let view = sessions
+        .iter()
+        .find(|s| s.id == id)
+        .map(|s| s.view)
+        .unwrap_or(SessionView::Terminal);
 
-    let req = SendInputRequest {
-        text,
-        submit: !args.no_enter,
-    };
-    client.send_input(id, &req).await?;
+    match view {
+        SessionView::Structured => {
+            client.send_structured_prompt(id, &text).await?;
+        }
+        SessionView::Terminal => {
+            let req = SendInputRequest {
+                text,
+                submit: !args.no_enter,
+            };
+            client.send_input(id, &req).await?;
+        }
+    }
     Ok(id)
 }
 
@@ -179,8 +208,8 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
     }
     writeln!(
         out,
-        "  {:<36}  {:<8}  {:<9}  {:<28}  {:<40}  {}",
-        "ID", "STATUS", "ACTIVITY", "DIR", "COMMAND", "BLOCKED"
+        "  {:<36}  {:<8}  {:<10}  {:<9}  {:<28}  {:<40}  {}",
+        "ID", "STATUS", "VIEW", "ACTIVITY", "DIR", "COMMAND", "BLOCKED"
     )
     .ok();
     for s in sorted {
@@ -190,11 +219,16 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
             SessionStatus::Running => "running",
             SessionStatus::Dead => "dead",
         };
+        let view = match s.view {
+            SessionView::Terminal => "terminal",
+            SessionView::Structured => "structured",
+        };
         let activity = match s.activity {
             ActivityState::Active => "active",
             ActivityState::Idle => "idle",
             ActivityState::AwaitingInput => "awaiting",
             ActivityState::Error => "error",
+            ActivityState::Starting => "starting",
         };
         // Show the live foreground command alongside the spawn command when
         // the daemon has observed one that differs (NAP-340).
@@ -207,8 +241,8 @@ fn print_session_table(out: &mut impl Write, sessions: &[Session], info: &Daemon
         let blocked = blocked_label(s);
         writeln!(
             out,
-            "  {:<36}  {:<8}  {:<9}  {:<28}  {:<40}  {blocked}",
-            s.id, status, activity, dir, command
+            "  {:<36}  {:<8}  {:<10}  {:<9}  {:<28}  {:<40}  {blocked}",
+            s.id, status, view, activity, dir, command
         )
         .ok();
     }
@@ -230,11 +264,67 @@ mod tests {
     use std::path::PathBuf;
 
     use chrono::{TimeZone, Utc};
-    use maestro_protocol::{ActivityState, Session, SessionStatus};
+    use maestro_protocol::{ActivityState, Session, SessionStatus, SessionView};
     use uuid::Uuid;
 
     use super::DaemonInfo;
 
+    use clap::Parser;
+
+    use crate::cli::{Cli, Command};
+
+    fn spawn_args(extra: &[&str]) -> crate::cli::SpawnArgs {
+        let mut argv = vec!["maestro", "spawn", "--cwd", "/tmp", "--command"];
+        argv.extend_from_slice(extra);
+        let cli = Cli::try_parse_from(argv).expect("parses");
+        let Command::Spawn(args) = cli.command else {
+            panic!("expected spawn")
+        };
+        args
+    }
+
+    /// The CLI follows the two interactive clients: a command with an ACP
+    /// adapter spawns structured unless `--terminal` says otherwise, and
+    /// `--structured` still forces the request for a command this side does
+    /// not recognise.
+    #[test]
+    fn spawn_defaults_to_structured_for_supported_agents() {
+        use super::spawn_view;
+        assert_eq!(
+            spawn_view(&spawn_args(&["claude"])),
+            SessionView::Structured
+        );
+        assert_eq!(
+            spawn_view(&spawn_args(&["npx codex exec"])),
+            SessionView::Structured
+        );
+        assert_eq!(spawn_view(&spawn_args(&["bash"])), SessionView::Terminal);
+        assert_eq!(
+            spawn_view(&spawn_args(&["claude", "--terminal"])),
+            SessionView::Terminal
+        );
+        assert_eq!(
+            spawn_view(&spawn_args(&["opencode", "--structured"])),
+            SessionView::Structured
+        );
+    }
+
+    #[test]
+    fn spawn_refuses_both_view_flags_at_once() {
+        let err = Cli::try_parse_from([
+            "maestro",
+            "spawn",
+            "--cwd",
+            "/tmp",
+            "--command",
+            "claude",
+            "--structured",
+            "--terminal",
+        ])
+        .unwrap_err();
+        assert!(err.to_string().contains("--terminal"), "{err}");
+    }
+
     fn session(cwd: &str, command: &str, id: u128) -> Session {
         Session {
             view: Default::default(),
@@ -286,6 +376,22 @@ mod tests {
         assert!(s.contains("idle"), "{s}");
     }
 
+    #[test]
+    fn table_exposes_terminal_and_structured_views() {
+        let terminal = session("/tmp", "bash", 1);
+        let mut structured = session("/tmp", "claude", 2);
+        structured.view = SessionView::Structured;
+
+        let mut buf = Vec::new();
+        super::print_session_table(&mut buf, &[terminal, structured], &info(""));
+        let out = String::from_utf8(buf).unwrap();
+        let lines: Vec<&str> = out.lines().collect();
+        let header = lines.iter().position(|line| line.contains("VIEW")).unwrap();
+
+        assert!(lines[header + 1].contains("terminal"), "{out}");
+        assert!(lines[header + 2].contains("structured"), "{out}");
+    }
+
     #[test]
     fn live_cwd_overrides_spawn_dir_in_table() {
         let mut s = session("/home/naps/maestro", "bash", 1);

crates/maestro-cli/tests/against_mock_daemon.rs

@@ -2,7 +2,7 @@
 //! was unit-tested, but nothing exercised the client, the error decoding, or
 //! the unreachable-daemon path without compiling and forking a real daemon.
 
-use maestro_protocol::{DaemonClient, DaemonInfo};
+use maestro_protocol::{DaemonClient, DaemonInfo, SessionView};
 use maestro_testing::{session, MockDaemon};
 use uuid::Uuid;
 
@@ -28,6 +28,7 @@ async fn info_carries_version_and_presets() {
             id: "claude".into(),
             label: "Claude".into(),
             command: "claude".into(),
+            auto_approve: false,
         }],
         ..Default::default()
     });
@@ -97,6 +98,7 @@ async fn spawn_round_trips_through_the_daemon() {
             env: Default::default(),
             metadata: Default::default(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -200,6 +202,35 @@ async fn send_resolves_a_session_by_name() {
     assert_eq!(sent, id);
 }
 
+/// A structured session routes through the ACP prompt endpoint, not the
+/// terminal input one — `--no-enter` is irrelevant (ACP prompts are
+/// complete messages).
+#[tokio::test]
+async fn send_to_structured_session_uses_acp_prompt() {
+    let mock = MockDaemon::start().await;
+    let id = Uuid::from_u128(13);
+    let mut s = session(id, "/tmp", "claude");
+    s.view = SessionView::Structured;
+    mock.add_session(s);
+
+    let args = maestro_cli::cli::SendArgs {
+        session: id.to_string(),
+        text: vec!["fix".into(), "the".into(), "tests".into()],
+        no_enter: false,
+    };
+    let sent = maestro_cli::sessions::run_send(&mock.client(), &args, &mut std::io::empty())
+        .await
+        .expect("send");
+
+    assert_eq!(sent, id);
+    // Terminal input must stay empty — the message went through ACP.
+    assert!(mock.inputs().is_empty());
+    let prompts = mock.structured_prompts();
+    assert_eq!(prompts.len(), 1);
+    assert_eq!(prompts[0].0, id);
+    assert_eq!(prompts[0].1.prompt, "fix the tests");
+}
+
 #[tokio::test]
 async fn send_to_an_unknown_session_fails_without_typing_anything() {
     let mock = MockDaemon::start().await;

crates/maestro-config/src/lib.rs

@@ -313,16 +313,19 @@ pub fn builtin_presets() -> Vec<SpawnPreset> {
             id: "claude".into(),
             label: "Claude".into(),
             command: "claude".into(),
+            auto_approve: false,
         },
         SpawnPreset {
             id: "opencode".into(),
             label: "opencode".into(),
             command: "opencode".into(),
+            auto_approve: false,
         },
         SpawnPreset {
             id: "zsh".into(),
             label: "Shell".into(),
             command: "zsh".into(),
+            auto_approve: false,
         },
     ]
 }
@@ -334,6 +337,7 @@ pub fn custom_preset() -> SpawnPreset {
         id: CUSTOM_PRESET_ID.into(),
         label: "Custom…".into(),
         command: String::new(),
+        auto_approve: false,
     }
 }
 
@@ -515,6 +519,7 @@ auto_install = false
                 id: "fish".into(),
                 label: "fish".into(),
                 command: "fish".into(),
+                auto_approve: false,
             }]),
             ..Default::default()
         };
@@ -551,6 +556,7 @@ auto_install = false
                 id: "  ".into(),
                 label: "x".into(),
                 command: "x".into(),
+                auto_approve: false,
             }]),
             ..Default::default()
         };
@@ -561,6 +567,7 @@ auto_install = false
                 id: "x".into(),
                 label: "x".into(),
                 command: "".into(),
+                auto_approve: false,
             }]),
             ..Default::default()
         };
@@ -578,11 +585,13 @@ auto_install = false
                     id: "a".into(),
                     label: "a".into(),
                     command: "a".into(),
+                    auto_approve: false,
                 },
                 SpawnPreset {
                     id: "a".into(),
                     label: "a2".into(),
                     command: "a2".into(),
+                    auto_approve: false,
                 },
             ]),
             ..Default::default()
@@ -597,6 +606,7 @@ auto_install = false
                 id: "custom".into(),
                 label: "Custom".into(),
                 command: "whatever".into(),
+                auto_approve: false,
             }]),
             ..Default::default()
         };

crates/maestro-daemon/src/activity.rs

@@ -66,6 +66,23 @@ pub fn decide(idle_for: Duration, awaiting_input: bool) -> ActivityState {
     }
 }
 
+/// Derive a structured session's sidebar state from its ACP projection.
+pub fn decide_structured(
+    turn_active: bool,
+    pending_approval: bool,
+    turn_failed: bool,
+) -> ActivityState {
+    if turn_failed {
+        ActivityState::Error
+    } else if pending_approval {
+        ActivityState::AwaitingInput
+    } else if turn_active {
+        ActivityState::Active
+    } else {
+        ActivityState::Idle
+    }
+}
+
 /// How long a session's pane must be continuously focused (a client's pane,
 /// not a sidebar highlight) before an `AwaitingInput` glow clears: the
 /// operator has looked, so the rail stops asking for attention.
@@ -136,6 +153,17 @@ mod tests {
         );
     }
 
+    #[test]
+    fn structured_activity_follows_lifecycle_with_approval_precedence() {
+        assert_eq!(decide_structured(false, false, false), ActivityState::Idle);
+        assert_eq!(decide_structured(true, false, false), ActivityState::Active);
+        assert_eq!(
+            decide_structured(true, true, false),
+            ActivityState::AwaitingInput
+        );
+        assert_eq!(decide_structured(false, false, true), ActivityState::Error);
+    }
+
     #[test]
     fn report_is_in_force_until_exactly_its_expiry() {
         let ttl = Duration::from_secs(300);

crates/maestro-daemon/src/gitroot.rs

@@ -80,13 +80,22 @@ mod tests {
     }
 
     #[test]
-    fn non_repo_dir_is_none() {
-        // A temp dir with no `.git` anywhere up the chain. Use the temp root so
-        // the walk can't accidentally hit a real repo above the test's cwd.
+    fn non_repo_dir_does_not_find_root_inside_fixture() {
+        // The fixture has no `.git`, so `find_root` must not return a path
+        // inside it. On hosts where an ancestor of the temp dir *is* a repo
+        // (e.g. `/tmp` lives inside a checkout), the function legitimately
+        // returns that ancestor — the test only asserts the fixture itself
+        // was not mistaken for a repo.
         let tmp = tempfile::tempdir().unwrap();
         let sub = tmp.path().join("plain/dir");
         fs::create_dir_all(&sub).unwrap();
-        assert_eq!(find_root(&sub), None);
+        match find_root(&sub) {
+            None => {} // expected on most hosts
+            Some(root) => assert!(
+                !root.starts_with(tmp.path()),
+                "found .git inside the fixture at {root:?}, but none was created"
+            ),
+        }
     }
 
     #[test]

crates/maestro-daemon/src/local_api.rs

@@ -12,7 +12,8 @@
 
 use std::sync::Arc;
 
-use axum::extract::{Path, Query, State};
+use axum::body::Bytes;
+use axum::extract::{DefaultBodyLimit, Path, Query, State};
 use axum::http::StatusCode;
 use axum::response::{IntoResponse, Response};
 use axum::routing::{any, delete, get, post};
@@ -21,12 +22,13 @@ use maestro_config::SpawnPreset;
 use maestro_protocol::{
     routes, ApiError, CatalogEvent, CreateSessionRequest, DaemonInfo, GitRoot, NameBatch,
     RenameSessionRequest, ReportActivityRequest, SendInputRequest, Session, SetFocusRequest,
-    StructuredApprovalDecision, StructuredEvent, StructuredPromptRequest, PROTOCOL_VERSION,
+    StructuredApprovalDecision, StructuredConfigRequest, StructuredEvent, StructuredPromptRequest,
+    PROTOCOL_VERSION,
 };
 use serde::Deserialize;
 use uuid::Uuid;
 
-use crate::session::{QueueAcpPrompt, SessionManager};
+use crate::session::{QueueAcpPrompt, SessionError, SessionManager, SetAcpConfig};
 use crate::sidecar::EventCursor;
 
 #[derive(Debug, Clone)]
@@ -69,7 +71,12 @@ pub fn router(state: LocalApiState) -> Router {
         .route(routes::patterns::STRUCTURED, any(structured_ws))
         .route(routes::patterns::STRUCTURED_REPLAY, get(structured_replay))
         .route(routes::patterns::STRUCTURED_PROMPT, post(structured_prompt))
+        .route(
+            routes::patterns::STRUCTURED_ATTACHMENT,
+            post(structured_attachment).layer(DefaultBodyLimit::max(20 * 1024 * 1024)),
+        )
         .route(routes::patterns::STRUCTURED_CANCEL, post(structured_cancel))
+        .route(routes::patterns::STRUCTURED_CONFIG, post(structured_config))
         .route(
             routes::patterns::STRUCTURED_APPROVAL,
             post(structured_approval),
@@ -173,12 +180,13 @@ fn dir_error_status(code: &str) -> StatusCode {
 fn session_error_status(code: &str) -> StatusCode {
     match code {
         "not_found" => StatusCode::NOT_FOUND,
-        "invalid_env" => StatusCode::BAD_REQUEST,
+        "invalid_env" | "bad_request" => StatusCode::BAD_REQUEST,
         // A guard refusal is the daemon doing its job, not a failure (#79).
         "kill_guarded" => StatusCode::CONFLICT,
         // The session outlived its pane: nothing to type into, and nothing
         // the daemon can do about it.
         "not_running" => StatusCode::CONFLICT,
+        "not_terminal" => StatusCode::CONFLICT,
         "shutting_down" => StatusCode::SERVICE_UNAVAILABLE,
         _ => StatusCode::BAD_GATEWAY,
     }
@@ -307,11 +315,10 @@ async fn rename_session(
     }
 }
 
-/// `POST /api/sessions/:id/activity` (#105): an agent reports its own state.
-/// The report holds above the daemon's inference for a TTL, then inference
-/// resumes — an agent that dies mid-run cannot pin its session at `Error`
-/// forever. Unknown session is 404; an unknown state value is rejected by the
-/// JSON decoder (422) rather than coerced. Answers `204 No Content`.
+/// `POST /api/sessions/:id/activity` (#105): an agent reports a terminal
+/// session's state. Structured sessions acknowledge and ignore these reports
+/// because their activity comes from ACP. Unknown session is 404; an unknown
+/// state value is rejected by the JSON decoder (422). Answers `204 No Content`.
 async fn report_activity(
     State(s): State<LocalApiState>,
     Path(id): Path<Uuid>,
@@ -430,13 +437,55 @@ async fn structured_replay(
     }
 }
 
+#[derive(Deserialize)]
+struct AttachmentQuery {
+    name: String,
+}
+
+async fn structured_attachment(
+    State(s): State<LocalApiState>,
+    Path(id): Path<Uuid>,
+    Query(query): Query<AttachmentQuery>,
+    bytes: Bytes,
+) -> Response {
+    let name = query.name;
+    if name.is_empty()
+        || name.len() > 180
+        || name == "."
+        || name == ".."
+        || name
+            .chars()
+            .any(|c| c.is_control() || c == '/' || c == '\\')
+    {
+        return error_response(
+            StatusCode::BAD_REQUEST,
+            "invalid_filename",
+            "use a filename without directory separators, up to 180 bytes",
+        );
+    }
+    match s.manager.store_acp_attachment(id, &name, &bytes).await {
+        Ok(Some(path)) => Json(serde_json::json!({ "path": path })).into_response(),
+        Ok(None) => error_response(
+            StatusCode::CONFLICT,
+            "not_structured",
+            "session is not a live structured session",
+        ),
+        Err(e) => {
+            let info = e.to_error_info();
+            error_response(session_error_status(&info.code), &info.code, &info.message)
+        }
+    }
+}
+
 async fn structured_prompt(
     State(s): State<LocalApiState>,
     Path(id): Path<Uuid>,
     Json(body): Json<StructuredPromptRequest>,
 ) -> Response {
     match s.manager.queue_acp_prompt(id, body.prompt).await {
-        Ok(QueueAcpPrompt::Queued) => StatusCode::NO_CONTENT.into_response(),
+        Ok(QueueAcpPrompt::Queued) | Ok(QueueAcpPrompt::Pending) => {
+            StatusCode::NO_CONTENT.into_response()
+        }
         Ok(QueueAcpPrompt::InFlight) => error_response(
             StatusCode::CONFLICT,
             "turn_in_flight",
@@ -472,6 +521,37 @@ async fn structured_cancel(State(s): State<LocalApiState>, Path(id): Path<Uuid>)
     }
 }
 
+async fn structured_config(
+    State(s): State<LocalApiState>,
+    Path(id): Path<Uuid>,
+    Json(body): Json<StructuredConfigRequest>,
+) -> Response {
+    match s
+        .manager
+        .set_acp_config(id, body.config_id, body.value)
+        .await
+    {
+        Ok(SetAcpConfig::Updated) => StatusCode::NO_CONTENT.into_response(),
+        Ok(SetAcpConfig::InvalidValue) => error_response(
+            StatusCode::BAD_REQUEST,
+            "invalid_config_value",
+            "configuration values must be strings or booleans",
+        ),
+        Ok(SetAcpConfig::Unavailable) => error_response(
+            StatusCode::CONFLICT,
+            "not_structured",
+            "session is not a live structured session",
+        ),
+        Ok(SetAcpConfig::Failed(message)) => {
+            error_response(StatusCode::BAD_GATEWAY, "acp_config_failed", &message)
+        }
+        Err(e) => {
+            let info = e.to_error_info();
+            error_response(session_error_status(&info.code), &info.code, &info.message)
+        }
+    }
+}
+
 async fn structured_approval(
     State(s): State<LocalApiState>,
     Path((id, nonce)): Path<(Uuid, String)>,
@@ -535,12 +615,23 @@ async fn attach_ws(
     State(s): State<LocalApiState>,
     ws: axum::extract::WebSocketUpgrade,
 ) -> Result<Response, Response> {
-    let Some((replay, rx)) = s.manager.subscribe_pty_with_replay(id).await else {
-        return Err(error_response(
-            StatusCode::NOT_FOUND,
-            "unknown_session",
-            "no such session on this daemon",
-        ));
+    let (replay, rx) = match s.manager.subscribe_pty_with_replay(id).await {
+        Ok(subscription) => subscription,
+        Err(SessionError::NotFound(_)) => {
+            return Err(error_response(
+                StatusCode::NOT_FOUND,
+                "unknown_session",
+                "no such session on this daemon",
+            ));
+        }
+        Err(error) => {
+            let info = error.to_error_info();
+            return Err(error_response(
+                session_error_status(&info.code),
+                &info.code,
+                &info.message,
+            ));
+        }
     };
     let manager = s.manager.clone();
     Ok(ws.on_upgrade(move |socket| async move {

crates/maestro-daemon/src/projection.rs

@@ -2,9 +2,11 @@
 
 use std::collections::{HashMap, HashSet};
 
+use chrono::{DateTime, Utc};
 use maestro_acp::schema::{ContentChunk, SessionNotification, SessionUpdate, ToolCall};
 use maestro_protocol::{
-    ReducedState, TranscriptDelta, TranscriptRow, TranscriptRowKind, TranscriptSnapshot,
+    ActivityState, ReducedState, TranscriptDelta, TranscriptRow, TranscriptRowKind,
+    TranscriptSnapshot,
 };
 use serde_json::Value;
 
@@ -36,8 +38,12 @@ pub struct Projection {
     pending_tool_updates: HashMap<String, Vec<maestro_acp::schema::ToolCallUpdateFields>>,
     state: ReducedState,
     active_turn: Option<u64>,
+    active_turn_started_at: Option<DateTime<Utc>>,
+    active_turn_context_tokens: Option<u64>,
+    turn_failed: bool,
     next_turn: u64,
     turn_tool_calls: HashSet<String>,
+    anonymous_content_row: Option<(String, String)>,
 }
 
 impl Projection {
@@ -58,6 +64,7 @@ impl Projection {
             SessionUpdate::ToolCall(tool) => self.tool_call(tool),
             SessionUpdate::ToolCallUpdate(update) => self.tool_update(update),
             SessionUpdate::Plan(plan) => {
+                self.anonymous_content_row = None;
                 let data = to_value(plan);
                 self.state.plan = Some(data.clone());
                 Some(self.replace("plan".into(), TranscriptRowKind::Plan, data))
@@ -75,16 +82,20 @@ impl Projection {
             SessionUpdate::ConfigOptionUpdate(options) => {
                 let value = to_value(options);
                 self.state.model = model_from_options(&value).or_else(|| self.state.model.clone());
+                self.state.config_options = Some(value);
                 None
             }
             // ACP deliberately adds notification variants over time. Known but
             // non-transcript updates become a generic notice instead of being
             // dropped or forcing clients to understand ACP's enum.
-            _ => Some(self.append(
-                format!("notice:{seq}"),
-                TranscriptRowKind::Notice,
-                to_value(&notification.update),
-            )),
+            _ => {
+                self.anonymous_content_row = None;
+                Some(self.append(
+                    format!("notice:{seq}"),
+                    TranscriptRowKind::Notice,
+                    to_value(&notification.update),
+                ))
+            }
         };
         ProjectionUpdate {
             transcript,
@@ -109,13 +120,30 @@ impl Projection {
         self.active_turn.is_some()
     }
 
+    /// Sidebar activity derived from the live turn projection.
+    pub fn activity(&self) -> ActivityState {
+        crate::activity::decide_structured(
+            self.active_turn.is_some(),
+            self.state.pending_approval.is_some(),
+            self.turn_failed,
+        )
+    }
+
     /// Start a prompt turn and return its monotonically increasing token.
     pub fn begin_turn(&mut self) -> (u64, ProjectionUpdate) {
+        self.anonymous_content_row = None;
         self.next_turn += 1;
         let turn = self.next_turn;
         self.active_turn = Some(turn);
+        let started_at = Utc::now();
+        let started_context_tokens = usage_tokens(self.state.usage.as_ref());
+        self.active_turn_started_at = Some(started_at);
+        self.active_turn_context_tokens = started_context_tokens;
+        self.turn_failed = false;
         self.state.turn.responding = true;
         self.state.turn.thinking = true;
+        self.state.turn.started_at = Some(started_at);
+        self.state.turn.started_context_tokens = started_context_tokens;
         self.turn_tool_calls.clear();
         self.state.turn.active_tool_calls.clear();
         (
@@ -141,12 +169,47 @@ impl Projection {
             return None;
         }
         self.active_turn = None;
+        self.turn_failed = lifecycle == TurnLifecycle::Failure;
         self.state.turn.responding = false;
         self.state.turn.thinking = false;
+        let finished_at = Utc::now();
+        let started_at = self.active_turn_started_at.take();
+        let started_context_tokens = self.active_turn_context_tokens.take();
+        self.state.turn.started_at = None;
+        self.state.turn.started_context_tokens = None;
         self.turn_tool_calls.clear();
         self.state.turn.active_tool_calls.clear();
+        let context_tokens = usage_tokens(self.state.usage.as_ref());
+        let context_delta = context_tokens
+            .zip(started_context_tokens)
+            .map(|(end, start)| i128::from(end) - i128::from(start));
+        let elapsed_ms = started_at.map_or(0, |started| {
+            finished_at
+                .signed_duration_since(started)
+                .num_milliseconds()
+                .max(0)
+        });
+        let outcome = match lifecycle {
+            TurnLifecycle::Finish => "completed",
+            TurnLifecycle::Cancel => "cancelled",
+            TurnLifecycle::Failure => "failed",
+            TurnLifecycle::Begin => unreachable!(),
+        };
+        let row = self.append(
+            format!("turn_meta:{}", uuid::Uuid::new_v4()),
+            TranscriptRowKind::Notice,
+            serde_json::json!({
+                "maestroTurnMeta": {
+                    "elapsedMs": elapsed_ms,
+                    "contextTokens": context_tokens,
+                    "contextDelta": context_delta,
+                    "outcome": outcome,
+                    "model": self.state.model,
+                }
+            }),
+        );
         Some(ProjectionUpdate {
-            transcript: None,
+            transcript: Some(row),
             state: self.state(),
         })
     }
@@ -173,7 +236,8 @@ impl Projection {
         }
     }
 
-    pub fn restore_approval(&mut self, row: TranscriptRow) -> ProjectionUpdate {
+    pub fn restore_row(&mut self, row: TranscriptRow) -> ProjectionUpdate {
+        self.anonymous_content_row = None;
         let transcript = if !self.row_index.contains_key(&row.id) {
             self.row_index.insert(row.id.clone(), self.rows.len());
             self.rows.push(row.clone());
@@ -210,6 +274,21 @@ impl Projection {
         })
     }
 
+    /// Undo an `append`ed row that a caller decides never happened — used
+    /// when persisting the row's own event fails (#184), so a snapshot taken
+    /// after the failure cannot show a row durable replay would never
+    /// reproduce. Only ever called for a row that was just appended and
+    /// never patched, so removing it by id fully reverses `append`.
+    pub fn rollback_row(&mut self, id: &str) {
+        let Some(index) = self.row_index.remove(id) else {
+            return;
+        };
+        self.rows.remove(index);
+        for (shifted_index, row) in self.rows.iter().enumerate().skip(index) {
+            self.row_index.insert(row.id.clone(), shifted_index);
+        }
+    }
+
     fn content(
         &mut self,
         seq: u64,
@@ -217,12 +296,32 @@ impl Projection {
         kind: TranscriptRowKind,
         prefix: &str,
     ) -> Option<TranscriptDelta> {
-        let id = chunk
-            .message_id
-            .as_ref()
-            .map(|id| format!("{prefix}:{id}"))
-            .unwrap_or_else(|| format!("{prefix}:{seq}"));
         let data = to_value(chunk);
+        let id = if let Some(message_id) = chunk.message_id.as_ref() {
+            self.anonymous_content_row = None;
+            format!("{prefix}:{message_id}")
+        } else {
+            let text = data.pointer("/content/text").and_then(Value::as_str);
+            let previous = self
+                .anonymous_content_row
+                .as_ref()
+                .filter(|(previous_prefix, _)| previous_prefix == prefix)
+                .map(|(_, id)| id.clone());
+            if text.is_some_and(|text| !text.is_empty()) {
+                if let Some(id) = previous {
+                    let index = *self
+                        .row_index
+                        .get(&id)
+                        .expect("anonymous content row remains addressable");
+                    let row = &mut self.rows[index];
+                    append_text(&mut row.data, &data);
+                    return Some(TranscriptDelta::Patch { row: row.clone() });
+                }
+            }
+            let id = format!("{prefix}:{seq}");
+            self.anonymous_content_row = text.map(|_| (prefix.to_owned(), id.clone()));
+            id
+        };
         if let Some(index) = self.row_index.get(&id).copied() {
             let row = &mut self.rows[index];
             append_text(&mut row.data, &data);
@@ -232,6 +331,7 @@ impl Projection {
     }
 
     fn tool_call(&mut self, tool: &ToolCall) -> Option<TranscriptDelta> {
+        self.anonymous_content_row = None;
         let id = format!("tool:{}", tool.tool_call_id);
         let tool_id = tool.tool_call_id.to_string();
         let mut canonical = tool.clone();
@@ -262,6 +362,7 @@ impl Projection {
         &mut self,
         update: &maestro_acp::schema::ToolCallUpdate,
     ) -> Option<TranscriptDelta> {
+        self.anonymous_content_row = None;
         let tool_id = update.tool_call_id.to_string();
         let Some(tool) = self.tools.get_mut(&tool_id) else {
             self.pending_tool_updates
@@ -355,6 +456,10 @@ impl Projection {
     }
 }
 
+fn usage_tokens(usage: Option<&Value>) -> Option<u64> {
+    usage?.get("used")?.as_u64()
+}
+
 fn to_value(value: &impl serde::Serialize) -> Value {
     serde_json::to_value(value).expect("ACP schema values serialize")
 }
@@ -398,7 +503,7 @@ fn model_from_options(value: &Value) -> Option<String> {
 #[cfg(test)]
 mod tests {
     use maestro_acp::schema::SessionNotification;
-    use maestro_protocol::{TranscriptDelta, TranscriptRowKind};
+    use maestro_protocol::{TranscriptDelta, TranscriptRow, TranscriptRowKind};
 
     use super::{Projection, TurnLifecycle};
 
@@ -410,6 +515,16 @@ mod tests {
         .unwrap()
     }
 
+    #[test]
+    fn a_session_update_tag_the_acp_dependency_does_not_know_fails_to_deserialize() {
+        // `SessionUpdate` has no unknown-variant fallback, so this never reaches `Projection::apply`.
+        let result: Result<SessionNotification, _> = serde_json::from_value(serde_json::json!({
+            "sessionId": "acp-1",
+            "update": {"sessionUpdate": "some_future_update_variant"},
+        }));
+        assert!(result.is_err());
+    }
+
     #[test]
     fn folds_content_tool_diff_plan_and_notice_rows() {
         let mut projection = Projection::default();
@@ -458,6 +573,137 @@ mod tests {
         );
     }
 
+    #[test]
+    fn projects_the_codex_adapter_fixture_without_provider_specific_rows() {
+        let fixture = include_str!("../tests/fixtures/codex-acp-session.jsonl");
+        let events = fixture
+            .lines()
+            .map(serde_json::from_str::<SessionNotification>)
+            .collect::<Result<Vec<_>, _>>()
+            .expect("Codex ACP fixture follows the supported schema");
+        let mut projection = Projection::default();
+
+        for (seq, event) in events.iter().enumerate() {
+            projection.apply((seq + 1) as u64, event);
+        }
+
+        let rows = projection.snapshot(events.len() as u64).rows;
+        assert_eq!(
+            rows.iter().map(|row| row.kind).collect::<Vec<_>>(),
+            [
+                TranscriptRowKind::User,
+                TranscriptRowKind::AgentThought,
+                TranscriptRowKind::ToolCall,
+                TranscriptRowKind::ToolDiff,
+                TranscriptRowKind::ToolCall,
+                TranscriptRowKind::ToolCall,
+                TranscriptRowKind::ToolCall,
+                TranscriptRowKind::ToolCall,
+                TranscriptRowKind::Plan,
+                TranscriptRowKind::Notice,
+                TranscriptRowKind::Notice,
+                TranscriptRowKind::AgentText,
+            ]
+        );
+        assert_eq!(rows[2].data["rawInput"]["command"], "rg TODO");
+        assert_eq!(rows[2].data["rawOutput"]["exit_code"], 0);
+        assert_eq!(rows[4].data["_meta"]["is_mcp_tool_call"], true);
+        assert_eq!(rows[5].data["rawInput"]["query"], "Agent Client Protocol");
+        assert_eq!(
+            rows[7].data["content"][0]["content"]["mimeType"],
+            "image/png"
+        );
+
+        let state = projection.state();
+        assert_eq!(state.model.as_deref(), Some("gpt-5.3-codex"));
+        assert_eq!(state.mode.as_deref(), Some("agent"));
+        assert_eq!(state.usage.as_ref().unwrap()["used"], 1200);
+        assert_eq!(state.context.as_ref().unwrap()["size"], 258400);
+        assert_eq!(
+            state.config_options.as_ref().unwrap()["configOptions"][2]["currentValue"],
+            "high"
+        );
+    }
+
+    #[test]
+    fn coalesces_anonymous_stream_chunks_without_joining_turns() {
+        let mut projection = Projection::default();
+        let (first_turn, _) = projection.begin_turn();
+        for (seq, text) in [(1, ""), (2, "p"), (3, "ong")] {
+            projection.apply(
+                seq,
+                &event(serde_json::json!({
+                    "sessionUpdate": "agent_message_chunk",
+                    "content": {"type": "text", "text": text},
+                })),
+            );
+        }
+        projection.turn_lifecycle(TurnLifecycle::Finish, first_turn);
+        projection.begin_turn();
+        projection.apply(
+            4,
+            &event(serde_json::json!({
+                "sessionUpdate": "agent_message_chunk",
+                "content": {"type": "text", "text": "next"},
+            })),
+        );
+
+        let rows = projection.snapshot(4).rows;
+        assert_eq!(rows.len(), 3);
+        assert_eq!(rows[0].data.pointer("/content/text").unwrap(), "pong");
+        assert!(rows[1].data.get("maestroTurnMeta").is_some());
+        assert_eq!(rows[2].data.pointer("/content/text").unwrap(), "next");
+    }
+
+    #[test]
+    fn anonymous_empty_chunk_delimits_turns_during_replay() {
+        let mut projection = Projection::default();
+        for (seq, text) in [(1, ""), (2, "visible"), (3, ""), (4, "p"), (5, "ong")] {
+            projection.apply(
+                seq,
+                &event(serde_json::json!({
+                    "sessionUpdate": "agent_message_chunk",
+                    "content": {"type": "text", "text": text},
+                })),
+            );
+        }
+
+        let rows = projection.snapshot(5).rows;
+        assert_eq!(rows.len(), 2);
+        assert_eq!(rows[0].data.pointer("/content/text").unwrap(), "visible");
+        assert_eq!(rows[1].data.pointer("/content/text").unwrap(), "pong");
+    }
+
+    #[test]
+    fn restored_user_prompt_delimits_anonymous_agent_rows() {
+        let mut projection = Projection::default();
+        projection.apply(
+            1,
+            &event(serde_json::json!({
+                "sessionUpdate": "agent_message_chunk",
+                "content": {"type": "text", "text": "before"},
+            })),
+        );
+        projection.restore_row(TranscriptRow {
+            id: "user:prompt".into(),
+            kind: TranscriptRowKind::User,
+            data: serde_json::json!({"content": {"type": "text", "text": "next"}}),
+        });
+        projection.apply(
+            2,
+            &event(serde_json::json!({
+                "sessionUpdate": "agent_message_chunk",
+                "content": {"type": "text", "text": "after"},
+            })),
+        );
+
+        let rows = projection.snapshot(2).rows;
+        assert_eq!(rows.len(), 3);
+        assert_eq!(rows[0].data.pointer("/content/text").unwrap(), "before");
+        assert_eq!(rows[1].kind, TranscriptRowKind::User);
+        assert_eq!(rows[2].data.pointer("/content/text").unwrap(), "after");
+    }
+
     #[test]
     fn tool_update_patches_the_original_stable_row() {
         let mut projection = Projection::default();
@@ -576,6 +822,10 @@ mod tests {
         assert_eq!(state.context.as_ref().unwrap()["size"], 200);
         assert_eq!(state.mode.as_deref(), Some("plan"));
         assert_eq!(state.model.as_deref(), Some("opus"));
+        assert_eq!(
+            state.config_options.as_ref().unwrap()["configOptions"][0]["currentValue"],
+            "opus"
+        );
         assert_eq!(
             state.plan.as_ref().unwrap()["entries"],
             serde_json::json!([])
@@ -647,6 +897,38 @@ mod tests {
         }
     }
 
+    #[test]
+    fn completed_turn_keeps_duration_and_context_delta_in_transcript() {
+        let mut projection = Projection::default();
+        projection.apply(
+            1,
+            &event(serde_json::json!({
+                "sessionUpdate":"usage_update", "used":10_000, "size":200_000
+            })),
+        );
+        let (turn, begun) = projection.begin_turn();
+        assert!(begun.state.turn.started_at.is_some());
+        assert_eq!(begun.state.turn.started_context_tokens, Some(10_000));
+        projection.apply(
+            2,
+            &event(serde_json::json!({
+                "sessionUpdate":"usage_update", "used":12_500, "size":200_000
+            })),
+        );
+
+        let finished = projection
+            .turn_lifecycle(TurnLifecycle::Finish, turn)
+            .expect("active turn finishes");
+        let TranscriptDelta::Append { row } = finished.transcript.unwrap() else {
+            panic!("turn footer");
+        };
+        assert_eq!(row.kind, TranscriptRowKind::Notice);
+        assert_eq!(row.data["maestroTurnMeta"]["contextDelta"], 2_500);
+        assert_eq!(row.data["maestroTurnMeta"]["contextTokens"], 12_500);
+        assert_eq!(row.data["maestroTurnMeta"]["outcome"], "completed");
+        assert!(finished.state.turn.started_at.is_none());
+    }
+
     fn terminal_turn_drops_unfinished_tools(
         terminal: TurnLifecycle,
         unfinished_id: &str,
@@ -665,7 +947,9 @@ mod tests {
 
         projection.turn_lifecycle(terminal, turn);
         assert!(projection.state().turn.active_tool_calls.is_empty());
-        assert_eq!(projection.snapshot(1).rows.len(), 1);
+        let rows = projection.snapshot(1).rows;
+        assert_eq!(rows.len(), 2);
+        assert!(rows[1].data.get("maestroTurnMeta").is_some());
 
         projection.begin_turn();
         projection.apply(
@@ -712,6 +996,74 @@ mod tests {
         assert_eq!(projection.snapshot(0).rows, vec![row]);
     }
 
+    #[test]
+    fn rollback_row_removes_only_that_row_and_keeps_others_addressable() {
+        let mut projection = Projection::default();
+        projection.apply(
+            1,
+            &event(serde_json::json!({
+                "sessionUpdate": "user_message_chunk",
+                "messageId": "m1",
+                "content": {"type": "text", "text": "hi"},
+            })),
+        );
+        let TranscriptDelta::Append { row } = projection
+            .request_approval("nonce".into(), serde_json::json!({"tool": "bash"}))
+            .transcript
+            .unwrap()
+        else {
+            panic!("approval row")
+        };
+        // A row after the one being rolled back, so removing the approval
+        // (index 1) shifts this one from index 2 down to index 1 — proving
+        // `row_index` gets reindexed, not just `rows`.
+        projection.apply(
+            2,
+            &event(serde_json::json!({
+                "sessionUpdate": "user_message_chunk",
+                "messageId": "m2",
+                "content": {"type": "text", "text": "hey"},
+            })),
+        );
+        assert_eq!(projection.snapshot(0).rows.len(), 3);
+
+        projection.rollback_row(&row.id);
+
+        assert_eq!(projection.snapshot(0).rows.len(), 2);
+        assert_eq!(projection.snapshot(0).rows[0].kind, TranscriptRowKind::User);
+        assert_eq!(projection.snapshot(0).rows[1].kind, TranscriptRowKind::User);
+
+        // The shifted row must still be independently patchable at its new
+        // index.
+        let update = projection.apply(
+            3,
+            &event(serde_json::json!({
+                "sessionUpdate": "user_message_chunk",
+                "messageId": "m2",
+                "content": {"type": "text", "text": " there"},
+            })),
+        );
+        let TranscriptDelta::Patch { row } = update.transcript.unwrap() else {
+            panic!("patched row")
+        };
+        assert_eq!(row.data.pointer("/content/text").unwrap(), "hey there");
+        assert_eq!(projection.snapshot(0).rows.len(), 2);
+    }
+
+    #[test]
+    fn rollback_row_is_a_no_op_for_an_unknown_id() {
+        let mut projection = Projection::default();
+        projection.apply(
+            1,
+            &event(serde_json::json!({
+                "sessionUpdate": "user_message_chunk",
+                "content": {"type": "text", "text": "hi"},
+            })),
+        );
+        projection.rollback_row("approval:does-not-exist");
+        assert_eq!(projection.snapshot(0).rows.len(), 1);
+    }
+
     #[test]
     fn recovered_approval_is_historical_not_pending() {
         let mut live = Projection::default();
@@ -723,7 +1075,7 @@ mod tests {
             panic!("approval row")
         };
         let mut recovered = Projection::default();
-        let update = recovered.restore_approval(row.clone());
+        let update = recovered.restore_row(row.clone());
         assert_eq!(
             update.transcript,
             Some(TranscriptDelta::Append { row: row.clone() })

crates/maestro-daemon/src/sidecar.rs

@@ -112,7 +112,7 @@ impl SidecarStore {
         }
         file.seek(SeekFrom::End(0))?;
         Ok(EventLog {
-            file,
+            file: Box::new(file),
             last_seq: lines,
         })
     }
@@ -263,9 +263,15 @@ pub struct LoggedEvent {
 #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
 #[serde(tag = "maestroEvent", rename_all = "snake_case")]
 pub enum PersistedEvent {
+    User {
+        row: TranscriptRow,
+    },
     Approval {
         row: TranscriptRow,
     },
+    Turn {
+        row: TranscriptRow,
+    },
     #[serde(skip)]
     Notification(Box<SessionNotification>),
 }
@@ -296,15 +302,82 @@ impl From<&PersistedEvent> for PersistedEvent {
     }
 }
 
+/// What an [`EventLog`] appends onto: something seekable by length and
+/// truncatable back to one, so a failed append can be rolled off the end
+/// again. A real [`File`] in production; an in-memory fault double in tests
+/// (#184) — the same [`EventLog::append`] rollback logic runs over both, so
+/// the behavior under test is the production behavior, not a stand-in for
+/// it.
+pub(crate) trait LogSink: Write + Send {
+    fn len(&mut self) -> std::io::Result<u64>;
+    fn truncate(&mut self, len: u64) -> std::io::Result<()>;
+}
+
+impl LogSink for File {
+    fn len(&mut self) -> std::io::Result<u64> {
+        Ok(self.metadata()?.len())
+    }
+
+    fn truncate(&mut self, len: u64) -> std::io::Result<()> {
+        self.set_len(len)
+    }
+}
+
+/// Outcome of a failed [`EventLog::append`].
+#[derive(Debug, thiserror::Error)]
+pub enum AppendError {
+    /// The write or flush failed, but the log was rolled back to exactly the
+    /// byte it was at before the call: `last_seq` and the file agree, and
+    /// this same [`EventLog`] is safe to keep appending to. The event itself
+    /// was never persisted or broadcast.
+    #[error("event append failed, rolled back cleanly: {0}")]
+    Failed(#[source] SidecarError),
+    /// The append failed *and* the rollback did not restore the log to its
+    /// prior length, so the file's line count and `last_seq` may now
+    /// disagree. The caller must not append to this [`EventLog`] again —
+    /// treat the session as dead rather than promise consistency it cannot
+    /// keep.
+    #[error("event append failed ({cause}) and rollback did not restore consistency ({rollback})")]
+    Fatal {
+        cause: SidecarError,
+        rollback: SidecarError,
+    },
+}
+
+impl From<SidecarError> for AppendError {
+    fn from(error: SidecarError) -> Self {
+        AppendError::Failed(error)
+    }
+}
+
 /// An open, append-only handle on one session's event log. Obtained from
 /// [`SidecarStore::open_events`]; held for the session's lifetime.
-#[derive(Debug)]
 pub struct EventLog {
-    file: File,
+    file: Box<dyn LogSink>,
     last_seq: u64,
 }
 
+impl std::fmt::Debug for EventLog {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("EventLog")
+            .field("last_seq", &self.last_seq)
+            .finish_non_exhaustive()
+    }
+}
+
 impl EventLog {
+    /// Wrap an arbitrary sink as an [`EventLog`], for tests that need to
+    /// inject a deterministic append failure (#184) — a partial write, a
+    /// flush that fails after the bytes are already down, or a rollback that
+    /// cannot itself complete.
+    #[cfg(test)]
+    pub(crate) fn for_test(file: impl LogSink + 'static, last_seq: u64) -> Self {
+        Self {
+            file: Box::new(file),
+            last_seq,
+        }
+    }
+
     /// The seq of the last line, `0` for an empty log.
     pub fn last_seq(&self) -> u64 {
         self.last_seq
@@ -314,16 +387,262 @@ impl EventLog {
     /// handed to the kernel in a single write before this returns, so a
     /// caller that broadcasts afterwards never announces an event the log
     /// would not replay — short of the machine losing power.
-    pub fn append(&mut self, event: impl Into<PersistedEvent>) -> Result<u64, SidecarError> {
+    ///
+    /// A `write_all` that errors partway can leave an unterminated prefix on
+    /// disk; a `flush` that errors after a *complete* `write_all` leaves
+    /// ambiguity about whether that full, well-formed line should count —
+    /// counting it would silently shift every later seq by one, since
+    /// `last_seq` was never bumped for it. Both cases are rolled back to the
+    /// exact pre-append length before returning, so `last_seq` and the file
+    /// never disagree and the same [`EventLog`] can be appended to again
+    /// immediately. If the rollback itself fails, the log's consistency can
+    /// no longer be promised and [`AppendError::Fatal`] is returned instead.
+    pub fn append(&mut self, event: impl Into<PersistedEvent>) -> Result<u64, AppendError> {
         let event = event.into();
         let mut line = match &event {
-            PersistedEvent::Notification(notification) => serde_json::to_vec(notification)?,
-            _ => serde_json::to_vec(&event)?,
+            PersistedEvent::Notification(notification) => serde_json::to_vec(notification)
+                .map_err(|e| AppendError::from(SidecarError::from(e)))?,
+            _ => {
+                serde_json::to_vec(&event).map_err(|e| AppendError::from(SidecarError::from(e)))?
+            }
         };
         line.push(b'\n');
-        self.file.write_all(&line)?;
-        self.file.flush()?;
+
+        let pre_len = self
+            .file
+            .len()
+            .map_err(|e| AppendError::from(SidecarError::from(e)))?;
+
+        if let Err(cause) = self.file.write_all(&line) {
+            return Err(self.rollback_after(pre_len, cause));
+        }
+        if let Err(cause) = self.file.flush() {
+            return Err(self.rollback_after(pre_len, cause));
+        }
+
         self.last_seq += 1;
         Ok(self.last_seq)
     }
+
+    fn rollback_after(&mut self, pre_len: u64, cause: std::io::Error) -> AppendError {
+        match self.file.truncate(pre_len) {
+            Ok(()) => AppendError::Failed(SidecarError::Io(cause)),
+            Err(rollback) => AppendError::Fatal {
+                cause: SidecarError::Io(cause),
+                rollback: SidecarError::Io(rollback),
+            },
+        }
+    }
+}
+
+/// Bytes shared between a [`FaultyLogSink`] moved into an [`EventLog`] and
+/// the test that planted it, so the test can inspect what actually ended up
+/// on the "disk" after a fault without reaching into `EventLog`'s private
+/// `file` field.
+#[cfg(test)]
+#[derive(Clone, Default)]
+pub(crate) struct SharedBuf(std::sync::Arc<std::sync::Mutex<Vec<u8>>>);
+
+#[cfg(test)]
+impl SharedBuf {
+    pub(crate) fn snapshot(&self) -> Vec<u8> {
+        self.0.lock().unwrap().clone()
+    }
+}
+
+/// An in-memory [`LogSink`] double that injects one deterministic fault — a
+/// short write, a flush that fails after a full write, or a rollback that
+/// cannot itself complete — then behaves like a healthy sink from then on.
+/// Lets a test prove the *same* [`EventLog`] recovers, rather than one with a
+/// handle swapped in from a healthy disk, which production never does
+/// (#184).
+#[cfg(test)]
+#[derive(Default)]
+pub(crate) struct FaultyLogSink {
+    pub(crate) buf: SharedBuf,
+    /// Accept this many bytes on the next `write` call, then fail the
+    /// *following* call — a short write followed by an error, exactly what
+    /// `write_all` sees from a real fd that dies mid-line. `Write::write`
+    /// must not report an error on a call that made partial progress, so
+    /// the fault is delivered one call later, via `pending_write_error`.
+    pub(crate) fail_write_after: Option<usize>,
+    pub(crate) pending_write_error: bool,
+    pub(crate) fail_flush_once: bool,
+    pub(crate) fail_truncate: bool,
+}
+
+#[cfg(test)]
+impl Write for FaultyLogSink {
+    fn write(&mut self, data: &[u8]) -> std::io::Result<usize> {
+        if self.pending_write_error {
+            self.pending_write_error = false;
+            return Err(std::io::Error::other("fault: write failed mid-line"));
+        }
+        if let Some(allowed) = self.fail_write_after.take() {
+            let allowed = allowed.min(data.len());
+            if allowed == 0 {
+                // No progress was made, so it's fine to report the error
+                // from this same call.
+                return Err(std::io::Error::other("fault: write failed mid-line"));
+            }
+            self.buf
+                .0
+                .lock()
+                .unwrap()
+                .extend_from_slice(&data[..allowed]);
+            self.pending_write_error = true;
+            return Ok(allowed);
+        }
+        self.buf.0.lock().unwrap().extend_from_slice(data);
+        Ok(data.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        if self.fail_flush_once {
+            self.fail_flush_once = false;
+            return Err(std::io::Error::other(
+                "fault: flush failed after a full write",
+            ));
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+impl LogSink for FaultyLogSink {
+    fn len(&mut self) -> std::io::Result<u64> {
+        Ok(self.buf.0.lock().unwrap().len() as u64)
+    }
+
+    fn truncate(&mut self, len: u64) -> std::io::Result<()> {
+        if self.fail_truncate {
+            return Err(std::io::Error::other("fault: rollback truncate failed"));
+        }
+        self.buf.0.lock().unwrap().truncate(len as usize);
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn sample_event(id: &str) -> PersistedEvent {
+        PersistedEvent::Approval {
+            row: TranscriptRow {
+                id: id.to_owned(),
+                kind: maestro_protocol::TranscriptRowKind::Approval,
+                data: serde_json::json!({"tool": "bash"}),
+            },
+        }
+    }
+
+    /// Replays `bytes` as a real on-disk log via the production read path,
+    /// so "live and durable agree" is checked with the same code a
+    /// reconnecting client would hit, not a hand-rolled line splitter.
+    fn replay(bytes: &[u8]) -> Vec<LoggedEvent> {
+        let dir = tempfile::tempdir().unwrap();
+        let store = SidecarStore::new(dir.path());
+        let id = Uuid::new_v4();
+        std::fs::create_dir_all(store.dir()).unwrap();
+        std::fs::write(store.events_path_for(id), bytes).unwrap();
+        store.read_events(id, EventCursor::Since(0), 100).unwrap()
+    }
+
+    #[test]
+    fn append_rolls_back_a_partial_write_and_the_same_instance_recovers() {
+        let buf = SharedBuf::default();
+        let writer = FaultyLogSink {
+            buf: buf.clone(),
+            fail_write_after: Some(5),
+            ..Default::default()
+        };
+        let mut log = EventLog::for_test(writer, 0);
+
+        let err = log.append(sample_event("r1")).unwrap_err();
+        assert!(
+            matches!(err, AppendError::Failed(_)),
+            "a repairable rollback must not be reported fatal"
+        );
+        assert_eq!(log.last_seq(), 0, "cursor must stay put on a failed append");
+        assert!(
+            buf.snapshot().is_empty(),
+            "the partial prefix a failed write_all leaves behind must be truncated away"
+        );
+
+        let seq = log
+            .append(sample_event("r1"))
+            .expect("the same instance must be able to append again after a clean rollback");
+        assert_eq!(seq, 1);
+        assert_eq!(log.last_seq(), 1);
+
+        let bytes = buf.snapshot();
+        assert_eq!(
+            bytes.iter().filter(|&&b| b == b'\n').count(),
+            1,
+            "exactly one well-formed line, not a partial prefix glued to the recovered append"
+        );
+
+        let replayed = replay(&bytes);
+        assert_eq!(replayed.len(), 1);
+        assert_eq!(replayed[0].seq, log.last_seq());
+        let PersistedEvent::Approval { row } = &replayed[0].event else {
+            panic!("approval event");
+        };
+        assert_eq!(row.id, "r1");
+    }
+
+    #[test]
+    fn append_rolls_back_when_flush_fails_after_a_full_write() {
+        let buf = SharedBuf::default();
+        let writer = FaultyLogSink {
+            buf: buf.clone(),
+            fail_flush_once: true,
+            ..Default::default()
+        };
+        let mut log = EventLog::for_test(writer, 0);
+
+        let err = log.append(sample_event("r1")).unwrap_err();
+        assert!(matches!(err, AppendError::Failed(_)));
+        assert_eq!(log.last_seq(), 0);
+        assert!(
+            buf.snapshot().is_empty(),
+            "a full-but-unflushed line must not survive uncounted by last_seq — it would \
+             silently shift every later seq by one"
+        );
+
+        let seq = log
+            .append(sample_event("r1"))
+            .expect("the same instance must recover once flush stops failing");
+        assert_eq!(seq, 1);
+
+        let bytes = buf.snapshot();
+        let replayed = replay(&bytes);
+        assert_eq!(replayed.len(), 1);
+        assert_eq!(replayed[0].seq, log.last_seq());
+    }
+
+    #[test]
+    fn append_reports_fatal_when_rollback_cannot_restore_consistency() {
+        let buf = SharedBuf::default();
+        let writer = FaultyLogSink {
+            buf,
+            fail_write_after: Some(3),
+            fail_truncate: true,
+            ..Default::default()
+        };
+        let mut log = EventLog::for_test(writer, 0);
+
+        let err = log.append(sample_event("r1")).unwrap_err();
+        assert!(
+            matches!(err, AppendError::Fatal { .. }),
+            "an unrepairable rollback must be surfaced as fatal, never silently treated as \
+             a clean recoverable failure"
+        );
+        assert_eq!(
+            log.last_seq(),
+            0,
+            "a fatal append must not advance the cursor either"
+        );
+    }
 }

crates/maestro-daemon/tests/acp.rs

@@ -11,7 +11,7 @@ use std::time::{Duration, Instant};
 
 use common::{init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture};
 use maestro_acp::schema::{ContentBlock, SessionUpdate};
-use maestro_acp::{ADAPTER_BIN, INSTALL_COMMAND};
+use maestro_acp::{AcpAdapter, ADAPTER_BIN};
 use maestro_daemon::projection::TurnLifecycle;
 use maestro_daemon::sidecar::{EventCursor, SidecarStore};
 use maestro_daemon::worktree::WorktreeManager;
@@ -38,6 +38,7 @@ impl Fake {
         let bin = dir.path().join("bin");
         std::fs::create_dir_all(&bin).unwrap();
         std::fs::copy(fake_agent(), bin.join(ADAPTER_BIN)).unwrap();
+        std::fs::copy(fake_agent(), bin.join(AcpAdapter::Codex.binary())).unwrap();
         Self { dir }
     }
 
@@ -96,13 +97,22 @@ fn event_text(event: &maestro_daemon::sidecar::LoggedEvent) -> &str {
 }
 
 fn structured(cwd: &Path, env: HashMap<String, String>) -> CreateSessionRequest {
+    structured_command(cwd, env, "claude")
+}
+
+fn structured_command(
+    cwd: &Path,
+    env: HashMap<String, String>,
+    command: &str,
+) -> CreateSessionRequest {
     CreateSessionRequest {
         view: SessionView::Structured,
         cwd: cwd.to_path_buf(),
-        command: "claude".into(),
+        command: command.into(),
         env,
         metadata: HashMap::new(),
         worktree: None,
+        auto_approve: false,
     }
 }
 
@@ -120,6 +130,25 @@ async fn wait_for_exit(pid: u32) {
     assert!(!pid_alive(pid), "pid {pid} still alive");
 }
 
+/// Wait for a session's background ACP handshake to complete (activity
+/// transitions out of `Starting`). Returns the refreshed session.
+async fn wait_for_ready(manager: &SessionManager, id: uuid::Uuid) -> maestro_protocol::Session {
+    let deadline = Instant::now() + Duration::from_secs(10);
+    loop {
+        let session = manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|s| s.id == id)
+            .expect("session exists");
+        if session.activity != ActivityState::Starting {
+            return session;
+        }
+        assert!(Instant::now() < deadline, "handshake timed out");
+        tokio::time::sleep(Duration::from_millis(20)).await;
+    }
+}
+
 #[tokio::test]
 async fn structured_spawn_starts_the_adapter_in_cwd_with_session_env() {
     let fx = DaemonFixture::new();
@@ -128,14 +157,23 @@ async fn structured_spawn_starts_the_adapter_in_cwd_with_session_env() {
     let mut env = fake.env();
     env.insert("FAKE_ACP_ECHO_ENV".into(), "MAESTRO_SESSION_ID".into());
 
-    let session = fx
+    let created = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(
+            cwd.path(),
+            env,
+            "codex --dangerously-bypass-approvals-and-sandbox",
+        ))
         .await
         .expect("create");
 
-    assert_eq!(session.view, SessionView::Structured);
-    assert_eq!(session.status, SessionStatus::Running);
+    assert_eq!(created.view, SessionView::Structured);
+    assert_eq!(created.status, SessionStatus::Running);
+    assert_eq!(created.activity, ActivityState::Starting);
+    assert!(created.acp_session_id.is_none());
+
+    let session = wait_for_ready(&fx.manager, created.id).await;
+    assert_eq!(session.activity, ActivityState::Idle);
     let acp_id = session.acp_session_id.clone().expect("acp session id");
     assert!(acp_id.starts_with("fake-"), "{acp_id}");
 
@@ -149,7 +187,7 @@ async fn structured_spawn_starts_the_adapter_in_cwd_with_session_env() {
         "{log}"
     );
     assert!(
-        log.contains(&format!("env MAESTRO_SESSION_ID={}", session.id)),
+        log.contains(&format!("env MAESTRO_SESSION_ID={}", created.id)),
         "{log}"
     );
 
@@ -204,16 +242,89 @@ async fn structured_spawn_starts_the_adapter_in_cwd_with_session_env() {
         .exists());
 }
 
+#[tokio::test]
+async fn structured_activity_tracks_turn_completion_and_failure() {
+    let fx = DaemonFixture::new();
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_DELAY_PROMPT_MS".into(), "100".into());
+    env.insert("FAKE_ACP_PROMPT_FAIL_ONCE".into(), "1".into());
+    let session = fx
+        .manager
+        .create(structured_command(cwd.path(), env, "codex"))
+        .await
+        .unwrap();
+    let session = wait_for_ready(&fx.manager, session.id).await;
+
+    assert!(matches!(
+        fx.manager
+            .queue_acp_prompt(session.id, "fail".into())
+            .await
+            .unwrap(),
+        maestro_daemon::session::QueueAcpPrompt::Queued
+    ));
+    assert_eq!(
+        fx.manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .unwrap()
+            .activity,
+        ActivityState::Active
+    );
+    wait_for_async(Duration::from_secs(2), || async {
+        fx.manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .is_some_and(|candidate| candidate.activity == ActivityState::Error)
+    })
+    .await;
+
+    assert!(matches!(
+        fx.manager
+            .queue_acp_prompt(session.id, "succeed".into())
+            .await
+            .unwrap(),
+        maestro_daemon::session::QueueAcpPrompt::Queued
+    ));
+    assert_eq!(
+        fx.manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .unwrap()
+            .activity,
+        ActivityState::Active
+    );
+    wait_for_async(Duration::from_secs(2), || async {
+        fx.manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .is_some_and(|candidate| candidate.activity == ActivityState::Idle)
+    })
+    .await;
+
+    fx.manager.kill(session.id, false).await.unwrap();
+}
+
 #[tokio::test]
 async fn projection_snapshot_and_live_stream_share_one_fold() {
     let fx = DaemonFixture::new();
     let fake = Fake::new();
     let cwd = TempDir::new().unwrap();
-    let session = fx
+    let created = fx
         .manager
         .create(structured(cwd.path(), fake.env()))
         .await
         .expect("create");
+    let session = wait_for_ready(&fx.manager, created.id).await;
 
     wait_for_async(Duration::from_secs(5), || async {
         fx.manager
@@ -277,12 +388,76 @@ async fn projection_snapshot_and_live_stream_share_one_fold() {
         .await
         .expect("finish lifecycle broadcast")
         .expect("projection broadcast");
-    assert_eq!(finish.transcript, None);
+    let Some(TranscriptDelta::Append { row }) = finish.transcript else {
+        panic!("finish should append durable turn metadata");
+    };
+    assert_eq!(row.kind, TranscriptRowKind::Notice);
+    assert_eq!(row.data["maestroTurnMeta"]["outcome"], "completed");
     assert_eq!(finish.state.turn, Default::default());
 
+    let recovered = fx
+        .manager
+        .read_acp_projection_replay(session.id, EventCursor::Since(0), 10)
+        .await
+        .expect("turn replay")
+        .expect("structured session");
+    assert!(recovered.iter().any(|event| {
+        matches!(
+            &event.transcript,
+            Some(TranscriptDelta::Append { row })
+                if row.data["maestroTurnMeta"]["outcome"] == "completed"
+        )
+    }));
+
     fx.manager.kill(session.id, false).await.expect("kill");
 }
 
+#[tokio::test]
+async fn queued_prompt_is_a_durable_user_transcript_row() {
+    let fx = DaemonFixture::new();
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let session = fx
+        .manager
+        .create(structured(cwd.path(), fake.env()))
+        .await
+        .expect("create");
+    let session = wait_for_ready(&fx.manager, session.id).await;
+
+    assert!(matches!(
+        fx.manager
+            .queue_acp_prompt(session.id, "show my prompt".into())
+            .await
+            .expect("queue prompt"),
+        maestro_daemon::session::QueueAcpPrompt::Queued
+    ));
+
+    let (snapshot, _, _) = fx
+        .manager
+        .subscribe_acp_projection(session.id, EventCursor::Since(0))
+        .await
+        .expect("projection subscription")
+        .expect("structured session");
+    let user = snapshot
+        .rows
+        .iter()
+        .find(|row| row.kind == TranscriptRowKind::User)
+        .expect("user prompt row");
+    assert_eq!(user.data["content"]["text"], "show my prompt");
+
+    let persisted = fx
+        .manager
+        .read_acp_events(session.id, EventCursor::Since(0), 100)
+        .expect("event replay");
+    assert!(persisted.iter().any(|event| matches!(
+        &event.event,
+        maestro_daemon::sidecar::PersistedEvent::User { row }
+            if row.data["content"]["text"] == "show my prompt"
+    )));
+
+    fx.manager.kill(session.id, false).await.unwrap();
+}
+
 #[tokio::test]
 async fn stale_turn_completion_cannot_end_the_next_turn() {
     let fx = DaemonFixture::new();
@@ -293,6 +468,7 @@ async fn stale_turn_completion_cannot_end_the_next_turn() {
         .create(structured(cwd.path(), fake.env()))
         .await
         .unwrap();
+    wait_for_ready(&fx.manager, session.id).await;
 
     let maestro_daemon::session::BeginAcpTurn::Started(_, first) =
         fx.manager.begin_acp_turn(session.id).await.unwrap()
@@ -336,6 +512,7 @@ async fn cancelled_prompt_that_never_settles_fails_the_session() {
         .create(structured(cwd.path(), env))
         .await
         .unwrap();
+    wait_for_ready(&fx.manager, session.id).await;
 
     assert!(matches!(
         fx.manager
@@ -374,6 +551,7 @@ async fn cancellation_settlement_allows_the_next_prompt_permission() {
         .create(structured(cwd.path(), env))
         .await
         .unwrap();
+    wait_for_ready(&fx.manager, session.id).await;
 
     assert!(matches!(
         fx.manager
@@ -433,11 +611,12 @@ async fn recovery_loads_the_acp_session_without_duplicating_history() {
     let mut env = fake.env();
     env.insert("FAKE_ACP_LOAD_REPLAY".into(), "2".into());
 
-    let session = fx
+    let created = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(cwd.path(), env, "codex"))
         .await
         .expect("create");
+    let session = wait_for_ready(&fx.manager, created.id).await;
     let acp_id = session.acp_session_id.clone().expect("acp id");
     wait_for_async(Duration::from_secs(5), || async {
         fx.manager
@@ -476,6 +655,16 @@ async fn recovery_loads_the_acp_session_without_duplicating_history() {
         revived.status(session.id).await,
         Some(SessionStatus::Running)
     );
+    assert_eq!(
+        revived
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .unwrap()
+            .activity,
+        ActivityState::Idle
+    );
     let log = fake.log();
     assert!(
         log.contains(&format!("recv session/load sessionId={acp_id}")),
@@ -539,7 +728,7 @@ async fn shutdown_preserves_a_pristine_structured_worktree_for_recovery() {
         .create(CreateSessionRequest {
             view: SessionView::Structured,
             cwd: repo.path().to_path_buf(),
-            command: "claude".into(),
+            command: "codex".into(),
             env: fake.env(),
             metadata: HashMap::new(),
             worktree: Some(WorktreeSpec {
@@ -547,10 +736,12 @@ async fn shutdown_preserves_a_pristine_structured_worktree_for_recovery() {
                 branch: branch.into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
     assert_eq!(session.cwd, worktree);
+    wait_for_ready(&fx.manager, session.id).await;
     push_all_to_origin(repo.path(), origin.path());
 
     fx.manager.shutdown().await;
@@ -599,6 +790,7 @@ async fn failed_recovery_cleans_its_fifo() {
         .create(structured(cwd.path(), fake.env()))
         .await
         .expect("create");
+    wait_for_ready(&fx.manager, session.id).await;
     let old_pid = fake.pid();
     fx.manager.shutdown().await;
     wait_for_exit(old_pid).await;
@@ -632,28 +824,56 @@ async fn missing_adapter_yields_a_failed_session_naming_the_install_command() {
         empty.path().to_string_lossy().into_owned(),
     )]);
 
-    let session = fx
+    let created = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(cwd.path(), env, "codex"))
         .await
-        .expect("a failed session, not an error");
+        .expect("create registers a Starting session");
+    assert_eq!(created.activity, ActivityState::Starting);
 
+    // The background handshake fails because the adapter binary is missing.
+    let session = wait_for_ready(&fx.manager, created.id).await;
     assert_eq!(session.status, SessionStatus::Dead);
     assert_eq!(session.activity, ActivityState::Error);
     let detail = session.activity_detail.clone().expect("actionable detail");
-    assert!(detail.contains(ADAPTER_BIN), "{detail}");
-    assert!(detail.contains(INSTALL_COMMAND), "{detail}");
+    assert!(detail.contains(AcpAdapter::Codex.binary()), "{detail}");
+    assert!(
+        detail.contains(AcpAdapter::Codex.install_command()),
+        "{detail}"
+    );
     assert_eq!(session.acp_session_id, None);
 
     // It is a real session: listed, on disk, and dismissable like any other
     // dead one.
-    assert!(fx.manager.has(session.id).await);
+    assert!(fx.manager.has(created.id).await);
     assert!(fx
         .sidecar_dir()
-        .join(format!("{}.json", session.id))
+        .join(format!("{}.json", created.id))
         .exists());
-    fx.manager.kill(session.id, false).await.expect("dismiss");
-    assert!(!fx.manager.has(session.id).await);
+    fx.manager.kill(created.id, false).await.expect("dismiss");
+    assert!(!fx.manager.has(created.id).await);
+}
+
+#[tokio::test]
+async fn unsupported_structured_command_fails_without_launching_claude() {
+    let fx = DaemonFixture::new();
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+
+    let err = fx
+        .manager
+        .create(structured_command(cwd.path(), fake.env(), "opencode"))
+        .await
+        .expect_err("unsupported command is rejected at request validation");
+
+    assert!(
+        matches!(err, maestro_daemon::SessionError::BadRequest(ref msg) if msg.contains("Claude Code or Codex")),
+        "{err:?}"
+    );
+    assert!(
+        fake.log().is_empty(),
+        "unsupported command launched an adapter"
+    );
 }
 
 #[tokio::test]
@@ -668,6 +888,7 @@ async fn kill_sends_cancel_then_sigterm_and_removes_the_sidecar() {
         .create(structured(cwd.path(), fake.env()))
         .await
         .expect("create");
+    wait_for_ready(&fx.manager, session.id).await;
     let pid = fake.pid();
     assert!(pid_alive(pid));
 
@@ -710,6 +931,8 @@ async fn shutdown_reaps_every_adapter_child() {
         .create(structured(cwd.path(), b.env()))
         .await
         .expect("create b");
+    wait_for_ready(&fx.manager, sa.id).await;
+    wait_for_ready(&fx.manager, sb.id).await;
     let (pa, pb) = (a.pid(), b.pid());
     assert!(pid_alive(pa) && pid_alive(pb));
 
@@ -744,10 +967,13 @@ async fn dismissal_during_shutdown_does_not_restore_recovery_artifacts() {
         .create(structured(cwd.path(), env))
         .await
         .expect("create");
-    fx.manager
+    let blocker_session = fx
+        .manager
         .create(structured(cwd.path(), blocker.env()))
         .await
         .expect("create blocker");
+    wait_for_ready(&fx.manager, session.id).await;
+    wait_for_ready(&fx.manager, blocker_session.id).await;
 
     let manager = fx.manager.clone();
     let shutdown = tokio::spawn(async move { manager.shutdown().await });
@@ -799,6 +1025,7 @@ async fn shutdown_does_not_recover_an_adapter_that_already_exited() {
         .create(structured(cwd.path(), env))
         .await
         .expect("create");
+    wait_for_ready(&fx.manager, session.id).await;
     wait_for_exit(fake.pid()).await;
 
     fx.manager.shutdown().await;
@@ -832,23 +1059,31 @@ async fn shutdown_waits_for_structured_creation_and_rejects_new_creates() {
     let mut env = fake.env();
     env.insert("FAKE_ACP_DELAY_SESSION_NEW_MS".into(), "500".into());
 
-    let create_cwd = cwd.path().to_path_buf();
-    let manager = fx.manager.clone();
-    let create = tokio::spawn(async move { manager.create(structured(&create_cwd, env)).await });
+    // create() returns immediately; the handshake runs in the background
+    // and holds a lifecycle permit.
+    let session = fx
+        .manager
+        .create(structured(cwd.path(), env))
+        .await
+        .expect("create");
+
+    // Wait until the adapter has received session/new (handshake in progress).
     wait_for_async(Duration::from_secs(5), || async {
         fake.log().contains("recv session/new")
     })
     .await;
 
+    // Shutdown must wait for the in-flight background handshake.
     let manager = fx.manager.clone();
     let shutdown = tokio::spawn(async move { manager.shutdown().await });
     tokio::time::sleep(Duration::from_millis(50)).await;
     assert!(
         !shutdown.is_finished(),
-        "shutdown returned before create finished"
+        "shutdown returned before handshake finished"
     );
 
-    let session = create.await.expect("create task").expect("create");
+    // The handshake completes in the background (500ms delay).
+    wait_for_ready(&fx.manager, session.id).await;
     let pid = fake.pid();
     shutdown.await.expect("shutdown task");
 
@@ -868,6 +1103,194 @@ async fn shutdown_waits_for_structured_creation_and_rejects_new_creates() {
     assert_eq!(fake.log().matches("signal SIGTERM").count(), 1);
 }
 
+#[tokio::test]
+async fn structured_handshakes_run_independently() {
+    let fx = DaemonFixture::new();
+    let blocked = Fake::new();
+    let ready = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let gate = cwd.path().join("release-first");
+    let mut blocked_env = blocked.env();
+    blocked_env.insert(
+        "FAKE_ACP_SESSION_NEW_GATE".into(),
+        gate.to_string_lossy().into_owned(),
+    );
+
+    // Both create() calls return immediately with Starting; the first
+    // adapter's handshake is gated while the second runs freely.
+    let first = fx
+        .manager
+        .create(structured(cwd.path(), blocked_env))
+        .await
+        .expect("first create");
+    let second = fx
+        .manager
+        .create(structured(cwd.path(), ready.env()))
+        .await
+        .expect("second create");
+
+    // The second handshake completes independently of the first.
+    let second_ready = wait_for_ready(&fx.manager, second.id).await;
+    assert_eq!(second_ready.activity, ActivityState::Idle);
+
+    // The first handshake is still blocked.
+    let first_snap = fx
+        .manager
+        .snapshot()
+        .await
+        .into_iter()
+        .find(|s| s.id == first.id)
+        .unwrap();
+    assert_eq!(first_snap.activity, ActivityState::Starting);
+
+    std::fs::write(&gate, b"release").unwrap();
+    let first_ready = wait_for_ready(&fx.manager, first.id).await;
+    assert_eq!(first_ready.activity, ActivityState::Idle);
+
+    fx.manager.kill(first.id, false).await.expect("kill first");
+    fx.manager
+        .kill(second.id, false)
+        .await
+        .expect("kill second");
+}
+
+#[tokio::test]
+async fn shutdown_waits_for_every_admitted_structured_create() {
+    let fx = DaemonFixture::new();
+    let a = Fake::new();
+    let b = Fake::new();
+    let late = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let gate_a = cwd.path().join("release-a");
+    let gate_b = cwd.path().join("release-b");
+    let mut env_a = a.env();
+    let mut env_b = b.env();
+    env_a.insert(
+        "FAKE_ACP_SESSION_NEW_GATE".into(),
+        gate_a.to_string_lossy().into_owned(),
+    );
+    env_b.insert(
+        "FAKE_ACP_SESSION_NEW_GATE".into(),
+        gate_b.to_string_lossy().into_owned(),
+    );
+
+    // Both create() calls return immediately; the background handshake
+    // tasks hold lifecycle permits and are blocked on their gates.
+    let session_a = fx
+        .manager
+        .create(structured(cwd.path(), env_a))
+        .await
+        .expect("create a");
+    let session_b = fx
+        .manager
+        .create(structured(cwd.path(), env_b))
+        .await
+        .expect("create b");
+    wait_for_async(Duration::from_secs(5), || async {
+        a.log().contains("recv session/new") && b.log().contains("recv session/new")
+    })
+    .await;
+
+    let shutdown = {
+        let manager = fx.manager.clone();
+        tokio::spawn(async move { manager.shutdown().await })
+    };
+    wait_for_async(Duration::from_secs(5), || async {
+        matches!(
+            fx.manager.create(structured(cwd.path(), late.env())).await,
+            Err(maestro_daemon::SessionError::ShuttingDown)
+        )
+    })
+    .await;
+    assert!(!shutdown.is_finished());
+
+    std::fs::write(&gate_a, b"release").unwrap();
+    wait_for_ready(&fx.manager, session_a.id).await;
+    assert!(
+        !shutdown.is_finished(),
+        "shutdown ignored the second create"
+    );
+
+    std::fs::write(&gate_b, b"release").unwrap();
+    wait_for_ready(&fx.manager, session_b.id).await;
+    shutdown.await.expect("shutdown task");
+
+    wait_for_exit(a.pid()).await;
+    wait_for_exit(b.pid()).await;
+    assert_eq!(
+        fx.manager.status(session_a.id).await,
+        Some(SessionStatus::Dead)
+    );
+    assert_eq!(
+        fx.manager.status(session_b.id).await,
+        Some(SessionStatus::Dead)
+    );
+}
+
+#[tokio::test]
+async fn killing_a_starting_session_rolls_back_and_settles_admission() {
+    let fx = DaemonFixture::new();
+    let fake = Fake::new();
+    let repo = TempDir::new().unwrap();
+    init_repo(repo.path());
+    let gate = repo.path().join("release-create");
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_ECHO_ENV".into(), "MAESTRO_SESSION_ID".into());
+    env.insert(
+        "FAKE_ACP_SESSION_NEW_GATE".into(),
+        gate.to_string_lossy().into_owned(),
+    );
+    let request = CreateSessionRequest {
+        view: SessionView::Structured,
+        cwd: repo.path().to_path_buf(),
+        command: "claude".into(),
+        env,
+        metadata: HashMap::new(),
+        worktree: Some(WorktreeSpec {
+            base_repo: repo.path().to_path_buf(),
+            branch: "cancelled-create".into(),
+            create_branch: true,
+        }),
+        auto_approve: false,
+    };
+
+    // create() returns immediately with Starting; the handshake is gated.
+    let session = fx.manager.create(request).await.expect("create");
+    assert_eq!(session.activity, ActivityState::Starting);
+    wait_for_async(Duration::from_secs(5), || async {
+        fake.log().contains("recv session/new")
+    })
+    .await;
+    let pid = fake.pid();
+
+    // Kill the session while its handshake is still in progress.
+    // force=true because the worktree has an unpushed branch commit.
+    fx.manager.kill(session.id, true).await.expect("kill");
+
+    // Release the gate so the background task can finish and settle.
+    std::fs::write(&gate, b"release").unwrap();
+
+    // Shutdown must not hang — the lifecycle permit is settled.
+    tokio::time::timeout(Duration::from_secs(5), fx.manager.shutdown())
+        .await
+        .expect("shutdown hung on a settled permit");
+
+    wait_for_exit(pid).await;
+    assert!(fx.manager.snapshot().await.is_empty());
+    let id = session.id.to_string();
+    assert!(
+        std::fs::read_dir(fx.sidecar_dir())
+            .into_iter()
+            .flatten()
+            .all(|entry| !entry
+                .unwrap()
+                .file_name()
+                .to_string_lossy()
+                .starts_with(&id)),
+        "killed Starting session left a sidecar artifact"
+    );
+}
+
 #[tokio::test]
 async fn shutdown_drains_final_notifications_to_the_log() {
     let fx = DaemonFixture::new();
@@ -881,6 +1304,7 @@ async fn shutdown_drains_final_notifications_to_the_log() {
         .create(structured(cwd.path(), env))
         .await
         .expect("create");
+    wait_for_ready(&fx.manager, session.id).await;
     wait_for_async(Duration::from_secs(5), || async {
         fx.manager
             .read_acp_events(session.id, EventCursor::Since(0), 10)
@@ -911,6 +1335,7 @@ async fn adapter_exit_marks_the_session_dead_and_keeps_it_listed() {
         .create(structured(cwd.path(), fake.env()))
         .await
         .expect("create");
+    wait_for_ready(&fx.manager, session.id).await;
     fx.manager.start_liveness_watcher(Duration::from_millis(50));
 
     // The agent dies out from under the daemon: the liveness pass, not tmux,
@@ -925,6 +1350,16 @@ async fn adapter_exit_marks_the_session_dead_and_keeps_it_listed() {
         fx.manager.status(session.id).await == Some(SessionStatus::Dead)
     })
     .await;
+    assert_eq!(
+        fx.manager
+            .snapshot()
+            .await
+            .into_iter()
+            .find(|candidate| candidate.id == session.id)
+            .unwrap()
+            .activity,
+        ActivityState::Error
+    );
     assert!(fx.manager.has(session.id).await);
     assert!(
         !fx.sidecar_dir()

crates/maestro-daemon/tests/activity_report.rs

@@ -48,6 +48,7 @@ async fn spawn_sleeping(manager: &SessionManager) -> Uuid {
             env: Default::default(),
             metadata: Default::default(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap()

crates/maestro-daemon/tests/attach.rs

@@ -81,6 +81,7 @@ async fn create_bash_session(h: &Harness) -> Uuid {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();

crates/maestro-daemon/tests/autoname.rs

@@ -56,6 +56,7 @@ async fn spawn(manager: &SessionManager, name: Option<&str>) -> Uuid {
             env: Default::default(),
             metadata,
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap()

crates/maestro-daemon/tests/blocked_work_cost.rs

@@ -29,6 +29,7 @@ fn request(cwd: &std::path::Path, repo: &std::path::Path, branch: &str) -> Creat
             branch: branch.into(),
             create_branch: true,
         }),
+        auto_approve: false,
     }
 }
 

crates/maestro-daemon/tests/fixtures/codex-acp-session.jsonl

@@ -0,0 +1,16 @@
+{"sessionId":"codex-session","update":{"sessionUpdate":"user_message_chunk","messageId":"user-1","content":{"type":"text","text":"Inspect the repository"}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"agent_thought_chunk","messageId":"thought-1","content":{"type":"text","text":"I should inspect the files first."}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"command-1","kind":"execute","title":"rg TODO","status":"in_progress","rawInput":{"command":"rg TODO","cwd":"/workspace"}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call_update","toolCallId":"command-1","status":"completed","rawOutput":{"formatted_output":"src/lib.rs: TODO","exit_code":0}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"change-1","kind":"edit","title":"Editing files","status":"completed","content":[{"type":"diff","path":"src/lib.rs","oldText":"old","newText":"new"}]}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"mcp-1","kind":"execute","title":"mcp.github.search","status":"completed","rawInput":{"server":"github","tool":"search","arguments":{"query":"ACP"}},"rawOutput":{"result":"found"},"_meta":{"is_mcp_tool_call":true}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"web-1","kind":"search","title":"Search the web for ACP","status":"completed","rawInput":{"type":"webSearch","query":"Agent Client Protocol"}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"image-view-1","kind":"read","title":"View Image /workspace/diagram.png","status":"completed","content":[{"type":"content","content":{"type":"resource_link","name":"/workspace/diagram.png","uri":"/workspace/diagram.png"}}]}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"tool_call","toolCallId":"image-gen-1","title":"Image generation","status":"completed","content":[{"type":"content","content":{"type":"image","data":"aW1hZ2U=","mimeType":"image/png"}}],"rawOutput":{"path":"/workspace/generated.png"}}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"plan","entries":[{"content":"Implement compatibility fixture","priority":"medium","status":"in_progress"}]}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"usage_update","used":1200,"size":258400}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"current_mode_update","currentModeId":"agent"}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"config_option_update","configOptions":[{"id":"agent-mode","name":"Agent mode","category":"mode","type":"select","currentValue":"agent","options":[{"value":"read-only","name":"Read-only"},{"value":"agent","name":"Agent"}]},{"id":"model","name":"Model","category":"model","type":"select","currentValue":"gpt-5.3-codex","options":[{"value":"gpt-5.3-codex","name":"GPT-5.3-Codex"}]},{"id":"reasoning_effort","name":"Reasoning effort","category":"thought_level","type":"select","currentValue":"high","options":[{"value":"high","name":"High"}]},{"id":"fast-mode","name":"Fast mode","category":"model_config","type":"select","currentValue":"off","options":[{"value":"off","name":"Off"}]}]}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"available_commands_update","availableCommands":[{"name":"status","description":"Show session status"}]}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"session_info_update","title":"Codex session"}}
+{"sessionId":"codex-session","update":{"sessionUpdate":"agent_message_chunk","messageId":"assistant-1","content":{"type":"text","text":"Done."}}}

crates/maestro-daemon/tests/local_api.rs

@@ -11,7 +11,8 @@ use common::DaemonFixture;
 use futures_util::{SinkExt, StreamExt};
 use maestro_daemon::local_api;
 use maestro_protocol::{
-    ApiError, CreateSessionRequest, Session, SessionStatus, SessionView, WorktreeSpec,
+    ActivityState, ApiError, CreateSessionRequest, Session, SessionStatus, SessionView,
+    WorktreeSpec,
 };
 use tempfile::TempDir;
 use tokio::net::TcpListener;
@@ -153,7 +154,8 @@ async fn structured_session(h: &Harness, fake: &FakeAcp) -> Uuid {
 }
 
 async fn structured_session_with_env(h: &Harness, env: HashMap<String, String>) -> Uuid {
-    h.manager
+    let id = h
+        .manager
         .create(CreateSessionRequest {
             view: SessionView::Structured,
             cwd: "/tmp".into(),
@@ -161,10 +163,36 @@ async fn structured_session_with_env(h: &Harness, env: HashMap<String, String>)
             env,
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap()
-        .id
+        .id;
+    wait_for_session_activity(h, id, ActivityState::Idle).await;
+    id
+}
+
+async fn wait_for_session_activity(h: &Harness, id: Uuid, expected: ActivityState) {
+    tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            let sessions: Vec<Session> = reqwest::get(url(h.addr, "/api/sessions"))
+                .await
+                .unwrap()
+                .json()
+                .await
+                .unwrap();
+            if sessions
+                .iter()
+                .find(|session| session.id == id)
+                .is_some_and(|session| session.activity == expected)
+            {
+                return;
+            }
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+    })
+    .await
+    .unwrap_or_else(|_| panic!("session {id} did not reach {expected:?}"));
 }
 
 #[tokio::test]
@@ -210,6 +238,60 @@ async fn structured_ws_sends_snapshot_then_live_projection() {
     );
 }
 
+#[tokio::test]
+async fn structured_attachments_preserve_bytes_and_reject_paths() {
+    let h = spawn("attachments").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+    let client = reqwest::Client::new();
+    let endpoint = url(
+        h.addr,
+        &format!("/api/sessions/{id}/structured/attachments"),
+    );
+    let bytes = vec![0, 255, 10, 13];
+    let response = client
+        .post(&endpoint)
+        .query(&[("name", "sample.bin")])
+        .body(bytes.clone())
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), 200);
+    let body: serde_json::Value = response.json().await.unwrap();
+    let path = body["path"].as_str().unwrap();
+    assert!(Path::new(path).is_absolute());
+    assert_eq!(std::fs::read(path).unwrap(), bytes);
+    for name in ["../escape", "a/b", "a\\b", "..", ""] {
+        let response = client
+            .post(&endpoint)
+            .query(&[("name", name)])
+            .body("text")
+            .send()
+            .await
+            .unwrap();
+        assert_eq!(response.status(), 400, "{name}");
+    }
+    let response = client
+        .post(&endpoint)
+        .query(&[("name", "large.bin")])
+        .body(vec![0; 20 * 1024 * 1024 + 1])
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), 413);
+    let response = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{}/structured/attachments", Uuid::new_v4()),
+        ))
+        .query(&[("name", "file.txt")])
+        .body("text")
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), 404);
+}
+
 #[tokio::test]
 async fn structured_prompt_rejects_a_second_in_flight_turn_and_cancel_clears_it() {
     let h = spawn("naps-laptop").await;
@@ -318,6 +400,7 @@ async fn structured_approval_is_secret_single_use_and_race_safe() {
     })
     .await
     .unwrap();
+    wait_for_session_activity(&h, id, ActivityState::AwaitingInput).await;
     assert!(
         !fake.log().contains(&nonce),
         "daemon nonce leaked to ACP agent"
@@ -373,6 +456,7 @@ async fn structured_approval_is_secret_single_use_and_race_safe() {
     })
     .await
     .expect("resolved approval clears the reduced state");
+    wait_for_session_activity(&h, id, ActivityState::Idle).await;
     assert_eq!(
         client
             .post(url(
@@ -429,6 +513,7 @@ async fn structured_prompt_failure_clears_the_turn() {
     })
     .await
     .expect("failed turn clears promptly");
+    wait_for_session_activity(&h, id, ActivityState::Error).await;
     let second = client
         .post(url(h.addr, &path))
         .json(&serde_json::json!({"prompt":"available"}))
@@ -466,6 +551,7 @@ async fn structured_prompt_rejects_unknown_and_unavailable_sessions() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -599,6 +685,7 @@ async fn structured_replay_rejects_unknown_terminal_and_dead_sessions() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -741,6 +828,7 @@ async fn list_sessions_starts_empty_and_reflects_creates() {
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: None,
+        auto_approve: false,
     };
     let created: Session = reqwest::Client::new()
         .post(url(h.addr, "/api/sessions"))
@@ -915,7 +1003,9 @@ async fn names_honors_count_and_caps_it() {
 #[tokio::test]
 async fn gitroot_probes_path() {
     // #26: resolves the query against the daemon home dir and walks up for a
-    // `.git`. A `/tmp`-rooted temp dir is not in a repo, so the root is null.
+    // `.git`. The tempdir itself has no `.git`, so the result must either be
+    // null (no repo anywhere above) or — in sandboxed environments where /tmp
+    // itself sits inside a repo — a path strictly above the tempdir.
     let h = spawn("naps-laptop").await;
     let tmp = tempfile::tempdir().unwrap();
     let resp: serde_json::Value = reqwest::get(url(
@@ -930,7 +1020,16 @@ async fn gitroot_probes_path() {
     .json()
     .await
     .unwrap();
-    assert!(resp.get("root").is_none() || resp["root"].is_null());
+    // On hosts where an ancestor of the temp dir is a repo (e.g. `/tmp`
+    // inside a checkout), the root legitimately points there. The test only
+    // asserts no root was found *inside* the temp dir.
+    match resp.get("root").and_then(|v| v.as_str()) {
+        None => {}
+        Some(root) => assert!(
+            !root.starts_with(tmp.path().to_string_lossy().as_ref()),
+            "found a repo root inside the fixture at {root:?}"
+        ),
+    }
 }
 
 #[tokio::test]
@@ -958,6 +1057,7 @@ async fn patch_session_renames_it() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1001,6 +1101,7 @@ async fn post_focus_stamps_last_focused_at() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1035,6 +1136,7 @@ async fn delete_owned_session_kills_it() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1057,6 +1159,7 @@ async fn spawn_via_manager(h: &Harness) -> Uuid {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap()
@@ -1171,6 +1274,7 @@ async fn delete_a_session_whose_worktree_holds_unsaved_work_returns_409_with_the
                 branch: "feat/guarded".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1224,6 +1328,7 @@ async fn delete_with_force_ends_the_session_and_keeps_the_worktree() {
                 branch: "feat/guarded".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1254,6 +1359,7 @@ async fn attach_ws_streams_pty_bytes() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -1284,6 +1390,39 @@ async fn attach_ws_streams_pty_bytes() {
     assert!(saw_hello, "PTY did not echo through the attach WS");
 }
 
+#[tokio::test]
+async fn pty_routes_reject_structured_sessions_as_not_terminal() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+
+    let response = reqwest::Client::new()
+        .post(url(h.addr, &format!("/api/sessions/{id}/input")))
+        .json(&maestro_protocol::SendInputRequest {
+            text: "ignored".into(),
+            submit: false,
+        })
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), reqwest::StatusCode::CONFLICT);
+    let error: ApiError = response.json().await.unwrap();
+    assert_eq!(error.error.code, "not_terminal");
+    assert_eq!(error.error.message, "session is not a terminal session");
+
+    let error = connect_async(ws_url(h.addr, &format!("/api/attach/{id}")))
+        .await
+        .expect_err("structured session must not upgrade to a PTY socket");
+    let tokio_tungstenite::tungstenite::Error::Http(response) = error else {
+        panic!("expected an HTTP handshake rejection, got {error}");
+    };
+    assert_eq!(response.status(), reqwest::StatusCode::CONFLICT);
+    let body = response.body().as_deref().expect("ApiError response body");
+    let error: ApiError = serde_json::from_slice(body).unwrap();
+    assert_eq!(error.error.code, "not_terminal");
+    assert_eq!(error.error.message, "session is not a terminal session");
+}
+
 #[tokio::test]
 async fn attach_ws_for_unknown_session_returns_404() {
     let h = spawn("naps-laptop").await;
@@ -1323,6 +1462,7 @@ async fn events_ws_sends_a_snapshot_then_streams_deltas() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1350,6 +1490,79 @@ async fn events_ws_sends_a_snapshot_then_streams_deltas() {
     }
 }
 
+#[tokio::test]
+async fn events_ws_streams_structured_activity_without_hook_overrides() {
+    let h = spawn("konishi").await;
+    let fake = FakeAcp::new();
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_DELAY_PROMPT_MS".into(), "500".into());
+    let (mut ws, _) = connect_async(ws_url(h.addr, "/api/events"))
+        .await
+        .expect("events ws");
+    assert!(matches!(
+        next_event(&mut ws).await,
+        maestro_protocol::CatalogEvent::Snapshot { .. }
+    ));
+
+    let id = structured_session_with_env(&h, env).await;
+    let maestro_protocol::CatalogEvent::SessionAdded { session } = next_event(&mut ws).await else {
+        panic!("expected structured SessionAdded")
+    };
+    assert_eq!(session.activity, ActivityState::Starting);
+    // The background handshake completes and sends SessionUpdated → Idle.
+    let maestro_protocol::CatalogEvent::SessionUpdated { session } = next_event(&mut ws).await
+    else {
+        panic!("expected SessionUpdated after handshake")
+    };
+    assert_eq!(session.activity, ActivityState::Idle);
+
+    let client = reqwest::Client::new();
+    let prompt = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/prompt"),
+        ))
+        .json(&serde_json::json!({"prompt": "hello"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(prompt.status(), reqwest::StatusCode::NO_CONTENT);
+    let report = client
+        .post(url(h.addr, &format!("/api/sessions/{id}/activity")))
+        .json(&serde_json::json!({"state": "Error"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(report.status(), reqwest::StatusCode::NO_CONTENT);
+    wait_for_session_activity(&h, id, ActivityState::Active).await;
+
+    let mut activities = Vec::new();
+    tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            if let maestro_protocol::CatalogEvent::SessionUpdated { session } =
+                next_event(&mut ws).await
+            {
+                activities.push(session.activity);
+                if session.activity == ActivityState::Idle {
+                    return;
+                }
+            }
+        }
+    })
+    .await
+    .expect("structured turn returns to idle");
+    assert!(
+        activities.contains(&ActivityState::Active),
+        "{activities:?}"
+    );
+    assert!(
+        !activities.contains(&ActivityState::Error),
+        "{activities:?}"
+    );
+
+    h.manager.kill(id, false).await.unwrap();
+}
+
 /// Each subscriber has its own lag domain now that the publisher task is gone:
 /// two clients connected at different times both get their own Snapshot.
 #[tokio::test]
@@ -1368,6 +1581,7 @@ async fn every_events_subscriber_gets_its_own_snapshot() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");

crates/maestro-daemon/tests/rename.rs

@@ -57,6 +57,7 @@ async fn spawn_named(manager: &SessionManager, name: Option<&str>) -> Uuid {
             env: Default::default(),
             metadata,
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap()

crates/maestro-daemon/tests/session_decisions.rs

@@ -70,6 +70,7 @@ impl Fx {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         }
     }
 }

crates/maestro-daemon/tests/session_manager.rs

@@ -28,6 +28,7 @@ async fn create_then_kill_round_trip() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -70,6 +71,7 @@ async fn create_appends_to_spawn_history() {
             env: HashMap::new(),
             metadata: HashMap::from([("name".into(), serde_json::json!("neon-drifter"))]),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -100,6 +102,7 @@ async fn create_without_history_logs_nothing() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -123,6 +126,7 @@ async fn recover_adopts_existing_tmux_sessions() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -166,6 +170,7 @@ async fn create_captures_initial_output_in_replay_buffer() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -215,6 +220,7 @@ async fn attach_replay_is_the_current_screen_not_the_byte_tail() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -273,6 +279,7 @@ async fn attach_replay_carries_the_panes_mouse_modes() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -324,6 +331,7 @@ async fn recover_re_pipes_pane_so_output_reaches_subscribers() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -387,6 +395,7 @@ async fn pty_broadcast_delivers_bytes_to_subscribers() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .unwrap();
@@ -438,6 +447,7 @@ async fn liveness_watcher_marks_dead_sessions_and_keeps_them_until_dismissed() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -508,6 +518,7 @@ async fn watcher_refreshes_the_blocked_work_indicator() {
                 branch: "feat/indicator".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -601,6 +612,7 @@ async fn kill_removes_worktree_even_when_spec_says_keep() {
                 branch: "feat/keep".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -639,6 +651,7 @@ async fn killing_refuses_a_worktree_with_unsaved_work_and_keeps_the_session() {
                 branch: "feat/guarded".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -703,6 +716,7 @@ async fn killing_refuses_until_the_branch_is_pushed() {
                 branch: "feat/pushed".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -753,6 +767,7 @@ async fn force_killing_a_guarded_worktree_leaves_it_on_disk() {
                 branch: "feat/forced".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -799,6 +814,7 @@ async fn force_on_a_clear_worktree_removes_it_as_usual() {
                 branch: "feat/clear".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -840,6 +856,7 @@ async fn killing_an_ignored_only_worktree_succeeds() {
                 branch: "feat/rusty".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -882,6 +899,7 @@ async fn natural_exit_of_a_guarded_worktree_leaves_it_on_disk() {
                 branch: "feat/exited".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -944,6 +962,7 @@ async fn natural_exit_of_a_pristine_worktree_removes_it() {
                 branch: "feat/clean".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1001,6 +1020,7 @@ async fn liveness_watcher_leaves_running_sessions_alone() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1040,6 +1060,7 @@ async fn worktree_base_repo_records_the_main_checkout_not_the_request() {
                 branch: "feat/one".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create first");
@@ -1058,6 +1079,7 @@ async fn worktree_base_repo_records_the_main_checkout_not_the_request() {
                 branch: "feat/two".into(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
         .await
         .expect("create second");
@@ -1093,6 +1115,7 @@ async fn spawned_sessions_export_maestro_session_id_and_url() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1132,6 +1155,7 @@ async fn a_freshly_created_session_has_never_been_focused() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1158,6 +1182,7 @@ async fn set_focused_true_stamps_last_focused_at() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");
@@ -1207,6 +1232,7 @@ async fn attaching_stamps_last_focused_at() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("create");

crates/maestro-daemon/tests/worktree.rs

@@ -405,15 +405,17 @@ fn run_git(dir: &std::path::Path, args: &[&str]) {
     );
 }
 
-/// 49ab7e9: a new-branch add onto a name that already exists suffixes the
-/// branch (and so the directory) instead of failing, per docs/WORKTREES.md.
+/// `git worktree add -b` alone fails outright when the branch already exists,
+/// even with the target directory free — a random handle commonly collides
+/// with one an earlier, already-removed worktree left behind. `add_new`
+/// sidesteps it on the branch name itself instead of erroring (#77).
 #[test]
-fn add_new_suffixes_when_branch_already_exists() {
+fn add_new_suffixes_branch_name_on_branch_collision() {
     let repo_dir = TempDir::new().unwrap();
     let repo = repo_dir.path().to_path_buf();
     init_repo(&repo);
 
-    // pre-create the branch
+    // pre-create the branch, unused by any worktree.
     let status = Command::new("git")
         .arg("-C")
         .arg(&repo)
@@ -425,9 +427,17 @@ fn add_new_suffixes_when_branch_already_exists() {
     let wt_root = TempDir::new().unwrap();
     let mgr = WorktreeManager::new(Some(wt_root.path().to_path_buf()));
 
-    let path = mgr.add_new(&repo, "feat/dup").unwrap();
+    let path = mgr
+        .add_new(&repo, "feat/dup")
+        .expect("sidesteps the branch collision");
     assert!(path.ends_with("feat/dup-2"), "{}", path.display());
-    assert!(path.is_dir());
+    assert!(path.exists());
+
+    // The pre-existing branch is untouched; the new worktree checked out the
+    // suffixed one instead of erroring or adopting `feat/dup`.
+    let branches = worktree_branches(&repo);
+    assert!(branches.contains(&"feat/dup-2".to_string()), "{branches:?}");
+    assert!(!branches.contains(&"feat/dup".to_string()), "{branches:?}");
 }
 
 /// The project picker lists linked worktrees as pickable rows, so `base_repo`

crates/maestro-e2e/tests/e2e.rs

@@ -33,6 +33,7 @@ fn create_req(cwd: &std::path::Path, command: &str) -> CreateSessionRequest {
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: None,
+        auto_approve: false,
     }
 }
 
@@ -111,6 +112,7 @@ fn worktree_req(base: &std::path::Path, branch: &str, create_branch: bool) -> Cr
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: Some(worktree_spec(base, branch, create_branch)),
+        auto_approve: false,
     }
 }
 
@@ -206,6 +208,7 @@ async fn kill_removes_clean_worktree() {
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: Some(worktree_spec(base.path(), "feature/e2e", true)),
+        auto_approve: false,
     };
 
     let s = client.spawn_session(&req).await.expect("spawn worktree");
@@ -260,6 +263,7 @@ async fn kill_refuses_worktree_with_uncommitted_changes() {
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: Some(worktree_spec(base.path(), "feature/unsaved", true)),
+        auto_approve: false,
     };
 
     let s = client.spawn_session(&req).await.expect("spawn worktree");
@@ -319,6 +323,7 @@ async fn spawn_on_existing_branch_checks_it_out() {
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: Some(worktree_spec(base.path(), "feature/existing", false)),
+        auto_approve: false,
     };
 
     let s = client
@@ -383,13 +388,11 @@ async fn spawn_new_branch_creates_worktree_and_runs_in_it() {
     client.kill_session(s.id).await.expect("kill");
 }
 
-/// #66: a second spawn onto an *existing* branch that already has a worktree
-/// is rejected with a structured worktree error; the first worktree stays
-/// intact. (A second `create_branch: true` spawn is a different case: 49ab7e9
-/// suffixes the new branch name instead, see
-/// `colliding_branch_name_gets_suffixed_too`.)
+/// #66/#77: a second spawn onto the same branch used to be rejected outright;
+/// since the branch-collision suffixing landed, it succeeds instead — the
+/// second worktree lands on `<branch>-2` and the first stays untouched.
 #[tokio::test(flavor = "multi_thread")]
-async fn second_spawn_on_same_branch_is_rejected() {
+async fn second_spawn_on_same_branch_gets_suffixed() {
     let (_daemon, client) = bring_up().await;
 
     let base = TempDir::new().unwrap();
@@ -399,28 +402,33 @@ async fn second_spawn_on_same_branch_is_rejected() {
         .spawn_session(&worktree_req(base.path(), "feature/dup", true))
         .await
         .expect("first spawn");
-    let dup = client
-        .spawn_session(&worktree_req(base.path(), "feature/dup", false))
-        .await;
-    match dup {
-        Err(maestro_e2e::ClientError::Api(maestro_protocol::ClientError::Api { info, .. })) => {
-            assert_eq!(
-                info.code, "worktree_failed",
-                "expected worktree error: {info:?}"
-            );
-        }
-        other => panic!("expected rejection for duplicate branch, got {other:?}"),
-    }
+    let second = client
+        .spawn_session(&worktree_req(base.path(), "feature/dup", true))
+        .await
+        .expect("second spawn suffixes instead of rejecting");
 
-    // Exactly one registration, one directory, still usable.
-    // Count branch records only: the worktree path now contains the branch
-    // name too (`worktrees/feature/dup`), so a substring match over every line
-    // would count the same tree twice.
-    let holders = git_worktree_list(base.path())
-        .iter()
-        .filter(|w| w.as_str() == "branch refs/heads/feature/dup")
-        .count();
-    assert_eq!(holders, 1, "duplicate spawn must not register another tree");
+    let suffixed = base.path().join("worktrees").join("feature").join("dup-2");
+    assert_eq!(
+        second.cwd, suffixed,
+        "second worktree must land on the suffixed path"
+    );
+    assert!(suffixed.is_dir());
+
+    // Both registrations exist: the original branch, untouched, and the
+    // suffixed one the second spawn created.
+    let registrations = git_worktree_list(base.path());
+    assert!(
+        registrations
+            .iter()
+            .any(|l| l.as_str() == "branch refs/heads/feature/dup"),
+        "original branch must stay registered: {registrations:?}"
+    );
+    assert!(
+        registrations
+            .iter()
+            .any(|l| l.as_str() == "branch refs/heads/feature/dup-2"),
+        "suffixed branch must be registered too: {registrations:?}"
+    );
     assert!(
         base.path()
             .join("worktrees")
@@ -431,7 +439,8 @@ async fn second_spawn_on_same_branch_is_rejected() {
     );
 
     let _origin = throwaway_origin(base.path());
-    client.kill_session(first.id).await.expect("kill");
+    client.kill_session(first.id).await.expect("kill first");
+    client.kill_session(second.id).await.expect("kill second");
 }
 
 /// #66/#56: when the client picks a *linked worktree* as base_repo, placement
@@ -823,6 +832,7 @@ async fn natural_exit_settles_dirty_and_pristine_worktrees_differently() {
             env: HashMap::new(),
             metadata: HashMap::new(),
             worktree: Some(worktree_spec(dirty_repo.path(), "feature/messy", true)),
+            auto_approve: false,
         })
         .await
         .expect("spawn dirty");
@@ -872,6 +882,7 @@ fn create_req_cmd(cwd: &std::path::Path, command: &str, branch: &str) -> CreateS
         env: HashMap::new(),
         metadata: HashMap::new(),
         worktree: Some(worktree_spec(cwd, branch, true)),
+        auto_approve: false,
     }
 }
 
@@ -1064,6 +1075,7 @@ async fn sigterm_stops_structured_child_before_events_ws_drains() {
             env: fake.env.clone(),
             metadata: HashMap::new(),
             worktree: None,
+            auto_approve: false,
         })
         .await
         .expect("spawn structured session");

crates/maestro-protocol/src/client.rs

@@ -17,7 +17,7 @@ use crate::routes::{self, UrlError};
 use crate::{
     ApiError, BranchInfo, CreateSessionRequest, DaemonInfo, DirListing, ErrorInfo, GitRoot,
     Project, RecentDirs, RenameSessionRequest, ReportActivityRequest, SendInputRequest, Session,
-    SetFocusRequest,
+    SetFocusRequest, StructuredApprovalDecision, StructuredPromptRequest,
 };
 
 /// Time budget for establishing a TCP connection to the daemon.
@@ -105,6 +105,11 @@ impl DaemonClient {
         Ok(routes::attach_url(&self.base, id)?)
     }
 
+    /// `WS /api/structured/:id` URL for this daemon.
+    pub fn structured_url(&self, id: Uuid) -> Result<String, ClientError> {
+        Ok(routes::structured_url(&self.base, id)?)
+    }
+
     // -- typed calls --------------------------------------------------------
 
     pub async fn list_sessions(&self) -> Result<Vec<Session>, ClientError> {
@@ -179,6 +184,57 @@ impl DaemonClient {
         Ok(())
     }
 
+    /// Send one prompt to a structured session. The daemon rejects a second
+    /// prompt while the preceding ACP turn is still active.
+    pub async fn send_structured_prompt(&self, id: Uuid, prompt: &str) -> Result<(), ClientError> {
+        let req = StructuredPromptRequest {
+            prompt: prompt.to_string(),
+        };
+        let resp = self
+            .send(
+                Method::POST,
+                &routes::structured_prompt(id),
+                &[],
+                Some(&req),
+            )
+            .await?;
+        check(resp).await?;
+        Ok(())
+    }
+
+    /// Cancel the structured session's active ACP turn.
+    pub async fn cancel_structured_turn(&self, id: Uuid) -> Result<(), ClientError> {
+        let resp = self
+            .send(
+                Method::POST,
+                &routes::structured_cancel(id),
+                &[],
+                None::<&()>,
+            )
+            .await?;
+        check(resp).await?;
+        Ok(())
+    }
+
+    /// Resolve the currently pending structured-session permission request.
+    pub async fn resolve_structured_approval(
+        &self,
+        id: Uuid,
+        nonce: &str,
+        decision: StructuredApprovalDecision,
+    ) -> Result<(), ClientError> {
+        let resp = self
+            .send(
+                Method::POST,
+                &routes::structured_approval(id, nonce),
+                &[],
+                Some(&decision),
+            )
+            .await?;
+        check(resp).await?;
+        Ok(())
+    }
+
     pub async fn daemon_info(&self) -> Result<DaemonInfo, ClientError> {
         self.get(routes::INFO, &[]).await
     }

crates/maestro-protocol/src/display.rs

@@ -166,45 +166,32 @@ pub fn merge_linear<T>(folder: TreeFolder<T>) -> TreeFolder<T> {
     cur
 }
 
-/// Command wrappers that run another program: the program is what follows.
-const WRAPPERS: [&str; 8] = [
-    "sudo", "env", "npx", "bunx", "uvx", "pnpm", "yarn", "command",
-];
-
 /// The program a command line runs, basenamed and stripped of its arguments —
 /// what a session card shows per `docs/SIDEBAR.md`, which names the program
 /// and never its flags. Leading `FOO=bar` assignments and wrappers (`sudo`,
-/// `npx`, `pnpm dlx`, …) are looked through. Mirrors the web's `splitCommand`.
+/// `npx`, `pnpm dlx`, …) are looked through, and quoting/escaping is honoured
+/// (never evaluated — no `$var`/`` `cmd` ``/`$(cmd)` expansion). A command a
+/// shell would need real grammar for (pipelines, `&&`/`;`, redirections,
+/// substitution, an unterminated quote) falls back to the naive first word
+/// rather than guessing through it (#199). Mirrors the web's `splitCommand`.
 pub fn command_program(command: &str) -> String {
-    let words: Vec<&str> = command.split_whitespace().collect();
-    let mut i = 0;
-    while i < words.len() {
-        let word = words[i];
-        if is_env_assignment(word) {
-            i += 1;
-            continue;
-        }
-        let wrapper = basename(word).to_lowercase();
-        if WRAPPERS.contains(&wrapper.as_str()) {
-            i += 1;
-            if (wrapper == "pnpm" || wrapper == "yarn") && words.get(i) == Some(&"dlx") {
-                i += 1;
-            }
-            continue;
-        }
-        break;
-    }
-    match words.get(i) {
-        Some(word) => basename(word).to_string(),
-        // Nothing but wrappers and assignments: say what was there rather than
-        // rendering an empty fragment.
-        None => command.trim().to_string(),
+    match resolve(command) {
+        Some(r) => match r.words.get(r.program_index) {
+            Some(word) => basename(word).to_string(),
+            // Nothing but wrappers and assignments: say what was there
+            // rather than rendering an empty fragment.
+            None => command.trim().to_string(),
+        },
+        None => legacy_first_word(command),
     }
 }
 
 /// Program name (already basenamed and lowercased) -> the tool id its mark
 /// stands for. Mirrors the web's `BY_PROGRAM` in `web/src/toolIcon.ts`;
 /// recognition is deliberately narrow, so an unrecognised program has no tool.
+/// `claude-code-acp` — the daemon's actual structured-session child — is
+/// deliberately absent: the daemon launches it directly and ignores
+/// `req.command`, so it is never itself a valid user-facing launch form.
 const BY_PROGRAM: [(&str, &str); 17] = [
     ("claude", "claude"),
     ("claude-code", "claude"),
@@ -226,29 +213,500 @@ const BY_PROGRAM: [(&str, &str); 17] = [
 ];
 
 /// The tool id a command line's icon stands for (`claude`, `codex`,
-/// `opencode`, ...), or `None` when the program is not one we have a mark for.
-/// The command bar matches this field (`docs/COMMAND-BAR.md`), so it must name
-/// the same tools the web's `splitCommand().tool` does.
+/// `opencode`, ...), or `None` when the program is not one we have a mark for
+/// — including a command line [`resolve`] would only guess at. The command
+/// bar matches this field (`docs/COMMAND-BAR.md`), so it must name the same
+/// tools the web's `splitCommand().tool` does.
 pub fn command_tool(command: &str) -> Option<&'static str> {
-    let program = command_program(command).to_lowercase();
+    let r = resolve(command)?;
+    let program = basename(r.words.get(r.program_index)?).to_lowercase();
     BY_PROGRAM
         .iter()
         .find(|(name, _)| *name == program)
         .map(|(_, tool)| *tool)
 }
 
-/// `FOO=bar`, the shell's own prefix for one command's environment.
-fn is_env_assignment(word: &str) -> bool {
-    let mut chars = word.chars();
+/// Whether a command line resolves to an agent Maestro can run as a
+/// structured (ACP) session — Claude Code or Codex, the two adapters
+/// `docs/STRUCTURED-VIEW.md` lists. Every client gates its structured-view
+/// control on this, and the daemon rejects a `Structured` request for
+/// anything else, so the answer has to come from one place.
+pub fn supports_structured_view(command: &str) -> bool {
+    matches!(command_tool(command), Some("claude" | "codex"))
+}
+
+/// [`resolve`]'s outcome: the tokenized command line, and the index within it
+/// of the word that is the actual program (past every assignment/wrapper it
+/// resolved through).
+struct Resolution {
+    words: Vec<String>,
+    program_index: usize,
+}
+
+/// Tokenize `command` and walk past leading `FOO=bar` assignments and known
+/// wrapper forms (interleaved in any order/count) to find the program. An
+/// assignment run is only consumed at the very start of the line or right
+/// after a wrapper whose own semantics accept one there ([`Wrapper::accepts_assignment`]) —
+/// `command FOO=1 claude` and `nohup FOO=1 claude` stop at `FOO=1` rather than
+/// skipping to `claude`, since `command`/`nohup` just exec their next argument
+/// as the program, they don't setenv from an assignment-shaped one (#199).
+/// `None` when [`tokenize`] can't safely make sense of the line at all.
+fn resolve(command: &str) -> Option<Resolution> {
+    let words = tokenize(command)?;
+    let refs: Vec<&str> = words.iter().map(|w| w.text.as_str()).collect();
+    let mut i = 0;
+    let mut assignment_allowed = true;
+    loop {
+        if assignment_allowed {
+            while matches!(words.get(i), Some(word) if is_env_assignment(word)) {
+                i += 1;
+            }
+        }
+        let Some(word) = words.get(i) else { break };
+        let wrapper = basename(&word.text).to_lowercase();
+        let Some(w) = wrapper_resolver(&wrapper) else {
+            break;
+        };
+        match (w.resolve)(&refs, i) {
+            Some(next) if next > i => {
+                i = next;
+                assignment_allowed = w.accepts_assignment;
+            }
+            // Not a form of the wrapper we recognise (an unknown option, or
+            // — for `pnpm`/`yarn`/`bun` — no `dlx`/`x` subcommand behind it):
+            // the wrapper word itself is the program, not a launcher.
+            _ => break,
+        }
+    }
+    Some(Resolution {
+        words: words.into_iter().map(|w| w.text).collect(),
+        program_index: i,
+    })
+}
+
+/// The naive "first whitespace word, basenamed" reading used only when
+/// [`tokenize`] rejects the line outright — still something sane to show,
+/// never a wrapper/tool match to act on.
+fn legacy_first_word(command: &str) -> String {
+    match command.split_whitespace().next() {
+        Some(word) => basename(word).to_string(),
+        None => command.trim().to_string(),
+    }
+}
+
+/// One token from [`tokenize`]: its dequoted text, and — when both the name
+/// and `=` were entirely unquoted/unescaped in the source — the byte length
+/// of the name. Quoting or escaping either (`"FOO"=1`, `F\OO=1`, `FOO\=1`)
+/// makes the word an executable named `FOO=1`; quoting/escaping only the value
+/// preserves the assignment, matching Bash's assignment-word grammar (#199).
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct Word {
+    text: String,
+    plain_eq: Option<usize>,
+}
+
+/// Word-split `command` the way a shell would (honouring `'…'`, `"…"` and
+/// `\` quoting/escaping — POSIX quote *removal*, not evaluation) and return
+/// `None` the moment it needs real shell grammar this resolver doesn't
+/// attempt: a pipeline/list operator (`|`, `&`, `;`, `<`, `>`), a subshell or
+/// substitution (`(`, `)`, `` ` ``, `$(`), an unescaped newline (a command
+/// separator, like `;` — #199), or an unterminated quote/escape. Never
+/// expands `$var`/`` `cmd` ``/`$(cmd)` — a bare `$` is kept literal. A
+/// backslash immediately before a newline, quoted or not, is a line
+/// continuation: removed entirely rather than embedding the newline or
+/// ending the word (#199).
+fn tokenize(command: &str) -> Option<Vec<Word>> {
+    let mut words = Vec::new();
+    let mut current = String::new();
+    let mut has_current = false;
+    let mut plain_eq: Option<usize> = None;
+    let mut assignment_name_is_plain = true;
+    let mut chars = command.chars().peekable();
+
+    while let Some(c) = chars.next() {
+        match c {
+            ' ' | '\t' | '\r' => {
+                if has_current {
+                    words.push(Word {
+                        text: std::mem::take(&mut current),
+                        plain_eq: plain_eq.take(),
+                    });
+                    has_current = false;
+                    assignment_name_is_plain = true;
+                }
+            }
+            '\n' => return None,
+            '|' | '&' | ';' | '<' | '>' | '(' | ')' | '`' => return None,
+            '$' if chars.peek() == Some(&'(') => return None,
+            '\'' => {
+                has_current = true;
+                if plain_eq.is_none() {
+                    assignment_name_is_plain = false;
+                }
+                loop {
+                    match chars.next() {
+                        Some('\'') => break,
+                        Some(c2) => current.push(c2),
+                        None => return None, // unterminated single quote
+                    }
+                }
+            }
+            '"' => {
+                has_current = true;
+                if plain_eq.is_none() {
+                    assignment_name_is_plain = false;
+                }
+                loop {
+                    match chars.next() {
+                        Some('"') => break,
+                        Some('\\') => match chars.next() {
+                            Some(c2 @ ('"' | '\\' | '$' | '`')) => current.push(c2),
+                            Some('\n') => {} // line continuation, removed entirely
+                            Some(c2) => {
+                                current.push('\\');
+                                current.push(c2);
+                            }
+                            None => return None, // trailing backslash
+                        },
+                        Some(c2) => current.push(c2),
+                        None => return None, // unterminated double quote
+                    }
+                }
+            }
+            '\\' => match chars.next() {
+                Some('\n') => {} // line continuation, removed entirely
+                Some(c2) => {
+                    has_current = true;
+                    if plain_eq.is_none() {
+                        assignment_name_is_plain = false;
+                    }
+                    current.push(c2);
+                }
+                None => return None, // trailing backslash
+            },
+            other => {
+                has_current = true;
+                if other == '=' && plain_eq.is_none() && assignment_name_is_plain {
+                    plain_eq = Some(current.len());
+                }
+                current.push(other);
+            }
+        }
+    }
+    if has_current {
+        words.push(Word {
+            text: current,
+            plain_eq,
+        });
+    }
+    Some(words)
+}
+
+/// A wrapper's known `-`/`--` options: which take no value, and which
+/// consume either a following word or a `--flag=value` as theirs. A
+/// `-`-prefixed word this table doesn't know halts resolution rather than
+/// guessing past it (#199) — callers read that as [`OptionTable::consume`]
+/// returning `None`.
+struct OptionTable {
+    flags: &'static [&'static str],
+    valued: &'static [&'static str],
+    /// Whether this wrapper's short options may be combined (`-iv`) or take
+    /// an attached value (`-uroot`), the way real getopt-based tools do
+    /// (#199). JS-toolchain wrappers (`npx`, `pnpm`, `yarn`, bun's `x`/
+    /// `dlx`) don't get this — guessing at bundling they don't actually
+    /// support would resolve through options they'd reject outright.
+    bundles_short_options: bool,
+}
+
+impl OptionTable {
+    /// Consume this table's options starting at `words[i]`, returning the
+    /// index just past them (which may equal `i` if there are none) — or
+    /// `None` on an option this table doesn't recognise, or a valued option
+    /// missing its operand.
+    fn consume(&self, words: &[&str], mut i: usize) -> Option<usize> {
+        loop {
+            let Some(&word) = words.get(i) else {
+                return Some(i);
+            };
+            if word == "--" {
+                return Some(i + 1);
+            }
+            if word == "-" || !word.starts_with('-') {
+                return Some(i);
+            }
+            if let Some((flag, value)) = word.split_once('=') {
+                return if self.valued.contains(&flag) && !value.is_empty() {
+                    i += 1;
+                    continue;
+                } else {
+                    None
+                };
+            }
+            if self.flags.contains(&word) {
+                i += 1;
+                continue;
+            }
+            if self.valued.contains(&word) {
+                let value = words.get(i + 1)?;
+                if value.is_empty() || value.starts_with('-') {
+                    return None;
+                }
+                i += 2;
+                continue;
+            }
+            if self.bundles_short_options
+                && !word.starts_with("--")
+                && word.len() > 2
+                && self.matches_short_cluster(word)
+            {
+                i += 1;
+                continue;
+            }
+            return None;
+        }
+    }
+
+    /// `-iv` (bundled boolean short flags) or `-uroot` (a valued short
+    /// option with its value attached) — getopt's traditional short-option
+    /// forms. `false` the moment a character isn't a short option this
+    /// table knows, or a valued one ends the word with no attached value
+    /// left to be its operand (#199: rejected rather than guessed to come
+    /// from the next word instead).
+    fn matches_short_cluster(&self, word: &str) -> bool {
+        if !word.is_ascii() {
+            return false;
+        }
+        let bytes = word.as_bytes();
+        let mut buf = [b'-', 0];
+        let mut idx = 1;
+        while idx < bytes.len() {
+            buf[1] = bytes[idx];
+            let short = std::str::from_utf8(&buf).expect("ascii buffer");
+            if self.flags.contains(&short) {
+                idx += 1;
+                continue;
+            }
+            if self.valued.contains(&short) {
+                return idx + 1 < bytes.len();
+            }
+            return false;
+        }
+        true
+    }
+}
+
+const NO_OPTIONS: OptionTable = OptionTable {
+    flags: &[],
+    valued: &[],
+    bundles_short_options: false,
+};
+
+const ENV_OPTS: OptionTable = OptionTable {
+    flags: &[
+        "-i",
+        "--ignore-environment",
+        "-0",
+        "--null",
+        "-v",
+        "--debug",
+    ],
+    valued: &["-u", "--unset", "-C", "--chdir"],
+    bundles_short_options: true,
+};
+
+const SUDO_OPTS: OptionTable = OptionTable {
+    flags: &[
+        "-i",
+        "--login",
+        "-n",
+        "--non-interactive",
+        "-E",
+        "--preserve-env",
+        "-H",
+        "--set-home",
+        "-A",
+        "--askpass",
+        "-b",
+        "--background",
+        "-k",
+        "--reset-timestamp",
+        "-K",
+        "--remove-timestamp",
+        "-S",
+        "--stdin",
+    ],
+    valued: &["-u", "--user", "-g", "--group"],
+    bundles_short_options: true,
+};
+
+/// `-v`/`-V` only print what would run — they never execute it — so
+/// resolving through them would claim a program runs that `command` never
+/// launches (#199). Only `-p`, which still executes normally, is safe to
+/// look through.
+const COMMAND_BUILTIN_OPTS: OptionTable = OptionTable {
+    flags: &["-p"],
+    valued: &[],
+    bundles_short_options: true,
+};
+
+/// The bash *keyword* `time` only ever parses `-p` (POSIX output format);
+/// `-o`/`-v`/`-a`/`-f`/`--verbose`/... belong to the external GNU
+/// `/usr/bin/time`, a different program a bare `time` word doesn't
+/// necessarily name. Assuming them here would be guessing which `time`
+/// resolves (#199).
+fn resolve_time(words: &[&str], i: usize) -> Option<usize> {
+    let mut next = i + 1;
+    if words.get(next) == Some(&"-p") {
+        next += 1;
+    }
+    if words.get(next) == Some(&"--") {
+        next += 1;
+    }
+    match words.get(next) {
+        Some(word) if word.starts_with('-') => None,
+        _ => Some(next),
+    }
+}
+
+/// `-c`/`--call` embeds a whole shell command string rather than naming the
+/// program positionally — resolving past it would mean guessing at a
+/// program buried inside that string, so it's left unrecognised and
+/// resolution stops at `npx` (#199).
+const NPX_OPTS: OptionTable = OptionTable {
+    flags: &["-y", "--yes", "--no", "-q", "--quiet", "--ignore-existing"],
+    valued: &["-p", "--package", "--shell"],
+    bundles_short_options: false,
+};
+
+const PNPM_OPTS: OptionTable = OptionTable {
+    flags: &[
+        "--silent",
+        "-s",
+        "--stream",
+        "--aggregate-output",
+        "--no-progress",
+    ],
+    // `--package`/`--package=value` is documented in this pre-`dlx`
+    // position (`pnpm --package=x dlx y`), alongside the identical flag
+    // `dlx` itself also accepts (`PNPM_DLX_OPTS`).
+    valued: &["-C", "--dir", "--filter", "--package"],
+    bundles_short_options: false,
+};
+
+const YARN_OPTS: OptionTable = OptionTable {
+    flags: &["--silent", "-s", "--no-progress", "--non-interactive"],
+    valued: &["--cwd"],
+    bundles_short_options: false,
+};
+
+const PNPM_DLX_OPTS: OptionTable = OptionTable {
+    flags: &["-s", "--silent"],
+    valued: &["--package"],
+    bundles_short_options: false,
+};
+
+const YARN_DLX_OPTS: OptionTable = OptionTable {
+    flags: &["-q", "--quiet"],
+    valued: &["-p", "--package"],
+    bundles_short_options: false,
+};
+
+const BUN_X_OPTS: OptionTable = OptionTable {
+    flags: &["--bun", "--no-install", "--verbose", "--silent"],
+    valued: &["-p", "--package"],
+    bundles_short_options: false,
+};
+
+/// A resolver for one wrapper form: given the tokenized command and the
+/// index of the wrapper word itself, the index of the word after it (past
+/// its options and any subcommand it requires), or `None` if this occurrence
+/// isn't a form we resolve through.
+type WrapperResolver = fn(&[&str], usize) -> Option<usize>;
+
+/// One recognised wrapper form: how to walk past it, and whether an
+/// assignment word is a valid follow-on once it's been walked past.
+struct Wrapper {
+    resolve: WrapperResolver,
+    /// `true` only for wrappers that themselves interpret a following
+    /// `FOO=bar` as an environment assignment for the command they launch
+    /// (`env`, `sudo`), or a shell keyword that restarts the assignment-prefix
+    /// grammar for a brand new simple command (`time`). Every other wrapper
+    /// here is a plain executable that execs its next argument as the
+    /// program outright — an assignment-shaped one names a program literally
+    /// called `FOO=1`, not an env var (#199).
+    accepts_assignment: bool,
+}
+
+fn wrapper_resolver(name: &str) -> Option<Wrapper> {
+    let (resolve, accepts_assignment): (WrapperResolver, bool) = match name {
+        "env" => (|words, i| ENV_OPTS.consume(words, i + 1), true),
+        "sudo" => (|words, i| SUDO_OPTS.consume(words, i + 1), true),
+        "command" => (|words, i| COMMAND_BUILTIN_OPTS.consume(words, i + 1), false),
+        "nohup" => (|words, i| NO_OPTIONS.consume(words, i + 1), false),
+        "time" => (resolve_time, true),
+        "npx" => (|words, i| NPX_OPTS.consume(words, i + 1), false),
+        "pnpm" => (
+            |words, i| resolve_dlx(&PNPM_OPTS, &PNPM_DLX_OPTS, words, i),
+            false,
+        ),
+        "yarn" => (
+            |words, i| resolve_dlx(&YARN_OPTS, &YARN_DLX_OPTS, words, i),
+            false,
+        ),
+        "bun" => (resolve_bun, false),
+        "bunx" => (|words, i| BUN_X_OPTS.consume(words, i + 1), false),
+        "uvx" => (|_words, i| Some(i + 1), false),
+        _ => return None,
+    };
+    Some(Wrapper {
+        resolve,
+        accepts_assignment,
+    })
+}
+
+/// `pnpm`/`yarn` only look through to the package behind an explicit `dlx`
+/// — without it, the next word is a `package.json` script name, not a
+/// package to run (#199: `pnpm claude` is not `pnpm dlx claude`). `dlx`
+/// itself takes launcher-specific options too, consumed before the executable.
+fn resolve_dlx(
+    opts: &OptionTable,
+    dlx_opts: &OptionTable,
+    words: &[&str],
+    i: usize,
+) -> Option<usize> {
+    let j = opts.consume(words, i + 1)?;
+    if words.get(j) != Some(&"dlx") {
+        return None;
+    }
+    dlx_opts.consume(words, j + 1)
+}
+
+/// `bun x <pkg>` is bun's `dlx`/`npx` equivalent; `bun run <script>` is not
+/// (the same package-script ambiguity as bare `pnpm`/`yarn`), so only an `x`
+/// subcommand is looked through. `--bun` (`BUN_X_OPTS`) may follow it before
+/// the executable.
+fn resolve_bun(words: &[&str], i: usize) -> Option<usize> {
+    if words.get(i + 1) != Some(&"x") {
+        return None;
+    }
+    BUN_X_OPTS.consume(words, i + 2)
+}
+
+/// `FOO=bar`, the shell's own prefix for one command's environment —
+/// recognised only when the `=` came from plain, unquoted/unescaped source
+/// text (#199): `"FOO=1"` and `FOO\=1` name a program called `FOO=1`, not
+/// an assignment.
+fn is_env_assignment(word: &Word) -> bool {
+    let Some(eq) = word.plain_eq else {
+        return false;
+    };
+    let name = &word.text[..eq];
+    let mut chars = name.chars();
     match chars.next() {
         Some(c) if c.is_ascii_alphabetic() || c == '_' => {}
         _ => return false,
     }
-    let rest: String = chars.collect();
-    match rest.split_once('=') {
-        Some((name, _)) => name.chars().all(|c| c.is_ascii_alphanumeric() || c == '_'),
-        None => false,
-    }
+    chars.all(|c| c.is_ascii_alphanumeric() || c == '_')
 }
 
 fn basename(word: &str) -> &str {
@@ -497,38 +955,132 @@ mod tests {
             "claude"
         );
         assert_eq!(command_program("  zsh   -l  "), "zsh");
-        assert_eq!(command_program("hx src/main.rs"), "hx");
+    }
+
+    /// The #199 resolver contract: every case in the shared parity fixture,
+    /// asserted identically here and by `web/src/toolIcon.test.ts`, so a
+    /// resolver regression in either language fails its own suite.
+    #[test]
+    fn resolves_the_shared_command_resolution_fixture() {
+        #[derive(serde::Deserialize)]
+        struct Case {
+            command: String,
+            program: String,
+            tool: Option<String>,
+        }
+        #[derive(serde::Deserialize)]
+        struct Fixture {
+            cases: Vec<Case>,
+        }
+        let raw = include_str!("../../../fixtures/command-resolution.json");
+        let fixture: Fixture = serde_json::from_str(raw).expect("valid fixture JSON");
+        assert!(!fixture.cases.is_empty());
+        for case in &fixture.cases {
+            assert_eq!(
+                command_program(&case.command),
+                case.program,
+                "program for {:?}",
+                case.command
+            );
+            assert_eq!(
+                command_tool(&case.command),
+                case.tool.as_deref(),
+                "tool for {:?}",
+                case.command
+            );
+        }
+    }
+
+    fn word(text: &str) -> Word {
+        Word {
+            text: text.into(),
+            plain_eq: None,
+        }
+    }
+
+    /// Shell-aware tokenization (#199): quoting/escaping is honoured, never
+    /// evaluated — no `$var`/`` `cmd` ``/`$(cmd)` expansion is attempted.
+    #[test]
+    fn tokenize_handles_quotes_and_escapes_without_expanding_anything() {
+        assert_eq!(
+            tokenize("claude --resume"),
+            Some(vec![word("claude"), word("--resume")])
+        );
+        assert_eq!(
+            tokenize("\"/opt/my agent/claude\" --resume"),
+            Some(vec![word("/opt/my agent/claude"), word("--resume")])
+        );
+        assert_eq!(
+            tokenize("FOO=\"bar baz\" claude"),
+            Some(vec![
+                Word {
+                    text: "FOO=bar baz".into(),
+                    plain_eq: Some(3),
+                },
+                word("claude"),
+            ])
+        );
+        assert_eq!(
+            tokenize("claude --name=$HOME"),
+            Some(vec![
+                word("claude"),
+                Word {
+                    text: "--name=$HOME".into(),
+                    plain_eq: Some(6),
+                },
+            ]),
+            "a bare $ is kept literal, never expanded"
+        );
+    }
+
+    /// Real shell grammar this resolver doesn't attempt — pipelines, list
+    /// operators, subshells/substitution, an unescaped newline, an
+    /// unterminated quote — is rejected outright rather than guessed
+    /// through (#199).
+    #[test]
+    fn tokenize_rejects_ambiguous_shell_grammar() {
+        for command in [
+            "claude | tee log.txt",
+            "claude; echo done",
+            "claude && echo done",
+            "echo hi $(claude)",
+            "claude \"unterminated",
+            "claude 'unterminated",
+            "claude \\",
+            "claude\nclaude-code", // an unescaped newline separates commands, like `;`
+        ] {
+            assert_eq!(tokenize(command), None, "{command:?}");
+        }
+    }
+
+    /// A backslash immediately before a newline is a line continuation:
+    /// removed entirely, joining what it split rather than embedding a
+    /// literal newline or ending the command (#199).
+    #[test]
+    fn tokenize_treats_backslash_newline_as_a_continuation() {
+        assert_eq!(
+            tokenize("clau\\\nde --resume"),
+            Some(vec![word("claude"), word("--resume")])
+        );
+    }
+
+    /// Only a plain, unquoted/unescaped `=` marks an assignment boundary —
+    /// quoting or escaping the `=` itself disqualifies the word, even
+    /// though the dequoted text looks identical (#199).
+    #[test]
+    fn tokenize_only_marks_plain_unquoted_equals_signs_as_assignments() {
+        assert_eq!(tokenize("FOO=1 claude").unwrap()[0].plain_eq, Some(3));
+        assert_eq!(tokenize("\"FOO=1\" claude").unwrap()[0].plain_eq, None);
+        assert_eq!(tokenize("FOO\\=1 claude").unwrap()[0].plain_eq, None);
     }
 
     #[test]
-    fn command_program_looks_through_paths_env_and_wrappers() {
-        assert_eq!(command_program("/usr/local/bin/claude -p hi"), "claude");
-        assert_eq!(command_program("FOO=1 BAR=2 claude"), "claude");
-        assert_eq!(command_program("npx opencode"), "opencode");
-        assert_eq!(command_program("pnpm dlx opencode run"), "opencode");
-    }
-
-    #[test]
-    fn command_program_keeps_a_line_that_is_only_wrappers() {
-        assert_eq!(command_program("sudo"), "sudo");
-        assert_eq!(command_program(""), "");
-    }
-
-    /// The command bar's `tool` field (docs/COMMAND-BAR.md) names the same
-    /// tools the web's `splitCommand().tool` does.
-    #[test]
-    fn command_tool_names_the_mark_the_card_shows() {
-        assert_eq!(command_tool("claude --resume"), Some("claude"));
-        assert_eq!(command_tool("npx opencode"), Some("opencode"));
-        assert_eq!(command_tool("/bin/zsh -l"), Some("shell"));
-        assert_eq!(command_tool("CLAUDE"), Some("claude"));
-    }
-
-    /// Narrow on purpose: an unrecognised program has no mark, so the
-    /// candidate has no `tool` field to match rather than a wrong one.
-    #[test]
-    fn command_tool_is_absent_for_an_unrecognised_program() {
-        assert_eq!(command_tool("hx src/main.rs"), None);
-        assert_eq!(command_tool(""), None);
+    fn structured_view_support_follows_the_resolved_program() {
+        assert!(supports_structured_view("claude --resume"));
+        assert!(supports_structured_view("FOO=1 /usr/local/bin/codex exec"));
+        assert!(supports_structured_view("npx claude-code"));
+        assert!(!supports_structured_view("opencode"));
+        assert!(!supports_structured_view("bash -l"));
+        assert!(!supports_structured_view("claude-code-acp"));
     }
 }

crates/maestro-protocol/src/lib.rs

@@ -123,7 +123,7 @@ pub struct Session {
     /// daemon that predates the field keeps working untouched.
     #[serde(default)]
     pub view: SessionView,
-    /// The ACP session id the `claude-code-acp` adapter handed back from
+    /// The ACP session id the selected provider adapter handed back from
     /// `session/new` (#134). Only a [`SessionView::Structured`] session has
     /// one, and only once its handshake succeeded; a later respawn passes it
     /// to `session/load` so the conversation continues (#135). Distinct from
@@ -156,9 +156,9 @@ pub enum SessionStatus {
     Dead,
 }
 
-/// Inferred session activity, orthogonal to [`SessionStatus`] (NAP-340). The
-/// daemon derives this from tmux pane state, PTY quiescence, and `/proc`
-/// inspection — never by parsing the terminal byte stream.
+/// Session activity, orthogonal to [`SessionStatus`] (NAP-340). Terminal
+/// sessions use pane/process inference and agent reports; structured sessions
+/// use their ACP turn lifecycle (docs/SIDEBAR.md).
 ///
 /// Deserializes leniently (#110, SIDEBAR.md Precedence): an unknown variant
 /// from a newer daemon becomes [`ActivityState::Idle`] instead of failing the
@@ -166,16 +166,19 @@ pub enum SessionStatus {
 /// forgiven.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Default)]
 pub enum ActivityState {
-    /// Producing output, or the foreground process is busy.
+    /// Producing output, the foreground process is busy, or an ACP turn is active.
     Active,
     /// Foreground process alive but quiescent. The forward-compatible default.
     #[default]
     Idle,
-    /// Blocked on a `read()` from the pty — waiting on the user.
+    /// Blocked on terminal input or waiting for an ACP approval.
     AwaitingInput,
-    /// The agent running in the session reported a failure (#102). Never
-    /// inferred by the daemon; only set when an agent reports it (#105).
+    /// An agent reported a failure, or a structured session/turn failed.
     Error,
+    /// The ACP adapter is booting; the session is registered but cannot accept
+    /// prompts yet. Older clients that do not know this variant degrade it to
+    /// `Idle` via the lenient deserializer — acceptable.
+    Starting,
 }
 
 impl<'de> Deserialize<'de> for ActivityState {
@@ -188,6 +191,7 @@ impl<'de> Deserialize<'de> for ActivityState {
             "Active" => Self::Active,
             "AwaitingInput" => Self::AwaitingInput,
             "Error" => Self::Error,
+            "Starting" => Self::Starting,
             // Known or not, any other spelling degrades to the neutral default
             _ => Self::Idle,
         })
@@ -226,9 +230,10 @@ where
         "Idle" => Ok(ActivityState::Idle),
         "AwaitingInput" => Ok(ActivityState::AwaitingInput),
         "Error" => Ok(ActivityState::Error),
+        "Starting" => Ok(ActivityState::Starting),
         other => Err(D::Error::unknown_variant(
             other,
-            &["Active", "Idle", "AwaitingInput", "Error"],
+            &["Active", "Idle", "AwaitingInput", "Error", "Starting"],
         )),
     }
 }
@@ -384,6 +389,10 @@ pub struct CreateSessionRequest {
     /// untouched.
     #[serde(default)]
     pub view: SessionView,
+    /// When `true`, the daemon auto-approves every ACP permission request
+    /// for this structured session.
+    #[serde(default)]
+    pub auto_approve: bool,
 }
 
 /// Result of `GET /api/dirs`: the immediate subdirectories of one directory.
@@ -523,6 +532,11 @@ pub struct SpawnPreset {
     pub id: String,
     pub label: String,
     pub command: String,
+    /// When `true`, the daemon auto-approves every ACP permission request
+    /// for structured sessions spawned from this preset instead of surfacing
+    /// them to the client.
+    #[serde(default)]
+    pub auto_approve: bool,
 }
 
 /// Build provenance of the running daemon: the commit it was compiled
@@ -825,6 +839,15 @@ pub struct TurnState {
     pub thinking: bool,
     #[serde(default)]
     pub active_tool_calls: Vec<String>,
+    /// Wall-clock start of the active prompt. This lets reconnecting clients
+    /// keep one continuous elapsed-time display instead of restarting at zero.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub started_at: Option<DateTime<Utc>>,
+    /// Context-window usage when the active prompt began. ACP exposes context
+    /// occupancy, not provider billing-token accounting, so clients must label
+    /// deltas as context tokens rather than tokens billed.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub started_context_tokens: Option<u64>,
 }
 
 /// A whole-session view derived from ACP notifications.
@@ -847,6 +870,8 @@ pub struct ReducedState {
     pub model: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub mode: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub config_options: Option<Value>,
 }
 
 /// Server messages sent over a structured-session WebSocket.
@@ -872,6 +897,13 @@ pub struct StructuredPromptRequest {
     pub prompt: String,
 }
 
+/// HTTP body for `POST /api/sessions/:id/structured/config`.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct StructuredConfigRequest {
+    pub config_id: String,
+    pub value: Value,
+}
+
 /// Operator decision for a pending ACP permission request.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
@@ -1234,6 +1266,7 @@ mod tests {
                 create_branch: true,
             }),
             view: SessionView::Terminal,
+            auto_approve: false,
         };
         assert_eq!(req, round_trip(&req));
     }

crates/maestro-protocol/src/routes.rs

@@ -86,11 +86,21 @@ pub fn structured_prompt(id: Uuid) -> String {
     format!("{SESSIONS}/{id}/structured/prompt")
 }
 
+/// `POST /api/sessions/:id/structured/attachments` — upload a file.
+pub fn structured_attachment(id: Uuid) -> String {
+    format!("{SESSIONS}/{id}/structured/attachments")
+}
+
 /// `POST /api/sessions/:id/structured/cancel` — cancel an ACP turn.
 pub fn structured_cancel(id: Uuid) -> String {
     format!("{SESSIONS}/{id}/structured/cancel")
 }
 
+/// `POST /api/sessions/:id/structured/config` — change an ACP session option.
+pub fn structured_config(id: Uuid) -> String {
+    format!("{SESSIONS}/{id}/structured/config")
+}
+
 /// `POST /api/sessions/:id/structured/approvals/:nonce` — answer ACP permission.
 pub fn structured_approval(id: Uuid, nonce: &str) -> String {
     format!("{SESSIONS}/{id}/structured/approvals/{nonce}")
@@ -108,7 +118,9 @@ pub mod patterns {
     pub const STRUCTURED: &str = "/api/structured/:id";
     pub const STRUCTURED_REPLAY: &str = "/api/sessions/:id/structured/replay";
     pub const STRUCTURED_PROMPT: &str = "/api/sessions/:id/structured/prompt";
+    pub const STRUCTURED_ATTACHMENT: &str = "/api/sessions/:id/structured/attachments";
     pub const STRUCTURED_CANCEL: &str = "/api/sessions/:id/structured/cancel";
+    pub const STRUCTURED_CONFIG: &str = "/api/sessions/:id/structured/config";
     pub const STRUCTURED_APPROVAL: &str = "/api/sessions/:id/structured/approvals/:nonce";
 }
 
@@ -159,6 +171,11 @@ pub fn attach_url(http_base: &str, id: Uuid) -> Result<String, UrlError> {
     Ok(format!("{}{}", ws_base(http_base)?, attach(id)))
 }
 
+/// Full `WS /api/structured/:id` URL for a daemon reachable at `http_base`.
+pub fn structured_url(http_base: &str, id: Uuid) -> Result<String, UrlError> {
+    Ok(format!("{}{}", ws_base(http_base)?, structured(id)))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -208,6 +225,10 @@ mod tests {
             events_url("http://host:7070/").unwrap(),
             "ws://host:7070/api/events"
         );
+        assert_eq!(
+            structured_url("http://host:7070/", id()).unwrap(),
+            "ws://host:7070/api/structured/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50"
+        );
     }
 
     #[test]

crates/maestro-testing/src/lib.rs

@@ -22,7 +22,8 @@ use chrono::Utc;
 use futures_util::{SinkExt, StreamExt};
 use maestro_protocol::{
     routes, ApiError, CatalogEvent, CreateSessionRequest, DaemonClient, DaemonInfo, DirListing,
-    GitRoot, RecentDirs, SendInputRequest, Session, SessionStatus, PROTOCOL_VERSION,
+    GitRoot, RecentDirs, SendInputRequest, Session, SessionStatus, StructuredPromptRequest,
+    PROTOCOL_VERSION,
 };
 use tokio::net::TcpListener;
 use tokio::sync::{broadcast, oneshot};
@@ -60,6 +61,8 @@ struct Inner {
     forced_error: Option<(u16, ApiError)>,
     /// Everything `POST /api/sessions/:id/input` was asked to type, in order.
     inputs: Vec<(Uuid, SendInputRequest)>,
+    /// Every ACP prompt sent to a structured session, in order.
+    structured_prompts: Vec<(Uuid, StructuredPromptRequest)>,
 }
 
 #[derive(Clone)]
@@ -92,6 +95,7 @@ impl MockDaemon {
             .route(routes::SESSIONS, get(list_sessions).post(create_session))
             .route(routes::patterns::SESSION, delete(kill_session))
             .route(routes::patterns::SESSION_INPUT, post(send_input))
+            .route(routes::patterns::STRUCTURED_PROMPT, post(structured_prompt))
             .route(routes::INFO, get(daemon_info))
             .route(routes::DIRS, get(list_dir))
             .route(routes::RECENT_DIRS, get(recent_dirs))
@@ -178,6 +182,16 @@ impl MockDaemon {
         self.state.inner.lock().expect("poisoned").inputs.clone()
     }
 
+    /// Every ACP prompt this daemon received, oldest first.
+    pub fn structured_prompts(&self) -> Vec<(Uuid, StructuredPromptRequest)> {
+        self.state
+            .inner
+            .lock()
+            .expect("poisoned")
+            .structured_prompts
+            .clone()
+    }
+
     pub fn session_count(&self) -> usize {
         self.state.inner.lock().expect("poisoned").sessions.len()
     }
@@ -266,6 +280,26 @@ async fn send_input(
     StatusCode::NO_CONTENT.into_response()
 }
 
+async fn structured_prompt(
+    State(s): State<AppState>,
+    Path(id): Path<Uuid>,
+    Json(req): Json<StructuredPromptRequest>,
+) -> Response {
+    if let Some(r) = forced(&s) {
+        return r;
+    }
+    let mut guard = s.inner.lock().expect("poisoned");
+    if !guard.sessions.iter().any(|x| x.id == id) {
+        return (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("not_found", "no such session on this daemon")),
+        )
+            .into_response();
+    }
+    guard.structured_prompts.push((id, req));
+    StatusCode::NO_CONTENT.into_response()
+}
+
 async fn daemon_info(State(s): State<AppState>) -> Response {
     if let Some(r) = forced(&s) {
         return r;

crates/maestro-tui/Cargo.toml

@@ -21,6 +21,7 @@ thiserror.workspace = true
 tokio = { workspace = true, features = ["sync", "time", "macros", "rt"] }
 tokio-tungstenite.workspace = true
 tracing.workspace = true
+unicode-width.workspace = true
 uuid.workspace = true
 vt100.workspace = true
 

crates/maestro-tui/src/app.rs

@@ -11,13 +11,17 @@
 //! `dispatch` / the overlay routing.
 
 use std::collections::{HashMap, HashSet};
+use std::io::Write;
 use std::path::PathBuf;
 use std::time::Duration;
 
 use chrono::Utc;
 use crossterm::event::{Event as CtEvent, EventStream};
 use futures_util::StreamExt;
-use maestro_protocol::{routes, BranchInfo, CreateSessionRequest, DaemonClient, NameBatch};
+use maestro_protocol::{
+    routes, BranchInfo, CreateSessionRequest, DaemonClient, NameBatch, SessionView,
+    StructuredApprovalDecision,
+};
 use ratatui::Terminal;
 use uuid::Uuid;
 
@@ -38,6 +42,8 @@ use crate::render::{draw, RegionMap, RenderInputs};
 use crate::session_task::{SessionInput, SessionTask};
 use crate::sidebar::Sidebar;
 use crate::state::{AppState, Focus, OverlayKind, SidebarItem};
+use crate::structured_pane::StructuredPane;
+use crate::structured_task::{StructuredHandle, StructuredTask};
 use crate::text_input::TextInput;
 use crate::TuiError;
 
@@ -49,11 +55,42 @@ enum OverlayDecision {
     Pass,
 }
 
+fn copy_to_terminal_clipboard(text: &str) -> std::io::Result<()> {
+    let encoded = base64_encode(text.as_bytes());
+    let mut output = std::io::stdout();
+    write!(output, "\x1b]52;c;{encoded}\x07")?;
+    output.flush()
+}
+
+fn base64_encode(bytes: &[u8]) -> String {
+    const TABLE: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    let mut output = String::with_capacity(bytes.len().div_ceil(3) * 4);
+    for chunk in bytes.chunks(3) {
+        let bits = (u32::from(chunk[0]) << 16)
+            | (u32::from(*chunk.get(1).unwrap_or(&0)) << 8)
+            | u32::from(*chunk.get(2).unwrap_or(&0));
+        output.push(TABLE[((bits >> 18) & 0x3f) as usize] as char);
+        output.push(TABLE[((bits >> 12) & 0x3f) as usize] as char);
+        output.push(if chunk.len() > 1 {
+            TABLE[((bits >> 6) & 0x3f) as usize] as char
+        } else {
+            '='
+        });
+        output.push(if chunk.len() > 2 {
+            TABLE[(bits & 0x3f) as usize] as char
+        } else {
+            '='
+        });
+    }
+    output
+}
+
 pub struct App {
     cfg: TuiConfig,
     home_dir: String,
     catalog: CatalogStore,
     emulators: SessionEmulators,
+    structured: HashMap<Uuid, StructuredHandle>,
     state: AppState,
     help: HelpOverlay,
     chord: ChordState,
@@ -163,6 +200,18 @@ pub enum Effect {
         id: Uuid,
         bytes: Vec<u8>,
     },
+    StructuredPrompt {
+        id: Uuid,
+        prompt: String,
+    },
+    StructuredCancel {
+        id: Uuid,
+    },
+    StructuredApproval {
+        id: Uuid,
+        nonce: String,
+        decision: StructuredApprovalDecision,
+    },
     /// Fetch presets / projects / names for a freshly opened form (#64).
     LoadDraft,
     /// Fast-forward spawn (#67): resolve every default from the daemon and
@@ -214,6 +263,7 @@ impl App {
             home_dir: std::env::var("HOME").unwrap_or_default(),
             catalog,
             emulators: SessionEmulators::default(),
+            structured: HashMap::new(),
             state: AppState::new(),
             draft: None,
             help,
@@ -321,6 +371,15 @@ impl App {
             return Ok(false);
         }
 
+        if self.handle_structured_mouse(&key) {
+            return Ok(false);
+        }
+
+        if let Some(effects) = self.handle_structured_key(&key) {
+            self.perform(effects).await;
+            return Ok(false);
+        }
+
         if let Some(effect) = self.handle_pane_scroll(&key) {
             self.perform(effect.into_iter().collect()).await;
             return Ok(false);
@@ -399,6 +458,61 @@ impl App {
         true
     }
 
+    /// Transcript blocks are pointer targets: click selects the whole block,
+    /// gives it the selection surface, and copies its complete text.
+    fn handle_structured_mouse(&mut self, key: &InputKey) -> bool {
+        let InputKey::Mouse {
+            kind,
+            region: Region::Pane,
+            row,
+            ..
+        } = key
+        else {
+            return false;
+        };
+        if !matches!(kind, MouseKind::Click | MouseKind::Hover) {
+            return false;
+        }
+        let Some(sid) = self.state.active_session() else {
+            return false;
+        };
+        let Some(handle) = self.structured.get(&sid) else {
+            return false;
+        };
+        let Some(pane) = self.region.pane else {
+            return false;
+        };
+        let offset = usize::from(row.saturating_sub(pane.y));
+        let transcript_height = pane.height.saturating_sub(pane.height.min(3));
+        if offset >= usize::from(transcript_height) {
+            return true;
+        }
+        let mut state = handle.state.lock().expect("structured state mutex");
+        let rendered_line = state.scroll.saturating_add(offset);
+        if !state.select_rendered_line(rendered_line) {
+            return true;
+        }
+        let Some(id) = state.selected.as_deref() else {
+            return true;
+        };
+        let Some(transcript) = state.rows.iter().find(|item| item.id == id) else {
+            return true;
+        };
+        if *kind == MouseKind::Hover {
+            return true;
+        }
+        let text = crate::structured_pane::copy_text(transcript);
+        drop(state);
+        if text.is_empty() {
+            return true;
+        }
+        match copy_to_terminal_clipboard(&text) {
+            Ok(()) => self.state.toast("copied transcript block"),
+            Err(error) => self.state.toast(format!("copy failed: {error}")),
+        }
+        true
+    }
+
     /// Carry out what `dispatch` decided. The only place in `App` that talks to
     /// the daemon.
     async fn perform(&mut self, effects: Vec<Effect>) {
@@ -419,6 +533,44 @@ impl App {
                         let _ = handle.tx.send(SessionInput::Bytes(bytes)).await;
                     }
                 }
+                Effect::StructuredPrompt { id, prompt } => {
+                    if let Err(error) = self.daemon.send_structured_prompt(id, &prompt).await {
+                        if let Some(handle) = self.structured.get(&id) {
+                            handle
+                                .state
+                                .lock()
+                                .expect("structured state mutex")
+                                .prompt_failed(prompt, error.to_string());
+                        }
+                    }
+                }
+                Effect::StructuredCancel { id } => {
+                    if let Err(error) = self.daemon.cancel_structured_turn(id).await {
+                        if let Some(handle) = self.structured.get(&id) {
+                            handle.state.lock().expect("structured state mutex").error =
+                                Some(error.to_string());
+                        }
+                    }
+                }
+                Effect::StructuredApproval {
+                    id,
+                    nonce,
+                    decision,
+                } => {
+                    if let Err(error) = self
+                        .daemon
+                        .resolve_structured_approval(id, &nonce, decision)
+                        .await
+                    {
+                        if let Some(handle) = self.structured.get(&id) {
+                            handle
+                                .state
+                                .lock()
+                                .expect("structured state mutex")
+                                .approval_failed(&nonce, error.to_string());
+                        }
+                    }
+                }
             }
         }
     }
@@ -563,13 +715,13 @@ impl App {
             Action::OpenCommandBar => effects.extend(self.open_command_bar()),
             // Escape hatch (#156): the literal byte, not the bar.
             Action::SendLiteralCtrlK => {
-                effects.extend(self.forward_to_session(&InputKey::ctrl_char('k')));
+                effects.extend(self.forward_literal_to_terminal(&InputKey::ctrl_char('k')));
             }
             // Escape hatch (#158): the leader's own byte, built from the
             // configured leader rather than a hardcoded key.
             Action::SendLiteralLeader => {
                 let leader = self.cfg.leader.clone();
-                effects.extend(self.forward_to_session(&leader));
+                effects.extend(self.forward_literal_to_terminal(&leader));
             }
             Action::OpenSpawnModal => {
                 self.open_spawn_modal();
@@ -587,7 +739,7 @@ impl App {
                         }
                         // A previewed session is already attached: committing
                         // to it keeps that stream rather than reopening one.
-                        if self.emulators.get(sid).is_none() {
+                        if !self.is_attached(sid) {
                             effects.push(Effect::Attach(sid));
                         }
                     }
@@ -595,6 +747,9 @@ impl App {
                     // preview budget.
                     self.preview_lru.retain(|s| *s != sid);
                     self.state.attach_to_focused(sid);
+                    if self.session_view(sid) == SessionView::Structured {
+                        self.state.mode = Mode::Normal;
+                    }
                 }
             }
             Action::KillHighlighted => {
@@ -663,7 +818,7 @@ impl App {
         self.state.preview = Some(sid);
         // Set outside the input path, so nothing else marks the frame stale.
         self.epoch = self.epoch.wrapping_add(1);
-        let fresh = self.emulators.get(sid).is_none();
+        let fresh = !self.is_attached(sid);
         if fresh {
             self.preview_lru.retain(|s| *s != sid);
             self.preview_lru.push(sid);
@@ -732,15 +887,27 @@ impl App {
 
     /// Open a stream for `sid` if one isn't already running.
     fn attach(&mut self, sid: Uuid) {
-        if self.emulators.get(sid).is_some() {
+        self.attach_with_view(sid, self.session_view(sid));
+    }
+
+    fn attach_with_view(&mut self, sid: Uuid, view: SessionView) {
+        if self.is_attached(sid) {
             return;
         }
-        match self.daemon.attach_url(sid) {
-            Ok(ws_url) => {
-                let handle = SessionTask::spawn(ws_url, 24, 80);
-                self.emulators.insert(sid, handle);
-            }
-            Err(e) => self.state.toast(format!("attach failed: {e}")),
+        match view {
+            SessionView::Terminal => match self.daemon.attach_url(sid) {
+                Ok(ws_url) => {
+                    let handle = SessionTask::spawn(ws_url, 24, 80);
+                    self.emulators.insert(sid, handle);
+                }
+                Err(e) => self.state.toast(format!("attach failed: {e}")),
+            },
+            SessionView::Structured => match self.daemon.structured_url(sid) {
+                Ok(ws_url) => {
+                    self.structured.insert(sid, StructuredTask::spawn(ws_url));
+                }
+                Err(e) => self.state.toast(format!("attach failed: {e}")),
+            },
         }
     }
 
@@ -748,9 +915,26 @@ impl App {
     /// dropping its vt100 parser.
     fn release_session(&mut self, sid: Uuid) {
         self.emulators.remove(sid);
+        if let Some(handle) = self.structured.remove(&sid) {
+            handle.end();
+        }
         self.last_sent_size.remove(&sid);
     }
 
+    fn session_view(&self, sid: Uuid) -> SessionView {
+        self.catalog
+            .snapshot()
+            .sessions
+            .iter()
+            .find(|session| session.id == sid)
+            .map(|session| session.view)
+            .unwrap_or_default()
+    }
+
+    fn is_attached(&self, sid: Uuid) -> bool {
+        self.emulators.get(sid).is_some() || self.structured.contains_key(&sid)
+    }
+
     /// Return the session under the sidebar highlight, falling back to the
     /// first listed session so the user can attach without arrowing first.
     fn pick_sidebar_target(&self) -> Option<Uuid> {
@@ -817,6 +1001,16 @@ impl App {
     /// attached to send it to.
     fn forward_to_session(&mut self, key: &InputKey) -> Option<Effect> {
         let sid = self.state.active_session()?;
+        if let Some(handle) = self.structured.get(&sid) {
+            let mut state = handle.state.lock().expect("structured state mutex");
+            if matches!(key, InputKey::Enter) {
+                return state
+                    .begin_prompt()
+                    .map(|prompt| Effect::StructuredPrompt { id: sid, prompt });
+            }
+            state.edit_composer(key);
+            return None;
+        }
         let handle = self.emulators.get(sid)?;
         let bytes = encode_key(key)?;
         handle
@@ -827,6 +1021,86 @@ impl App {
         Some(Effect::Forward { id: sid, bytes })
     }
 
+    fn forward_literal_to_terminal(&mut self, key: &InputKey) -> Option<Effect> {
+        let sid = self.state.active_session()?;
+        if self.session_view(sid) == SessionView::Structured {
+            return None;
+        }
+        self.forward_to_session(key)
+    }
+
+    fn handle_structured_key(&mut self, key: &InputKey) -> Option<Vec<Effect>> {
+        if self.state.focus != Focus::Pane || self.state.preview.is_some() {
+            return None;
+        }
+        let sid = self.state.active_session()?;
+        let handle = self.structured.get(&sid)?;
+        let mut state = handle.state.lock().expect("structured state mutex");
+        if self.state.mode == Mode::Insert {
+            if matches!(key, InputKey::Esc) && state.turn_active() {
+                return Some(vec![Effect::StructuredCancel { id: sid }]);
+            }
+            return None;
+        }
+        let effects = match key {
+            InputKey::Char {
+                c: 'j',
+                ctrl: false,
+                alt: false,
+                ..
+            }
+            | InputKey::Down => {
+                state.select(1);
+                Vec::new()
+            }
+            InputKey::Char {
+                c: 'k',
+                ctrl: false,
+                alt: false,
+                ..
+            }
+            | InputKey::Up => {
+                state.select(-1);
+                Vec::new()
+            }
+            InputKey::Enter => {
+                state.toggle_selected();
+                Vec::new()
+            }
+            InputKey::Esc => {
+                if state.turn_active() {
+                    vec![Effect::StructuredCancel { id: sid }]
+                } else {
+                    Vec::new()
+                }
+            }
+            InputKey::Char {
+                c: key @ ('a' | 'A' | 'd'),
+                ctrl: false,
+                alt: false,
+                ..
+            } => state
+                .approval_decision(*key)
+                .map(|(nonce, decision)| Effect::StructuredApproval {
+                    id: sid,
+                    nonce,
+                    decision,
+                })
+                .into_iter()
+                .collect(),
+            InputKey::PageUp => {
+                state.scroll_by(self.pane_page_rows() as isize);
+                Vec::new()
+            }
+            InputKey::PageDown => {
+                state.scroll_by(-(self.pane_page_rows() as isize));
+                Vec::new()
+            }
+            _ => return None,
+        };
+        Some(effects)
+    }
+
     fn pane_page_rows(&self) -> usize {
         self.region
             .pane
@@ -839,6 +1113,14 @@ impl App {
         let Some(sid) = self.state.active_session() else {
             return;
         };
+        if let Some(handle) = self.structured.get(&sid) {
+            handle
+                .state
+                .lock()
+                .expect("structured state mutex")
+                .scroll_by(rows);
+            return;
+        }
         let Some(handle) = self.emulators.get(sid) else {
             return;
         };
@@ -872,6 +1154,14 @@ impl App {
             _ => return None,
         };
         let sid = self.state.active_session()?;
+        if let Some(handle) = self.structured.get(&sid) {
+            handle
+                .state
+                .lock()
+                .expect("structured state mutex")
+                .scroll_by(lines);
+            return Some(None);
+        }
         let handle = self.emulators.get(sid)?;
         let pane = self.region.pane?;
         let parser = handle.screen.lock().expect("vt100 parser mutex");
@@ -1294,7 +1584,10 @@ impl App {
                 }
                 self.draft = None;
                 self.state.complete_spawn(sid);
-                self.attach(sid);
+                if session.view == SessionView::Structured {
+                    self.state.mode = Mode::Normal;
+                }
+                self.attach_with_view(sid, session.view);
             }
             Err(e) => {
                 // A failed POST belongs in the form it came from (#64), not a
@@ -1355,6 +1648,11 @@ impl App {
             self.emulators
                 .get(sid)
                 .map(|h| (sid, h.revision(), h.state()))
+                .or_else(|| {
+                    self.structured
+                        .get(&sid)
+                        .map(|h| (sid, h.revision(), h.connection()))
+                })
         });
         FrameKey {
             catalog: self.catalog.version(),
@@ -1416,6 +1714,17 @@ impl App {
                 focused: matches!(self.state.focus, Focus::Pane) && !previewing,
             })
         });
+        let structured_pane = shown_sid.and_then(|sid| {
+            let handle = self.structured.get(&sid)?;
+            let session = snap.sessions.iter().find(|session| session.id == sid)?;
+            Some(StructuredPane {
+                handle: handle.clone(),
+                focused: matches!(self.state.focus, Focus::Pane) && !previewing,
+                mode: self.state.mode,
+                session_status: session.status,
+                activity_detail: session.activity_detail.clone(),
+            })
+        });
         let pane_title = match shown_sid {
             Some(sid) => {
                 let name = snap
@@ -1439,6 +1748,7 @@ impl App {
             home_dir: &self.home_dir,
             pane_title: &pane_title,
             pane: pane.as_ref(),
+            structured_pane: structured_pane.as_ref(),
             state: &self.state,
             draft: self.draft.as_ref(),
             help: &self.help,
@@ -1685,6 +1995,12 @@ async fn fetch_branches(
 #[cfg(test)]
 mod tests {
     use super::*;
+
+    #[test]
+    fn clipboard_payload_uses_standard_base64() {
+        assert_eq!(base64_encode(b"hello"), "aGVsbG8=");
+        assert_eq!(base64_encode("✓".as_bytes()), "4pyT");
+    }
     use crate::action::Action;
     use crate::draft::DraftField;
     use crate::keymap::Mode;
@@ -2789,6 +3105,7 @@ mod tests {
             env: Default::default(),
             metadata: Default::default(),
             worktree: None,
+            auto_approve: false,
         };
         app.submit_spawn(req).await;
 
@@ -2805,6 +3122,56 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn create_response_selects_transport_before_catalog_event() {
+        use axum::routing::post;
+        use axum::Json;
+
+        async fn spawn_session(
+            Json(req): Json<CreateSessionRequest>,
+        ) -> Json<maestro_protocol::Session> {
+            let id = match req.view {
+                SessionView::Terminal => Uuid::from_u128(187),
+                SessionView::Structured => Uuid::from_u128(188),
+            };
+            let mut session = test_session(id, req.cwd.to_str().unwrap());
+            session.view = req.view;
+            session.command = req.command;
+            Json(session)
+        }
+
+        let router =
+            axum::Router::new().route(maestro_protocol::routes::SESSIONS, post(spawn_session));
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let base = format!("http://{}", listener.local_addr().unwrap());
+        tokio::spawn(async move { axum::serve(listener, router).await.unwrap() });
+
+        let mut app = make_app_at(&base);
+        let request = |view| CreateSessionRequest {
+            view,
+            cwd: std::path::PathBuf::from("/srv/work"),
+            command: "codex".into(),
+            env: Default::default(),
+            metadata: Default::default(),
+            worktree: None,
+            auto_approve: false,
+        };
+
+        let structured_id = Uuid::from_u128(188);
+        app.state.mode = Mode::Insert;
+        app.submit_spawn(request(SessionView::Structured)).await;
+        assert!(app.catalog.snapshot().sessions.is_empty());
+        assert!(app.structured.contains_key(&structured_id));
+        assert!(app.emulators.get(structured_id).is_none());
+        assert_eq!(app.state.mode, Mode::Normal);
+
+        let terminal_id = Uuid::from_u128(187);
+        app.submit_spawn(request(SessionView::Terminal)).await;
+        assert!(app.catalog.snapshot().sessions.is_empty());
+        assert!(app.emulators.get(terminal_id).is_some());
+        assert!(!app.structured.contains_key(&terminal_id));
+    }
+
     /// The full data load against a live daemon stub: presets replace the
     /// built-ins, projects land sorted, and the first generated name seeds
     /// the field.
@@ -3697,4 +4064,112 @@ mod tests {
         assert!(app.command_bar.is_none());
         assert!(app.state.overlay().is_none());
     }
+
+    fn structured_app(sid: Uuid) -> App {
+        let mut app = app_with_highlighted_session(sid);
+        let mut session = app.catalog.snapshot().sessions[0].clone();
+        session.view = SessionView::Structured;
+        app.catalog
+            .apply_event(maestro_protocol::CatalogEvent::SessionUpdated { session });
+        app.structured.insert(
+            sid,
+            StructuredHandle::test_handle(crate::structured_task::StructuredState::default()),
+        );
+        app.state.attach_to_focused(sid);
+        app
+    }
+
+    #[tokio::test]
+    async fn session_view_selects_the_structured_connection_and_cleanup_stops_it() {
+        let sid = Uuid::from_u128(141);
+        let mut app = app_with_highlighted_session(sid);
+        let mut session = app.catalog.snapshot().sessions[0].clone();
+        session.view = SessionView::Structured;
+        app.catalog
+            .apply_event(maestro_protocol::CatalogEvent::SessionUpdated { session });
+
+        app.attach(sid);
+        assert!(app.structured.contains_key(&sid));
+        assert!(app.emulators.get(sid).is_none());
+        let handle = app.structured.get(&sid).unwrap().clone();
+        app.release_session(sid);
+        assert_eq!(
+            handle.connection(),
+            crate::session_task::SessionState::Ended
+        );
+    }
+
+    #[test]
+    fn structured_normal_mode_routes_navigation_expansion_and_approval_by_row() {
+        use maestro_protocol::{ReducedState, TranscriptRow, TranscriptRowKind};
+        use serde_json::json;
+
+        let sid = Uuid::from_u128(141);
+        let mut app = structured_app(sid);
+        app.dispatch(Action::AttachHighlighted);
+        assert_eq!(app.state.focus, Focus::Pane);
+        assert_eq!(app.state.mode, Mode::Normal);
+        let handle = app.structured.get(&sid).unwrap().clone();
+        {
+            let mut state = handle.state.lock().unwrap();
+            state.rows = vec![
+                TranscriptRow {
+                    id: "text".into(),
+                    kind: TranscriptRowKind::AgentText,
+                    data: json!({"content":{"type":"text","text":"hello"}}),
+                },
+                TranscriptRow {
+                    id: "approval".into(),
+                    kind: TranscriptRowKind::Approval,
+                    data: json!({"options":[{"kind":"allow_once"}]}),
+                },
+            ];
+            state.selected = Some("text".into());
+            state.reduced = ReducedState {
+                pending_approval: Some(json!({"nonce":"n"})),
+                ..ReducedState::default()
+            };
+        }
+
+        assert_eq!(
+            app.handle_structured_key(&InputKey::char('j')),
+            Some(vec![])
+        );
+        assert_eq!(
+            app.handle_structured_key(&InputKey::char('a')),
+            Some(vec![Effect::StructuredApproval {
+                id: sid,
+                nonce: "n".into(),
+                decision: StructuredApprovalDecision::AllowOnce,
+            }])
+        );
+        assert_eq!(
+            handle.state.lock().unwrap().selected.as_deref(),
+            Some("approval")
+        );
+    }
+
+    #[test]
+    fn structured_insert_mode_edits_submits_and_cancels_without_pty_bytes() {
+        let sid = Uuid::from_u128(141);
+        let mut app = structured_app(sid);
+        assert!(app.emulators.get(sid).is_none());
+        app.forward_to_session(&InputKey::char('h'));
+        app.forward_to_session(&InputKey::char('i'));
+        assert_eq!(
+            app.forward_to_session(&InputKey::Enter),
+            Some(Effect::StructuredPrompt {
+                id: sid,
+                prompt: "hi".into(),
+            })
+        );
+        assert_eq!(
+            app.handle_structured_key(&InputKey::Esc),
+            Some(vec![Effect::StructuredCancel { id: sid }])
+        );
+        assert_eq!(
+            app.forward_literal_to_terminal(&app.cfg.leader.clone()),
+            None
+        );
+    }
 }

crates/maestro-tui/src/draft.rs

@@ -41,8 +41,10 @@ use std::time::{Duration, Instant};
 
 use chrono::{DateTime, Utc};
 use maestro_config::{builtin_presets, custom_preset};
-use maestro_protocol::display::abbreviate_dir;
-use maestro_protocol::{BranchInfo, CreateSessionRequest, Project, SpawnPreset, WorktreeSpec};
+use maestro_protocol::display::{abbreviate_dir, supports_structured_view};
+use maestro_protocol::{
+    BranchInfo, CreateSessionRequest, Project, SessionView, SpawnPreset, WorktreeSpec,
+};
 use ratatui::layout::{Constraint, Layout, Rect};
 use ratatui::style::{Modifier, Style};
 use ratatui::text::{Line, Span};
@@ -86,9 +88,11 @@ pub enum DraftField {
     /// apply immediately, mirroring the web form's per-click choice.
     WorktreeChoice,
     Name,
-    /// Disclosure collapsing the worktree/branch controls below (#93).
+    /// Disclosure collapsing the optional view and worktree controls below.
     /// Closed by default; Enter / Space toggles.
     Advanced,
+    /// ACP-backed transcript instead of a terminal. Claude Code or Codex.
+    StructuredToggle,
     /// Worktree on/off for this session (#65). Enter / Space toggles.
     WorktreeToggle,
     /// New-vs-existing branch source; Left / Right switches.
@@ -251,6 +255,14 @@ pub struct DraftPane {
     /// "Advanced options" disclosure (#93). Closed by default — most spawns
     /// take the default target.
     pub advanced_collapsed: bool,
+    /// ACP-backed structured transcript. Supported only when the resolved
+    /// command is Claude Code or Codex, and on by default whenever it is —
+    /// until the operator works the toggle themselves.
+    pub structured_view: bool,
+    /// Set once the operator toggles structured view by hand. From then on a
+    /// command change never re-enables what they turned off, the same guard
+    /// `name_touched` gives the name field.
+    pub structured_view_touched: bool,
     /// Enclosing repository of the chosen target — from the project scan for
     /// picked rows, `/api/gitroot` for raw paths. `None` until known.
     pub base_repo: Option<PathBuf>,
@@ -291,7 +303,7 @@ impl Default for DraftPane {
         // while its data loads, and stay usable when the daemon reports none.
         let mut presets = builtin_presets();
         presets.push(custom_preset());
-        Self {
+        let mut draft = Self {
             id: NEXT_DRAFT_ID.fetch_add(1, std::sync::atomic::Ordering::Relaxed),
             presets,
             selected_preset: 0,
@@ -311,6 +323,8 @@ impl Default for DraftPane {
             name_touched: false,
             worktree_enabled: true,
             advanced_collapsed: true,
+            structured_view: false,
+            structured_view_touched: false,
             base_repo: None,
             probed_cwd: None,
             probe_seq: 0,
@@ -329,7 +343,11 @@ impl Default for DraftPane {
             // straight away, and Tab from here reaches the command tiles.
             focused_field: DraftField::DirPicker,
             home_dir: String::new(),
-        }
+        };
+        // The built-in tile the form opens on decides whether structured view
+        // starts ticked, exactly as a later preset list would.
+        draft.sync_structured_view();
+        draft
     }
 }
 
@@ -348,6 +366,7 @@ impl DraftPane {
             .position(|p| !p.command.is_empty())
             .unwrap_or(0);
         self.apply_seed_command();
+        self.sync_structured_view();
     }
 
     /// Land a seeded command on the tile that runs it: its own preset when the
@@ -663,6 +682,28 @@ impl DraftPane {
         }
     }
 
+    fn supports_structured_view(&self) -> bool {
+        supports_structured_view(self.command())
+    }
+
+    /// Re-resolve the toggle after the command changed: an unsupported
+    /// command forces it off, a supported one turns it back on unless the
+    /// operator has already made the choice themselves.
+    fn sync_structured_view(&mut self) {
+        if !self.supports_structured_view() {
+            self.structured_view = false;
+        } else if !self.structured_view_touched {
+            self.structured_view = true;
+        }
+    }
+
+    pub fn toggle_structured_view(&mut self) {
+        if self.supports_structured_view() {
+            self.structured_view = !self.structured_view;
+            self.structured_view_touched = true;
+        }
+    }
+
     /// The chosen working directory: a picked project row, else the raw path
     /// input when it holds something.
     pub fn cwd(&self) -> Option<PathBuf> {
@@ -693,13 +734,22 @@ impl DraftPane {
             );
         }
         let worktree = self.build_worktree()?;
+        let auto_approve = self
+            .presets
+            .get(self.selected_preset)
+            .is_some_and(|p| p.auto_approve);
         Ok(CreateSessionRequest {
-            view: Default::default(),
+            view: if self.structured_view && self.supports_structured_view() {
+                SessionView::Structured
+            } else {
+                SessionView::Terminal
+            },
             cwd,
             command: command.to_string(),
             env: Default::default(),
             metadata,
             worktree,
+            auto_approve,
         })
     }
 
@@ -754,6 +804,9 @@ impl DraftPane {
         order.push(DraftField::Name);
         order.push(DraftField::Advanced);
         if !self.advanced_collapsed {
+            if self.supports_structured_view() {
+                order.push(DraftField::StructuredToggle);
+            }
             if !self.cwd_raw_visible && self.selected_group_key.is_some() {
                 order.push(DraftField::WorktreeChoice);
             }
@@ -795,6 +848,7 @@ impl DraftPane {
         }
         self.selected_preset =
             ((self.selected_preset as i32) + delta).rem_euclid(len as i32) as usize;
+        self.sync_structured_view();
     }
 
     /// Step-one boxes surviving the type-to-filter, in display order. A
@@ -1001,9 +1055,9 @@ impl DraftPane {
             // Two fields keep their own Enter instead: `DirPicker`, whose
             // highlighted row isn't the picked one until a first Enter chooses
             // it (the next Enter, now that it's active, falls through to
-            // submit); and the disclosure/toggle pair (`Advanced`,
-            // `WorktreeToggle`), which activate on Enter like a button rather
-            // than submitting, same as the web form's own `<button>` controls.
+            // submit); and the disclosure/checkbox fields, which activate on
+            // Enter like buttons rather than submitting, matching the web
+            // form controls.
             InputKey::Enter if self.focused_field == DraftField::DirPicker => {
                 let is_other_row = self.selection() >= self.visible_groups().len();
                 let choose_only =
@@ -1023,6 +1077,10 @@ impl DraftPane {
                 self.toggle_worktree();
                 DraftInputResult::Consumed
             }
+            InputKey::Enter if self.focused_field == DraftField::StructuredToggle => {
+                self.toggle_structured_view();
+                DraftInputResult::Consumed
+            }
             InputKey::Enter => DraftInputResult::Submit,
             InputKey::Char {
                 c: ' ',
@@ -1040,6 +1098,14 @@ impl DraftPane {
                 self.toggle_worktree();
                 DraftInputResult::Consumed
             }
+            InputKey::Char {
+                c: ' ',
+                ctrl: false,
+                ..
+            } if self.focused_field == DraftField::StructuredToggle => {
+                self.toggle_structured_view();
+                DraftInputResult::Consumed
+            }
             InputKey::Up if self.focused_field == DraftField::DirPicker => {
                 self.move_selection(-1);
                 DraftInputResult::Consumed
@@ -1083,7 +1149,10 @@ impl DraftPane {
             other => {
                 match self.focused_field {
                     DraftField::Preset | DraftField::Submit => {}
-                    DraftField::CustomCommand => self.custom_command.handle_key(other),
+                    DraftField::CustomCommand => {
+                        self.custom_command.handle_key(other);
+                        self.sync_structured_view();
+                    }
                     // Typing filters the list; the highlight resets to the top
                     // so a narrowed search always starts at its best match.
                     DraftField::DirPicker => {
@@ -1121,9 +1190,9 @@ impl DraftPane {
 
         let show_custom = self.is_custom();
         let show_raw = self.cwd_raw_visible;
-        // The worktree choice step, the worktree toggle and its body all stay
-        // behind the "Advanced options" disclosure (#93): collapsed hides
-        // them, regardless of what they'd otherwise show.
+        let show_structured = !self.advanced_collapsed && self.supports_structured_view();
+        // Optional view and worktree controls stay behind the "Advanced
+        // options" disclosure (#93), regardless of what they'd otherwise show.
         let show_wt_toggle = !self.advanced_collapsed;
         let show_wt_body = show_wt_toggle && self.worktree_body_visible();
         let show_wt_choice =
@@ -1142,6 +1211,7 @@ impl DraftPane {
         let fixed: u16 = 3 /* tiles + dir + name */ + 1 /* advanced header */ + 1 /* spawn */
             + u16::from(show_custom)
             + u16::from(show_raw)
+            + u16::from(show_structured)
             + u16::from(show_wt_toggle)
             + u16::from(show_wt_choice) * wt_choice_capacity
             + u16::from(show_wt_body) * (1 + if self.branch_mode == WorktreeBranchMode::New { 1 } else { branch_rows })
@@ -1161,6 +1231,9 @@ impl DraftPane {
         }
         constraints.push(Constraint::Length(1)); // name
         constraints.push(Constraint::Length(1)); // advanced header
+        if show_structured {
+            constraints.push(Constraint::Length(1));
+        }
         if show_wt_choice {
             constraints.push(Constraint::Length(wt_choice_capacity));
         }
@@ -1359,6 +1432,24 @@ impl DraftPane {
             advanced_row,
         );
 
+        if show_structured {
+            let row = next_row();
+            f.render_widget(
+                Paragraph::new(Line::from(vec![
+                    Span::raw(format!("{:<GUTTER$}", "view:")),
+                    Span::styled(
+                        if self.structured_view {
+                            "[x] structured view"
+                        } else {
+                            "[ ] structured view"
+                        },
+                        field_style(DraftField::StructuredToggle),
+                    ),
+                ])),
+                row,
+            );
+        }
+
         if show_wt_choice {
             // Step two (#96 rule 3): "+ new" first, then the repository's
             // worktrees newest-first.
@@ -1706,6 +1797,7 @@ mod tests {
             id: "aider".into(),
             label: "Aider".into(),
             command: "aider".into(),
+            auto_approve: false,
         }]);
         assert_eq!(
             draft.command(),
@@ -1728,11 +1820,13 @@ mod tests {
                 id: "claude".into(),
                 label: "Claude".into(),
                 command: "claude".into(),
+                auto_approve: false,
             },
             SpawnPreset {
                 id: "aider".into(),
                 label: "Aider".into(),
                 command: "aider".into(),
+                auto_approve: false,
             },
         ]);
         assert_eq!(draft.command(), "aider");
@@ -1752,6 +1846,7 @@ mod tests {
             id: "claude".into(),
             label: "Claude".into(),
             command: "claude".into(),
+            auto_approve: false,
         }]);
         assert!(draft.is_custom());
         assert_eq!(draft.command(), "bash -l");
@@ -1817,6 +1912,280 @@ mod tests {
         assert_eq!(req.cwd, PathBuf::from("/srv/work"));
     }
 
+    #[test]
+    fn structured_view_is_default_on_and_visible_for_supported_agents() {
+        let mut draft = DraftPane {
+            advanced_collapsed: false,
+            ..DraftPane::default()
+        };
+        draft.set_presets(vec![
+            SpawnPreset {
+                id: "claude".into(),
+                label: "Claude".into(),
+                command: "claude".into(),
+                auto_approve: false,
+            },
+            SpawnPreset {
+                id: "codex".into(),
+                label: "Codex".into(),
+                command: "codex".into(),
+                auto_approve: false,
+            },
+            SpawnPreset {
+                id: "opencode".into(),
+                label: "OpenCode".into(),
+                command: "opencode".into(),
+                auto_approve: false,
+            },
+        ]);
+        assert!(draft.structured_view, "on by default for a supported agent");
+        assert!(draft.field_order().contains(&DraftField::StructuredToggle));
+        let rendered = render_to_string(100, 24, |f| draft.render(f, f.area(), true));
+        assert!(rendered.contains("[x] structured view"), "{rendered}");
+
+        draft.cycle_preset(1);
+        assert_eq!(draft.command(), "codex");
+        assert!(
+            draft.structured_view,
+            "Codex keeps the structured selection"
+        );
+        draft.cycle_preset(1);
+        assert_eq!(draft.command(), "opencode");
+        assert!(
+            !draft.structured_view,
+            "a hidden value must not stay checked"
+        );
+        assert!(!draft.field_order().contains(&DraftField::StructuredToggle));
+        let rendered = render_to_string(100, 24, |f| draft.render(f, f.area(), true));
+        assert!(!rendered.contains("structured view"), "{rendered}");
+    }
+
+    #[test]
+    fn structured_view_request_is_guarded_against_a_stale_command() {
+        let mut draft = DraftPane {
+            picked_cwd: Some(PathBuf::from("/srv/work")),
+            worktree_enabled: false,
+            structured_view: true,
+            ..DraftPane::default()
+        };
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Structured);
+
+        draft.selected_preset = 1;
+        assert_eq!(draft.command(), "opencode");
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Terminal);
+    }
+
+    /// A custom command typed into the free-text field, run through the same
+    /// resolver the daemon/web gate uses (`command_tool`, #199): a path, an
+    /// env prefix, or a wrapper still resolves to Claude Code or Codex, so
+    /// the toggle stays offered and the request carries `Structured`; an
+    /// unrelated program does not.
+    #[test]
+    fn structured_view_follows_command_resolution_for_custom_commands() {
+        let cases: &[(&str, bool)] = &[
+            ("claude", true),
+            ("claude --resume", true),
+            ("CLAUDE", true),
+            ("/usr/local/bin/claude -p hi", true),
+            ("./bin/claude", true),
+            ("FOO=1 BAR=2 claude", true),
+            ("npx claude-code", true),
+            ("npx --yes claude-code", true),
+            ("sudo claude", true),
+            ("sudo -u root claude", true),
+            ("env -i claude", true),
+            ("nohup claude", true),
+            ("time claude", true),
+            ("command claude", true),
+            ("pnpm --silent dlx claude-code", true),
+            ("yarn --silent dlx claude-code", true),
+            ("bun x claude-code", true),
+            ("\"/opt/my agent/claude\" --resume", true),
+            ("codex", true),
+            ("codex --full-auto", true),
+            ("CODEX=1 codex", true),
+            ("/usr/local/bin/codex exec", true),
+            ("npx codex", true),
+            ("sudo -u root codex", true),
+            ("env -i codex", true),
+            ("command codex", true),
+            ("pnpm --silent dlx codex", true),
+            ("\"/opt/my agent/codex\" exec", true),
+            ("bash", false),
+            ("opencode", false),
+            ("/usr/local/bin/bash -l", false),
+            // A package-manager wrapper without `dlx`/`x` runs a
+            // `package.json` script, not the package (#199) — must not be
+            // mistaken for a Claude launch.
+            ("pnpm claude", false),
+            ("yarn claude", false),
+            // The daemon's structured-session child, never a valid
+            // user-facing launch form (#199).
+            ("claude-code-acp", false),
+        ];
+        for &(command, supported) in cases {
+            let mut draft = DraftPane {
+                picked_cwd: Some(PathBuf::from("/srv/work")),
+                worktree_enabled: false,
+                advanced_collapsed: false,
+                ..DraftPane::default()
+            };
+            draft.selected_preset = draft.presets.len() - 1;
+            draft.custom_command = crate::text_input::TextInput::with_value(command);
+            draft.sync_structured_view();
+
+            assert_eq!(
+                draft.field_order().contains(&DraftField::StructuredToggle),
+                supported,
+                "toggle visibility for {command:?}"
+            );
+            assert_eq!(
+                draft.structured_view, supported,
+                "default selection for {command:?}"
+            );
+            let view = draft.build_request().unwrap().view;
+            assert_eq!(
+                view,
+                if supported {
+                    SessionView::Structured
+                } else {
+                    SessionView::Terminal
+                },
+                "request view for {command:?}"
+            );
+
+            draft.toggle_structured_view();
+            assert!(
+                !draft.structured_view,
+                "the toggle turns the default off for {command:?}"
+            );
+        }
+    }
+
+    /// A configured preset (the spawn-form "alias" for a command) is gated
+    /// the same way as free text: a preset whose command resolves to Claude
+    /// Code or Codex through a wrapper still offers structured view.
+    #[test]
+    fn structured_view_follows_command_resolution_for_presets() {
+        let mut draft = DraftPane {
+            picked_cwd: Some(PathBuf::from("/srv/work")),
+            worktree_enabled: false,
+            advanced_collapsed: false,
+            ..DraftPane::default()
+        };
+        draft.set_presets(vec![
+            SpawnPreset {
+                id: "claude-wrapped".into(),
+                label: "Claude (npx)".into(),
+                command: "npx claude-code --resume".into(),
+                auto_approve: false,
+            },
+            SpawnPreset {
+                id: "codex-wrapped".into(),
+                label: "Codex (npx)".into(),
+                command: "npx codex exec".into(),
+                auto_approve: false,
+            },
+            SpawnPreset {
+                id: "aider".into(),
+                label: "Aider".into(),
+                command: "aider".into(),
+                auto_approve: false,
+            },
+        ]);
+
+        assert_eq!(draft.command(), "npx claude-code --resume");
+        assert!(draft.field_order().contains(&DraftField::StructuredToggle));
+        assert!(draft.structured_view);
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Structured);
+
+        // Switching between supported presets preserves the selection.
+        draft.cycle_preset(1);
+        assert_eq!(draft.command(), "npx codex exec");
+        assert!(draft.structured_view);
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Structured);
+
+        // Switching to a preset that does not resolve to an ACP agent clears the
+        // stale selection instead of letting an invalid request through.
+        draft.cycle_preset(1);
+        assert_eq!(draft.command(), "aider");
+        assert!(!draft.structured_view, "stale selection must clear");
+        assert!(!draft.field_order().contains(&DraftField::StructuredToggle));
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Terminal);
+    }
+
+    /// The default only applies until the operator has an opinion: once they
+    /// untick the box, moving between supported commands leaves it unticked
+    /// instead of turning it back on under them.
+    #[test]
+    fn an_unticked_structured_view_survives_a_command_change() {
+        let mut draft = DraftPane {
+            picked_cwd: Some(PathBuf::from("/srv/work")),
+            worktree_enabled: false,
+            advanced_collapsed: false,
+            ..DraftPane::default()
+        };
+        draft.set_presets(vec![
+            SpawnPreset {
+                id: "claude".into(),
+                label: "Claude".into(),
+                command: "claude".into(),
+                auto_approve: false,
+            },
+            SpawnPreset {
+                id: "codex".into(),
+                label: "Codex".into(),
+                command: "codex".into(),
+                auto_approve: false,
+            },
+        ]);
+        assert!(draft.structured_view);
+
+        draft.toggle_structured_view();
+        assert!(!draft.structured_view);
+
+        draft.cycle_preset(1);
+        assert_eq!(draft.command(), "codex");
+        assert!(
+            !draft.structured_view,
+            "the operator's choice outranks the default"
+        );
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Terminal);
+    }
+
+    /// Editing the custom-command text away from a supported agent clears an armed
+    /// selection immediately, matching the preset-switch case above — an
+    /// invalid `Structured` request can never reach `build_request`.
+    #[test]
+    fn structured_view_clears_when_custom_command_edited_away_from_supported_agent() {
+        let mut draft = DraftPane {
+            picked_cwd: Some(PathBuf::from("/srv/work")),
+            worktree_enabled: false,
+            advanced_collapsed: false,
+            focused_field: DraftField::CustomCommand,
+            ..DraftPane::default()
+        };
+        draft.selected_preset = draft.presets.len() - 1;
+        draft.custom_command = crate::text_input::TextInput::with_value("codex");
+        draft.sync_structured_view();
+        assert!(draft.structured_view);
+
+        typed(&mut draft, " -p");
+        assert_eq!(draft.command(), "codex -p");
+        assert!(draft.structured_view, "still Codex, selection survives");
+
+        for _ in 0.."codex -p".chars().count() {
+            draft.on_input(&InputKey::Backspace);
+        }
+        typed(&mut draft, "bash");
+        assert_eq!(draft.command(), "bash");
+        assert!(
+            !draft.structured_view,
+            "editing the program away from Codex clears the stale selection"
+        );
+        assert_eq!(draft.build_request().unwrap().view, SessionView::Terminal);
+    }
+
     #[test]
     fn projects_render_sorted_with_stale_dimmed_and_other_directory_last() {
         let mut draft = DraftPane {

crates/maestro-tui/src/fast_forward.rs

@@ -121,6 +121,7 @@ impl FastForwardDefaults {
                 branch: handle.to_string(),
                 create_branch: true,
             }),
+            auto_approve: false,
         })
     }
 
@@ -184,6 +185,7 @@ mod tests {
             id: id.into(),
             label: id.into(),
             command: command.into(),
+            auto_approve: false,
         }
     }
 

crates/maestro-tui/src/input.rs

@@ -55,6 +55,7 @@ pub enum MouseKind {
     Click,
     DblClick,
     Drag,
+    Hover,
     ScrollUp,
     ScrollDown,
 }
@@ -148,6 +149,7 @@ impl InputKey {
                     MouseKind::Click => "click",
                     MouseKind::DblClick => "dblclick",
                     MouseKind::Drag => "drag",
+                    MouseKind::Hover => "hover",
                     MouseKind::ScrollUp => "scrollup",
                     MouseKind::ScrollDown => "scrolldown",
                 };
@@ -178,6 +180,7 @@ impl InputKey {
                 "click" => MouseKind::Click,
                 "dblclick" => MouseKind::DblClick,
                 "drag" => MouseKind::Drag,
+                "hover" => MouseKind::Hover,
                 "scrollup" => MouseKind::ScrollUp,
                 "scrolldown" => MouseKind::ScrollDown,
                 other => return Err(InputParseError::UnknownMouseKind(other.into())),
@@ -297,6 +300,7 @@ where
             let mk = match kind {
                 MouseEventKind::Down(MouseButton::Left) => MouseKind::Click,
                 MouseEventKind::Drag(MouseButton::Left) => MouseKind::Drag,
+                MouseEventKind::Moved => MouseKind::Hover,
                 MouseEventKind::ScrollUp => MouseKind::ScrollUp,
                 MouseEventKind::ScrollDown => MouseKind::ScrollDown,
                 _ => return None,
@@ -681,6 +685,9 @@ mod tests {
         let s = "mouse:dblclick(sidebar-row)";
         let k = InputKey::parse(s).unwrap();
         assert_eq!(k.canonical(), s);
+        let s = "mouse:hover(pane)";
+        let k = InputKey::parse(s).unwrap();
+        assert_eq!(k.canonical(), s);
     }
 
     #[test]

crates/maestro-tui/src/lib.rs

@@ -23,6 +23,8 @@ pub mod render;
 pub mod session_task;
 pub mod sidebar;
 pub mod state;
+pub mod structured_pane;
+pub mod structured_task;
 pub mod terminal;
 pub mod text_input;
 

crates/maestro-tui/src/palette.rs

@@ -82,7 +82,7 @@ impl Surface {
     pub fn activity(&self, state: ActivityState) -> Color {
         match state {
             ActivityState::Active => self.active,
-            ActivityState::Idle => self.idle,
+            ActivityState::Idle | ActivityState::Starting => self.idle,
             ActivityState::AwaitingInput => self.awaiting,
             ActivityState::Error => self.error,
         }
@@ -928,9 +928,10 @@ pub fn contrast_ratio(a: Color, b: Color) -> Option<f64> {
 mod tests {
     use super::*;
 
-    const STATES: [ActivityState; 4] = [
+    const STATES: [ActivityState; 5] = [
         ActivityState::Active,
         ActivityState::Idle,
+        ActivityState::Starting,
         ActivityState::AwaitingInput,
         ActivityState::Error,
     ];

crates/maestro-tui/src/render.rs

@@ -18,6 +18,7 @@ use crate::palette;
 use crate::pane::Pane;
 use crate::sidebar::Sidebar;
 use crate::state::{AppState, Focus, OverlayKind, SidebarItem};
+use crate::structured_pane::StructuredPane;
 
 /// Tagged regions for mouse hit-testing. The input router resolves a mouse
 /// coordinate to one of these via [`RegionMap::region_at`].
@@ -80,6 +81,7 @@ pub struct RenderInputs<'a> {
     pub home_dir: &'a str,
     pub pane_title: &'a str,
     pub pane: Option<&'a Pane>,
+    pub structured_pane: Option<&'a StructuredPane>,
     /// The spawn form behind [`OverlayKind::Spawn`], when one is up.
     pub draft: Option<&'a crate::draft::DraftPane>,
     pub state: &'a AppState,
@@ -147,14 +149,22 @@ pub fn draw(f: &mut Frame, inputs: RenderInputs<'_>) -> RegionMap {
     render_title_bar(f, title_area, inputs.pane_title, pane_focused);
     if let Some(p) = inputs.pane {
         p.render(f, pane_area);
+    } else if let Some(p) = inputs.structured_pane {
+        p.render(f, pane_area);
     }
     // `RegionMap::pane` is also the PTY resize source. The title bar is
-    // chrome; every remaining cell belongs to the emulator.
+    // chrome; every remaining cell belongs to the active session pane.
     map.pane = Some(pane_area);
 
     // Status bar — always visible, never eclipsed by overlays so the user can
     // always see the current mode + key hints.
-    render_status_bar(f, status_area, inputs.state, inputs.link);
+    render_status_bar(
+        f,
+        status_area,
+        inputs.state,
+        inputs.link,
+        inputs.structured_pane.is_some(),
+    );
 
     match inputs.state.overlay() {
         Some(OverlayKind::Spawn) => {
@@ -253,7 +263,13 @@ fn render_title_bar(f: &mut Frame, area: Rect, title: &str, focused: bool) {
 /// Render the always-visible status bar at the bottom of the frame. Surfaces
 /// mode + focused panel + the most useful key hints so the user is never
 /// guessing what state they're in.
-fn render_status_bar(f: &mut Frame, area: Rect, state: &AppState, link: &LinkStatus) {
+fn render_status_bar(
+    f: &mut Frame,
+    area: Rect,
+    state: &AppState,
+    link: &LinkStatus,
+    structured: bool,
+) {
     // The daemon indicator is pinned right and sized to its own text, so a
     // narrow terminal truncates the key hints rather than the release.
     let label = link_label(link);
@@ -271,9 +287,13 @@ fn render_status_bar(f: &mut Frame, area: Rect, state: &AppState, link: &LinkSta
         Focus::Sidebar => "sidebar",
         Focus::Pane => "pane",
     };
-    let hint = match state.mode {
-        Mode::Normal => "j/k: nav  •  enter: attach  •  s: spawn  •  ?: help  •  ^Wq: quit",
-        Mode::Insert => "^a: return to sidebar",
+    let hint = match (structured && state.focus == Focus::Pane, state.mode) {
+        (true, Mode::Normal) => "j/k: rows  •  enter: expand  •  i: compose  •  esc: cancel",
+        (true, Mode::Insert) => "enter: send  •  esc: cancel  •  ^a: sidebar",
+        (false, Mode::Normal) => {
+            "j/k: nav  •  enter: attach  •  s: spawn  •  ?: help  •  ^Wq: quit"
+        }
+        (false, Mode::Insert) => "^a: return to sidebar",
     };
     let mode_style = palette::active().mode_style(state.mode == Mode::Insert);
     let line = ratatui::text::Line::from(vec![
@@ -435,6 +455,7 @@ mod tests {
             home_dir: "",
             pane_title: "session",
             pane: None,
+            structured_pane: None,
             draft: None,
             state: &state,
             help: &help,
@@ -532,6 +553,7 @@ mod tests {
             home_dir: "",
             pane_title: "session",
             pane: None,
+            structured_pane: None,
             draft: Some(&draft),
             state: &state,
             help: &help,
@@ -587,6 +609,7 @@ mod tests {
                 home_dir: "",
                 pane_title: "session",
                 pane: None,
+                structured_pane: None,
                 draft: None,
                 state: &state,
                 help: &help,
@@ -629,6 +652,7 @@ mod tests {
                 home_dir: "",
                 pane_title: "session",
                 pane: None,
+                structured_pane: None,
                 draft: None,
                 state: &state,
                 help: &help,

crates/maestro-tui/src/session_task.rs

@@ -221,7 +221,7 @@ impl SessionTask {
     }
 }
 
-fn jitter(base: Duration) -> Duration {
+pub(crate) fn jitter(base: Duration) -> Duration {
     let ms = base.as_millis() as u64;
     let now_nanos = std::time::SystemTime::now()
         .duration_since(std::time::UNIX_EPOCH)

crates/maestro-tui/src/sidebar.rs

@@ -979,6 +979,7 @@ mod tests {
         for state in [
             ActivityState::Active,
             ActivityState::Idle,
+            ActivityState::Starting,
             ActivityState::AwaitingInput,
             ActivityState::Error,
         ] {
@@ -1009,6 +1010,7 @@ mod tests {
         for state in [
             ActivityState::Active,
             ActivityState::Idle,
+            ActivityState::Starting,
             ActivityState::AwaitingInput,
             ActivityState::Error,
         ] {

crates/maestro-tui/src/structured_task.rs

@@ -0,0 +1,773 @@
+//! Live projection state for one structured session.
+
+use std::collections::HashSet;
+use std::sync::atomic::{AtomicU64, AtomicU8, Ordering};
+use std::sync::{Arc, Mutex};
+use std::time::Duration;
+
+use futures_util::StreamExt;
+use maestro_protocol::{
+    ReducedState, StructuredApprovalDecision, StructuredEvent, TranscriptDelta, TranscriptRow,
+    TranscriptRowKind,
+};
+use tokio::sync::watch;
+use tokio_tungstenite::tungstenite::{Error as WsError, Message};
+
+use crate::input::InputKey;
+use crate::session_task::SessionState;
+use crate::text_input::TextInput;
+
+/// Renderer and input state built directly from the daemon's two projections.
+#[derive(Debug, Clone)]
+pub struct StructuredState {
+    pub rows: Vec<TranscriptRow>,
+    pub reduced: ReducedState,
+    pub selected: Option<String>,
+    pub expanded: HashSet<String>,
+    pub scroll: usize,
+    /// Row id per rendered line from the last render pass, parallel to that
+    /// pass's `lines`. Lets the next render translate `scroll` — a raw index
+    /// into that now-stale layout — back into a row identity before mapping
+    /// it onto the freshly rebuilt layout, so growth/shrinkage above the
+    /// viewport shifts indices without shifting what's on screen.
+    pub(crate) line_rows: Vec<Option<String>>,
+    pub follow_selection: bool,
+    pub composer: TextInput,
+    pub error: Option<String>,
+    submitting: bool,
+    submission_generation: u64,
+    reconcile_submission_on_snapshot: Option<u64>,
+    approval_submitting: bool,
+}
+
+impl Default for StructuredState {
+    fn default() -> Self {
+        Self {
+            rows: Vec::new(),
+            reduced: ReducedState::default(),
+            selected: None,
+            expanded: HashSet::new(),
+            scroll: 0,
+            line_rows: Vec::new(),
+            follow_selection: true,
+            composer: TextInput::default(),
+            error: None,
+            submitting: false,
+            submission_generation: 0,
+            reconcile_submission_on_snapshot: None,
+            approval_submitting: false,
+        }
+    }
+}
+
+impl StructuredState {
+    pub fn apply(&mut self, event: StructuredEvent) {
+        match event {
+            StructuredEvent::TranscriptSnapshot { snapshot } => {
+                let selected = self.selected.clone();
+                self.rows = snapshot.rows;
+                self.selected = selected
+                    .filter(|id| self.rows.iter().any(|row| &row.id == id))
+                    .or_else(|| {
+                        self.rows
+                            .iter()
+                            .rev()
+                            .find(|row| row.kind != TranscriptRowKind::Plan)
+                            .map(|row| row.id.clone())
+                    });
+                self.expanded
+                    .retain(|id| self.rows.iter().any(|row| &row.id == id));
+            }
+            StructuredEvent::ReducedState { state } => {
+                let reconcile_submission = self
+                    .reconcile_submission_on_snapshot
+                    .take()
+                    .is_some_and(|generation| {
+                        self.submitting && generation == self.submission_generation
+                    });
+                self.apply_reduced(state, reconcile_submission);
+            }
+            StructuredEvent::ProjectionUpdate { transcript, state } => {
+                if let Some(delta) = transcript {
+                    self.apply_delta(delta);
+                }
+                self.apply_reduced(state, false);
+            }
+        }
+    }
+
+    fn apply_delta(&mut self, delta: TranscriptDelta) {
+        match delta {
+            TranscriptDelta::Append { row } => {
+                let followed_tail = self.follow_selection
+                    && self.selected.as_ref().is_some_and(|id| {
+                        self.rows
+                            .iter()
+                            .rev()
+                            .find(|old| old.kind != TranscriptRowKind::Plan)
+                            .is_some_and(|old| &old.id == id)
+                    });
+                if let Some(index) = self.rows.iter().position(|old| old.id == row.id) {
+                    self.rows[index] = row.clone();
+                } else {
+                    self.rows.push(row.clone());
+                }
+                if row.kind != TranscriptRowKind::Plan && (self.selected.is_none() || followed_tail)
+                {
+                    self.selected = Some(row.id);
+                }
+            }
+            TranscriptDelta::Patch { row } => {
+                if let Some(index) = self.rows.iter().position(|old| old.id == row.id) {
+                    self.rows[index] = row.clone();
+                } else {
+                    self.rows.push(row.clone());
+                }
+            }
+            TranscriptDelta::Remove { id } => {
+                let removed = self.rows.iter().position(|row| row.id == id);
+                self.rows.retain(|row| row.id != id);
+                self.expanded.remove(&id);
+                if self.selected.as_deref() == Some(&id) {
+                    self.selected = removed.and_then(|index| {
+                        let split = index.min(self.rows.len());
+                        self.rows[split..]
+                            .iter()
+                            .find(|row| row.kind != TranscriptRowKind::Plan)
+                            .or_else(|| {
+                                self.rows[..split]
+                                    .iter()
+                                    .rev()
+                                    .find(|row| row.kind != TranscriptRowKind::Plan)
+                            })
+                            .map(|row| row.id.clone())
+                    });
+                }
+            }
+        }
+    }
+
+    fn apply_reduced(&mut self, state: ReducedState, reconcile_submission: bool) {
+        let previous_nonce = self.pending_nonce().map(str::to_owned);
+        if reconcile_submission || state.turn.responding || state.turn.thinking {
+            self.submitting = false;
+        }
+        self.reduced = state;
+        let next_nonce = self.pending_nonce().map(str::to_owned);
+        if next_nonce != previous_nonce {
+            self.approval_submitting = false;
+            if next_nonce.is_some() {
+                self.selected = self
+                    .rows
+                    .iter()
+                    .rev()
+                    .find(|row| row.kind == TranscriptRowKind::Approval)
+                    .map(|row| row.id.clone());
+                self.follow_selection = true;
+            }
+        }
+    }
+
+    fn prepare_snapshot_reconciliation(&mut self) {
+        self.reconcile_submission_on_snapshot =
+            self.submitting.then_some(self.submission_generation);
+    }
+
+    pub fn select(&mut self, delta: isize) {
+        let selectable: Vec<&TranscriptRow> = self
+            .rows
+            .iter()
+            .filter(|row| row.kind != TranscriptRowKind::Plan)
+            .collect();
+        if selectable.is_empty() {
+            self.selected = None;
+            return;
+        }
+        let current = self
+            .selected
+            .as_ref()
+            .and_then(|id| selectable.iter().position(|row| &row.id == id))
+            .unwrap_or(selectable.len() - 1);
+        let next = if delta >= 0 {
+            current
+                .saturating_add(delta as usize)
+                .min(selectable.len() - 1)
+        } else {
+            current.saturating_sub(delta.unsigned_abs())
+        };
+        self.selected = Some(selectable[next].id.clone());
+        self.follow_selection = true;
+    }
+
+    /// Select the transcript block under a rendered transcript line. Pointer
+    /// input uses the same row identity map as scroll reconciliation, so a
+    /// wrapped block behaves as one target.
+    pub fn select_rendered_line(&mut self, line: usize) -> bool {
+        let Some(id) = self.line_rows.get(line).and_then(Clone::clone) else {
+            return false;
+        };
+        self.selected = Some(id);
+        self.follow_selection = false;
+        true
+    }
+
+    pub fn toggle_selected(&mut self) {
+        let Some(id) = self.selected.clone() else {
+            return;
+        };
+        let expandable = self.rows.iter().any(|row| {
+            row.id == id
+                && matches!(
+                    row.kind,
+                    TranscriptRowKind::ToolCall | TranscriptRowKind::ToolDiff
+                )
+        });
+        if !expandable {
+            return;
+        }
+        if !self.expanded.insert(id.clone()) {
+            self.expanded.remove(&id);
+        }
+        self.follow_selection = true;
+    }
+
+    pub fn scroll_by(&mut self, lines: isize) {
+        self.scroll = if lines >= 0 {
+            self.scroll.saturating_sub(lines as usize)
+        } else {
+            self.scroll.saturating_add(lines.unsigned_abs())
+        };
+        self.follow_selection = false;
+    }
+
+    pub fn edit_composer(&mut self, key: &InputKey) {
+        if !self.turn_active() {
+            self.composer.handle_key(key);
+            self.error = None;
+        }
+    }
+
+    pub fn begin_prompt(&mut self) -> Option<String> {
+        if self.turn_active() || self.composer.value().trim().is_empty() {
+            return None;
+        }
+        let prompt = self.composer.value().to_string();
+        self.composer = TextInput::default();
+        self.submission_generation = self.submission_generation.wrapping_add(1);
+        self.submitting = true;
+        self.error = None;
+        Some(prompt)
+    }
+
+    pub fn prompt_failed(&mut self, prompt: String, error: String) {
+        if self.composer.value().is_empty() {
+            self.composer = TextInput::with_value(prompt);
+        }
+        self.submitting = false;
+        self.error = Some(error);
+    }
+
+    pub fn turn_active(&self) -> bool {
+        self.submitting || self.reduced.turn.responding || self.reduced.turn.thinking
+    }
+
+    pub fn pending_nonce(&self) -> Option<&str> {
+        self.reduced
+            .pending_approval
+            .as_ref()?
+            .get("nonce")?
+            .as_str()
+    }
+
+    pub fn approval_decision(&mut self, key: char) -> Option<(String, StructuredApprovalDecision)> {
+        if self.approval_submitting {
+            return None;
+        }
+        let selected = self.selected.as_deref()?;
+        let pending_row = self
+            .rows
+            .iter()
+            .rev()
+            .find(|row| row.kind == TranscriptRowKind::Approval)?;
+        if pending_row.id != selected {
+            return None;
+        }
+        let decision = match key {
+            'a' => StructuredApprovalDecision::AllowOnce,
+            'A' => StructuredApprovalDecision::AllowForSession,
+            'd' => StructuredApprovalDecision::Deny,
+            _ => return None,
+        };
+        let offered = offered_decisions(&pending_row.data);
+        if !offered.contains(&decision) {
+            return None;
+        }
+        let nonce = self.pending_nonce()?.to_string();
+        self.approval_submitting = true;
+        self.error = None;
+        Some((nonce, decision))
+    }
+
+    pub fn approval_failed(&mut self, nonce: &str, error: String) {
+        if self.pending_nonce() != Some(nonce) {
+            return;
+        }
+        self.approval_submitting = false;
+        self.error = Some(error);
+    }
+}
+
+pub fn offered_decisions(data: &serde_json::Value) -> Vec<StructuredApprovalDecision> {
+    let mut out = Vec::new();
+    for kind in data
+        .get("options")
+        .and_then(serde_json::Value::as_array)
+        .into_iter()
+        .flatten()
+        .filter_map(|option| option.get("kind").and_then(serde_json::Value::as_str))
+    {
+        match kind {
+            "allow_once" if !out.contains(&StructuredApprovalDecision::AllowOnce) => {
+                out.push(StructuredApprovalDecision::AllowOnce)
+            }
+            "allow_always" if !out.contains(&StructuredApprovalDecision::AllowForSession) => {
+                out.push(StructuredApprovalDecision::AllowForSession)
+            }
+            "reject_once" | "reject_always" if !out.contains(&StructuredApprovalDecision::Deny) => {
+                out.push(StructuredApprovalDecision::Deny)
+            }
+            _ => {}
+        }
+    }
+    out
+}
+
+/// Cheap shared handle for a structured projection connection.
+#[derive(Clone)]
+pub struct StructuredHandle {
+    pub state: Arc<Mutex<StructuredState>>,
+    connection: Arc<AtomicU8>,
+    revision: Arc<AtomicU64>,
+    stop: watch::Sender<bool>,
+}
+
+impl std::fmt::Debug for StructuredHandle {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("StructuredHandle")
+            .field("connection", &self.connection())
+            .field("revision", &self.revision())
+            .finish_non_exhaustive()
+    }
+}
+
+impl StructuredHandle {
+    pub fn connection(&self) -> SessionState {
+        match self.connection.load(Ordering::Acquire) {
+            0 => SessionState::Connecting,
+            1 => SessionState::Live,
+            2 => SessionState::Reconnecting,
+            _ => SessionState::Ended,
+        }
+    }
+
+    pub fn revision(&self) -> u64 {
+        self.revision.load(Ordering::Acquire)
+    }
+
+    pub fn end(&self) {
+        self.connection
+            .store(SessionState::Ended as u8, Ordering::Release);
+        let _ = self.stop.send(true);
+    }
+
+    #[cfg(test)]
+    pub(crate) fn test_handle(state: StructuredState) -> Self {
+        let (stop, _) = watch::channel(false);
+        Self {
+            state: Arc::new(Mutex::new(state)),
+            connection: Arc::new(AtomicU8::new(SessionState::Live as u8)),
+            revision: Arc::new(AtomicU64::new(0)),
+            stop,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct StructuredTask;
+
+impl StructuredTask {
+    pub fn spawn(ws_url: String) -> StructuredHandle {
+        let state = Arc::new(Mutex::new(StructuredState::default()));
+        let connection = Arc::new(AtomicU8::new(SessionState::Connecting as u8));
+        let revision = Arc::new(AtomicU64::new(0));
+        let (stop, mut stopped) = watch::channel(false);
+        let handle = StructuredHandle {
+            state: state.clone(),
+            connection: connection.clone(),
+            revision: revision.clone(),
+            stop,
+        };
+
+        tokio::spawn(async move {
+            let mut backoff = Duration::from_secs(1);
+            loop {
+                if *stopped.borrow() {
+                    return;
+                }
+                state
+                    .lock()
+                    .expect("structured state mutex")
+                    .prepare_snapshot_reconciliation();
+                connection.store(SessionState::Connecting as u8, Ordering::Release);
+                let connected = tokio::select! {
+                    result = tokio_tungstenite::connect_async(&ws_url) => result,
+                    _ = stopped.changed() => return,
+                };
+                let (mut ws, _) = match connected {
+                    Ok(value) => value,
+                    Err(error) => {
+                        if terminal_handshake_error(&error) {
+                            state.lock().expect("structured state mutex").error =
+                                Some(format!("cannot open structured session: {error}"));
+                            connection.store(SessionState::Ended as u8, Ordering::Release);
+                            revision.fetch_add(1, Ordering::Release);
+                            return;
+                        }
+                        connection.store(SessionState::Reconnecting as u8, Ordering::Release);
+                        revision.fetch_add(1, Ordering::Release);
+                        tokio::select! {
+                            _ = tokio::time::sleep(super::session_task::jitter(backoff)) => {},
+                            _ = stopped.changed() => return,
+                        }
+                        backoff = backoff.saturating_mul(2).min(Duration::from_secs(30));
+                        continue;
+                    }
+                };
+                backoff = Duration::from_secs(1);
+                connection.store(SessionState::Live as u8, Ordering::Release);
+                revision.fetch_add(1, Ordering::Release);
+
+                loop {
+                    let frame = tokio::select! {
+                        frame = ws.next() => frame,
+                        _ = stopped.changed() => return,
+                    };
+                    match frame {
+                        Some(Ok(Message::Text(text))) => {
+                            if let Ok(event) = serde_json::from_str::<StructuredEvent>(&text) {
+                                state.lock().expect("structured state mutex").apply(event);
+                                revision.fetch_add(1, Ordering::Release);
+                            }
+                        }
+                        Some(Ok(Message::Close(_))) | None | Some(Err(_)) => break,
+                        _ => {}
+                    }
+                }
+                connection.store(SessionState::Reconnecting as u8, Ordering::Release);
+                revision.fetch_add(1, Ordering::Release);
+                tokio::select! {
+                    _ = tokio::time::sleep(super::session_task::jitter(backoff)) => {},
+                    _ = stopped.changed() => return,
+                }
+                backoff = backoff.saturating_mul(2).min(Duration::from_secs(30));
+            }
+        });
+        handle
+    }
+}
+
+fn terminal_handshake_error(error: &WsError) -> bool {
+    matches!(error, WsError::Http(response) if response.status().is_client_error())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use maestro_protocol::{TranscriptSnapshot, TurnState};
+    use serde_json::json;
+
+    fn row(id: &str, kind: TranscriptRowKind, data: serde_json::Value) -> TranscriptRow {
+        TranscriptRow {
+            id: id.into(),
+            kind,
+            data,
+        }
+    }
+
+    #[test]
+    fn snapshots_replace_and_deltas_address_rows_by_id() {
+        let mut state = StructuredState::default();
+        state.apply(StructuredEvent::TranscriptSnapshot {
+            snapshot: TranscriptSnapshot {
+                cursor: 2,
+                rows: vec![row("a", TranscriptRowKind::AgentText, json!({}))],
+            },
+        });
+        state.apply(StructuredEvent::ProjectionUpdate {
+            transcript: Some(TranscriptDelta::Patch {
+                row: row("a", TranscriptRowKind::AgentText, json!({"n": 2})),
+            }),
+            state: ReducedState::default(),
+        });
+        state.apply(StructuredEvent::ProjectionUpdate {
+            transcript: Some(TranscriptDelta::Append {
+                row: row("b", TranscriptRowKind::Notice, json!({})),
+            }),
+            state: ReducedState::default(),
+        });
+        assert_eq!(state.rows.len(), 2);
+        assert_eq!(state.rows[0].data["n"], 2);
+
+        state.apply(StructuredEvent::TranscriptSnapshot {
+            snapshot: TranscriptSnapshot {
+                cursor: 5,
+                rows: vec![row("b", TranscriptRowKind::Notice, json!({"fresh": true}))],
+            },
+        });
+        assert_eq!(state.rows.len(), 1);
+        assert_eq!(state.rows[0].data["fresh"], true);
+    }
+
+    #[test]
+    fn selection_survives_patch_and_moves_after_remove() {
+        let mut state = StructuredState {
+            rows: vec![
+                row("a", TranscriptRowKind::Notice, json!({})),
+                row("b", TranscriptRowKind::ToolCall, json!({})),
+                row("plan", TranscriptRowKind::Plan, json!({})),
+            ],
+            selected: Some("a".into()),
+            ..StructuredState::default()
+        };
+        state.select(1);
+        assert_eq!(state.selected.as_deref(), Some("b"));
+        state.toggle_selected();
+        assert!(state.expanded.contains("b"));
+        state.apply_delta(TranscriptDelta::Remove { id: "b".into() });
+        assert_eq!(state.selected.as_deref(), Some("a"));
+
+        state.apply_delta(TranscriptDelta::Remove { id: "a".into() });
+        assert_eq!(
+            state.selected, None,
+            "collapsed plan rows are not selectable"
+        );
+    }
+
+    #[test]
+    fn approval_keys_only_offer_server_backed_decisions() {
+        let mut state = StructuredState::default();
+        state.rows.push(row(
+            "approval:1",
+            TranscriptRowKind::Approval,
+            json!({"options":[
+                {"kind":"allow_once"}, {"kind":"reject_always"}
+            ]}),
+        ));
+        state.selected = Some("approval:1".into());
+        state.reduced.pending_approval = Some(json!({"nonce":"secret"}));
+        assert_eq!(
+            state.approval_decision('A'),
+            None,
+            "allow-for-session was not offered"
+        );
+        assert_eq!(
+            state.approval_decision('a'),
+            Some(("secret".into(), StructuredApprovalDecision::AllowOnce))
+        );
+    }
+
+    #[test]
+    fn resolved_approval_ignores_its_late_failure() {
+        let mut state = StructuredState::default();
+        state.rows.push(row(
+            "approval:1",
+            TranscriptRowKind::Approval,
+            json!({"options":[{"kind":"allow_once"}]}),
+        ));
+        state.selected = Some("approval:1".into());
+        state.reduced.pending_approval = Some(json!({"nonce":"old"}));
+        assert!(state.approval_decision('a').is_some());
+
+        state.apply(StructuredEvent::ProjectionUpdate {
+            transcript: None,
+            state: ReducedState::default(),
+        });
+        state.approval_failed("old", "response lost".into());
+
+        assert_eq!(state.error, None);
+        assert!(!state.approval_submitting);
+    }
+
+    #[test]
+    fn superseded_approval_ignores_its_late_failure() {
+        let mut state = StructuredState::default();
+        state.rows.push(row(
+            "approval:1",
+            TranscriptRowKind::Approval,
+            json!({"options":[{"kind":"allow_once"}]}),
+        ));
+        state.selected = Some("approval:1".into());
+        state.reduced.pending_approval = Some(json!({"nonce":"old"}));
+        assert!(state.approval_decision('a').is_some());
+
+        state.rows.push(row(
+            "approval:2",
+            TranscriptRowKind::Approval,
+            json!({"options":[{"kind":"allow_once"}]}),
+        ));
+        state.apply(StructuredEvent::ProjectionUpdate {
+            transcript: None,
+            state: ReducedState {
+                pending_approval: Some(json!({"nonce":"new"})),
+                ..ReducedState::default()
+            },
+        });
+        assert_eq!(
+            state.approval_decision('a'),
+            Some(("new".into(), StructuredApprovalDecision::AllowOnce))
+        );
+
+        state.approval_failed("old", "response lost".into());
+
+        assert_eq!(state.error, None);
+        assert!(state.approval_submitting);
+    }
+
+    #[test]
+    fn matching_approval_surfaces_its_failure() {
+        let mut state = StructuredState::default();
+        state.rows.push(row(
+            "approval:1",
+            TranscriptRowKind::Approval,
+            json!({"options":[{"kind":"allow_once"}]}),
+        ));
+        state.selected = Some("approval:1".into());
+        state.reduced.pending_approval = Some(json!({"nonce":"current"}));
+        assert!(state.approval_decision('a').is_some());
+
+        state.approval_failed("current", "request failed".into());
+
+        assert_eq!(state.error.as_deref(), Some("request failed"));
+        assert!(!state.approval_submitting);
+    }
+
+    #[test]
+    fn composer_is_gated_by_the_projected_turn_lifecycle() {
+        let mut state = StructuredState::default();
+        state.edit_composer(&InputKey::char('h'));
+        state.edit_composer(&InputKey::char('i'));
+        assert_eq!(state.begin_prompt().as_deref(), Some("hi"));
+        assert!(state.turn_active());
+        state.prompt_failed("hi".into(), "nope".into());
+        assert_eq!(state.composer.value(), "hi");
+
+        state.reduced.turn = TurnState {
+            responding: true,
+            ..TurnState::default()
+        };
+        state.edit_composer(&InputKey::char('x'));
+        assert_eq!(state.composer.value(), "hi");
+    }
+
+    #[test]
+    fn selecting_a_rendered_line_selects_its_whole_block() {
+        let mut state = StructuredState {
+            line_rows: vec![
+                Some("one".into()),
+                Some("one".into()),
+                None,
+                Some("two".into()),
+            ],
+            ..Default::default()
+        };
+
+        assert!(state.select_rendered_line(1));
+        assert_eq!(state.selected.as_deref(), Some("one"));
+        assert!(!state.follow_selection);
+        assert!(!state.select_rendered_line(2));
+        assert_eq!(state.selected.as_deref(), Some("one"));
+    }
+
+    #[test]
+    fn authoritative_idle_snapshot_reconciles_a_wholly_missed_turn() {
+        let mut state = StructuredState::default();
+        state.edit_composer(&InputKey::char('h'));
+        state.edit_composer(&InputKey::char('i'));
+        assert_eq!(state.begin_prompt().as_deref(), Some("hi"));
+
+        state.apply(StructuredEvent::ProjectionUpdate {
+            transcript: None,
+            state: ReducedState::default(),
+        });
+        assert!(
+            state.turn_active(),
+            "an ordinary idle update must not reopen the composer before turn begin"
+        );
+
+        state.prepare_snapshot_reconciliation();
+        state.apply(StructuredEvent::TranscriptSnapshot {
+            snapshot: TranscriptSnapshot {
+                cursor: 0,
+                rows: Vec::new(),
+            },
+        });
+        state.apply(StructuredEvent::ReducedState {
+            state: ReducedState::default(),
+        });
+        assert!(
+            !state.turn_active(),
+            "a reconnect snapshot must settle a submission whose whole turn was missed"
+        );
+    }
+
+    #[test]
+    fn stale_handshake_state_does_not_settle_a_new_submission() {
+        let mut state = StructuredState::default();
+        state.prepare_snapshot_reconciliation();
+        state.apply(StructuredEvent::TranscriptSnapshot {
+            snapshot: TranscriptSnapshot {
+                cursor: 0,
+                rows: Vec::new(),
+            },
+        });
+
+        state.edit_composer(&InputKey::char('h'));
+        state.edit_composer(&InputKey::char('i'));
+        assert_eq!(state.begin_prompt().as_deref(), Some("hi"));
+        state.apply(StructuredEvent::ReducedState {
+            state: ReducedState::default(),
+        });
+
+        assert!(
+            state.turn_active(),
+            "state captured before this submission must not reopen the composer"
+        );
+    }
+
+    #[test]
+    fn failed_submission_reconciliation_does_not_settle_its_successor() {
+        let mut state = StructuredState::default();
+        state.edit_composer(&InputKey::char('a'));
+        assert_eq!(state.begin_prompt().as_deref(), Some("a"));
+        state.prepare_snapshot_reconciliation();
+
+        state.prompt_failed("a".into(), "nope".into());
+        state.composer = TextInput::with_value("b");
+        assert_eq!(state.begin_prompt().as_deref(), Some("b"));
+
+        state.apply(StructuredEvent::TranscriptSnapshot {
+            snapshot: TranscriptSnapshot {
+                cursor: 0,
+                rows: Vec::new(),
+            },
+        });
+        state.apply(StructuredEvent::ReducedState {
+            state: ReducedState::default(),
+        });
+
+        assert!(
+            state.turn_active(),
+            "a reconnect for the failed submission must not settle its successor"
+        );
+    }
+}

crates/maestro-tui/tests/structured_http.rs

@@ -0,0 +1,79 @@
+//! The TUI's structured actions use the shared typed daemon client; assert the
+//! exact route and bare approval decision body at the HTTP boundary.
+
+use std::sync::{Arc, Mutex};
+
+use axum::extract::{Path, State};
+use axum::routing::post;
+use axum::{Json, Router};
+use maestro_protocol::{DaemonClient, StructuredApprovalDecision, StructuredPromptRequest};
+use uuid::Uuid;
+
+#[derive(Debug, Default)]
+struct Seen {
+    prompt: Option<String>,
+    cancelled: bool,
+    approval: Option<(String, StructuredApprovalDecision)>,
+}
+
+type Shared = Arc<Mutex<Seen>>;
+
+async fn prompt(
+    State(seen): State<Shared>,
+    Path(_id): Path<Uuid>,
+    Json(body): Json<StructuredPromptRequest>,
+) {
+    seen.lock().unwrap().prompt = Some(body.prompt);
+}
+
+async fn cancel(State(seen): State<Shared>, Path(_id): Path<Uuid>) {
+    seen.lock().unwrap().cancelled = true;
+}
+
+async fn approval(
+    State(seen): State<Shared>,
+    Path((_id, nonce)): Path<(Uuid, String)>,
+    Json(decision): Json<StructuredApprovalDecision>,
+) {
+    seen.lock().unwrap().approval = Some((nonce, decision));
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn prompt_cancel_and_approval_use_structured_api_contract() {
+    let seen = Shared::default();
+    let app = Router::new()
+        .route("/api/sessions/:id/structured/prompt", post(prompt))
+        .route("/api/sessions/:id/structured/cancel", post(cancel))
+        .route(
+            "/api/sessions/:id/structured/approvals/:nonce",
+            post(approval),
+        )
+        .with_state(seen.clone());
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let addr = listener.local_addr().unwrap();
+    tokio::spawn(async move { axum::serve(listener, app).await.unwrap() });
+
+    let client = DaemonClient::new(format!("http://{addr}"));
+    let id = Uuid::from_u128(141);
+    client.send_structured_prompt(id, "ship it").await.unwrap();
+    client.cancel_structured_turn(id).await.unwrap();
+    client
+        .resolve_structured_approval(
+            id,
+            "one-use-nonce",
+            StructuredApprovalDecision::AllowForSession,
+        )
+        .await
+        .unwrap();
+
+    let seen = seen.lock().unwrap();
+    assert_eq!(seen.prompt.as_deref(), Some("ship it"));
+    assert!(seen.cancelled);
+    assert_eq!(
+        seen.approval,
+        Some((
+            "one-use-nonce".into(),
+            StructuredApprovalDecision::AllowForSession
+        ))
+    );
+}

crates/maestro-tui/tests/structured_task_ws.rs

@@ -0,0 +1,107 @@
+//! Projection socket coverage: snapshots replace state on reconnect and live
+//! deltas patch rows without client-side event folding.
+
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+
+use axum::extract::ws::{Message, WebSocketUpgrade};
+use axum::extract::State;
+use axum::response::Response;
+use axum::routing::any;
+use axum::Router;
+use maestro_protocol::{
+    ReducedState, StructuredEvent, TranscriptDelta, TranscriptRow, TranscriptRowKind,
+    TranscriptSnapshot,
+};
+use maestro_tui::session_task::SessionState;
+use maestro_tui::structured_task::StructuredTask;
+use serde_json::json;
+
+async fn structured_handler(
+    State(connects): State<Arc<AtomicUsize>>,
+    ws: WebSocketUpgrade,
+) -> Response {
+    ws.on_upgrade(move |mut socket| async move {
+        let attempt = connects.fetch_add(1, Ordering::SeqCst);
+        let snapshot = if attempt == 0 {
+            TranscriptSnapshot {
+                cursor: 1,
+                rows: vec![row("old", json!({"content":{"type":"text","text":"old"}}))],
+            }
+        } else {
+            TranscriptSnapshot {
+                cursor: 3,
+                rows: vec![row("live", json!({"content":{"type":"text","text":"one"}}))],
+            }
+        };
+        send(
+            &mut socket,
+            StructuredEvent::TranscriptSnapshot { snapshot },
+        )
+        .await;
+        if attempt == 0 {
+            let _ = socket.close().await;
+            return;
+        }
+        send(
+            &mut socket,
+            StructuredEvent::ProjectionUpdate {
+                transcript: Some(TranscriptDelta::Patch {
+                    row: row("live", json!({"content":{"type":"text","text":"two"}})),
+                }),
+                state: ReducedState {
+                    model: Some("test-model".into()),
+                    ..ReducedState::default()
+                },
+            },
+        )
+        .await;
+        tokio::time::sleep(Duration::from_secs(3)).await;
+    })
+}
+
+fn row(id: &str, data: serde_json::Value) -> TranscriptRow {
+    TranscriptRow {
+        id: id.into(),
+        kind: TranscriptRowKind::AgentText,
+        data,
+    }
+}
+
+async fn send(socket: &mut axum::extract::ws::WebSocket, event: StructuredEvent) {
+    socket
+        .send(Message::Text(serde_json::to_string(&event).unwrap()))
+        .await
+        .unwrap();
+}
+
+#[tokio::test(flavor = "multi_thread")]
+async fn reconnect_snapshot_replaces_then_delta_patches_projection() {
+    let connects = Arc::new(AtomicUsize::new(0));
+    let app = Router::new()
+        .route("/api/structured/x", any(structured_handler))
+        .with_state(connects.clone());
+    let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let addr = listener.local_addr().unwrap();
+    tokio::spawn(async move { axum::serve(listener, app).await.unwrap() });
+
+    let handle = StructuredTask::spawn(format!("ws://{addr}/api/structured/x"));
+    for _ in 0..250 {
+        tokio::time::sleep(Duration::from_millis(10)).await;
+        let state = handle.state.lock().unwrap().clone();
+        if state.reduced.model.as_deref() == Some("test-model") {
+            assert_eq!(state.rows.len(), 1);
+            assert_eq!(state.rows[0].id, "live");
+            assert_eq!(state.rows[0].data["content"]["text"], "two");
+            assert!(connects.load(Ordering::SeqCst) >= 2);
+            handle.end();
+            assert_eq!(handle.connection(), SessionState::Ended);
+            return;
+        }
+    }
+    panic!(
+        "structured projection never reached reconnect delta; connection={:?}",
+        handle.connection()
+    );
+}

crates/maestro/Cargo.toml

@@ -29,3 +29,6 @@ tracing-subscriber.workspace = true
 maestro-cli = { path = "../maestro-cli", optional = true, default-features = false }
 maestro-daemon = { path = "../maestro-daemon", optional = true, default-features = false }
 maestro-tui = { path = "../maestro-tui", optional = true }
+
+[dev-dependencies]
+tempfile.workspace = true

crates/maestro/tests/subcommand_routing.rs

@@ -0,0 +1,102 @@
+//! Process-level routing for the umbrella `maestro` binary (#10): each
+//! enabled top-level subcommand must reach its own crate's runtime dispatch,
+//! not just parse successfully.
+//!
+//! A malformed `--config` file makes every crate's dispatch fail identically
+//! at config load, before any subcommand touches tmux, the network, or a
+//! terminal. That lets the assertions tell "clap parsed it but the handler
+//! never ran" (a usage error, exit 2) apart from "it dispatched into the real
+//! crate" (a `toml decode` runtime error via `main`'s `maestro: {e}` printer,
+//! exit 1).
+//!
+//! The absence tests below only compile when the matching feature is off, so
+//! they run under CI's per-feature-subset matrix (`--no-default-features
+//! --features cli|daemon|tui`) rather than the default all-features build.
+
+use std::io::Write;
+use std::path::PathBuf;
+use std::process::{Command, Output};
+
+fn bin() -> PathBuf {
+    PathBuf::from(env!("CARGO_BIN_EXE_maestro"))
+}
+
+fn bad_config() -> tempfile::NamedTempFile {
+    let mut f = tempfile::NamedTempFile::new().expect("create temp config file");
+    write!(f, "this is not valid toml {{{{{{").expect("write temp config");
+    f
+}
+
+fn run(args: &[&str]) -> Output {
+    Command::new(bin())
+        .args(args)
+        .output()
+        .unwrap_or_else(|e| panic!("spawn `maestro {args:?}`: {e}"))
+}
+
+/// Real dispatch happened: exit 1, `main`'s `"maestro: {e}"` prefix, and the
+/// config crate's error surfacing through — never clap's own usage-error
+/// page, which would mean the subcommand never reached its handler.
+fn assert_dispatched(out: &Output) {
+    let stderr = String::from_utf8_lossy(&out.stderr);
+    assert_eq!(out.status.code(), Some(1), "stderr:\n{stderr}");
+    assert!(stderr.starts_with("maestro: "), "stderr:\n{stderr}");
+    assert!(stderr.contains("toml decode"), "stderr:\n{stderr}");
+    assert!(!stderr.contains("Usage:"), "stderr:\n{stderr}");
+}
+
+/// Never reached a handler: clap rejected the subcommand outright because the
+/// feature that defines it is off. Only used by the `not(feature = "...")`
+/// tests below, which themselves only exist in a single-feature build.
+#[cfg(not(all(feature = "cli", feature = "daemon", feature = "tui")))]
+fn assert_unrecognized(out: &Output, name: &str) {
+    let stderr = String::from_utf8_lossy(&out.stderr);
+    assert_eq!(out.status.code(), Some(2), "stderr:\n{stderr}");
+    assert!(
+        stderr.contains("unrecognized subcommand"),
+        "stderr:\n{stderr}"
+    );
+    assert!(stderr.contains(name), "stderr:\n{stderr}");
+}
+
+#[cfg(feature = "cli")]
+#[test]
+fn list_dispatches_into_maestro_cli() {
+    let cfg = bad_config();
+    let out = run(&["list", "--config", cfg.path().to_str().unwrap()]);
+    assert_dispatched(&out);
+}
+
+#[cfg(not(feature = "cli"))]
+#[test]
+fn list_is_unrecognized_without_cli_feature() {
+    assert_unrecognized(&run(&["list"]), "list");
+}
+
+#[cfg(feature = "daemon")]
+#[test]
+fn daemon_dispatches_into_maestro_daemon() {
+    let cfg = bad_config();
+    let out = run(&["daemon", "--config", cfg.path().to_str().unwrap()]);
+    assert_dispatched(&out);
+}
+
+#[cfg(not(feature = "daemon"))]
+#[test]
+fn daemon_is_unrecognized_without_daemon_feature() {
+    assert_unrecognized(&run(&["daemon"]), "daemon");
+}
+
+#[cfg(feature = "tui")]
+#[test]
+fn tui_dispatches_into_maestro_tui() {
+    let cfg = bad_config();
+    let out = run(&["tui", "--config", cfg.path().to_str().unwrap()]);
+    assert_dispatched(&out);
+}
+
+#[cfg(not(feature = "tui"))]
+#[test]
+fn tui_is_unrecognized_without_tui_feature() {
+    assert_unrecognized(&run(&["tui"]), "tui");
+}

docs/INSTALL.md

@@ -18,10 +18,14 @@ wizard, and cleans up — only the unified `maestro` binary ends up persisted in
 
 **Updating is the same command.** Re-running `./install.sh` detects an existing
 systemd unit, refreshes it, and runs `systemctl --user restart maestro` instead
-of `start`. No `--update` flag needed. **The restart keeps your sessions:** the unit sets
+of `start`. No `--update` flag needed. **The restart keeps your terminal sessions:** the unit sets
 `KillMode=process`, so systemd signals only the daemon — the tmux server (and
-every session) survives, and the new daemon re-adopts them on start. A unit
-written before this default lacks the line; re-run `./install.sh` to refresh it.
+every tmux-backed session) survives, and the new daemon re-adopts them on
+start. Structured sessions (an agent run as a daemon child over ACP) are not
+tmux panes, so shutdown ends their active turn; the transcript survives and
+the next daemon attempts one resume (`docs/RESTART.md#structured-sessions`). A
+unit written before this default lacks the line; re-run `./install.sh` to
+refresh it.
 
 Inside the script, `cargo install --git https://git.naps.pt/naps62/maestro …`
 uses your already-configured git credentials for this host (HTTPS helper or
@@ -94,7 +98,10 @@ running a local daemon, for a host that only talks to another machine's.
 
 The daemon unit carries the same `KillMode=process` as the wizard-written one,
 so `systemctl --user restart maestro-daemon` leaves the tmux server and every
-session alive.
+terminal session alive. Structured sessions end their active turn on
+shutdown and resume once on the next daemon: ACP state comes back via
+`session/load`, while the event log only replays Maestro's own transcript
+projection (`docs/RESTART.md#structured-sessions`).
 
 ## Thin builds for single-role hosts
 
@@ -188,30 +195,36 @@ An unknown name is rejected as an `[tui].theme` configuration error.
 The full action vocabulary is the `Action` enum in
 `crates/maestro-tui/src/action.rs`.
 
-## Structured sessions: `claude-code-acp`
+## Structured sessions: ACP adapters
 
-A session spawned with `view: Structured` (#134) runs Claude Code as a child
+A session spawned with `view: Structured` runs Claude Code or Codex as a child
 of the daemon over the Agent Client Protocol instead of in a tmux pane. The
-daemon resolves the adapter binary, `claude-code-acp`, on its `PATH` at spawn
-time. Install it once per host:
+resolved session command selects the adapter binary, which must be on the
+session's `PATH` when the spawn request sets one, or the daemon's `PATH`
+otherwise. Install the adapter for each provider you use:
 
 ```sh
 npm install -g --prefix ~/.local @zed-industries/claude-code-acp
+npm install -g --prefix ~/.local @agentclientprotocol/codex-acp
 ```
 
-That puts `claude-code-acp` in `~/.local/bin`, which must be on the daemon's
-`PATH` (a systemd user unit does not read your shell profile; set
+That puts `claude-code-acp` and `codex-acp` in `~/.local/bin`, which must be on
+the applicable `PATH` (a systemd user unit does not read your shell profile; set
 `Environment=PATH=…` in the unit or install somewhere already on it). The
-adapter needs a logged-in Claude Code (`claude /login`).
+Claude adapter needs a logged-in Claude Code (`claude /login`); Codex uses the
+Codex CLI's or adapter's configured authentication.
 
 When the adapter is missing the spawn still creates the session, marked dead
-with the install command above as its activity detail, so the sidebar says
-what to run. The adapter is a child of the daemon: it ends with a `DELETE
+with the provider-specific install command as its activity detail, so clients
+say what to run. The adapter is a child of the daemon: it ends with a `DELETE
 /api/sessions/:id` (`session/cancel`, then `SIGTERM`) and with the daemon
 itself. A daemon restart ends an in-flight structured turn, but preserves its
 worktree, session record, and event-log transcript. The replacement daemon
 starts a new adapter, resumes it with `session/load`, and replays the
-transcript. Terminal sessions keep surviving restarts through tmux.
+transcript. Terminal sessions keep surviving restarts through tmux. See
+`docs/STRUCTURED-VIEW.md` for the full contract — row kinds, projections, the
+handshake, and the approval and recovery rules — and `docs/RESTART.md` for
+what a client observes across the restart.
 
 ## The browser UI
 

docs/RESTART.md

@@ -2,10 +2,16 @@
 
 Maestro is upgraded in place: the operator reinstalls the binary and systemd
 restarts the daemon under every browser tab and TUI that is attached to it.
-tmux keeps the sessions alive across that (see `docs/INSTALL.md`), but clients
-lose their sockets. This document is the contract for what a client does about
-it — what the daemon publishes, how a client tells a restart from a blip, and
-what the user sees while it happens.
+tmux keeps **terminal** sessions alive across that (see `docs/INSTALL.md`),
+but clients lose their sockets either way. This document is the contract for
+what a client does about it — what the daemon publishes, how a client tells a
+restart from a blip, and what the user sees while it happens.
+
+A **structured** session (`docs/STRUCTURED-VIEW.md`) has no tmux pane behind
+it to survive on: its agent is a child of the daemon process itself, so a
+restart takes it down with the daemon. See
+[Structured sessions](#structured-sessions) below for exactly what that
+costs and what it doesn't.
 
 ## What the daemon publishes
 
@@ -68,6 +74,35 @@ resolves, so a blocked client is never a trapped one. It clears itself the
 moment a probe succeeds — there is no "retry" button, because the client is
 already retrying.
 
+## Structured sessions
+
+Everything above describes a **client's** view of a restart, and it holds for
+a structured session exactly as written — the same three verdicts, the same
+status indicator, the same overlay. What differs is what survives on the
+**daemon** side, because a structured session's agent is a daemon child, not
+a tmux pane:
+
+- A restart **ends the active turn**. There is no adapter process left to
+  finish it, and no tmux pane keeping it alive underneath.
+- The **transcript survives**, in the per-session event log
+  (`docs/STRUCTURED-VIEW.md#persistence-recovery-and-dead-sessions`) — a
+  graceful shutdown marks the session for one resume attempt. Recovery is
+  two separate operations, not one: the next daemon calls `session/load` so
+  the adapter restores its own ACP session, but whatever history the
+  adapter emits during that call is discarded, not replayed into anything —
+  the daemon already has that history on disk. Separately, the daemon
+  rebuilds its own projection by folding the persisted event log back
+  through it. An ungraceful death (a crash, `kill -9`) leaves no resume
+  marker, and the session stays dead permanently.
+- **Pending approvals and their nonces do not survive.** Both live only in
+  the old daemon's memory; any ACP permission request still mid-flight when
+  the daemon exits is answered `Cancelled` on the way down, and a resumed
+  session starts with no pending approval at all.
+
+`docs/STRUCTURED-VIEW.md` is the full contract for all of this — the event
+log's shape, the recovery marker, and exactly which kind of session death is
+resumable.
+
 ## Timing
 
 - **Grace window** — 1200 ms between the socket dropping and the overlay

docs/SIDEBAR.md

@@ -160,6 +160,7 @@ The state word is never spelled out — the colour carries it.
 | ---------------- | --------- | ---------------- |
 | `Active`         | `--live`  | `active`         |
 | `Idle`           | `--muted` | `idle`           |
+| `Starting`       | `--muted` | `idle`           |
 | `AwaitingInput`  | `--warn`  | `awaiting`       |
 | `Error`          | `--danger`| `error`          |
 
@@ -231,7 +232,24 @@ cutover points land within one tick.
 
 ## Precedence
 
-An agent-reported `ActivityState` (#105) overrides the daemon's inference for
+### Activity source by session kind
+
+The daemon supplies one `activity` field to both clients, but its source depends
+on the session kind:
+
+| Session kind | Source |
+|---|---|
+| Terminal | The existing agent-report override and five-minute TTL, falling back to PTY quiescence, foreground process and `/proc` input-block inference. |
+| Structured | ACP state directly: a pending approval is `AwaitingInput`; otherwise an in-flight turn is `Active`; no turn is `Idle`. A failed turn or dead structured session is `Error`, and the next turn clears a failed-turn error. |
+
+Structured sessions never enter the terminal inference path and ignore activity
+reports inherited through agent hooks. They have no PTY whose output or blocked
+read could describe their state. This is a second source, not a replacement for
+the terminal source.
+
+### Terminal report override
+
+For terminal sessions, an agent-reported `ActivityState` (#105) overrides the daemon's inference for
 **five minutes** (the TTL is fixed by the daemon; re-reporting extends it).
 When the TTL expires, inference resumes and the session's reported detail —
 if any — clears with the report. Clients never blend the two: whichever source
@@ -281,10 +299,10 @@ session is genuinely `Active` again — new work, not merely a refocus. Only
 after that fresh `Active` cycle does the *next* `AwaitingInput` glow again.
 Unfocusing and refocusing alone never re-arms it.
 
-This applies uniformly to `AwaitingInput` from either source — the daemon's
-own inference or an agent's report (#105) — since the rail draws them
-identically. It does not touch `Error`; that state's own TTL (below) is
-unrelated and unaffected by focus.
+This applies uniformly to `AwaitingInput` from terminal inference, an agent
+report (#105), or a structured session's pending approval, since the rail draws
+them identically. It does not touch `Error`; terminal reports keep their TTL,
+while a structured failed-turn error clears when the next turn starts.
 
 Each client reports its own pane's focus with `POST /api/sessions/:id/focus`
 (`{"focused": bool}`) whenever the pane it is showing changes — on attach, on

docs/STRUCTURED-VIEW.md

@@ -0,0 +1,459 @@
+# STRUCTURED-VIEW.md — the structured session contract
+
+The contract for a structured session (`view: Structured`, #133): an agent run
+as a daemon child over the Agent Client Protocol (ACP) instead of in a tmux
+pane. Alongside `docs/WORKTREES.md`, `docs/SIDEBAR.md` and `docs/RESTART.md`,
+read this before changing anything that renders a structured session — both
+the web and TUI renderers are written against it.
+
+It covers the eight transcript row kinds, what the daemon decides versus what
+a client decides, the two projections and their delta/cursor semantics, the
+ACP handshake and the capabilities it declines, the adapter's install
+command, and the approval nonce rules. **Non-goal: the detached runner.** It
+does not exist yet, and nothing here describes it.
+
+## What a structured session is
+
+A terminal session's agent runs inside a tmux pane; a structured session's
+agent runs as a subprocess of the daemon itself, speaking ACP over stdio. The
+daemon is the ACP **client**; the provider adapter process is the ACP
+**agent**. It translates the provider's events into ACP `session/update`
+notifications instead of drawing them to a pane. `crates/maestro-acp` owns the
+daemon's side of that connection;
+`crates/maestro-daemon/src/projection.rs` folds what it receives into the two
+projections below.
+
+The child is a real child of the daemon process: same process group, and on
+Linux marked with `PR_SET_PDEATHSIG` so it dies with the daemon even if the
+daemon exits without cleaning up; other platforms have no such signal and
+depend on an orderly shutdown/drop to terminate it. The ordinary path on
+every platform is `AcpSession::terminate` (`session/cancel`, a short grace,
+`SIGTERM`, then `SIGKILL`), called from both `DELETE /api/sessions/:id` and
+daemon shutdown.
+`docs/WORKTREES.md`'s kill-guard rule — an unforced kill refused while the
+session's worktree holds unsaved work — applies to a structured session
+exactly as it does to a terminal one; only what gets terminated differs (an
+ACP handle instead of a tmux pane).
+
+## Choosing the view
+
+`view` is fixed at spawn and never changes. Every client picks it the same
+way, from the resolved command alone
+(`maestro_protocol::display::supports_structured_view`): a command that
+resolves to Claude Code or Codex spawns **Structured** by default, anything
+else spawns **Terminal**. The operator can override the default — the web and
+TUI spawn forms show the checkbox ticked and let it be unticked, and
+`maestro spawn` takes `--terminal` (or `--structured`, which sends the request
+even for a command the CLI does not recognise and lets the daemon refuse it).
+Once the operator works the toggle, a later command change never re-ticks it
+under them; it can still be forced off when the new command has no adapter.
+
+The daemon is the last word: a `Structured` request for a command with no
+adapter is refused there, whichever client sent it.
+
+## The adapter
+
+The resolved structured command selects a provider adapter. Its binary is
+resolved by walking the session's `PATH` when the spawn request sets one, or
+the daemon's `PATH` otherwise, and taking the first executable with that name.
+
+| Command | Adapter binary | Install command | Provider detail |
+| --- | --- | --- | --- |
+| `claude` | `claude-code-acp` | `npm install -g --prefix ~/.local @zed-industries/claude-code-acp` | Needs a logged-in Claude Code. |
+| `codex` | `codex-acp` | `npm install -g --prefix ~/.local @agentclientprotocol/codex-acp` | Uses Codex CLI or adapter-configured authentication; it advertises model, reasoning-effort, agent-mode, and optional fast-mode configuration. |
+
+The selected install command is baked into `AcpError::AdapterMissing`. When an
+adapter cannot be found, spawn still creates a **Dead** session with that
+command as `activity_detail` (see `docs/INSTALL.md` for the systemd `PATH`
+caveat). Provider authentication failures surface through the adapter's stderr
+tail in the same field.
+
+The handshake is bounded by `HANDSHAKE_TIMEOUT` (60s) — long enough for a
+slow machine to boot an adapter and its provider process, never long enough
+to hang a spawn indefinitely. Any handshake failure — missing adapter, early
+exit, a protocol error, or the timeout — leaves no orphaned process: `spawn`
+closes and reaps the child itself before returning the error.
+
+## The ACP handshake
+
+`initialize` is where the daemon states what kind of client it is. It
+declares, deliberately, almost nothing:
+
+| Capability | Declared | Why |
+| --- | --- | --- |
+| `fs.readTextFile` | `false` | Providers read the session workspace through their own tool surface. |
+| `fs.writeTextFile` | `false` | Providers write the session workspace through their own tool surface. |
+| `terminal` | `false` | Providers run commands through their own tool surface. |
+
+Declining all three keeps the daemon out of the file/terminal surface
+entirely — the adapter already has direct access to the session's `cwd`, and
+routing every read, write, and shell command through the daemon would only
+add a hop with no new capability. Every other capability namespace ACP
+defines (session extensions, auth, elicitation) is simply left at its
+default; the daemon does not advertise support because neither supported
+adapter needs it, not because it was weighed and refused.
+
+The one client method that *is* implemented for real is
+`session/request_permission` (#139) — see [Approvals](#approvals) below.
+Before #139 it was a stub that declined every request; that stub is gone now
+that a live implementation exists.
+
+`session/new` opens a fresh ACP session on every ordinary spawn. A respawn
+after a daemon restart instead sets `SpawnConfig::load_session(id)` and runs
+`session/load` with the ACP session id the original handshake returned
+(`Session::acp_session_id` on the wire) — the adapter must advertise
+`agent_capabilities.load_session`, or the handshake fails outright naming
+that. Whatever history the adapter streams back while `session/load` is in
+flight is dropped on arrival, deliberately: the daemon's own event log
+already holds that history, and forwarding it too would duplicate every row
+in the projections below.
+
+Codex and Claude differ in what they emit, not in this lifecycle. Codex maps
+shell commands, file changes, MCP calls, web search, image generation/view,
+reasoning, plans, and token usage into standard ACP chunks and tool calls;
+those fold into the same eight rows. Codex's `available_commands_update` and
+`session_info_update`, like equivalent Claude updates, remain opaque
+`Notice` rows. Its `session/load` capability is required for daemon recovery
+just as it is for Claude.
+
+## The eight transcript row kinds
+
+`TranscriptRowKind` (`maestro-protocol`) is the alphabet a structured
+transcript is written in. Every row has a stable `id` (so later deltas can
+address it), a `kind`, and a `data: Value` that preserves the underlying ACP
+payload — clients depend on ACP's *shape* without depending on ACP as a
+crate.
+
+| Kind | Carries | Row identity |
+| --- | --- | --- |
+| `User` | The prompt accepted by Maestro's structured prompt endpoint, persisted before ACP dispatch. An adapter `user_message_chunk` is also supported for imported ACP history. | `user:<uuid>` for a daemon-recorded prompt; `user:<message_id>` or `user:<seq>` for an ACP chunk. |
+| `AgentText` | An `agent_message_chunk` — the agent's visible reply, streamed. | `agent:<message_id>`, or `agent:<seq>` from the first chunk when no id is supplied. Later chunks for the same id—or consecutive anonymous text chunks—are appended into `data.content.text` in place. An empty anonymous chunk starts a fresh row, matching the turn marker emitted by adapters that omit message ids. |
+| `AgentThought` | An `agent_thought_chunk` — the model's reasoning stream. | `thought:<message_id>` / first anonymous `thought:<seq>`, coalesced the same way as `AgentText`. |
+| `ToolCall` | A `tool_call` / `tool_call_update` pair whose content carries no diff. | `tool:<tool_call_id>` — one row for the call's whole life; updates patch it in place, they never create a second row. |
+| `ToolDiff` | The same tool-call machinery, when the tool's content includes a `Diff` block. | Same `tool:<tool_call_id>` identity as `ToolCall`; the *kind* flips between the two as the tool's own content changes, not the row. |
+| `Approval` | A daemon-originated permission request (`RequestPermissionRequest`), serialized without its nonce. | `approval:<uuid>` — minted fresh per request, unrelated to the ACP request's own id. |
+| `Plan` | A `plan` update — the agent's current step list. | The fixed id `"plan"`. Each new plan **replaces** the row wholesale; entries are not diffed against the previous plan. |
+| `Notice` | The raw JSON of any `session/update` variant the ACP dependency already decodes but the projection does not special-case. Maestro also uses a tagged `maestroTurnMeta` notice as the durable footer for a completed, cancelled, or failed turn. | `notice:<seq>` for ACP updates; `turn_meta:<uuid>` for a turn footer. |
+
+`Notice` covers known-but-unspecialized `SessionUpdate` variants: ones the
+`agent-client-protocol` dependency's schema already deserializes (it
+currently folds `available_commands_update` and `session_info_update`
+there) but the projection's `match` doesn't fold into one of the other
+seven kinds. It is not a wire-level forward-compatibility seam:
+`SessionUpdate` is an internally-tagged enum with no unknown-variant
+fallback, so a `session/update` whose `sessionUpdate` tag this build's
+dependency has never heard of — including a variant gated behind an
+unstable ACP feature this build doesn't enable, which is compiled out of
+the enum entirely — fails to deserialize before the projection ever runs,
+rather than becoming a `Notice`. A genuinely new ACP variant needs the
+`agent-client-protocol` dependency upgraded (and, typically, the projection's
+`match` taught about it) before it can appear on this transcript at all — see
+`projection.rs`'s test asserting that an unrecognised `sessionUpdate` tag is a
+deserialization error, not a `Notice`. A client that does not know what to do
+with a `Notice` can still render it as an opaque, collapsed line — that
+remains a reasonable floor, not a client bug.
+
+Rendering is entirely a client concern. The projection's job stops at
+folding ACP into these eight shapes; markdown formatting, diff rendering,
+tool-card treatment, and how a `Notice` is presented are all renderer
+choices, not daemon ones.
+
+## Daemon decisions vs. client decisions
+
+**The daemon decides:**
+
+- Which ACP `session/update` becomes which row kind, and under what id — the
+  fold in `projection.rs` is the one place this logic lives, so the web and
+  TUI renderers can never disagree about it.
+- Turn lifecycle: when a turn begins, and whether an ACP response, a cancel,
+  or a failure ends it (`TurnState.responding` / `.thinking` /
+  `.active_tool_calls` / `.started_at` are derived, not renderer-computed).
+  Ending a turn appends a durable `maestroTurnMeta` footer with its elapsed
+  time, outcome, model, and context-window usage/delta. ACP does not expose
+  provider billing-token counts, so these are explicitly context tokens.
+- Approval nonce minting, secrecy, and the single-active-approval rule (see
+  below) — a client never sees an ACP permission request before the daemon
+  has already turned it into an `Approval` row and a nonce.
+- What happens to an ACP update variant the dependency decodes but nobody has
+  taught the projection to special-case (falls back to `Notice` rather than
+  erroring). A variant the dependency itself can't decode is a deserialization
+  error, not a `Notice` — see [The eight transcript row
+  kinds](#the-eight-transcript-row-kinds).
+- Persistence and replay: what is written to the event log, in what order,
+  and how a restart resumes it.
+
+**A client decides:**
+
+- How each row kind is drawn — markdown for `AgentText`/`AgentThought`, a
+  diff view for `ToolDiff`, a tool card for `ToolCall`, and a floor
+  presentation for `Notice`. `Plan` is the exception: both clients omit it
+  from the transcript; the TUI may show the current plan in its status line,
+  while the web client deliberately has no stats or plan rail.
+- The web client groups two or more tool rows after the same `User` row into
+  one collapsed turn activity block. `AgentText` and `AgentThought` rows that
+  appear *between* tool rows in the same turn are absorbed into the group
+  (intermediate narration); the last `AgentText` with no subsequent tool stays
+  outside as the prominent final answer. While a turn is still active
+  (responding or thinking), the most recent intermediate `AgentText` or
+  `AgentThought` in the group is kept outside as visible narration — replaced
+  by the next text row when one arrives, and absorbed into the group when the
+  turn ends. The header still reads "N tool calls" (counting only tool rows).
+  Opening the group reveals tools and intermediate text in chronological
+  order, with the text rendered in a subdued style.
+- The web client's user, agent, thought, tool-detail, and notice text blocks
+  copy their complete source text when clicked or keyboard-activated.
+- The web client consumes `available_commands_update` notices as the live
+  source for composer `/` autocomplete at any whitespace-delimited token under
+  the caret. Completing a command replaces only that token. The client omits
+  those state-only notices, along with `session_info_update`, from the visible
+  transcript.
+- How live `responding`, `thinking`, tool activity, elapsed time, and context
+  usage are drawn. The web client keeps these in a compact strip above the
+  composer and renders each durable turn footer inline with the transcript.
+- How the operator is asked to resolve an `Approval` row — the daemon only
+  exposes the three-way decision (`AllowOnce` / `AllowForSession` / `Deny`),
+  never the UI that solicits it.
+- Scrolling, collapsing, and every other presentation-only behaviour.
+
+## The two projections
+
+`Projection` (daemon-only) is folded once from the durable ACP stream and
+exposes two independent views, both defined in `maestro-protocol`:
+
+- **`TranscriptSnapshot { cursor, rows }`** — the complete ordered list of
+  transcript rows built so far, plus the log position (`cursor`) it reflects.
+  It is intentionally always the *whole* transcript, not a windowed one: a
+  tool row patched much later must still find its original entry.
+- **`ReducedState`** — one whole-session snapshot folded over every event
+  seen: `turn` (the per-turn indicators above), `pending_approval`, `plan`,
+  `usage`/`context`, `model`, and `mode`. Like `TranscriptSnapshot`, it is
+  always full-history, never a delta — a client that only wants "is a turn
+  active right now" never has to replay anything to answer that.
+
+Changes to the transcript travel as `TranscriptDelta`, tagged `type`:
+`Append { row }` (a new row), `Patch { row }` (an existing row, addressed by
+`id`, replaced wholesale), and `Remove { id }`. `Remove` is defined on the
+wire for forward compatibility; nothing in the current projection emits it —
+every row, once appended, is only ever patched or left alone.
+
+### Cursor and replay semantics
+
+The event log's own line position is the cursor: 1-based, shared by ACP
+notifications and daemon-generated rows alike (`sidecar.rs`'s
+`PersistedEvent` envelope is what lets `User` and `Approval` rows share a cursor
+sequence with raw ACP JSON without pretending to be ACP traffic; the envelope
+also carries durable `Turn` footers). Two ways to
+read it:
+
+- **`WS /api/structured/:id`** — on connect, sends a `TranscriptSnapshot` and
+  a `ReducedState` covering the whole log as it stands, then streams
+  `ProjectionUpdate { transcript, state }` for everything that happens next.
+  There is no client-supplied resume cursor on this socket: every connection
+  gets the full snapshot, not a gap-filled continuation, so a client never
+  needs the replay endpoint just to obtain the current transcript. Use
+  replay instead for cursor-bounded pagination through the durable log —
+  history from before this connection, fetched a page at a time.
+- **`GET /api/sessions/:id/structured/replay`** — cursor-bounded pagination
+  over the durable log, returning one `StructuredReplayEvent` (`cursor`,
+  `transcript`, `state`) per matching line. `?since=<n>` returns the first
+  page after `n` (`since=0` selects from the beginning, i.e. the first
+  page); a client pages forward from there using the cursor of the last
+  event returned. `?before=<n>` returns the page immediately before `n`,
+  still in ascending order — passing both is a `400`. `?limit` defaults to
+  100 and is clamped to 500. Each call re-folds
+  the entire log from scratch to compute the state at every returned cursor,
+  so a page reflects exactly the *durable* state at its cursor, not an
+  approximation of it — at the cost of redoing the whole fold per request.
+  That durable state is not always identical to what a live client saw at
+  that moment, though: turn lifecycle transitions are broadcast live without
+  a durable event backing them (see [Prompt and cancel](#prompt-and-cancel-bounded-liveness)),
+  and a restored `Approval` row carries no pending nonce, because the nonce
+  never reached disk (see [Approvals](#approvals)) — replay is exact and
+  reconstructible, not a perfect record of everything the live view showed.
+  A session that is not a live structured session (terminal, or a dead
+  adapter) answers `409 not_structured` from either route rather than a
+  coherent-looking but stale reply.
+
+## Approvals
+
+An ACP `session/request_permission` callback becomes an `Approval` row plus a
+pending decision, entirely on the daemon side:
+
+- **Generation.** The daemon mints the nonce itself — a fresh
+  `Uuid::new_v4()` string per request — rather than using anything ACP's own
+  request carries. ACP permission callbacks have no request id of their own
+  that would double as one.
+- **Live-only placement.** The nonce lives in exactly one place: the
+  in-memory `pending_approvals` map keyed by nonce, and its mirror in
+  `ReducedState.pending_approval.nonce` on the live wire. It is never part of
+  the `Approval` row's `data` — the row is `RequestPermissionRequest`
+  serialized *without* the nonce.
+- **Secrecy from the agent and from durable history.** The adapter itself
+  never learns the nonce — it is a daemon-to-client secret, never sent back
+  over the ACP connection. It is likewise never written to the event log:
+  restoring an `Approval` row from disk (`Projection::restore_row`)
+  produces a historical row with no `pending_approval` in state, because the
+  nonce that would make it "pending" never made it to disk in the first
+  place. A restart therefore cannot resume a pending approval — see
+  [Persistence](#persistence-recovery-and-dead-sessions).
+- **One live approval at a time.** A new permission request mints its own
+  nonce, then cancels whatever was already pending (`cancel_pending_approvals`)
+  before installing itself as the new pending approval — ACP serializes
+  requests through one connection, so this only ever fires if an adapter
+  nonetheless overlaps two. Either way, the prior pending request is
+  cancelled/cleared before the new one is installed, so the newest request
+  wins.
+- **Single-use and duplicate resolution.**
+  `POST /api/sessions/:id/structured/approvals/:nonce` **always answers
+  `204`** for a known, live structured session — whether the nonce is the
+  one currently pending, one already consumed by an earlier answer, or one
+  that never existed. Only an unknown or non-structured *session* answers
+  otherwise (`404` / `409`). This is deliberate: two clients racing to answer the same
+  approval must not turn a harmless duplicate click into a client-visible
+  error. Whichever `POST` reaches the daemon first removes the nonce from
+  `pending_approvals` and is the one whose decision actually reaches the
+  adapter; every later `POST` for that nonce is a no-op `204`.
+- **Cancellation vs. denial.** A turn cancel or a session shutdown resolves
+  any pending approval with ACP's `Cancelled` outcome, not a `Deny` decision
+  — the adapter should read those as "the operation was withdrawn," not "the
+  operator refused it."
+- **Decision mapping.** `AllowOnce` and `AllowForSession` select the ACP
+  option of kind `AllowOnce` / `AllowAlways` from the request's own option
+  list. `Deny` prefers a one-shot refusal (`RejectOnce`) and falls back to a
+  permanent one (`RejectAlways`) only when that is the sole rejection option
+  offered; if neither is present, it answers `Cancelled`.
+
+## Prompt and cancel: bounded liveness
+
+The web composer accepts up to ten files through its attachment picker, file
+drop, or clipboard. Pasted text of at least 4,000 characters or 40 lines becomes
+a UTF-8 `.txt` attachment. Shorter pastes stay in the composer. Attachments can
+be removed before sending; failed sends retain the draft and attachments.
+Pastes also stay inline when all ten attachment slots are occupied or the text
+exceeds the 20 MiB file limit.
+
+On send, `POST /api/sessions/:id/structured/attachments?name=<filename>` uploads
+each file as raw bytes (20 MiB maximum) and returns its absolute `path`.
+Only live structured sessions accept uploads. Filenames are limited to 180
+bytes and cannot contain directory separators or control characters. Files get unique names and private
+file permissions in `<id>.attachments` beside the session sidecar. They persist
+across daemon restarts; removing a composer chip does not delete uploaded data.
+There is currently no automatic attachment cleanup.
+
+The prompt includes each filename and host path so the adapter can read it
+through its own file tools, including images when the provider supports them.
+These references are persisted in the ordinary user transcript row. Attachment
+bytes are not embedded in ACP messages or transcript history.
+
+`POST /api/sessions/:id/structured/prompt` and `.../cancel` are serialized
+against each other through one per-session `operation` lock
+(`AcpEventStream::operation`), because ACP permission callbacks carry no
+per-request id — the daemon's own notion of "the active turn" is the only
+thing a callback can be attributed to, so at most one turn may ever be
+in flight, and a cancelled turn must fully settle before the next prompt is
+allowed to claim the daemon's idea of "the active turn."
+
+- Web clients may collect a visible FIFO of operator messages while a turn is
+  active. They submit each queued message only after the projected turn becomes
+  idle; the queue is client-local and unsent messages do not survive a reload.
+- A submitted prompt is appended as a durable `User` row before it claims the turn and
+  dispatches to ACP, so the transcript never depends on an adapter echoing the
+  operator's input. If that append fails, the prompt is not dispatched. While a
+  turn is active, a second prompt gets `409 turn_in_flight` rather than
+  queuing in the daemon — one active turn per session, never a hidden
+  server-side queue of prompts.
+- Cancel sends `session/cancel`, clears any pending approval as `Cancelled`,
+  and ends the turn's client-visible lifecycle immediately. If the cancelled
+  turn was still *dispatched* to ACP (waiting on its response), the daemon
+  cannot simply forget it: ACP has not confirmed the cancel yet, and a new
+  prompt claiming "the active turn" while the old one is still outstanding
+  would make the next permission callback ambiguous between the two.
+- So a cancelled-but-still-dispatched turn must **settle within
+  `CANCEL_GRACE` (500ms)** — either ACP acknowledges the prompt (however it
+  resolves) or that grace period runs out. If it settles in time, the next
+  prompt proceeds normally. If it does not, the daemon does not guess: it
+  marks the whole structured session dead (`fail_cancelled_acp_turn`) rather
+  than risk a callback resolving against the wrong turn. This is the bounded
+  half of "bounded liveness" — a structured session's prompt/cancel dance
+  either resolves promptly or the session is declared unusable, never left
+  in an indefinite ambiguous state.
+
+## Persistence, recovery, and dead sessions
+
+A structured session's durable state is three files in the sidecar
+directory: the sidecar itself (`<id>.json`), plus two next to it:
+
+- **`<id>.events.jsonl`** — the unified event log. Each line is either a raw
+  ACP `SessionNotification` (kept in its original JSON so old logs stay
+  readable) or a `{"maestroEvent": "user"|"approval", "row": …}` envelope
+  for a daemon-generated row. Both share the same 1-based line-position cursor. A
+  line a hard kill left half-written is terminated before the next append, so
+  it keeps its position and is skipped as malformed rather than corrupting
+  what follows. An append that fails *while the daemon is running* — a
+  `write_all` that errors after only a prefix reached disk, or a `flush` that
+  errors after a complete write — is rolled back to the exact byte length the
+  file was at before the call, so `last_seq` and the file's line count never
+  disagree and the same log handle can be appended to again immediately (#184).
+  If that rollback itself cannot restore the prior length, the append is
+  fatal: the log's consistency can no longer be promised, so the caller kills
+  the session instead of appending to it again.
+- **`<id>.recover`** — an empty marker file. Its only meaning is "the daemon
+  that wrote this shut down gracefully while this session was running, and
+  the next daemon may attempt to resume it." It is consumed (deleted) the
+  moment a recovery attempt reads it — one recovery attempt per graceful
+  shutdown, never a standing flag.
+
+Three ways a structured session ends up `Dead`, each with different
+persistence consequences:
+
+1. **The adapter exits, or a notification append to the event log fails,
+   while the daemon keeps running.** (An approval-row append failure is
+   narrower: as long as the log rolled back cleanly, it only cancels the
+   pending approval and rolls the unpersisted `Approval` row back out of the
+   live transcript, without marking the session dead — a snapshot taken after
+   the failure must never show a row durable replay could not reproduce
+   (#184). If the rollback itself did not restore the log's prior length,
+   this narrower path does not apply either: the session is marked dead the
+   same as any other append failure, since the log can no longer promise
+   `last_seq` matches its file.)
+   `mark_session_dead` applies the same natural-exit worktree rule
+   as a terminal session's own pane exiting (`docs/WORKTREES.md`): a pristine
+   worktree is removed, one holding unsaved work is left on disk. No recovery
+   marker is written. This death is permanent — a later daemon restart's
+   `recover()` finds the sidecar, sees no marker, and leaves the session
+   `Dead` without attempting to resume it.
+2. **A cancelled turn fails to settle within `CANCEL_GRACE`.** Same
+   consequence as (1): the session is marked dead through the same path, no
+   marker, no future resumption.
+3. **Graceful daemon shutdown**, while the session was still `Running`.
+   `mark_session_dead_after_shutdown` marks the session dead **without**
+   applying the worktree exit rule — the tree is kept exactly as it is,
+   pristine or not, because there is nothing "natural" about this exit — and
+   writes the `.recover` marker. The sidecar on disk therefore says `Dead`,
+   but is eligible for resumption.
+
+Recovery, on the next daemon's `recover()`: for every `Structured` sidecar
+not already adopted, the marker is consumed. When one was present and the
+sidecar carries a stored `acp_session_id`, the daemon spawns a fresh adapter
+with `SpawnConfig::load_session(acp_session_id)`, replays the
+entire durable event log into a new `Projection` (rebuilding the transcript
+and reduced state exactly as they were, with any restored `Approval` row
+landing as history — never as a re-armed pending approval, since its nonce
+never reached disk), and only then reopens the log for further appends. What
+the adapter streams back while its own `session/load` is in flight is
+discarded rather than appended, so the replayed history is not duplicated
+(see [The ACP handshake](#the-acp-handshake)). Success flips the session back
+to `Running`/`Idle`; failure (no stored `acp_session_id`, or the handshake
+itself failing) leaves it `Dead` with the failure reason as
+`activity_detail` — the same "tell the operator what to fix" pattern as a
+missing adapter binary.
+
+Pending approvals and their nonces never survive any of this. They live only
+in the in-memory `pending_approvals` map and the live `ReducedState`, both
+gone the instant the daemon that held them exits. Whatever ACP permission
+request was mid-flight when the old daemon died was already answered
+`Cancelled` on that daemon's own shutdown path, so a resumed session always
+starts with no pending approval.
+
+See `docs/RESTART.md` for what a *client* observes across a daemon restart,
+now that structured sessions exist alongside terminal ones.

fixtures/command-resolution.json

@@ -0,0 +1,120 @@
+{
+  "_description": "the parity fixture for #199's command resolver — every case here is asserted identically by crates/maestro-protocol/src/display.rs (command_program/command_tool) and web/src/toolIcon.ts (splitCommand). `program` is the resolved, basenamed program; `tool` is the icon id it maps to, or null when unrecognised/ambiguous.",
+  "cases": [
+    { "command": "claude", "program": "claude", "tool": "claude" },
+    { "command": "claude --resume", "program": "claude", "tool": "claude" },
+    { "command": "CLAUDE", "program": "CLAUDE", "tool": "claude" },
+    { "command": "/usr/local/bin/claude -p hi", "program": "claude", "tool": "claude" },
+    { "command": "./bin/claude", "program": "claude", "tool": "claude" },
+    { "command": "FOO=1 BAR=2 claude", "program": "claude", "tool": "claude" },
+    { "command": "FOO=\"bar baz\" claude", "program": "claude", "tool": "claude" },
+    { "command": "FOO='bar baz' claude", "program": "claude", "tool": "claude" },
+    { "command": "FOO=bar\\ baz claude", "program": "claude", "tool": "claude" },
+    { "command": "'/usr/local/bin/claude'", "program": "claude", "tool": "claude" },
+    { "command": "\"/opt/my agent/claude\" --resume", "program": "claude", "tool": "claude" },
+    { "command": "env -i claude", "program": "claude", "tool": "claude" },
+    { "command": "env --ignore-environment claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo -u root claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo --user=root claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo -- claude --resume", "program": "claude", "tool": "claude" },
+    { "command": "nohup claude", "program": "claude", "tool": "claude" },
+    { "command": "time claude", "program": "claude", "tool": "claude" },
+    { "command": "time -p claude", "program": "claude", "tool": "claude" },
+    { "command": "time -- claude", "program": "claude", "tool": "claude" },
+    { "command": "time -p -- claude", "program": "claude", "tool": "claude" },
+    { "command": "time -pp claude", "program": "time", "tool": null },
+    { "command": "time -p -p claude", "program": "time", "tool": null },
+    { "command": "time -o /tmp/t.log claude", "program": "time", "tool": null },
+    { "command": "command claude", "program": "claude", "tool": "claude" },
+    { "command": "command -v claude", "program": "command", "tool": null },
+    { "command": "command -V claude", "program": "command", "tool": null },
+    { "command": "npx --yes claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "npx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm --silent dlx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm -C ./pkg dlx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm dlx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm dlx -s claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm dlx --silent claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn --silent dlx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn dlx -q claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn dlx --quiet claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun x claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bunx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "uvx claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun x --bun claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bunx --bun claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun x -p @anthropic-ai/claude-code claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bunx --package @anthropic-ai/claude-code claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun x --package=@anthropic-ai/claude-code claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bunx --no-install claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun x --verbose claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bunx --silent claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "bun --bun x claude-code", "program": "bun", "tool": null },
+    { "command": "pnpm dlx --package foo claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm dlx --package=foo claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "pnpm dlx --package= claude-code", "program": "pnpm", "tool": null },
+    { "command": "pnpm dlx --package", "program": "pnpm", "tool": null },
+    { "command": "pnpm dlx -c \"claude-code\"", "program": "pnpm", "tool": null },
+    { "command": "pnpm --package=typescript dlx tsc", "program": "tsc", "tool": null },
+    { "command": "pnpm dlx --unknown-flag claude-code", "program": "pnpm", "tool": null },
+    { "command": "yarn dlx --package foo claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn dlx --package=foo claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn dlx -p foo claude-code", "program": "claude-code", "tool": "claude" },
+    { "command": "yarn dlx --package= claude-code", "program": "yarn", "tool": null },
+    { "command": "yarn dlx -p", "program": "yarn", "tool": null },
+    { "command": "yarn dlx -p --quiet claude-code", "program": "yarn", "tool": null },
+    { "command": "bunx --package= claude-code", "program": "bunx", "tool": null },
+    { "command": "bunx --package", "program": "bunx", "tool": null },
+    { "command": "bun x -p --silent claude-code", "program": "bun", "tool": null },
+    { "command": "sudo env -i claude", "program": "claude", "tool": "claude" },
+    { "command": "FOO=1 sudo BAR=2 claude", "program": "claude", "tool": "claude" },
+    { "command": "env -iv claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo -nE claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo -uroot claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo -u", "program": "sudo", "tool": null },
+    { "command": "env --unset= claude", "program": "env", "tool": null },
+    { "command": "sudo --user= claude", "program": "sudo", "tool": null },
+    { "command": "sudo --user \"\" claude", "program": "sudo", "tool": null },
+    { "command": "sudo -nu claude", "program": "sudo", "tool": null },
+    { "command": "env -S 'python3 -u' script.py", "program": "env", "tool": null },
+    { "command": "npx -c \"claude --version\"", "program": "npx", "tool": null },
+    { "command": "npx --call \"claude --version\"", "program": "npx", "tool": null },
+    { "command": "command FOO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "nohup FOO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "npx FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "pnpm dlx FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "yarn dlx FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "bun x FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "bunx FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "uvx FOO=1 claude-code", "program": "FOO=1", "tool": null },
+    { "command": "sudo time FOO=1 claude", "program": "claude", "tool": "claude" },
+    { "command": "nohup env FOO=1 claude", "program": "claude", "tool": "claude" },
+    { "command": "sudo command FOO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "command nohup FOO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "time command FOO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "\"FOO=1\" claude", "program": "FOO=1", "tool": null },
+    { "command": "FOO\\=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "F\"O\"O=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "F\\OO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "\"FOO\"=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "F\"\"OO=1 claude", "program": "FOO=1", "tool": null },
+    { "command": "claude\nclaude-code", "program": "claude", "tool": null },
+    { "command": "clau\\\nde --resume", "program": "claude", "tool": "claude" },
+    { "command": "npx opencode", "program": "opencode", "tool": "opencode" },
+    { "command": "pnpm dlx opencode run", "program": "opencode", "tool": "opencode" },
+    { "command": "pnpm claude", "program": "pnpm", "tool": null },
+    { "command": "yarn claude", "program": "yarn", "tool": null },
+    { "command": "claude-code-acp", "program": "claude-code-acp", "tool": null },
+    { "command": "hx src/main.rs", "program": "hx", "tool": null },
+    { "command": "bash", "program": "bash", "tool": "shell" },
+    { "command": "opencode", "program": "opencode", "tool": "opencode" },
+    { "command": "sudo", "program": "sudo", "tool": null },
+    { "command": "", "program": "", "tool": null },
+    { "command": "npx --unknown-flag claude-code", "program": "npx", "tool": null },
+    { "command": "claude | tee log.txt", "program": "claude", "tool": null },
+    { "command": "claude; echo done", "program": "claude;", "tool": null },
+    { "command": "claude && echo done", "program": "claude", "tool": null },
+    { "command": "echo hi $(claude)", "program": "echo", "tool": null },
+    { "command": "claude \"unterminated", "program": "claude", "tool": null }
+  ]
+}

flake.nix

@@ -148,7 +148,7 @@
             pnpmDeps = (pkgs.fetchPnpmDeps.override { pnpm = pkgs.pnpm_10; }) {
               inherit (finalAttrs) pname version src;
               fetcherVersion = 3;
-              hash = "sha256-hOqiAbnjKsoQnV8lgto5HspDsLIb+48sNLkShIjCZPQ=";
+              hash = "sha256-AzF/rrhqbvl613hNsC18YSylBSVxtatg7fEiUEF1u2o=";
             };
 
             buildPhase = ''

web/index.html

@@ -24,6 +24,7 @@
   </head>
   <body>
     <div id="app"></div>
+    <div id="root"></div>
     <script type="module" src="/src/main.ts"></script>
   </body>
 </html>

web/package-lock.json

@@ -11,7 +11,8 @@
         "@fontsource/jetbrains-mono": "^5.3.0",
         "@xterm/addon-fit": "^0.10.0",
         "@xterm/addon-webgl": "^0.19.0",
-        "@xterm/xterm": "^5.5.0"
+        "@xterm/xterm": "^5.5.0",
+        "marked": "^18.0.11"
       },
       "devDependencies": {
         "happy-dom": "^20.11.6",
@@ -1222,6 +1223,18 @@
         "@jridgewell/sourcemap-codec": "^1.5.5"
       }
     },
+    "node_modules/marked": {
+      "version": "18.0.11",
+      "resolved": "https://registry.npmjs.org/marked/-/marked-18.0.11.tgz",
+      "integrity": "sha512-HnslJfsZkRPBDJRHvVtAaWlZHEpSu7u8LgQuJCELjRKuWR+hpq4A7sLq3p8HaI9ypVoXDXxV34CsQJEe1+J5Aw==",
+      "license": "MIT",
+      "bin": {
+        "marked": "bin/marked.js"
+      },
+      "engines": {
+        "node": ">= 20"
+      }
+    },
     "node_modules/ms": {
       "version": "2.1.3",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",

web/package.json

@@ -6,7 +6,7 @@
   "packageManager": "pnpm@9.15.4",
   "scripts": {
     "dev": "vite",
-    "build": "tsc -b && vite build",
+    "build": "tsc -b tsconfig.build.json && vite build",
     "preview": "vite preview",
     "typecheck": "tsc -b --noEmit",
     "test": "vitest run",
@@ -16,12 +16,23 @@
     "@fontsource/jetbrains-mono": "^5.3.0",
     "@xterm/addon-fit": "^0.10.0",
     "@xterm/addon-webgl": "^0.19.0",
-    "@xterm/xterm": "^5.5.0"
+    "@xterm/xterm": "^5.5.0",
+    "marked": "^18.0.11",
+    "react": "^19.2.8",
+    "react-dom": "^19.2.8"
   },
   "devDependencies": {
+    "@tailwindcss/vite": "^4.3.3",
+    "@testing-library/jest-dom": "^7.0.1",
+    "@testing-library/react": "^16.3.3",
+    "@types/react": "^19.2.18",
+    "@types/react-dom": "^19.2.7",
+    "@vitejs/plugin-react": "^4.7.0",
     "happy-dom": "^20.11.6",
+    "tailwindcss": "^4.3.3",
     "typescript": "^5.6.3",
     "vite": "^5.4.10",
-    "vitest": "^2.1.9"
+    "vitest": "^2.1.9",
+    "zustand": "^5.0.15"
   }
 }

web/src/App.tsx

@@ -0,0 +1,9 @@
+import { ThemeProvider } from "./contexts/ThemeContext";
+
+export function App() {
+  return (
+    <ThemeProvider>
+      <div id="react-root" />
+    </ThemeProvider>
+  );
+}

web/src/api.ts

@@ -11,6 +11,9 @@ import type {
   Projects,
   RecentDirs,
   Session,
+  StructuredApprovalDecision,
+  StructuredConfigRequest,
+  StructuredPromptRequest,
   Uuid,
 } from "./types.js";
 
@@ -91,6 +94,21 @@ export async function killSession(id: Uuid, force = false): Promise<void> {
   );
 }
 
+/** Change one option advertised by a live ACP session. */
+export async function setStructuredConfig(
+  id: Uuid,
+  req: StructuredConfigRequest,
+): Promise<void> {
+  await jsonOrError(
+    await fetch(routes.structuredConfig(id), {
+      method: "POST",
+      credentials: "same-origin",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(req),
+    }),
+  );
+}
+
 /** Report whether this client's pane is the one currently showing `id` — not
  * merely highlighted in a sidebar. The daemon uses this to clear an
  * `AwaitingInput` glow once the pane has been looked at long enough
@@ -152,4 +170,53 @@ export async function fetchBranches(path: string): Promise<Branches> {
   return jsonOrError(await fetch(url, { credentials: "same-origin" }));
 }
 
-export { eventsWsUrl } from "./routes.js";
+/** Send a prompt to a structured session's ACP turn (#138). `409
+ * turn_in_flight` when one is already active — the caller reflects that from
+ * `ReducedState.turn` instead of racing this call. */
+export async function sendStructuredPrompt(id: Uuid, prompt: string): Promise<void> {
+  await jsonOrError(
+    await fetch(routes.structuredPrompt(id), {
+      method: "POST",
+      credentials: "same-origin",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({ prompt } satisfies StructuredPromptRequest),
+    }),
+  );
+}
+
+export async function uploadStructuredFile(id: Uuid, file: File): Promise<{ path: string }> {
+  return jsonOrError(await fetch(`${routes.structuredAttachment(id)}?name=${encodeURIComponent(file.name)}`, {
+    method: "POST",
+    credentials: "same-origin",
+    headers: { "content-type": "application/octet-stream" },
+    body: file,
+  }));
+}
+
+/** Cancel a structured session's active ACP turn (#138). */
+export async function cancelStructuredTurn(id: Uuid): Promise<void> {
+  await jsonOrError(
+    await fetch(routes.structuredCancel(id), { method: "POST", credentials: "same-origin" }),
+  );
+}
+
+/** Answer a pending ACP permission request (#139). Always resolves once the
+ * session itself is a live structured session — a nonce that is unknown or
+ * already consumed still answers `204` (docs/STRUCTURED-VIEW.md), so two
+ * clients racing the same approval never see this reject. */
+export async function resolveStructuredApproval(
+  id: Uuid,
+  nonce: string,
+  decision: StructuredApprovalDecision,
+): Promise<void> {
+  await jsonOrError(
+    await fetch(routes.structuredApproval(id, nonce), {
+      method: "POST",
+      credentials: "same-origin",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(decision),
+    }),
+  );
+}
+
+export { eventsWsUrl, structuredWsUrl } from "./routes.js";

web/src/attach.ts

@@ -4,14 +4,16 @@ import { Terminal } from "@xterm/xterm";
 import "@xterm/xterm/css/xterm.css";
 
 import { attachWsUrl } from "./routes.js";
-import { escapeHtml } from "./html.js";
 import { INITIAL_RECONNECT_MS, MAX_RECONNECT_MS } from "./reconnect.js";
 import { applyModsToChar, cursorSeq, tildeSeq } from "./keys.js";
 import { requestToggleDrawer } from "./drawer.js";
-import { splitCommand, toolIconSvg } from "./toolIcon.js";
+import { paneTitleAttr, paneTitleHtml, type AttachInfo } from "./paneTitle.js";
+import type { PaneConnection } from "./pane.js";
 import type { ClientControl, Uuid } from "./types.js";
 import { WebglPolicy } from "./webglRenderer.js";
 
+export type { AttachInfo } from "./paneTitle.js";
+
 /** One budget for the whole page — see webglRenderer.ts for why contexts are
  *  rationed rather than handed to every connection. */
 const webglPolicy = new WebglPolicy();
@@ -27,25 +29,7 @@ const webglPolicy = new WebglPolicy();
  * session ending) tears the socket down — so switching away and back is
  * instant, with scrollback already in place.
  */
-export interface AttachConnection {
-  readonly sessionId: Uuid;
-  /** The `.attach` element (header + terminal body) to mount into a pane. */
-  readonly el: HTMLElement;
-  /** Becomes the visible view: fit to the pane, focus, sync size.
-   *  `focus: false` mounts without taking the keyboard — what a sidebar
-   *  preview needs, so j/k keeps working while the pane is on screen. */
-  onMount(opts?: { focus?: boolean }): void;
-  /** Parked into the cache: keep streaming, just stop driving focus/resize. */
-  onUnmount(): void;
-  /** Put the keyboard back into this terminal — what leaving the sidebar does. */
-  focusTerminal(): void;
-  /** Type raw bytes straight into the PTY, bypassing the terminal's own key
-   *  handling — the leader's literal Ctrl-K escape hatch
-   *  (docs/COMMAND-BAR.md). */
-  sendInput(data: string): void;
-  /** Fully disconnect: close the WS, dispose the terminal, remove the element. */
-  dispose(): void;
-}
+export interface AttachConnection extends PaneConnection {}
 
 export interface AttachOptions {
   /** Invoked when the user clicks the view's explicit "disconnect" control. */
@@ -59,23 +43,6 @@ export interface AttachOptions {
   shouldReconnect?: (sessionId: Uuid, code: number) => boolean;
 }
 
-/** What the header shows about the session (name / command). Optional — falls
- * back to a short session id when the session isn't known yet. */
-export interface AttachInfo {
-  name: string;
-  command: string;
-}
-
-/** Header echoes the sidebar: the program becomes its tool icon when we have a
- * mark for it and stays as its bare name when we do not. Arguments are
- * dropped, as on the card. */
-function commandFragment(command: string): string {
-  const { tool, program } = splitCommand(command);
-  const icon = tool ? toolIconSvg(tool) : null;
-  const text = icon ? "" : program;
-  return `<span class="at-cmd">${icon ?? ""}${text ? escapeHtml(text) : ""}</span>`;
-}
-
 export function createAttachConnection(
   sessionId: Uuid,
   opts: AttachOptions = {},
@@ -85,21 +52,19 @@ export function createAttachConnection(
   el.className = "attach";
   // Useful identity over a bare UUID: name · command. The full id stays in the
   // tooltip for when you really need it.
-  const titleHtml = info
-    ? `<span class="at-name">${escapeHtml(info.name)}</span>` +
-      (info.command && info.command !== info.name ? commandFragment(info.command) : "")
-    : `session <span class="sid">${escapeHtml(sessionId.slice(0, 8))}</span>`;
-  const titleAttr = info ? `${info.name} · ${info.command}  (${sessionId})` : sessionId;
+  const titleHtml = paneTitleHtml(sessionId, info);
+  const titleAttr = paneTitleAttr(sessionId, info);
   el.innerHTML = `
     <header class="attach-header">
       <button type="button" class="btn btn-ghost btn-icon sessions-btn" aria-label="Show sessions" title="Show sessions">☰</button>
-      <span class="attach-title" title="${escapeHtml(titleAttr)}">${titleHtml}</span>
+      <span class="attach-title" title="${titleAttr}">${titleHtml}</span>
       <span class="attach-state" data-state="connecting">connecting…</span>
       <button class="btn btn-ghost btn-icon disconnect" type="button" aria-label="Disconnect" title="Disconnect this session">⏻</button>
     </header>
     <div class="attach-body"></div>
   `;
 
+  const titleEl = el.querySelector(".attach-title") as HTMLSpanElement;
   const body = el.querySelector(".attach-body") as HTMLDivElement;
   const stateEl = el.querySelector(".attach-state") as HTMLSpanElement;
   const disconnectBtn = el.querySelector(".disconnect") as HTMLButtonElement;
@@ -359,6 +324,9 @@ export function createAttachConnection(
   let ws: WebSocket;
   let reconnectMs = INITIAL_RECONNECT_MS;
   let reconnectTimer: number | null = null;
+  // Snapshot replay starts at row zero, which can leave Codex at its oldest line.
+  // Follow it once per socket; later scrolling remains under the operator's control.
+  let awaitingReplay = true;
 
   const sendControl = (msg: ClientControl) => {
     if (ws.readyState !== WebSocket.OPEN) return;
@@ -378,6 +346,7 @@ export function createAttachConnection(
   };
 
   function connect(): void {
+    awaitingReplay = true;
     ws = new WebSocket(attachWsUrl(sessionId));
     ws.binaryType = "arraybuffer";
 
@@ -398,10 +367,20 @@ export function createAttachConnection(
         return;
       }
       if (ev.data instanceof ArrayBuffer) {
-        term.write(new Uint8Array(ev.data));
+        const replay = awaitingReplay;
+        awaitingReplay = false;
+        term.write(new Uint8Array(ev.data), () => {
+          if (replay) term.scrollToBottom();
+        });
       } else if (ev.data instanceof Blob) {
         // Some browsers may default to Blob despite binaryType="arraybuffer".
-        ev.data.arrayBuffer().then((b) => term.write(new Uint8Array(b)));
+        void ev.data.arrayBuffer().then((b) => {
+          const replay = awaitingReplay;
+          awaitingReplay = false;
+          term.write(new Uint8Array(b), () => {
+            if (replay) term.scrollToBottom();
+          });
+        });
       }
     };
 
@@ -499,6 +478,10 @@ export function createAttachConnection(
     // The closure above: the same bytes-out path keystrokes and the mobile key
     // bar already take.
     sendInput,
+    updateInfo(next: AttachInfo) {
+      titleEl.innerHTML = paneTitleHtml(sessionId, next);
+      titleEl.title = paneTitleAttr(sessionId, next);
+    },
     dispose() {
       if (disposed) return;
       disposed = true;

web/src/catalog.ts

@@ -663,8 +663,9 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     applyNav();
   };
 
-  // Hover previews the row under the pointer (docs/PREVIEW.md). Touch is left
-  // out: there is no hover there, and a tap already opens the session.
+  // Pointer hover previews only while Ctrl is held — plain hover was too
+  // disruptive when sweeping the sidebar. Keyboard walk (j/k) still previews
+  // unconditionally via applyNav.
   let hovered: string | null = null;
   const setHovered = (id: string | null) => {
     if (hovered === id) return;
@@ -672,7 +673,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     opts.onPreview?.(id);
   };
   treeHost.addEventListener("pointerover", (e) => {
-    if (e.pointerType === "touch") return;
+    if (e.pointerType === "touch" || !e.ctrlKey) return;
     const row = (e.target as HTMLElement | null)?.closest<HTMLElement>(".tree-leaf");
     setHovered(row?.dataset.sessionId ?? null);
   });

web/src/commandBar.ts

@@ -21,7 +21,7 @@ import {
   type MatchRange,
   type MatchResult,
   type SessionCandidate,
-} from "./matcher.js";
+} from "./utils/matcher.js";
 import { splitPath } from "./paths.js";
 import { splitCommand } from "./toolIcon.js";
 import { abbreviateCwd, sessionName, sessionTreePath, type Session } from "./types.js";

web/src/components/commandBar/ActionPage.tsx

@@ -0,0 +1,34 @@
+// A session's action page (docs/COMMAND-BAR.md, "Drill-in"): the same overlay
+// over kill, rename and spawn similar, still fuzzy searchable. The page names
+// the session it acts on, so the target is never ambiguous.
+
+import { sessionName, type Session } from "../../types.js";
+import { ResultList } from "./ResultList.js";
+import type { BarGroup } from "./model.js";
+
+export interface ActionPageProps {
+  session: Session;
+  /** The three actions, ranked by the query line — one kind, so no headers. */
+  groups: BarGroup[];
+  highlighted: number;
+  onActivate(index: number): void;
+}
+
+export function ActionPage({ session, groups, highlighted, onActivate }: ActionPageProps) {
+  return (
+    <>
+      <div
+        role="presentation"
+        className="cmdbar-page-header border-b border-border px-sp-3 py-sp-1 text-fs-11 text-muted"
+      >
+        {`Actions for "${sessionName(session)}"`}
+      </div>
+      <ResultList
+        groups={groups}
+        showHeaders={false}
+        highlighted={highlighted}
+        onActivate={onActivate}
+      />
+    </>
+  );
+}

web/src/components/commandBar/CommandBar.test.tsx

@@ -0,0 +1,407 @@
+// @vitest-environment happy-dom
+import { cleanup, fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import {
+  KILL_SESSION_EVENT,
+  RENAME_SESSION_EVENT,
+  SESSION_SELECT_EVENT,
+  SPAWN_SIMILAR_EVENT,
+} from "../../catalog.js";
+import { COMMAND_SPECS, type Command } from "../../commands.js";
+import type { Session } from "../../types.js";
+import { CommandBar, SPAWN_DIRECTORY_EVENT, type CommandBarProps } from "./CommandBar.js";
+
+vi.mock("../../api.js", async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  listDir: vi.fn(async () => ({ path: "", entries: [] })),
+  projects: vi.fn(async () => []),
+  recentDirs: vi.fn(async () => ({ dirs: [] })),
+}));
+
+function session(id: string, over: Partial<Session> = {}): Session {
+  return {
+    id,
+    cwd: "/home/me/dev/api",
+    command: "bash",
+    env: {},
+    metadata: { name: id },
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  };
+}
+
+function command(over: Partial<Command> = {}): Command {
+  return {
+    id: "cmd",
+    label: "A command",
+    group: "Test",
+    keys: ["a"],
+    scope: "global",
+    run: () => {},
+    ...over,
+  };
+}
+
+const sessions = [
+  session("api", { current_cwd: "/home/me/dev/api", last_focused_at: "2026-01-01T11:00:00Z" }),
+  session("worker", {
+    current_cwd: "/home/me/dev/worker",
+    last_focused_at: "2026-01-01T10:00:00Z",
+  }),
+  session("notes", { current_cwd: "/home/me/notes" }),
+];
+
+function open(over: Partial<CommandBarProps> = {}) {
+  return render(
+    <CommandBar
+      sessions={sessions}
+      homeDir="/home/me"
+      commands={[]}
+      onOpenSession={() => {}}
+      onClose={() => {}}
+      {...over}
+    />,
+  );
+}
+
+function input(): HTMLInputElement {
+  return screen.getByRole("combobox") as HTMLInputElement;
+}
+
+function type(value: string): void {
+  fireEvent.change(input(), { target: { value } });
+}
+
+function press(key: string, init: Record<string, unknown> = {}): void {
+  fireEvent.keyDown(input(), { key, ...init });
+}
+
+function rowNames(): string[] {
+  return [...document.querySelectorAll(".cmdbar-row-name")].map((r) => r.textContent ?? "");
+}
+
+function activeName(): string | undefined {
+  return document.querySelector(".cmdbar-row.is-active .cmdbar-row-name")?.textContent ?? undefined;
+}
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+describe("the overlay", () => {
+  it("is a registry command, so the help overlay lists it", () => {
+    const spec = COMMAND_SPECS.find((s) => s.id === "bar.open");
+    expect(spec?.keys).toEqual(["ctrl-k"]);
+    expect(spec?.scope).toBe("global");
+  });
+
+  it("lists sessions by recency under a kind header on an empty query", () => {
+    open();
+    expect([...document.querySelectorAll(".cmdbar-group-title")].map((h) => h.textContent)).toEqual([
+      "Sessions",
+    ]);
+    expect(rowNames()).toEqual(["api", "worker", "notes"]);
+    expect(activeName()).toBe("api");
+  });
+
+  it("ranks a typed query through the matcher and highlights the matched range", () => {
+    open();
+    type("wor");
+    expect(rowNames()).toEqual(["worker"]);
+    expect([...document.querySelectorAll(".cmdbar-row-name mark")].map((m) => m.textContent)).toEqual(
+      ["wor"],
+    );
+  });
+
+  it("highlights inside the directory when that is the field that matched", () => {
+    open();
+    type("dev/wor");
+    expect(rowNames()).toEqual(["worker"]);
+    expect(
+      [...document.querySelectorAll(".cmdbar-row-meta mark")].map((m) => m.textContent).join(""),
+    ).toBe("dev/wor");
+  });
+
+  it("renders a no-results state rather than an empty list", () => {
+    open();
+    type("zzz");
+    expect(rowNames()).toEqual([]);
+    expect(screen.getByText("No matches")).toBeDefined();
+  });
+
+  it("moves the highlight with the arrows and ctrl-p/ctrl-n, without wrapping", () => {
+    open();
+    press("ArrowUp");
+    expect(activeName()).toBe("api");
+    press("ArrowDown");
+    expect(activeName()).toBe("worker");
+    press("n", { ctrlKey: true });
+    expect(activeName()).toBe("notes");
+    press("ArrowDown");
+    expect(activeName()).toBe("notes");
+    press("p", { ctrlKey: true });
+    expect(activeName()).toBe("worker");
+  });
+
+  it("puts the highlight back on the best row whenever the query changes", () => {
+    open();
+    press("ArrowDown");
+    expect(activeName()).toBe("worker");
+    type("o");
+    expect(activeName()).toBe(rowNames()[0]);
+  });
+
+  it("opens the highlighted session through the caller's open path on Enter", () => {
+    const onOpenSession = vi.fn();
+    const onClose = vi.fn();
+    open({ onOpenSession, onClose });
+    press("ArrowDown");
+    press("Enter");
+    expect(onOpenSession).toHaveBeenCalledWith("worker");
+    expect(onClose).toHaveBeenCalled();
+  });
+
+  it("raises the shared select event when the caller supplies no handler", () => {
+    const listener = vi.fn();
+    document.addEventListener(SESSION_SELECT_EVENT, listener);
+    open({ onOpenSession: undefined });
+    press("Enter");
+    document.removeEventListener(SESSION_SELECT_EVENT, listener);
+    expect((listener.mock.calls[0][0] as CustomEvent).detail).toBe("api");
+  });
+
+  it("Enter on an empty result list does nothing", () => {
+    const onOpenSession = vi.fn();
+    const onClose = vi.fn();
+    open({ onOpenSession, onClose });
+    type("zzz");
+    press("Enter");
+    expect(onOpenSession).not.toHaveBeenCalled();
+    expect(onClose).not.toHaveBeenCalled();
+  });
+
+  it("closes on Escape and on a press outside the panel", () => {
+    const onClose = vi.fn();
+    open({ onClose });
+    press("Escape");
+    expect(onClose).toHaveBeenCalledTimes(1);
+    fireEvent.mouseDown(document.querySelector(".cmdbar-overlay") as HTMLElement);
+    expect(onClose).toHaveBeenCalledTimes(2);
+  });
+
+  it("stays open for a press inside the panel", () => {
+    const onClose = vi.fn();
+    open({ onClose });
+    fireEvent.mouseDown(document.querySelector(".cmdbar-panel") as HTMLElement);
+    expect(onClose).not.toHaveBeenCalled();
+  });
+
+  it("returns the keyboard to whatever held it when it opened", () => {
+    const before = document.createElement("input");
+    document.body.appendChild(before);
+    before.focus();
+    const view = open();
+    expect(document.activeElement).toBe(input());
+    view.unmount();
+    expect(document.activeElement).toBe(before);
+    before.remove();
+  });
+
+  it("clicking a row opens that session", () => {
+    const onOpenSession = vi.fn();
+    open({ onOpenSession });
+    fireEvent.click(document.querySelectorAll(".cmdbar-row")[1]);
+    expect(onOpenSession).toHaveBeenCalledWith("worker");
+  });
+});
+
+describe("the sigils", () => {
+  const commands = [
+    command({ id: "help.toggle", label: "Show help", keys: ["?"] }),
+    command({ id: "spawn.open", label: "Open the spawn form", keys: ["n"], run: vi.fn() }),
+  ];
+
+  it("lists every command in registry order under `>`, with its chord and no header", () => {
+    open({ commands });
+    type(">");
+    expect(rowNames()).toEqual(["Show help", "Open the spawn form"]);
+    expect(document.querySelectorAll(".cmdbar-group-title")).toHaveLength(0);
+    expect([...document.querySelectorAll(".cmdbar-row-keys kbd")].map((k) => k.textContent)).toEqual(
+      ["?", "n"],
+    );
+  });
+
+  it("matches a command on its label and never on its chord", () => {
+    open({ commands });
+    type(">help");
+    expect(rowNames()).toEqual(["Show help"]);
+    type(">?");
+    expect(rowNames()).toEqual([]);
+  });
+
+  it("runs the highlighted command on Enter", () => {
+    const run = vi.fn();
+    open({ commands: [command({ label: "Run me", run })] });
+    type(">run");
+    press("Enter");
+    expect(run).toHaveBeenCalled();
+  });
+
+  it("keeps the list mixed with no sigil, and returns to it when the sigil goes", () => {
+    open({ commands });
+    type(">show");
+    expect(rowNames()).toEqual(["Show help"]);
+    type("");
+    expect(rowNames()).toEqual(["api", "worker", "notes"]);
+  });
+
+  it("lists recent dirs then projects under `~`", async () => {
+    open({ loadDirectories: async () => ["/home/me/dev/api", "/srv/x"] });
+    type("~");
+    await waitFor(() => expect(rowNames()).toEqual(["~/dev/api", "/srv/x"]));
+    expect(document.querySelectorAll(".cmdbar-group-title")).toHaveLength(0);
+  });
+
+  it("fills the list in from /api/dirs as a path is typed", async () => {
+    const listDirEntries = vi.fn(async () => ["maestro", "api"]);
+    open({ loadDirectories: async () => ["/home/me/notes"], listDirEntries });
+    // The second `~` is a literal query character and reaches the matcher.
+    type("~~/dev/mae");
+    await waitFor(() => expect(rowNames()).toEqual(["~/dev/maestro"]));
+    expect(listDirEntries).toHaveBeenCalledWith("~/dev/");
+  });
+
+  it("spawns in the highlighted directory on Enter", async () => {
+    const onSpawnDirectory = vi.fn();
+    open({ loadDirectories: async () => ["/srv/x"], onSpawnDirectory });
+    type("~");
+    await waitFor(() => expect(rowNames()).toEqual(["/srv/x"]));
+    press("Enter");
+    expect(onSpawnDirectory).toHaveBeenCalledWith("/srv/x");
+  });
+
+  it("raises the spawn event when the caller supplies no handler", async () => {
+    const listener = vi.fn();
+    document.addEventListener(SPAWN_DIRECTORY_EVENT, listener);
+    open({ loadDirectories: async () => ["/srv/x"] });
+    type("~");
+    await waitFor(() => expect(rowNames()).toEqual(["/srv/x"]));
+    press("Enter");
+    document.removeEventListener(SPAWN_DIRECTORY_EVENT, listener);
+    expect((listener.mock.calls[0][0] as CustomEvent).detail).toBe("/srv/x");
+  });
+});
+
+describe("the session action page", () => {
+  function drill(over: Partial<CommandBarProps> = {}) {
+    const view = open(over);
+    press("Tab");
+    return view;
+  }
+
+  it("lists kill, rename and spawn similar for the highlighted session", () => {
+    drill();
+    expect(rowNames()).toEqual(["Kill session", "Rename session", "Spawn similar"]);
+  });
+
+  it("names the session being acted on", () => {
+    drill();
+    expect(screen.getByText('Actions for "api"')).toBeDefined();
+  });
+
+  it("drops the kind headers, since the page is one kind", () => {
+    drill();
+    expect(document.querySelectorAll(".cmdbar-group-title")).toHaveLength(0);
+  });
+
+  it("stays fuzzy-searchable over the three actions", () => {
+    drill();
+    type("ren");
+    expect(rowNames()).toEqual(["Rename session"]);
+  });
+
+  it("does nothing on a command row", () => {
+    open({ commands: [command({ label: "Show help" })] });
+    type(">show");
+    press("Tab");
+    expect(rowNames()).toEqual(["Show help"]);
+  });
+
+  it("does nothing on a directory row", async () => {
+    open({ loadDirectories: async () => ["/srv/x"] });
+    type("~");
+    await waitFor(() => expect(rowNames()).toEqual(["/srv/x"]));
+    press("Tab");
+    expect(rowNames()).toEqual(["/srv/x"]);
+  });
+
+  it("returns to the result list on Escape, with the previous query intact", () => {
+    const onClose = vi.fn();
+    open({ onClose });
+    type("wor");
+    press("Tab");
+    expect(rowNames()).toEqual(["Kill session", "Rename session", "Spawn similar"]);
+    press("Escape");
+    expect(onClose).not.toHaveBeenCalled();
+    expect(input().value).toBe("wor");
+    expect(rowNames()).toEqual(["worker"]);
+  });
+
+  it("returns to the result list on backspace at an empty query", () => {
+    drill();
+    fireEvent.keyDown(input(), { key: "Backspace" });
+    expect(rowNames()).toEqual(["api", "worker", "notes"]);
+  });
+
+  it("keeps backspace ordinary while the page's query has text", () => {
+    drill();
+    type("ren");
+    fireEvent.keyDown(input(), { key: "Backspace" });
+    expect(rowNames()).toEqual(["Rename session"]);
+  });
+
+  it("closes the bar when the page's Escape has already been used", () => {
+    const onClose = vi.fn();
+    drill({ onClose });
+    press("Escape");
+    press("Escape");
+    expect(onClose).toHaveBeenCalledTimes(1);
+  });
+
+  it("raises kill, rename and spawn similar with the session, closing the bar", () => {
+    for (const [query, key] of [
+      ["kill", "onKillSession"],
+      ["rename", "onRenameSession"],
+      ["spawn", "onSpawnSimilar"],
+    ] as const) {
+      const handler = vi.fn();
+      const onClose = vi.fn();
+      drill({ [key]: handler, onClose });
+      type(query);
+      press("Enter");
+      expect(handler).toHaveBeenCalledWith(expect.objectContaining({ id: "api" }));
+      expect(onClose).toHaveBeenCalled();
+      cleanup();
+    }
+  });
+
+  it("hands each action to the flow it already has, by default", () => {
+    for (const [query, event] of [
+      ["kill", KILL_SESSION_EVENT],
+      ["rename", RENAME_SESSION_EVENT],
+      ["spawn", SPAWN_SIMILAR_EVENT],
+    ] as const) {
+      const listener = vi.fn();
+      document.addEventListener(event, listener);
+      drill();
+      type(query);
+      press("Enter");
+      document.removeEventListener(event, listener);
+      expect((listener.mock.calls[0][0] as CustomEvent).detail.id).toBe("api");
+      cleanup();
+    }
+  });
+});

web/src/components/commandBar/CommandBar.tsx

@@ -0,0 +1,379 @@
+// The `ctrl-k` command bar (docs/COMMAND-BAR.md): a query line over a result
+// list. Sessions and commands rank together by default; `>` narrows to
+// commands, `~` to directories. `tab` on a session drills into its action page.
+//
+// The bar picks an action and hands off — it never reimplements one. Each
+// handler defaults to the event the flow that already implements it listens
+// on, so the React bar and the legacy shell raise the same flows.
+
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
+import { createPortal } from "react-dom";
+
+import {
+  KILL_SESSION_EVENT,
+  RENAME_SESSION_EVENT,
+  SESSION_SELECT_EVENT,
+  SPAWN_SIMILAR_EVENT,
+} from "../../catalog.js";
+import { publishedCommands, type Command } from "../../commands.js";
+import { sessionName, type Session } from "../../types.js";
+import { ActionPage } from "./ActionPage.js";
+import { ResultList } from "./ResultList.js";
+import {
+  barGroups,
+  barRows,
+  commandBarCandidates,
+  dirEntryPaths,
+  directoryBarCandidates,
+  isActionCandidate,
+  listDirEntries as defaultListDirEntries,
+  loadBarDirectories,
+  parseBarQuery,
+  probeDir,
+  sessionActionCandidates,
+  sessionBarCandidates,
+  PLACEHOLDERS,
+  type BarCandidate,
+  type BarResult,
+  type DirectoryBarCandidate,
+  type SessionAction,
+} from "./model.js";
+
+/** Raised when Enter lands on a directory row and no handler was given. The
+ *  bar picks the directory; the shell owns the spawn, which is the same
+ *  fast-forward path `N` takes. */
+export const SPAWN_DIRECTORY_EVENT = "cmdbar-spawn-directory";
+
+export interface CommandBarProps {
+  /** Sessions to build candidates from, as the store has them right now. */
+  sessions: readonly Session[];
+  /** The daemon's home dir, for the directory field's `~/…` abbreviation. */
+  homeDir?: string;
+  /** The command registry to list under `>`. Defaults to every bound command,
+   * in registry order. */
+  commands?: readonly Command[];
+  /** The directory list behind `~`, fetched once on first use. */
+  loadDirectories?: () => Promise<string[]>;
+  /** One directory's subdirectories, for filling the list in as a path is
+   * typed. Defaults to `GET /api/dirs`. */
+  listDirEntries?: (dir: string) => Promise<string[]>;
+  onOpenSession?(sessionId: string): void;
+  onSpawnDirectory?(path: string): void;
+  onKillSession?(session: Session): void;
+  onRenameSession?(session: Session): void;
+  onSpawnSimilar?(session: Session): void;
+  /** Closing returns the keyboard to whatever held it when the bar opened. */
+  onClose(): void;
+}
+
+function raise(name: string, detail: unknown): void {
+  document.dispatchEvent(new CustomEvent(name, { detail }));
+}
+
+export function CommandBar(props: CommandBarProps) {
+  const {
+    sessions,
+    homeDir,
+    commands,
+    loadDirectories = loadBarDirectories,
+    listDirEntries = defaultListDirEntries,
+    onClose,
+  } = props;
+
+  const inputRef = useRef<HTMLInputElement>(null);
+  const panelRef = useRef<HTMLDivElement>(null);
+
+  const [raw, setRaw] = useState("");
+  const [highlighted, setHighlighted] = useState(0);
+  // The action page: `page` is the session being acted on, `stashed` the
+  // result-list query it was drilled into from — backing out restores it, so
+  // the round trip costs the operator nothing.
+  const [page, setPage] = useState<Session | null>(null);
+  const [stashed, setStashed] = useState("");
+
+  // `~`'s candidates: the recents-and-projects list, fetched once, plus
+  // whatever `/api/dirs` has filled in for the directory being typed.
+  const [directories, setDirectories] = useState<DirectoryBarCandidate[]>([]);
+  const [probed, setProbed] = useState<DirectoryBarCandidate[]>([]);
+  const requestedRef = useRef(false);
+  const listingsRef = useRef(new Map<string, string[]>());
+
+  // On the action page the query line is over the three actions, so there is
+  // no sigil to read: `>` and `~` are ordinary characters there.
+  const parsed = useMemo(() => (page ? { sigil: null, query: raw } : parseBarQuery(raw)), [page, raw]);
+
+  const sessionCandidates = useMemo(
+    () => sessionBarCandidates(sessions, homeDir),
+    [sessions, homeDir],
+  );
+  const commandCandidates = useMemo(
+    () => commandBarCandidates(commands ?? publishedCommands()),
+    [commands],
+  );
+
+  // Closing returns the keyboard to whatever held it when the bar opened: a
+  // round trip through the bar never silently moves focus.
+  useEffect(() => {
+    const previouslyFocused = document.activeElement as HTMLElement | null;
+    inputRef.current?.focus();
+    return () => {
+      if (previouslyFocused?.isConnected) previouslyFocused.focus();
+    };
+  }, []);
+
+  // The recents-and-projects list, the first time `~` is used. No directories
+  // is a shorter list, not an error state.
+  useEffect(() => {
+    if (parsed.sigil !== "~" || requestedRef.current) return;
+    requestedRef.current = true;
+    let live = true;
+    loadDirectories()
+      .then((paths) => {
+        if (live) setDirectories(directoryBarCandidates(paths, homeDir));
+      })
+      .catch(() => {});
+    return () => {
+      live = false;
+    };
+  }, [parsed.sigil, loadDirectories, homeDir]);
+
+  // Fill the list in from `GET /api/dirs` once the query looks like a path: the
+  // directory it names is listed and its children join the candidates, so `~`
+  // reaches a directory that was never spawned in.
+  const dir = parsed.sigil === "~" ? probeDir(parsed.query) : "";
+  useEffect(() => {
+    if (dir === "") {
+      setProbed([]);
+      return;
+    }
+    const cached = listingsRef.current.get(dir);
+    if (cached) {
+      setProbed(directoryBarCandidates(dirEntryPaths(dir, cached), homeDir));
+      return;
+    }
+    let live = true;
+    setProbed([]);
+    listDirEntries(dir)
+      .then((entries) => {
+        listingsRef.current.set(dir, entries);
+        if (live) setProbed(directoryBarCandidates(dirEntryPaths(dir, entries), homeDir));
+      })
+      .catch(() => {
+        /* an unreadable directory contributes nothing */
+      });
+    return () => {
+      live = false;
+    };
+  }, [dir, listDirEntries, homeDir]);
+
+  /** What the matcher sees for the query line as it stands. With no sigil the
+   *  list is mixed — sessions and commands together — except on an empty query,
+   *  where the bar is a session switcher. */
+  const candidates: BarCandidate[] = useMemo(() => {
+    if (page) return sessionActionCandidates();
+    switch (parsed.sigil) {
+      case ">":
+        return [...commandCandidates];
+      case "~": {
+        const seen = new Set<string>();
+        return [...directories, ...probed].filter((c) =>
+          seen.has(c.path) ? false : (seen.add(c.path), true),
+        );
+      }
+      default:
+        return parsed.query === ""
+          ? [...sessionCandidates]
+          : [...sessionCandidates, ...commandCandidates];
+    }
+  }, [page, parsed.sigil, parsed.query, sessionCandidates, commandCandidates, directories, probed]);
+
+  const groups = useMemo(
+    () => barGroups(barRows(parsed.query, candidates)),
+    [parsed.query, candidates],
+  );
+  // Grouping is a rendering of the ranking, so the flattened groups are the
+  // rows in the order they appear — which is the order the highlight walks and
+  // Enter acts on.
+  const rows: BarResult[] = useMemo(() => groups.flatMap((g) => g.results), [groups]);
+
+  // The highlight starts on the globally best row every time the list changes:
+  // an old index would point at a different result.
+  useEffect(() => {
+    setHighlighted(0);
+  }, [rows]);
+
+  /** The highlight does not wrap: it stops at the first and last row. */
+  const move = useCallback(
+    (delta: number) => {
+      setHighlighted((at) => Math.min(rows.length - 1, Math.max(0, at + delta)));
+    },
+    [rows.length],
+  );
+
+  const runAction = useCallback(
+    (action: SessionAction, session: Session) => {
+      onClose();
+      switch (action.id) {
+        case "kill":
+          (props.onKillSession ?? ((s: Session) => raise(KILL_SESSION_EVENT, s)))(session);
+          return;
+        case "rename":
+          (props.onRenameSession ?? ((s: Session) => raise(RENAME_SESSION_EVENT, s)))(session);
+          return;
+        case "spawn-similar":
+          (props.onSpawnSimilar ?? ((s: Session) => raise(SPAWN_SIMILAR_EVENT, s)))(session);
+          return;
+      }
+    },
+    [onClose, props.onKillSession, props.onRenameSession, props.onSpawnSimilar],
+  );
+
+  const activate = useCallback(
+    (index: number) => {
+      const result = rows[index];
+      if (!result) return;
+      const candidate = result.candidate;
+      if (isActionCandidate(candidate)) {
+        // The page cannot be up without a session to act on.
+        if (page) runAction(candidate.action, page);
+        return;
+      }
+      onClose();
+      switch (candidate.kind) {
+        case "session":
+          (props.onOpenSession ?? ((id: string) => raise(SESSION_SELECT_EVENT, id)))(
+            candidate.session.id,
+          );
+          return;
+        case "command":
+          candidate.command.run();
+          return;
+        case "directory":
+          (props.onSpawnDirectory ?? ((p: string) => raise(SPAWN_DIRECTORY_EVENT, p)))(
+            candidate.path,
+          );
+          return;
+      }
+    },
+    [rows, page, runAction, onClose, props.onOpenSession, props.onSpawnDirectory],
+  );
+
+  /** `tab`: drill into the highlighted session's action page. No effect on any
+   *  other kind, and none on the page itself, which has no session rows. */
+  const drillIn = useCallback(() => {
+    const candidate = rows[highlighted]?.candidate;
+    if (page || candidate?.kind !== "session") return;
+    setPage(candidate.session);
+    setStashed(raw);
+    setRaw("");
+  }, [rows, highlighted, page, raw]);
+
+  /** Escape, or backspace at an empty query: back to the result list with the
+   *  query the drill-in was made from. */
+  const leavePage = useCallback(() => {
+    setPage(null);
+    setRaw(stashed);
+    setStashed("");
+  }, [stashed]);
+
+  const onKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
+    switch (e.key) {
+      case "Escape":
+        e.preventDefault();
+        // On an action page Escape is one level up, not the way out.
+        if (page) leavePage();
+        else onClose();
+        return;
+      case "Tab":
+        e.preventDefault();
+        drillIn();
+        return;
+      case "Backspace":
+        // Ordinary editing, except at an empty query on the action page.
+        if (page && raw === "") {
+          e.preventDefault();
+          leavePage();
+        }
+        return;
+      case "Enter":
+        e.preventDefault();
+        activate(highlighted);
+        return;
+      case "ArrowDown":
+        e.preventDefault();
+        move(1);
+        return;
+      case "ArrowUp":
+        e.preventDefault();
+        move(-1);
+        return;
+      case "n":
+        if (e.ctrlKey) {
+          e.preventDefault();
+          move(1);
+        }
+        return;
+      case "p":
+        if (e.ctrlKey) {
+          e.preventDefault();
+          move(-1);
+        }
+        return;
+    }
+  };
+
+  const activeRowId = rows.length > 0 ? `cmdbar-row-${highlighted}` : undefined;
+
+  return createPortal(
+    <div
+      className="cmdbar-overlay fixed inset-0 z-modal flex items-start justify-center bg-bg/70 pt-[12vh] backdrop-blur-sm max-[600px]:items-end max-[600px]:pt-0"
+      role="dialog"
+      aria-modal="true"
+      aria-label="Command bar"
+      onMouseDown={(e) => {
+        // A press on the scrim closes; one inside the panel is left alone.
+        if (!panelRef.current?.contains(e.target as Node)) onClose();
+      }}
+    >
+      <div
+        ref={panelRef}
+        className="cmdbar-panel flex w-full max-w-[560px] flex-col overflow-hidden rounded-r-3 border border-border bg-surface shadow-2 max-[600px]:max-w-none max-[600px]:rounded-b-none"
+      >
+        <input
+          ref={inputRef}
+          type="text"
+          role="combobox"
+          aria-expanded="true"
+          aria-controls="cmdbar-results"
+          aria-label="Search sessions, commands and directories"
+          aria-activedescendant={activeRowId}
+          autoComplete="off"
+          spellCheck={false}
+          className="cmdbar-input w-full border-b border-border bg-transparent px-sp-3 py-sp-2 text-fs-15 text-ink outline-none"
+          placeholder={page ? `Act on ${sessionName(page)}…` : PLACEHOLDERS[parsed.sigil ?? "mixed"]}
+          value={raw}
+          onChange={(e) => setRaw(e.currentTarget.value)}
+          onKeyDown={onKeyDown}
+        />
+        {page ? (
+          <ActionPage
+            session={page}
+            groups={groups}
+            highlighted={highlighted}
+            onActivate={activate}
+          />
+        ) : (
+          <ResultList
+            groups={groups}
+            // While a sigil is in force there is one kind, so the header is
+            // dropped.
+            showHeaders={parsed.sigil === null}
+            highlighted={highlighted}
+            onActivate={activate}
+          />
+        )}
+      </div>
+    </div>,
+    document.body,
+  );
+}

web/src/components/commandBar/ResultList.tsx

@@ -0,0 +1,171 @@
+// The bar's result list: kind headers over rank-ordered rows
+// (docs/COMMAND-BAR.md, "Structure"). Headers are labels, never rows — the
+// highlight walks the rows alone, in the order they are rendered.
+
+import { useEffect, useRef } from "react";
+
+import { keyCaps } from "../../commands.js";
+import {
+  highlightSegments,
+  isActionCandidate,
+  metaText,
+  rowName,
+  type BarGroup,
+  type BarResult,
+} from "./model.js";
+
+export interface ResultListProps {
+  groups: BarGroup[];
+  /** Dropped while a sigil is in force or on the action page: one kind needs
+   * no header. */
+  showHeaders: boolean;
+  /** Index into the flattened rows, in the order they render. */
+  highlighted: number;
+  onActivate(index: number): void;
+}
+
+function Highlighted({ text, ranges }: { text: string; ranges: BarResult["ranges"] }) {
+  return (
+    <>
+      {highlightSegments(text, ranges).map((segment, i) =>
+        segment.hit ? (
+          <mark key={i} className="cmdbar-hit bg-transparent font-semibold text-accent">
+            {segment.text}
+          </mark>
+        ) : (
+          <span key={i}>{segment.text}</span>
+        ),
+      )}
+    </>
+  );
+}
+
+function Row({
+  result,
+  index,
+  active,
+  onActivate,
+}: {
+  result: BarResult;
+  index: number;
+  active: boolean;
+  onActivate(index: number): void;
+}) {
+  const ref = useRef<HTMLDivElement>(null);
+  const candidate = result.candidate;
+
+  useEffect(() => {
+    if (active) ref.current?.scrollIntoView({ block: "nearest" });
+  }, [active]);
+
+  const name = rowName(candidate);
+  const nameMatched =
+    result.field === "name" || result.field === "label" || result.field === "path";
+  const meta = metaText(result);
+  const dead = candidate.kind === "session" && candidate.session.status === "Dead";
+  const chord =
+    candidate.kind === "command" && !isActionCandidate(candidate)
+      ? candidate.command.keys[0]
+      : undefined;
+
+  return (
+    <div
+      ref={ref}
+      role="option"
+      id={`cmdbar-row-${index}`}
+      aria-selected={active}
+      data-index={index}
+      data-kind={candidate.kind}
+      data-session-id={candidate.kind === "session" ? candidate.session.id : undefined}
+      data-action-id={isActionCandidate(candidate) ? candidate.action.id : undefined}
+      data-command-id={
+        candidate.kind === "command" && !isActionCandidate(candidate)
+          ? candidate.command.id
+          : undefined
+      }
+      data-path={candidate.kind === "directory" ? candidate.path : undefined}
+      className={[
+        "cmdbar-row flex cursor-pointer items-baseline gap-sp-2 rounded-r-1 px-sp-3 py-sp-1 text-fs-13",
+        active ? "is-active bg-surface-2 text-ink" : "text-ink",
+        dead ? "is-dead opacity-60" : "",
+      ]
+        .filter(Boolean)
+        .join(" ")}
+      onClick={() => onActivate(index)}
+    >
+      <span className="cmdbar-row-name truncate">
+        {nameMatched ? <Highlighted text={name} ranges={result.ranges} /> : name}
+      </span>
+      {chord !== undefined ? (
+        <span className="cmdbar-row-keys ml-auto flex gap-1">
+          {keyCaps(chord).map((cap, i) => (
+            <kbd
+              key={i}
+              className="rounded-r-1 border border-border px-1 text-fs-11 text-muted"
+            >
+              {cap}
+            </kbd>
+          ))}
+        </span>
+      ) : meta ? (
+        <span className="cmdbar-row-meta ml-auto truncate text-fs-11 text-muted">
+          {result.field !== undefined && result.field !== "name" ? (
+            <Highlighted text={meta} ranges={result.ranges} />
+          ) : (
+            meta
+          )}
+        </span>
+      ) : null}
+    </div>
+  );
+}
+
+export function ResultList({ groups, showHeaders, highlighted, onActivate }: ResultListProps) {
+  if (groups.length === 0) {
+    return (
+      <div
+        id="cmdbar-results"
+        role="listbox"
+        aria-label="Results"
+        className="cmdbar-results max-h-[50vh] overflow-auto p-sp-1"
+      >
+        <div className="cmdbar-empty px-sp-3 py-sp-2 text-fs-12 text-muted">No matches</div>
+      </div>
+    );
+  }
+
+  let index = 0;
+  return (
+    <div
+      id="cmdbar-results"
+      role="listbox"
+      aria-label="Results"
+      className="cmdbar-results max-h-[50vh] overflow-auto p-sp-1"
+    >
+      {groups.map((group) => (
+        <div key={group.kind}>
+          {showHeaders ? (
+            <div
+              role="presentation"
+              className="cmdbar-group-title px-sp-3 pt-sp-2 pb-1 text-fs-11 uppercase tracking-wide text-muted"
+            >
+              {group.title}
+            </div>
+          ) : null}
+          {group.results.map((result) => {
+            const at = index++;
+            return (
+              <Row
+                key={at}
+                result={result}
+                index={at}
+                active={at === highlighted}
+                onActivate={onActivate}
+              />
+            );
+          })}
+        </div>
+      ))}
+    </div>
+  );
+}

web/src/components/commandBar/index.ts

@@ -0,0 +1,5 @@
+export { CommandBar, SPAWN_DIRECTORY_EVENT, type CommandBarProps } from "./CommandBar.js";
+export { ResultList, type ResultListProps } from "./ResultList.js";
+export { ActionPage, type ActionPageProps } from "./ActionPage.js";
+export { useCommandBar, type CommandBarControls, type UseCommandBarOptions } from "./useCommandBar.js";
+export * from "./model.js";

web/src/components/commandBar/model.test.ts

@@ -0,0 +1,197 @@
+import { describe, expect, it } from "vitest";
+
+import type { Command } from "../../commands.js";
+import type { Session } from "../../types.js";
+import {
+  barGroups,
+  barRows,
+  commandBarCandidates,
+  dedupeCommands,
+  directoryBarCandidates,
+  directoryCandidate,
+  highlightSegments,
+  orderSessionsForBar,
+  parseBarQuery,
+  sessionActionCandidates,
+  sessionBarCandidates,
+  sessionCandidate,
+} from "./model.js";
+
+function session(id: string, over: Partial<Session> = {}): Session {
+  return {
+    id,
+    cwd: "/home/me/dev/api",
+    command: "bash",
+    env: {},
+    metadata: { name: id },
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  };
+}
+
+function command(over: Partial<Command> = {}): Command {
+  return {
+    id: "a",
+    label: "A command",
+    group: "Test",
+    keys: ["a"],
+    scope: "global",
+    run: () => {},
+    ...over,
+  };
+}
+
+describe("empty-query ordering", () => {
+  it("sorts most recently focused first", () => {
+    const older = session("older", { last_focused_at: "2026-01-01T10:00:00Z" });
+    const newer = session("newer", { last_focused_at: "2026-01-01T11:00:00Z" });
+    expect(orderSessionsForBar([older, newer]).map((s) => s.id)).toEqual(["newer", "older"]);
+  });
+
+  it("sorts a never-focused session after every focused one, newest created first", () => {
+    const focused = session("focused", { last_focused_at: "2026-01-01T09:00:00Z" });
+    const old = session("old", { created_at: "2026-01-01T00:00:00Z" });
+    const fresh = session("fresh", { created_at: "2026-01-02T00:00:00Z" });
+    expect(orderSessionsForBar([old, fresh, focused]).map((s) => s.id)).toEqual([
+      "focused",
+      "fresh",
+      "old",
+    ]);
+  });
+
+  it("sorts dead sessions after live ones regardless of recency", () => {
+    const dead = session("dead", { status: "Dead", last_focused_at: "2026-01-01T12:00:00Z" });
+    const live = session("live", { last_focused_at: "2026-01-01T10:00:00Z" });
+    expect(orderSessionsForBar([dead, live]).map((s) => s.id)).toEqual(["live", "dead"]);
+  });
+
+  it("treats an empty last_focused_at as never focused", () => {
+    const blank = session("blank", { last_focused_at: "" });
+    const focused = session("focused", { last_focused_at: "2026-01-01T10:00:00Z" });
+    expect(orderSessionsForBar([blank, focused]).map((s) => s.id)).toEqual(["focused", "blank"]);
+  });
+});
+
+describe("session candidates", () => {
+  it("carries the candidate table's fields, with the directory abbreviated", () => {
+    const s = session("api", {
+      metadata: { name: "api" },
+      current_cwd: "/home/me/dev/api",
+      command: "claude --resume",
+    });
+    expect(sessionCandidate(s, "/home/me").fields).toEqual({
+      name: "api",
+      directory: "~/dev/api",
+      command: "claude --resume",
+      tool: "claude",
+    });
+  });
+
+  it("leaves the tool out when the program has no mark, and groups a worktree by its repo", () => {
+    const s = session("edit", {
+      metadata: {},
+      command: "hx src/",
+      worktree: { path: "/home/me/dev/api/wt/x", base_repo: "/home/me/dev/api" },
+    });
+    const candidate = sessionCandidate(s, "/home/me");
+    expect(candidate.fields.tool).toBeUndefined();
+    expect(candidate.fields.directory).toBe("~/dev/api");
+    // No `metadata.name`: the sidebar's fallback is the command line.
+    expect(candidate.fields.name).toBe("hx src/");
+  });
+
+  it("builds candidates in the empty-query order", () => {
+    const a = session("a", { last_focused_at: "2026-01-01T10:00:00Z" });
+    const b = session("b", { last_focused_at: "2026-01-01T11:00:00Z" });
+    expect(sessionBarCandidates([a, b]).map((c) => c.session.id)).toEqual(["b", "a"]);
+  });
+});
+
+describe("rows and grouping", () => {
+  it("an empty query keeps every candidate in input order", () => {
+    const candidates = sessionBarCandidates([session("a"), session("b")]);
+    expect(barRows("", candidates).map((r) => r.score)).toEqual([0, 0]);
+  });
+
+  it("groups by kind without reordering the ranking", () => {
+    const rows = barRows("kill", [
+      ...sessionBarCandidates([session("killer-app", { metadata: { name: "killer-app" } })]),
+      ...commandBarCandidates([command({ label: "Kill selected session" })]),
+    ]);
+    const groups = barGroups(rows);
+    expect(groups.map((g) => g.title)).toEqual(["Sessions", "Commands"]);
+    expect(groups.flatMap((g) => g.results)).toEqual(rows);
+  });
+});
+
+describe("parsing the query line", () => {
+  it("reads a sigil only in first position", () => {
+    expect(parseBarQuery(">help")).toEqual({ sigil: ">", query: "help" });
+    expect(parseBarQuery("~dev")).toEqual({ sigil: "~", query: "dev" });
+  });
+
+  it("leaves a sigil character elsewhere in the query literal", () => {
+    expect(parseBarQuery("~dev/~scratch")).toEqual({ sigil: "~", query: "dev/~scratch" });
+    expect(parseBarQuery("a>b")).toEqual({ sigil: null, query: "a>b" });
+  });
+
+  it("returns to the mixed list when the sigil is backspaced away", () => {
+    expect(parseBarQuery("")).toEqual({ sigil: null, query: "" });
+  });
+});
+
+describe("command candidates", () => {
+  it("dedupes by action, not by chord", () => {
+    const run = () => {};
+    const cmds = [
+      command({ id: "one", label: "Do it", keys: ["j"], run }),
+      command({ id: "two", label: "Do it", keys: ["down"], run }),
+    ];
+    expect(commandBarCandidates(cmds)).toHaveLength(1);
+    expect(dedupeCommands(cmds)).toHaveLength(1);
+  });
+
+  it("matches on the label only, never on the chord", () => {
+    const candidates = commandBarCandidates([command({ label: "Show help", keys: ["ctrl-q"] })]);
+    expect(barRows("ctrlq", candidates)).toEqual([]);
+    expect(barRows("show", candidates)).toHaveLength(1);
+  });
+});
+
+describe("directory candidates", () => {
+  it("abbreviates the path it shows and keeps the one it spawns in", () => {
+    const candidate = directoryCandidate("/home/me/dev/api", "/home/me");
+    expect(candidate.fields.path).toBe("~/dev/api");
+    expect(candidate.path).toBe("/home/me/dev/api");
+  });
+
+  it("expands a typed `~` and dedupes by the directory spawned in", () => {
+    const candidates = directoryBarCandidates(
+      ["~/dev/api", "/home/me/dev/api", "", "/srv/x"],
+      "/home/me",
+    );
+    expect(candidates.map((c) => c.path)).toEqual(["/home/me/dev/api", "/srv/x"]);
+  });
+});
+
+describe("the action page's candidates", () => {
+  it("offers no action beyond the three", () => {
+    expect(sessionActionCandidates().map((c) => c.action.id)).toEqual([
+      "kill",
+      "rename",
+      "spawn-similar",
+    ]);
+  });
+});
+
+describe("highlight segments", () => {
+  it("splits the text on the matcher's ranges", () => {
+    expect(highlightSegments("web-search", [[0, 1], [4, 5]])).toEqual([
+      { text: "w", hit: true },
+      { text: "eb-", hit: false },
+      { text: "s", hit: true },
+      { text: "earch", hit: false },
+    ]);
+  });
+});

web/src/components/commandBar/model.ts

@@ -0,0 +1,366 @@
+// The command bar's pure model (docs/COMMAND-BAR.md), lifted from
+// ../../commandBar.ts for the React port (#247): what a candidate is, the
+// order an empty query lists them in, how a query line splits into a sigil and
+// a query, and how a ranked list groups for rendering.
+//
+// Nothing here touches the DOM or the network apart from `loadBarDirectories`,
+// which is the one place the `~` list comes from.
+
+import { listDir, projects as fetchProjects, recentDirs } from "../../api.js";
+import type { Command } from "../../commands.js";
+import { splitPath } from "../../paths.js";
+import { splitCommand } from "../../toolIcon.js";
+import { abbreviateCwd, sessionName, sessionTreePath, type Session } from "../../types.js";
+import {
+  matchAndRank,
+  type CandidateKind,
+  type CommandCandidate,
+  type DirectoryCandidate,
+  type MatchRange,
+  type MatchResult,
+  type SessionCandidate,
+} from "../../utils/matcher.js";
+
+/** A matcher candidate that remembers what it came from, so a result can be
+ *  acted on without a second lookup. The extra property is invisible to the
+ *  matcher, which only ever reads `kind` and `fields`. */
+export type SessionBarCandidate = SessionCandidate & { session: Session };
+export type CommandBarCandidate = CommandCandidate & { command: Command };
+/** `fields.path` is the abbreviated path the operator reads and the matcher
+ *  ranks; `path` is the one a spawn is made in. */
+export type DirectoryBarCandidate = DirectoryCandidate & { path: string };
+
+/** One row of a session's action page. It is a `command` to the matcher — a
+ *  single `label` field, ranked exactly like a registry command — and carries
+ *  the action it stands for instead of a registry entry. */
+export type ActionBarCandidate = CommandCandidate & { action: SessionAction };
+
+export type BarCandidate =
+  | SessionBarCandidate
+  | CommandBarCandidate
+  | ActionBarCandidate
+  | DirectoryBarCandidate;
+export type BarResult = MatchResult<BarCandidate>;
+
+/** One kind's slice of the ranked list, in rank order. */
+export interface BarGroup<C extends BarCandidate = BarCandidate> {
+  kind: CandidateKind;
+  title: string;
+  results: MatchResult<C>[];
+}
+
+const KIND_TITLES: Record<CandidateKind, string> = {
+  session: "Sessions",
+  command: "Commands",
+  directory: "Directories",
+};
+
+// ---- the sigils ----
+
+export type BarSigil = ">" | "~";
+
+export interface BarQuery {
+  /** The sigil in force, or null for the mixed list. */
+  sigil: BarSigil | null;
+  /** What the matcher sees: everything after a sigil, or the whole query. */
+  query: string;
+}
+
+export const PLACEHOLDERS: Record<"mixed" | BarSigil, string> = {
+  mixed: "Go to a session…",
+  ">": "Run a command…",
+  "~": "Spawn in a directory…",
+};
+
+/** Split a raw query line into its sigil and the query proper.
+ *
+ *  A sigil is only a sigil in first position: `>` or `~` anywhere else is a
+ *  literal query character, which is what a directory query with a second `~`
+ *  in it depends on. Backspacing past a sigil needs no special case either —
+ *  the first character goes and the query is a mixed one again. */
+export function parseBarQuery(raw: string): BarQuery {
+  const first = raw[0];
+  if (first === ">" || first === "~") return { sigil: first, query: raw.slice(1) };
+  return { sigil: null, query: raw };
+}
+
+// ---- the session action page ----
+
+/** The actions a session's action page offers, and no others: the bar picks
+ *  one and hands off to the flow that already implements it
+ *  (docs/COMMAND-BAR.md, "Drill-in"). */
+export type SessionActionId = "kill" | "rename" | "spawn-similar";
+
+export interface SessionAction {
+  id: SessionActionId;
+  label: string;
+}
+
+export const SESSION_ACTIONS: readonly SessionAction[] = [
+  { id: "kill", label: "Kill session" },
+  { id: "rename", label: "Rename session" },
+  { id: "spawn-similar", label: "Spawn similar" },
+];
+
+/** The action page's candidates, in the order above — which is the order an
+ *  empty query lists them in, since the matcher keeps input order. */
+export function sessionActionCandidates(): ActionBarCandidate[] {
+  return SESSION_ACTIONS.map((action) => ({
+    kind: "command",
+    action,
+    fields: { label: action.label },
+  }));
+}
+
+/** Narrow a `command` candidate to an action row. Both share the matcher's
+ *  `command` kind, so what separates them is what they carry. */
+export function isActionCandidate(candidate: BarCandidate): candidate is ActionBarCandidate {
+  return candidate.kind === "command" && "action" in candidate;
+}
+
+// ---- candidates ----
+
+function focusedAt(s: Session): number | null {
+  const stamp = s.last_focused_at;
+  if (typeof stamp !== "string" || stamp === "") return null;
+  const ms = Date.parse(stamp);
+  return Number.isNaN(ms) ? null : ms;
+}
+
+function createdAt(s: Session): number {
+  const ms = Date.parse(s.created_at ?? "");
+  return Number.isNaN(ms) ? 0 : ms;
+}
+
+/** The empty-query order (docs/COMMAND-BAR.md, "Empty query"): most recently
+ *  focused first; a session that has never been focused sorts after every
+ *  session that has, most recently created first among those; and a dead
+ *  session sorts after every live one regardless of recency, because a session
+ *  you cannot attach to is not where you just were.
+ *
+ *  This is also the input order for a non-empty query, which is what the
+ *  matcher's last tie-break preserves. */
+export function orderSessionsForBar(sessions: readonly Session[]): Session[] {
+  return [...sessions].sort((a, b) => {
+    const deadA = a.status === "Dead" ? 1 : 0;
+    const deadB = b.status === "Dead" ? 1 : 0;
+    if (deadA !== deadB) return deadA - deadB;
+
+    const focusA = focusedAt(a);
+    const focusB = focusedAt(b);
+    if ((focusA === null) !== (focusB === null)) return focusA === null ? 1 : -1;
+    if (focusA !== null && focusB !== null && focusA !== focusB) return focusB - focusA;
+
+    return createdAt(b) - createdAt(a);
+  });
+}
+
+/** Build one session's candidate: the fields docs/COMMAND-BAR.md's candidate
+ *  table names, with the directory abbreviated the way the sidebar shows it. */
+export function sessionCandidate(s: Session, homeDir?: string): SessionBarCandidate {
+  const treePath = sessionTreePath(s);
+  const directory = treePath ? abbreviateCwd(treePath, homeDir) : undefined;
+  const tool = splitCommand(s.command).tool ?? undefined;
+  return {
+    kind: "session",
+    session: s,
+    fields: {
+      name: sessionName(s),
+      ...(directory ? { directory } : {}),
+      ...(s.command ? { command: s.command } : {}),
+      ...(tool ? { tool } : {}),
+    },
+  };
+}
+
+/** Every session as a candidate, in the empty-query order. */
+export function sessionBarCandidates(
+  sessions: readonly Session[],
+  homeDir?: string,
+): SessionBarCandidate[] {
+  return orderSessionsForBar(sessions).map((s) => sessionCandidate(s, homeDir));
+}
+
+/** Drop the commands that would list twice. Several chords can be bound to one
+ *  action — the registry already carries its aliases on one entry, but nothing
+ *  stops two entries running the same handler, and listed naively that is two
+ *  identical rows. The dedupe is by **action**, never by chord: the chord is
+ *  displayed, so a command with two of them is still one row. */
+export function dedupeCommands(commands: readonly Command[]): Command[] {
+  const seenRun = new Set<Command["run"]>();
+  const seenLabel = new Set<string>();
+  const kept: Command[] = [];
+  for (const command of commands) {
+    if (seenRun.has(command.run) || seenLabel.has(command.label)) continue;
+    seenRun.add(command.run);
+    seenLabel.add(command.label);
+    kept.push(command);
+  }
+  return kept;
+}
+
+/** Every bound command as a candidate, in registry order. Only the label is a
+ *  field: the chord is displayed beside the row, never matched, because
+ *  matching it would make `>` results depend on a user's rebinds. */
+export function commandBarCandidates(commands: readonly Command[]): CommandBarCandidate[] {
+  return dedupeCommands(commands).map((command) => ({
+    kind: "command",
+    command,
+    fields: { label: command.label },
+  }));
+}
+
+/** `~/dev/api` back to `/home/me/dev/api` — the inverse of `abbreviateCwd`, for
+ *  a path the operator typed or `/api/dirs` completed. */
+export function expandHome(path: string, homeDir?: string): string {
+  if (!homeDir) return path;
+  if (path === "~") return homeDir;
+  return path.startsWith("~/") ? `${homeDir}${path.slice(1)}` : path;
+}
+
+export function directoryCandidate(path: string, homeDir?: string): DirectoryBarCandidate {
+  const absolute = expandHome(path, homeDir);
+  return { kind: "directory", path: absolute, fields: { path: abbreviateCwd(absolute, homeDir) } };
+}
+
+/** Candidates for `~`, deduped by the directory they spawn in and keeping the
+ *  first mention of each — recent dirs (newest first) ahead of the project
+ *  list, which is the empty-query order the contract asks for. */
+export function directoryBarCandidates(
+  paths: readonly string[],
+  homeDir?: string,
+): DirectoryBarCandidate[] {
+  const seen = new Set<string>();
+  const out: DirectoryBarCandidate[] = [];
+  for (const path of paths) {
+    if (path === "") continue;
+    const candidate = directoryCandidate(path, homeDir);
+    if (seen.has(candidate.path)) continue;
+    seen.add(candidate.path);
+    out.push(candidate);
+  }
+  return out;
+}
+
+/** The directory list the bar starts from: what the spawn form already knows —
+ *  `GET /api/recent-dirs` and the project list — either alone if the other
+ *  fails. */
+export async function loadBarDirectories(): Promise<string[]> {
+  const [recents, discovered] = await Promise.all([
+    recentDirs()
+      .then((r) => r.dirs.map((d) => d.cwd))
+      .catch(() => [] as string[]),
+    fetchProjects()
+      .then((list) => list.map((p) => p.path))
+      .catch(() => [] as string[]),
+  ]);
+  return [...recents, ...discovered];
+}
+
+/** One directory's children as candidate paths, for filling the `~` list in as
+ *  a path is typed. The directory being listed comes from the query itself. */
+export function dirEntryPaths(dir: string, entries: readonly string[]): string[] {
+  return entries.map((entry) => `${dir}${entry}`);
+}
+
+/** The directory a `~` query names, or `""` when it names none yet. */
+export function probeDir(query: string): string {
+  return splitPath(query).dir;
+}
+
+/** `GET /api/dirs`, in the shape the bar wants it. */
+export function listDirEntries(dir: string): Promise<string[]> {
+  return listDir(dir).then((listing) => listing.entries);
+}
+
+// ---- grouping ----
+
+/** Bucket a ranked list by kind for rendering. Grouping is a rendering of the
+ *  ranking, never a reordering of it: a group holds its matches in rank order,
+ *  and groups appear in the order their best-scoring member does — so the first
+ *  row under the first header is the globally best result. */
+export function barGroups<C extends BarCandidate>(
+  results: readonly MatchResult<C>[],
+): BarGroup<C>[] {
+  const groups: BarGroup<C>[] = [];
+  for (const result of results) {
+    const kind = result.candidate.kind;
+    let group = groups.find((g) => g.kind === kind);
+    if (!group) {
+      group = { kind, title: KIND_TITLES[kind], results: [] };
+      groups.push(group);
+    }
+    group.results.push(result);
+  }
+  return groups;
+}
+
+/** The rows a query produces, flat and in rank order — what the highlight walks
+ *  and what Enter acts on. Headers are labels, not rows, so they are never in
+ *  this list. */
+export function barRows<C extends BarCandidate>(
+  query: string,
+  candidates: readonly C[],
+): MatchResult<C>[] {
+  return matchAndRank(query, candidates);
+}
+
+// ---- row text ----
+
+/** The name line of a row: the session's name, the command's label, or the
+ *  directory's path. */
+export function rowName(candidate: BarCandidate): string {
+  switch (candidate.kind) {
+    case "session":
+      return candidate.fields.name;
+    case "command":
+      return candidate.fields.label;
+    case "directory":
+      return candidate.fields.path;
+  }
+}
+
+/** The secondary line under a session row: the field the match was found in
+ *  when that was not the name, so a session found through its directory says
+ *  so. Only sessions have one — a command shows keycaps instead, and a
+ *  directory's path is already the name. */
+export function metaText(result: BarResult): string | undefined {
+  if (result.candidate.kind !== "session") return undefined;
+  const fields = result.candidate.fields;
+  switch (result.field) {
+    case "directory":
+      return fields.directory;
+    case "command":
+      return fields.command;
+    case "tool":
+      return fields.tool;
+    default:
+      return fields.directory;
+  }
+}
+
+/** One run of a row's text, flagged when the matcher matched inside it. The
+ *  React rendering of `renderHighlighted`: ranges come from the matcher as
+ *  `[start, end)` character pairs over the field that won. */
+export interface HighlightSegment {
+  text: string;
+  hit: boolean;
+}
+
+export function highlightSegments(
+  text: string,
+  ranges: readonly MatchRange[],
+): HighlightSegment[] {
+  const out: HighlightSegment[] = [];
+  let cursor = 0;
+  for (const [start, end] of ranges) {
+    if (start > cursor) out.push({ text: text.slice(cursor, start), hit: false });
+    out.push({ text: text.slice(start, end), hit: true });
+    cursor = end;
+  }
+  if (cursor < text.length) out.push({ text: text.slice(cursor), hit: false });
+  return out;
+}
+
+export { sessionName };
+export type { CandidateKind, MatchRange, MatchResult };

web/src/components/commandBar/useCommandBar.test.tsx

@@ -0,0 +1,76 @@
+// @vitest-environment happy-dom
+import { act, cleanup, render } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { OPEN_COMMAND_BAR_EVENT } from "../../catalog.js";
+import { useCommandBar, type UseCommandBarOptions } from "./useCommandBar.js";
+
+let controls: ReturnType<typeof useCommandBar>;
+
+function Probe(opts: UseCommandBarOptions) {
+  controls = useCommandBar(opts);
+  return <div>{controls.open ? "open" : "closed"}</div>;
+}
+
+function ctrlK(target: EventTarget = window): void {
+  act(() => {
+    target.dispatchEvent(
+      new KeyboardEvent("keydown", { key: "k", ctrlKey: true, bubbles: true, cancelable: true }),
+    );
+  });
+}
+
+afterEach(cleanup);
+
+describe("useCommandBar", () => {
+  it("opens on ctrl-k, from the capture phase so an attached xterm never sees it", () => {
+    const view = render(<Probe />);
+    ctrlK();
+    expect(view.container.textContent).toBe("open");
+  });
+
+  it("stays deaf while the bar is already up — its own input owns the keys", () => {
+    const onOpen = vi.fn();
+    render(<Probe onOpen={onOpen} />);
+    ctrlK();
+    ctrlK();
+    expect(onOpen).toHaveBeenCalledTimes(1);
+  });
+
+  it("leaves a form field's own Ctrl-K alone", () => {
+    const field = document.createElement("input");
+    document.body.appendChild(field);
+    const view = render(<Probe />);
+    ctrlK(field);
+    expect(view.container.textContent).toBe("closed");
+    field.remove();
+  });
+
+  it("opens from the sidebar's search field, the touch entry point", () => {
+    const view = render(<Probe />);
+    act(() => {
+      document.dispatchEvent(new CustomEvent(OPEN_COMMAND_BAR_EVENT));
+    });
+    expect(view.container.textContent).toBe("open");
+  });
+
+  it("runs the caller's hook before opening, so a preview is discarded first", () => {
+    const onOpen = vi.fn();
+    render(<Probe onOpen={onOpen} />);
+    ctrlK();
+    expect(onOpen).toHaveBeenCalledTimes(1);
+  });
+
+  it("closes on demand", () => {
+    const view = render(<Probe />);
+    ctrlK();
+    act(() => controls.closeBar());
+    expect(view.container.textContent).toBe("closed");
+  });
+
+  it("binds nothing while disabled — another overlay owns the keyboard", () => {
+    const view = render(<Probe enabled={false} />);
+    ctrlK();
+    expect(view.container.textContent).toBe("closed");
+  });
+});

web/src/components/commandBar/useCommandBar.ts

@@ -0,0 +1,65 @@
+// Opening and closing the bar (docs/COMMAND-BAR.md, "Opening"). `ctrl-k` is a
+// registry command like any other, so the `?` overlay lists it without a
+// second list; the touch entry point — the sidebar's search field — raises
+// `OPEN_COMMAND_BAR_EVENT` and lands on the same open.
+
+import { useCallback, useEffect, useState } from "react";
+
+import { OPEN_COMMAND_BAR_EVENT } from "../../catalog.js";
+import { CommandSet, defineCommands, isBarTypingTarget } from "../../commands.js";
+
+export interface UseCommandBarOptions {
+  /** Run before the bar opens — the shell discards a preview here, since the
+   * bar is not previewed into (docs/PREVIEW.md). */
+  onOpen?(): void;
+  /** Off while another overlay owns the keyboard (the restart overlay, the
+   * help dialog). Defaults to on. */
+  enabled?: boolean;
+}
+
+export interface CommandBarControls {
+  open: boolean;
+  openBar(): void;
+  closeBar(): void;
+}
+
+export function useCommandBar(opts: UseCommandBarOptions = {}): CommandBarControls {
+  const { onOpen, enabled = true } = opts;
+  const [open, setOpen] = useState(false);
+
+  const openBar = useCallback(() => {
+    onOpen?.();
+    setOpen(true);
+  }, [onOpen]);
+
+  const closeBar = useCallback(() => setOpen(false), []);
+
+  useEffect(() => {
+    if (!enabled) return;
+    const keys = new CommandSet(defineCommands({ "bar.open": openBar }));
+
+    // Capture phase: an attached xterm swallows every keystroke it is given, so
+    // the bar's binding has to be seen ahead of the terminal.
+    const onKeydown = (e: KeyboardEvent) => {
+      // The bar owns the keyboard while it is up; its own input handles the keys.
+      if (open) return;
+      // The pane's hidden textarea is not a typing target for the bar: ctrl-k
+      // is seen ahead of xterm and opens the bar. A real form field — the spawn
+      // form's inputs — keeps its own Ctrl+K.
+      if (isBarTypingTarget(e.target)) return;
+      keys.handle(e);
+    };
+    const onTouchEntry = () => {
+      if (!open) openBar();
+    };
+
+    window.addEventListener("keydown", onKeydown, true);
+    document.addEventListener(OPEN_COMMAND_BAR_EVENT, onTouchEntry);
+    return () => {
+      window.removeEventListener("keydown", onKeydown, true);
+      document.removeEventListener(OPEN_COMMAND_BAR_EVENT, onTouchEntry);
+    };
+  }, [enabled, open, openBar]);
+
+  return { open, openBar, closeBar };
+}

web/src/components/layout/MultiView.test.tsx

@@ -0,0 +1,152 @@
+// @vitest-environment happy-dom
+import { act, cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { leaves } from "../../layout.js";
+import { createLayoutStore } from "../../stores/layoutStore.js";
+import type { Session } from "../../types.js";
+import { MultiView } from "./MultiView.js";
+
+vi.mock("../terminal/TerminalPane.js", () => ({
+  TerminalPane: ({ sessionId }: { sessionId: string }) => <div data-testid={`terminal-${sessionId}`} />,
+}));
+
+vi.mock("../structured/StructuredPane.js", () => ({
+  StructuredPane: ({ sessionId }: { sessionId: string }) => <div data-testid={`structured-${sessionId}`} />,
+}));
+
+afterEach(cleanup);
+
+function store() {
+  return createLayoutStore({
+    load: () => null,
+    save: vi.fn(),
+    scheduler: { setTimer: () => 1, clearTimer: () => {} },
+  });
+}
+
+function session(id: string, over: Partial<Session> = {}): Session {
+  return {
+    id,
+    cwd: "/home/n",
+    command: "claude",
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  } as Session;
+}
+
+describe("MultiView", () => {
+  it("shows the empty state when the active tab has no panes", () => {
+    const s = store();
+    render(<MultiView store={s} />);
+    expect(screen.getByText(/No session open/)).toBeTruthy();
+  });
+
+  it("renders a pane per leaf, dispatching to the terminal or structured body", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    s.getState().openSessionBeside("s2");
+    const sessions = new Map([
+      ["s1", session("s1")],
+      ["s2", session("s2", { view: "Structured" })],
+    ]);
+    render(<MultiView store={s} sessions={sessions} />);
+    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
+    expect(screen.getByTestId("structured-s2")).toBeTruthy();
+  });
+
+  it("split right adds a second pane to the tree", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+    fireEvent.click(screen.getByTitle("Split right"));
+    expect(screen.getAllByText("Empty pane")).toHaveLength(1);
+  });
+
+  it("close pane removes it", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    const leafId = leaves(s.getState().layout.tabs[0].root)[0].id;
+    s.getState().splitFocused(leafId, "row"); // adds an empty leaf beside s1
+    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+    // splitFocused(after: true) puts the fresh empty leaf second — close it.
+    fireEvent.click(screen.getAllByTitle("Close pane")[1]);
+    expect(screen.queryByText("Empty pane")).toBeNull();
+    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
+  });
+
+  it("prunes a leaf whose session no longer exists, once the live set is known", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    s.getState().openSessionBeside("dead");
+    render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
+    expect(screen.queryByTestId("terminal-dead")).toBeNull();
+  });
+
+  it("does not touch the layout while the live set is still unknown", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    render(<MultiView store={s} />);
+    expect(screen.getByTestId("terminal-s1")).toBeTruthy();
+  });
+
+  describe("preview mode (docs/PREVIEW.md)", () => {
+    it("shows a session no pane holds in a throwaway tab, marked as a preview", () => {
+      const s = store();
+      s.getState().openSession("s1");
+      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+
+      act(() => s.getState().previewSession("s9"));
+      // s1's own tab is still in the strip — the preview never touched it.
+      expect(screen.getByText("Tab 1 · 1")).toBeTruthy();
+      const pane = document.querySelector('[data-session-id="s9"]');
+      expect(pane).toBeTruthy();
+      expect(pane!.querySelector(".bg-preview-tint")).toBeTruthy();
+      expect(screen.getByText("preview")).toBeTruthy();
+    });
+
+    it("puts the layout back byte for byte once the preview ends", () => {
+      const s = store();
+      s.getState().openSession("s1");
+      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+      const before = JSON.stringify(s.getState().layout);
+
+      act(() => s.getState().previewSession("s9"));
+      act(() => s.getState().previewSession(null));
+
+      expect(JSON.stringify(s.getState().layout)).toBe(before);
+      expect(screen.queryByText("preview")).toBeNull();
+    });
+
+    it("does not grab the keyboard while previewing", () => {
+      const s = store();
+      s.getState().openSession("s1");
+      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+
+      act(() => s.getState().previewSession("s9"));
+      const pane = document.querySelector('[data-session-id="s9"]') as HTMLElement;
+      expect(pane.querySelector('[data-testid="terminal-s9"]')).toBeTruthy();
+      // TerminalPane's `focus` prop is verified by TerminalPane's own tests;
+      // here the preview must never end up as the active-tab's accent pane.
+      expect(pane.className).not.toContain("border-accent");
+    });
+
+    it("clicking into a previewed pane commits it: no more preview, nothing moves a second time", () => {
+      const s = store();
+      s.getState().openSession("s1");
+      render(<MultiView store={s} sessions={new Map([["s1", session("s1")]])} />);
+
+      act(() => s.getState().previewSession("s9"));
+      const pane = document.querySelector('[data-session-id="s9"]') as HTMLElement;
+      fireEvent.pointerDown(pane);
+
+      expect(s.getState().preview).toBeNull();
+      expect(screen.queryByText("preview")).toBeNull();
+      expect(leaves(s.getState().layout.tabs[1].root).map((l) => l.sessionId)).toEqual(["s9"]);
+    });
+  });
+});

web/src/components/layout/MultiView.tsx

@@ -0,0 +1,237 @@
+// React port of multiview.ts's tab + split tree (issue #249) plus its preview
+// mode (issue #251, docs/PREVIEW.md). Sidebar drag-to-dock and the mobile
+// single-pane collapse stay with whichever issue wires this into the shell
+// (#253) — this renders the tree itself: tabs, nested splits, pane chrome.
+
+import type { ReactNode } from "react";
+import { useEffect, useRef } from "react";
+import { useStore } from "zustand";
+
+import { activeTab, type Dir, type Node } from "../../layout.js";
+import { usePreview } from "../../hooks/usePreview.js";
+import type { LayoutStore, LayoutStoreApi } from "../../stores/layoutStore.js";
+import type { Session, Uuid } from "../../types.js";
+import { PaneContainer } from "./PaneContainer.js";
+import { PaneTitle } from "./PaneTitle.js";
+import { TabBar } from "./TabBar.js";
+
+export interface MultiViewProps {
+  store: LayoutStoreApi;
+  /** Live sessions, keyed by id — drives pane titles and (once known) boot
+   *  reconciliation. Passing `undefined` defers reconciliation. */
+  sessions?: ReadonlyMap<Uuid, Session>;
+  onDisconnect?: (sessionId: Uuid) => void;
+  emptyState?: ReactNode;
+}
+
+export function MultiView({ store, sessions, onDisconnect, emptyState }: MultiViewProps) {
+  const layout = useStore(store, (s: LayoutStore) => s.layout);
+  const tab = activeTab(layout);
+  const { previewedSessionId, commit: commitPreview } = usePreview({ store });
+  const isPreviewing = previewedSessionId !== null;
+
+  const reconciledRef = useRef(false);
+  useEffect(() => {
+    if (reconciledRef.current || !sessions) return;
+    reconciledRef.current = true;
+    store.getState().reconcile(new Set(sessions.keys()));
+  }, [sessions, store]);
+
+  return (
+    <div className="mv flex h-full min-h-0 flex-col">
+      <TabBar store={store} />
+      <div className="mv-canvas relative min-h-0 flex-1">
+        {tab.root ? (
+          <SplitNode
+            node={tab.root}
+            tab={tab}
+            store={store}
+            sessions={sessions}
+            onDisconnect={onDisconnect}
+            previewedSessionId={previewedSessionId}
+            commitPreview={commitPreview}
+          />
+        ) : (
+          (emptyState ?? (
+            <div className="mv-empty flex h-full items-center justify-center p-sp-4 text-fs-13 text-faint">
+              No session open — pick one from the sidebar, or spawn a new one.
+            </div>
+          ))
+        )}
+        {isPreviewing && (
+          <>
+            <div className="mv-preview-ring pointer-events-none absolute inset-0 rounded-r-2 border border-dashed border-preview-ring" />
+            <div className="mv-preview-chip pointer-events-none absolute right-sp-2 top-sp-2 z-sticky rounded-r-pill bg-preview px-sp-2 py-[2px] text-fs-11 text-preview-ink">
+              preview
+            </div>
+          </>
+        )}
+      </div>
+    </div>
+  );
+}
+
+interface TreeProps {
+  tab: { id: string; focusedLeafId: string | null };
+  store: LayoutStoreApi;
+  sessions?: ReadonlyMap<Uuid, Session>;
+  onDisconnect?: (sessionId: Uuid) => void;
+  previewedSessionId: Uuid | null;
+  commitPreview: (sessionId: Uuid) => void;
+}
+
+function SplitNode({ node, ...rest }: TreeProps & { node: Node }) {
+  if (node.kind === "leaf") {
+    return <Pane leaf={node} isFocused={rest.tab.focusedLeafId === node.id} {...rest} />;
+  }
+  return <SplitContainer node={node} {...rest} />;
+}
+
+function SplitContainer({ node, ...rest }: TreeProps & { node: Extract<Node, { kind: "split" }> }) {
+  const slotA = useRef<HTMLDivElement | null>(null);
+  const slotB = useRef<HTMLDivElement | null>(null);
+  const containerRef = useRef<HTMLDivElement | null>(null);
+
+  const onDividerPointerDown = (e: React.PointerEvent<HTMLDivElement>) => {
+    e.preventDefault();
+    const divider = e.currentTarget;
+    const container = containerRef.current;
+    if (!container) return;
+    divider.setPointerCapture(e.pointerId);
+    const rect = container.getBoundingClientRect();
+    const move = (ev: PointerEvent) => {
+      const frac =
+        node.dir === "row" ? (ev.clientX - rect.left) / rect.width : (ev.clientY - rect.top) / rect.height;
+      node.ratio = Math.max(0.1, Math.min(0.9, frac));
+      if (slotA.current) slotA.current.style.flexGrow = String(node.ratio);
+      if (slotB.current) slotB.current.style.flexGrow = String(1 - node.ratio);
+    };
+    const up = (ev: PointerEvent) => {
+      try {
+        divider.releasePointerCapture(ev.pointerId);
+      } catch {
+        // already released
+      }
+      divider.removeEventListener("pointermove", move);
+      divider.removeEventListener("pointerup", up);
+      rest.store.getState().commitLayout();
+    };
+    divider.addEventListener("pointermove", move);
+    divider.addEventListener("pointerup", up);
+  };
+
+  return (
+    <div
+      ref={containerRef}
+      className={`mv-split flex h-full min-h-0 w-full ${node.dir === "row" ? "flex-row" : "flex-col"}`}
+    >
+      <div ref={slotA} className="mv-slot min-h-0 min-w-0" style={{ flex: `${node.ratio} 1 0` }}>
+        <SplitNode node={node.a} {...rest} />
+      </div>
+      <div
+        className={
+          "mv-divider flex-none bg-border-strong hover:bg-accent " +
+          (node.dir === "row" ? "w-[3px] cursor-col-resize" : "h-[3px] cursor-row-resize")
+        }
+        onPointerDown={onDividerPointerDown}
+      />
+      <div ref={slotB} className="mv-slot min-h-0 min-w-0" style={{ flex: `${1 - node.ratio} 1 0` }}>
+        <SplitNode node={node.b} {...rest} />
+      </div>
+    </div>
+  );
+}
+
+function Pane({
+  leaf,
+  isFocused,
+  store,
+  sessions,
+  onDisconnect,
+  previewedSessionId,
+  commitPreview,
+}: TreeProps & { leaf: Extract<Node, { kind: "leaf" }>; isFocused: boolean }) {
+  const session = leaf.sessionId ? sessions?.get(leaf.sessionId) : undefined;
+  const isPreview = leaf.sessionId !== null && leaf.sessionId === previewedSessionId;
+  const splitFocused = (dir: Dir) => store.getState().splitFocused(leaf.id, dir);
+
+  return (
+    <div
+      className={
+        "mv-pane flex h-full min-h-0 min-w-0 flex-col border " +
+        (isFocused && !isPreview ? "border-accent" : "border-border-strong")
+      }
+      data-leaf-id={leaf.id}
+      data-session-id={leaf.sessionId ?? undefined}
+      onPointerDownCapture={() => {
+        // Clicking into a previewed pane is the operator choosing it
+        // (docs/PREVIEW.md).
+        if (isPreview) commitPreview(leaf.sessionId!);
+        store.getState().focusLeaf(leaf.id);
+      }}
+    >
+      <div
+        className={
+          "mv-pane-header flex items-center justify-between gap-sp-2 border-b border-border-strong px-sp-2 py-sp-1 text-fs-12 " +
+          (isPreview ? "bg-preview-tint text-preview" : "bg-surface")
+        }
+      >
+        {leaf.sessionId ? (
+          <PaneTitle sessionId={leaf.sessionId} session={session} />
+        ) : (
+          <span className="text-faint">Empty pane</span>
+        )}
+        <div className="mv-pane-tools flex items-center gap-sp-1">
+          {leaf.sessionId && onDisconnect && (
+            <button
+              type="button"
+              className="mv-tool rounded-r-1 px-sp-1 text-faint hover:bg-surface-3 hover:text-ink"
+              title="Disconnect"
+              onClick={() => onDisconnect(leaf.sessionId!)}
+            >
+              ⏻
+            </button>
+          )}
+          <button
+            type="button"
+            className="mv-tool rounded-r-1 px-sp-1 text-faint hover:bg-surface-3 hover:text-ink"
+            title="Split right"
+            onClick={() => splitFocused("row")}
+          >
+            ▥
+          </button>
+          <button
+            type="button"
+            className="mv-tool rounded-r-1 px-sp-1 text-faint hover:bg-surface-3 hover:text-ink"
+            title="Split down"
+            onClick={() => splitFocused("col")}
+          >
+            ▤
+          </button>
+          <button
+            type="button"
+            className="mv-tool rounded-r-1 px-sp-1 text-faint hover:bg-surface-3 hover:text-ink"
+            title="Close pane"
+            onClick={() => store.getState().closePane(leaf.id)}
+          >
+            ✕
+          </button>
+        </div>
+      </div>
+      <div className="mv-pane-host min-h-0 flex-1">
+        {leaf.sessionId ? (
+          <PaneContainer
+            sessionId={leaf.sessionId}
+            session={session}
+            focus={isFocused && previewedSessionId === null}
+            onClosed={() => store.getState().closeSession(leaf.sessionId!)}
+          />
+        ) : (
+          <div className="mv-pane-empty flex h-full items-center justify-center p-sp-4 text-fs-13 text-faint">
+            Empty pane — pick a session from the sidebar, or spawn one.
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}

web/src/components/layout/PaneContainer.test.tsx

@@ -0,0 +1,54 @@
+// @vitest-environment happy-dom
+import { cleanup, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import type { Session } from "../../types.js";
+import { PaneContainer } from "./PaneContainer.js";
+
+vi.mock("../terminal/TerminalPane.js", () => ({
+  TerminalPane: ({ sessionId, focus }: { sessionId: string; focus?: boolean }) => (
+    <div data-testid="terminal-pane" data-session-id={sessionId} data-focus={String(focus)} />
+  ),
+}));
+
+vi.mock("../structured/StructuredPane.js", () => ({
+  StructuredPane: ({ sessionId, focus }: { sessionId: string; focus?: boolean }) => (
+    <div data-testid="structured-pane" data-session-id={sessionId} data-focus={String(focus)} />
+  ),
+}));
+
+afterEach(cleanup);
+
+function session(over: Partial<Session> = {}): Session {
+  return {
+    id: "s1",
+    cwd: "/home/n",
+    command: "claude",
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  } as Session;
+}
+
+describe("PaneContainer", () => {
+  it("renders TerminalPane when the session has no view (defaults to Terminal)", () => {
+    render(<PaneContainer sessionId="s1" session={session()} />);
+    expect(screen.getByTestId("terminal-pane")).toBeTruthy();
+    expect(screen.queryByTestId("structured-pane")).toBeNull();
+  });
+
+  it("renders TerminalPane when the session isn't known yet", () => {
+    render(<PaneContainer sessionId="s1" />);
+    expect(screen.getByTestId("terminal-pane")).toBeTruthy();
+  });
+
+  it("renders StructuredPane for a Structured session", () => {
+    render(<PaneContainer sessionId="s1" session={session({ view: "Structured" })} focus={false} />);
+    const pane = screen.getByTestId("structured-pane");
+    expect(pane.dataset.sessionId).toBe("s1");
+    expect(pane.dataset.focus).toBe("false");
+    expect(screen.queryByTestId("terminal-pane")).toBeNull();
+  });
+});

web/src/components/layout/PaneContainer.tsx

@@ -0,0 +1,49 @@
+// Dispatches a leaf's session to the right body — TerminalPane for a PTY
+// session, StructuredPane for an ACP one (session.view, #133/#140/#249).
+
+import { forwardRef, useImperativeHandle, useRef } from "react";
+
+import type { Session, Uuid } from "../../types.js";
+import { StructuredPane, type StructuredPaneHandle } from "../structured/StructuredPane.js";
+import { TerminalPane, type TerminalPaneHandle } from "../terminal/TerminalPane.js";
+
+export interface PaneContainerHandle {
+  focusTerminal(): void;
+  /** No-op for a structured pane — it has no PTY (pane.ts's PaneConnection contract). */
+  sendInput(data: string): void;
+}
+
+export interface PaneContainerProps {
+  sessionId: Uuid;
+  session?: Session;
+  /** Grabs the keyboard once connected. A sidebar preview passes `false`. */
+  focus?: boolean;
+  onClosed?: () => void;
+  className?: string;
+}
+
+export const PaneContainer = forwardRef<PaneContainerHandle, PaneContainerProps>(function PaneContainer(
+  { sessionId, session, focus, onClosed, className },
+  ref,
+) {
+  const terminalRef = useRef<TerminalPaneHandle>(null);
+  const structuredRef = useRef<StructuredPaneHandle>(null);
+
+  useImperativeHandle(
+    ref,
+    () => ({
+      focusTerminal: () => {
+        terminalRef.current?.focusTerminal();
+        structuredRef.current?.focusComposer();
+      },
+      sendInput: (data: string) => terminalRef.current?.sendInput(data),
+    }),
+    [],
+  );
+
+  return session?.view === "Structured" ? (
+    <StructuredPane ref={structuredRef} sessionId={sessionId} focus={focus} onClosed={onClosed} className={className} />
+  ) : (
+    <TerminalPane ref={terminalRef} sessionId={sessionId} focus={focus} onClosed={onClosed} className={className} />
+  );
+});

web/src/components/layout/PaneTitle.test.tsx

@@ -0,0 +1,48 @@
+// @vitest-environment happy-dom
+import { cleanup, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it } from "vitest";
+
+import type { Session } from "../../types.js";
+import { PaneTitle } from "./PaneTitle.js";
+
+afterEach(cleanup);
+
+function session(over: Partial<Session> = {}): Session {
+  return {
+    id: "s1",
+    cwd: "/home/n",
+    command: "claude",
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  } as Session;
+}
+
+describe("PaneTitle", () => {
+  it("falls back to a short session id when the session isn't known yet", () => {
+    render(<PaneTitle sessionId="abcdef12-3456-7890-abcd-ef1234567890" />);
+    expect(screen.getByText(/abcdef12/)).toBeTruthy();
+  });
+
+  it("shows the name alone when the command matches it", () => {
+    render(<PaneTitle sessionId="s1" session={session({ command: "claude", metadata: { name: "claude" } })} />);
+    expect(screen.getByText("claude")).toBeTruthy();
+    expect(document.querySelector(".at-cmd")).toBeNull();
+  });
+
+  it("shows the command alongside a custom name", () => {
+    render(
+      <PaneTitle sessionId="s1" session={session({ command: "hx src/main.rs", metadata: { name: "editor" } })} />,
+    );
+    expect(screen.getByText("editor")).toBeTruthy();
+    expect(document.querySelector(".at-cmd")).not.toBeNull();
+  });
+
+  it("never injects markup from a session name", () => {
+    render(<PaneTitle sessionId="s1" session={session({ metadata: { name: "<img onerror=x>" } })} />);
+    expect(document.querySelector("img")).toBeNull();
+    expect(screen.getByText("<img onerror=x>")).toBeTruthy();
+  });
+});

web/src/components/layout/PaneTitle.tsx

@@ -0,0 +1,39 @@
+// React port of paneTitle.ts: a pane header's session identity — the name,
+// then the command as its tool mark when recognised, same as the sidebar
+// card's own CommandFragment (SessionCard.tsx). JSX escapes text nodes, so
+// unlike the vanilla string-builder this needs no manual HTML escaping.
+
+import { splitCommand, toolIconSvg } from "../../toolIcon.js";
+import { sessionName, type Session, type Uuid } from "../../types.js";
+
+export interface PaneTitleProps {
+  sessionId: Uuid;
+  session?: Session;
+  className?: string;
+}
+
+export function PaneTitle({ sessionId, session, className }: PaneTitleProps) {
+  if (!session) {
+    return (
+      <span className={className ?? "at-title"} title={sessionId}>
+        session <span className="sid">{sessionId.slice(0, 8)}</span>
+      </span>
+    );
+  }
+
+  const name = sessionName(session);
+  const showCommand = Boolean(session.command) && session.command !== name;
+  const { tool, program } = splitCommand(session.command);
+  const icon = tool ? toolIconSvg(tool) : null;
+
+  return (
+    <span className={className ?? "at-title"} title={`${name} · ${session.command}  (${sessionId})`}>
+      <span className="at-name">{name}</span>
+      {showCommand && (
+        <span className="at-cmd">
+          {icon ? <span className="contents" dangerouslySetInnerHTML={{ __html: icon }} /> : <span>{program}</span>}
+        </span>
+      )}
+    </span>
+  );
+}

web/src/components/layout/TabBar.test.tsx

@@ -0,0 +1,88 @@
+// @vitest-environment happy-dom
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { createLayoutStore } from "../../stores/layoutStore.js";
+import { TabBar } from "./TabBar.js";
+
+afterEach(cleanup);
+
+function store() {
+  return createLayoutStore({
+    load: () => null,
+    save: vi.fn(),
+    scheduler: { setTimer: () => 1, clearTimer: () => {} },
+  });
+}
+
+function dataTransfer() {
+  const data = new Map<string, string>();
+  return {
+    setData: (type: string, value: string) => data.set(type, value),
+    getData: (type: string) => data.get(type) ?? "",
+    effectAllowed: "",
+  };
+}
+
+describe("TabBar", () => {
+  it("renders one tab per layout tab, marking the active one", () => {
+    const s = store();
+    s.getState().addTab();
+    render(<TabBar store={s} />);
+    const tabs = screen.getAllByRole("tab");
+    expect(tabs).toHaveLength(2);
+    expect(tabs[1].getAttribute("aria-selected")).toBe("true");
+    expect(tabs[0].getAttribute("aria-selected")).toBe("false");
+  });
+
+  it("shows the open-session count next to a tab's title", () => {
+    const s = store();
+    s.getState().openSession("s1");
+    render(<TabBar store={s} />);
+    expect(screen.getByText(/· 1/)).toBeTruthy();
+  });
+
+  it("clicking a tab selects it", () => {
+    const s = store();
+    s.getState().addTab();
+    const [first] = s.getState().layout.tabs;
+    render(<TabBar store={s} />);
+    fireEvent.click(screen.getAllByRole("tab")[0]);
+    expect(s.getState().layout.activeTabId).toBe(first.id);
+  });
+
+  it("the + button adds a tab", () => {
+    const s = store();
+    render(<TabBar store={s} />);
+    fireEvent.click(screen.getByTitle("New tab"));
+    expect(s.getState().layout.tabs).toHaveLength(2);
+  });
+
+  it("hides the close control on the last remaining tab", () => {
+    const s = store();
+    render(<TabBar store={s} />);
+    expect(screen.queryByTitle("Close tab")).toBeNull();
+  });
+
+  it("closing a tab removes it", () => {
+    const s = store();
+    s.getState().addTab();
+    render(<TabBar store={s} />);
+    fireEvent.click(screen.getAllByTitle("Close tab")[0]);
+    expect(s.getState().layout.tabs).toHaveLength(1);
+  });
+
+  it("dragging a tab onto another reorders them", () => {
+    const s = store();
+    s.getState().addTab();
+    s.getState().addTab();
+    const [a, b, c] = s.getState().layout.tabs;
+    render(<TabBar store={s} />);
+    const tabs = screen.getAllByRole("tab");
+    const dt = dataTransfer();
+    fireEvent.dragStart(tabs[0], { dataTransfer: dt });
+    fireEvent.dragOver(tabs[2], { dataTransfer: dt });
+    fireEvent.drop(tabs[2], { dataTransfer: dt });
+    expect(s.getState().layout.tabs.map((t) => t.id)).toEqual([b.id, c.id, a.id]);
+  });
+});

web/src/components/layout/TabBar.tsx

@@ -0,0 +1,102 @@
+// The tab strip above the canvas (issue #249): click to switch, drag to
+// reorder, a close ✕ per tab (hidden on the last one), a trailing + to add.
+
+import { useState } from "react";
+import { useStore } from "zustand";
+
+import { leaves } from "../../layout.js";
+import type { LayoutStore, LayoutStoreApi } from "../../stores/layoutStore.js";
+
+export interface TabBarProps {
+  store: LayoutStoreApi;
+}
+
+export function TabBar({ store }: TabBarProps) {
+  const layout = useStore(store, (s: LayoutStore) => s.layout);
+  const previewTempTabId = useStore(store, (s: LayoutStore) => s.preview?.tempTabId ?? null);
+  const [draggingId, setDraggingId] = useState<string | null>(null);
+  const [overId, setOverId] = useState<string | null>(null);
+
+  return (
+    <div className="mv-tabs flex items-center gap-sp-1 overflow-x-auto border-b border-border-strong bg-surface px-sp-2 text-fs-12" role="tablist">
+      {layout.tabs.map((tab) => {
+        const count = leaves(tab.root).filter((l) => l.sessionId).length;
+        const isActive = tab.id === layout.activeTabId;
+        const isDropTarget = overId === tab.id && draggingId !== null && draggingId !== tab.id;
+        // A preview's throwaway tab is not a place to go — it goes on its
+        // own the moment the preview ends (docs/PREVIEW.md).
+        const isPreviewTab = tab.id === previewTempTabId;
+        return (
+          <button
+            key={tab.id}
+            type="button"
+            role="tab"
+            aria-selected={isActive}
+            draggable
+            data-tab-id={tab.id}
+            className={
+              "mv-tab flex items-center gap-sp-1 rounded-t-r-1 px-sp-2 py-sp-1 " +
+              (isPreviewTab
+                ? "border border-dashed border-preview-ring italic text-preview"
+                : isActive
+                  ? "bg-surface-2 text-ink"
+                  : "text-faint hover:text-ink") +
+              (isDropTarget ? " outline outline-2 outline-accent" : "")
+            }
+            onDragStart={(e) => {
+              setDraggingId(tab.id);
+              e.dataTransfer.setData("text/plain", tab.id);
+              e.dataTransfer.effectAllowed = "move";
+            }}
+            onDragOver={(e) => {
+              if (!draggingId || draggingId === tab.id) return;
+              e.preventDefault();
+              setOverId(tab.id);
+            }}
+            onDragLeave={() => setOverId((current) => (current === tab.id ? null : current))}
+            onDrop={(e) => {
+              e.preventDefault();
+              const fromId = e.dataTransfer.getData("text/plain") || draggingId;
+              setDraggingId(null);
+              setOverId(null);
+              if (fromId && fromId !== tab.id) store.getState().reorderTab(fromId, tab.id);
+            }}
+            onDragEnd={() => {
+              setDraggingId(null);
+              setOverId(null);
+            }}
+            onClick={() => {
+              if (isPreviewTab) return;
+              store.getState().selectTab(tab.id);
+            }}
+          >
+            <span>
+              {tab.title}
+              {count ? ` · ${count}` : ""}
+            </span>
+            {layout.tabs.length > 1 && !isPreviewTab && (
+              <span
+                className="mv-tab-close text-faint hover:text-ink"
+                title="Close tab"
+                onClick={(e) => {
+                  e.stopPropagation();
+                  store.getState().closeTab(tab.id);
+                }}
+              >
+                ✕
+              </span>
+            )}
+          </button>
+        );
+      })}
+      <button
+        type="button"
+        className="mv-tab-add px-sp-2 py-sp-1 text-muted hover:text-ink"
+        title="New tab"
+        onClick={() => store.getState().addTab()}
+      >
+        +
+      </button>
+    </div>
+  );
+}

web/src/components/sidebar/ActivityRail.tsx

@@ -0,0 +1,47 @@
+// docs/SIDEBAR.md: a 5px bar pinned to the row's own left edge, square
+// corners, full card height. It paints for every card, Idle included, and it
+// carries the accessible name of the state so status is never colour-only.
+
+import { activityColorSlug } from "../../activity.js";
+import type { ActivityState } from "../../types.js";
+
+export const STATE_WORDS: Record<string, string> = {
+  active: "Active",
+  idle: "Idle",
+  "awaiting-input": "Awaiting input",
+  error: "Error",
+};
+
+/** Rail fill per state, and the motion the state earns. */
+const RAIL_CLASS: Record<string, string> = {
+  active: "bg-live",
+  idle: "bg-border-strong",
+  "awaiting-input": "bg-warn rail-blink",
+  error: "bg-danger rail-flash",
+};
+
+/** Duration text inherits the rail's colour (docs/SIDEBAR.md). */
+export const DURATION_CLASS: Record<string, string> = {
+  active: "text-live",
+  idle: "text-muted",
+  "awaiting-input": "text-warn",
+  error: "text-danger",
+};
+
+export function stateWordFor(activity: ActivityState | string | undefined): string {
+  return STATE_WORDS[activityColorSlug(activity ?? "Idle")] ?? STATE_WORDS.idle;
+}
+
+export function ActivityRail({ activity }: { activity: ActivityState | string | undefined }) {
+  const slug = activityColorSlug(activity ?? "Idle");
+  const word = STATE_WORDS[slug] ?? STATE_WORDS.idle;
+  return (
+    <span
+      className={`absolute left-0 top-0 bottom-0 w-[5px] ${RAIL_CLASS[slug] ?? RAIL_CLASS.idle}`}
+      data-activity={slug}
+      role="img"
+      title={word}
+      aria-label={word}
+    />
+  );
+}

web/src/components/sidebar/ContextMenu.tsx

@@ -0,0 +1,64 @@
+// Right-click menu on a session card (docs/SIDEBAR.md): rename, spawn similar,
+// kill. Rendered into <body> so a scrolling sidebar cannot clip it.
+
+import { useEffect, useRef } from "react";
+import { createPortal } from "react-dom";
+
+export interface ContextMenuItem {
+  label: string;
+  danger?: boolean;
+  onSelect(): void;
+}
+
+export interface ContextMenuProps {
+  x: number;
+  y: number;
+  items: ContextMenuItem[];
+  onClose(): void;
+}
+
+export function ContextMenu({ x, y, items, onClose }: ContextMenuProps) {
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") onClose();
+    };
+    const onDown = (e: Event) => {
+      if (!ref.current?.contains(e.target as Node)) onClose();
+    };
+    document.addEventListener("keydown", onKey);
+    document.addEventListener("pointerdown", onDown, true);
+    return () => {
+      document.removeEventListener("keydown", onKey);
+      document.removeEventListener("pointerdown", onDown, true);
+    };
+  }, [onClose]);
+
+  return createPortal(
+    <div
+      ref={ref}
+      role="menu"
+      className="context-menu fixed z-modal min-w-[160px] rounded-r-2 border border-border-strong bg-surface py-sp-1 shadow-2"
+      style={{ left: x, top: y }}
+    >
+      {items.map((item) => (
+        <button
+          key={item.label}
+          type="button"
+          role="menuitem"
+          className={`block w-full px-sp-3 py-sp-1 text-left text-fs-12 hover:bg-surface-2 ${
+            item.danger ? "text-danger" : "text-ink"
+          }`}
+          onClick={() => {
+            onClose();
+            item.onSelect();
+          }}
+        >
+          {item.label}
+        </button>
+      ))}
+    </div>,
+    document.body,
+  );
+}

web/src/components/sidebar/FolderNode.tsx

@@ -0,0 +1,51 @@
+// A collapsible directory in the sidebar tree. Only a *collapsed* header is a
+// keyboard-walk stop (docs/SIDEBAR.md); an expanded one is decoration in front
+// of the cards it holds, so it carries no highlight of its own.
+
+import type { ReactNode } from "react";
+
+import { splitFolderLabel } from "./model.js";
+
+export interface FolderNodeProps {
+  name: string;
+  path: string;
+  depth: number;
+  collapsed: boolean;
+  highlighted: boolean;
+  onToggle(): void;
+  children: ReactNode;
+}
+
+export function FolderNode(props: FolderNodeProps) {
+  const { stem, last } = splitFolderLabel(props.name);
+  return (
+    <div className="tree-folder">
+      <button
+        type="button"
+        className={`tree-folder-header flex w-full items-center gap-sp-1 py-[2px] text-fs-11 text-muted ${
+          props.highlighted ? "ring-1 ring-accent-ring" : ""
+        }`}
+        style={{ paddingLeft: props.depth * 16 }}
+        aria-expanded={!props.collapsed}
+        data-nav-key={`folder:${props.path}`}
+        data-highlighted={props.highlighted ? "true" : undefined}
+        title={props.name}
+        onClick={props.onToggle}
+      >
+        {/* One glyph, rotated when collapsed, so the mark and the rotation
+            never disagree about which way the folder points. */}
+        <span
+          aria-hidden="true"
+          className={`inline-block transition-transform ${props.collapsed ? "-rotate-90" : ""}`}
+        >
+          ▾
+        </span>
+        <span className="truncate">
+          {stem && <span className="text-faint">{stem}/</span>}
+          {last}
+        </span>
+      </button>
+      {!props.collapsed && props.children}
+    </div>
+  );
+}

web/src/components/sidebar/KillConfirm.tsx

@@ -0,0 +1,63 @@
+// docs/SIDEBAR.md "Killing a session": every kill confirms first, and the
+// confirmation names what the card last saw in the way — the daemon refuses an
+// unforced kill over such a tree, and saying so beforehand is cheaper than the
+// refusal. Cancel holds the focus so a stray Enter kills nothing.
+
+import { useEffect, useRef } from "react";
+import { createPortal } from "react-dom";
+
+import type { InTheWay } from "../../types.js";
+import { formatInTheWay } from "../../types.js";
+
+export interface KillConfirmProps {
+  name: string;
+  blockers: InTheWay | null;
+  /** Set when the daemon already refused an unforced kill: this pass forces. */
+  force?: boolean;
+  onConfirm(): void;
+  onCancel(): void;
+}
+
+export function KillConfirm(props: KillConfirmProps) {
+  const cancel = useRef<HTMLButtonElement>(null);
+  useEffect(() => cancel.current?.focus(), []);
+
+  return createPortal(
+    <div
+      role="dialog"
+      aria-modal="true"
+      aria-label={props.force ? "Force kill session" : "Kill session"}
+      className="kill-confirm fixed inset-0 z-modal flex items-center justify-center bg-bg/70"
+      onKeyDown={(e) => {
+        if (e.key === "Escape") props.onCancel();
+      }}
+    >
+      <div className="min-w-[280px] rounded-r-2 border border-border-strong bg-surface p-sp-4 shadow-2">
+        <p className="text-fs-13 text-ink">
+          {props.force ? "Force kill" : "Kill"} <strong>{props.name}</strong>?
+        </p>
+        {props.blockers && (
+          <p className="mt-sp-2 text-fs-12 text-warn">{formatInTheWay(props.blockers)}</p>
+        )}
+        <div className="mt-sp-3 flex justify-end gap-sp-2">
+          <button
+            ref={cancel}
+            type="button"
+            className="rounded-r-1 border border-border px-sp-3 py-sp-1 text-fs-12 text-ink"
+            onClick={props.onCancel}
+          >
+            Cancel
+          </button>
+          <button
+            type="button"
+            className="rounded-r-1 bg-danger px-sp-3 py-sp-1 text-fs-12 text-accent-ink"
+            onClick={props.onConfirm}
+          >
+            {props.force ? "Force kill" : "Kill"}
+          </button>
+        </div>
+      </div>
+    </div>,
+    document.body,
+  );
+}

web/src/components/sidebar/SessionCard.tsx

@@ -0,0 +1,264 @@
+// docs/SIDEBAR.md: a session card is always two lines — the name, then the
+// adaptive meta line — with the activity rail in the gutter beside them.
+
+import { useEffect, useRef, type MouseEvent } from "react";
+
+import {
+  activityDurationLabel,
+  activityHeldMs,
+  META_LINE_MIN_HOLD_MS,
+} from "../../activity.js";
+import { splitCommand, toolIconSvg } from "../../toolIcon.js";
+import type { InTheWay, Session } from "../../types.js";
+import {
+  blockerStats,
+  customSessionName,
+  formatInTheWay,
+  isProvisionalName,
+  MAX_SESSION_NAME_LEN,
+  normalizeSessionName,
+  sessionBlockers,
+  sessionName,
+} from "../../types.js";
+import { ActivityRail, DURATION_CLASS, stateWordFor } from "./ActivityRail.js";
+import { activityColorSlug } from "../../activity.js";
+
+export interface SessionCardProps {
+  session: Session;
+  /** Nesting depth; the row's padding (and so the rail) shifts outward with it. */
+  depth: number;
+  /** Clock the duration is measured against — the sidebar ticks it. */
+  now: number;
+  highlighted: boolean;
+  /** Showing in the focused pane. */
+  active: boolean;
+  /** Open in some pane, not the focused one. */
+  open: boolean;
+  previewing: boolean;
+  renaming: boolean;
+  onSelect(): void;
+  onOpenMenu(x: number, y: number): void;
+  onSpawnSimilar(): void;
+  onKill(): void;
+  onRenameCommit(name: string): void;
+  onRenameCancel(): void;
+}
+
+/** The fill ladder from docs/SIDEBAR.md "Which row is filled", furthest down
+ * wins. Written as one ordered run so the precedence is the order it reads in. */
+function rowFill(p: SessionCardProps): string {
+  if (p.active) return "bg-accent-fill";
+  if (p.previewing) return "bg-preview-tint";
+  if (p.open) return "bg-accent/[0.06]";
+  if (p.highlighted) return "bg-preview-tint";
+  return "";
+}
+
+export function SessionCard(props: SessionCardProps) {
+  const { session: s, depth, now, renaming } = props;
+  const name = sessionName(s);
+  const running = s.status === "Running";
+  const word = stateWordFor(s.activity);
+
+  return (
+    <a
+      className={`session-card tree-leaf relative flex flex-col gap-[1px] py-sp-1 pr-sp-2 no-underline ${rowFill(props)} ${
+        running ? "" : "opacity-60"
+      }`}
+      href={`#/attach/${encodeURIComponent(s.id)}`}
+      style={{ paddingLeft: depth * 16 + 8 }}
+      data-session-id={s.id}
+      data-nav-key={`session:${s.id}`}
+      data-status={running ? "running" : "dead"}
+      data-highlighted={props.highlighted ? "true" : undefined}
+      aria-label={`${name}, ${running ? "running" : "exited"}, ${word}`}
+      onClick={(e) => {
+        if (renaming) return;
+        e.preventDefault();
+        props.onSelect();
+      }}
+      onContextMenu={(e: MouseEvent) => {
+        e.preventDefault();
+        e.stopPropagation();
+        props.onOpenMenu(e.clientX, e.clientY);
+      }}
+    >
+      <ActivityRail activity={s.activity} />
+      <span className="flex min-w-0 items-center gap-sp-2">
+        {renaming ? (
+          <RenameField
+            session={s}
+            onCommit={props.onRenameCommit}
+            onCancel={props.onRenameCancel}
+          />
+        ) : (
+          <span
+            className={`min-w-0 flex-1 truncate text-fs-13 ${
+              isProvisionalName(s) ? "text-muted" : "text-ink"
+            }`}
+          >
+            {name}
+          </span>
+        )}
+        <span className="flex flex-none items-center gap-[2px]">
+          <button
+            type="button"
+            className="leaf-clone text-faint hover:text-ink"
+            title="Spawn similar"
+            aria-label={`Spawn similar to ${name}`}
+            onClick={(e) => {
+              e.preventDefault();
+              e.stopPropagation();
+              props.onSpawnSimilar();
+            }}
+          >
+            ⧉
+          </button>
+          <button
+            type="button"
+            className="leaf-kill text-faint hover:text-danger"
+            title="Kill session"
+            aria-label={`Kill ${name}`}
+            onClick={(e) => {
+              e.preventDefault();
+              e.stopPropagation();
+              props.onKill();
+            }}
+          >
+            ✕
+          </button>
+        </span>
+      </span>
+      <MetaLine session={s} now={now} />
+    </a>
+  );
+}
+
+/** Line 2, left to right: `[duration] [detail] command [diff stat | exited]`.
+ * The line itself is unconditional; only its fragments are adaptive. */
+export function MetaLine({ session: s, now }: { session: Session; now: number }) {
+  const slug = activityColorSlug(s.activity ?? "Idle");
+  const held = activityHeldMs(s.activity_since, now);
+  const duration =
+    held !== null && held >= META_LINE_MIN_HOLD_MS ? activityDurationLabel(held) : null;
+  const blockers = sessionBlockers(s);
+
+  return (
+    <span
+      className="card-line2 flex min-w-0 items-center gap-sp-2 text-fs-11"
+      data-activity={slug}
+    >
+      {duration && (
+        <span className={`activity-duration flex-none ${DURATION_CLASS[slug] ?? "text-muted"}`}>
+          {duration}
+        </span>
+      )}
+      {s.activity_detail && (
+        <span className="activity-detail min-w-0 flex-1 truncate text-faint">
+          {s.activity_detail}
+        </span>
+      )}
+      <CommandFragment command={s.command} />
+      {blockers && <BlockedFragment blockers={blockers} />}
+      {s.status === "Dead" && <span className="flex-none text-faint">exited</span>}
+    </span>
+  );
+}
+
+/** docs/SIDEBAR.md: the card names the program only, as its tool mark when we
+ * have one. The full command line stays in the tooltip either way. */
+function CommandFragment({ command }: { command: string }) {
+  const { tool, program } = splitCommand(command);
+  const icon = tool ? toolIconSvg(tool) : null;
+  return (
+    <span
+      className="leaf-cmd flex min-w-0 flex-none items-center gap-[4px] truncate text-faint"
+      title={command}
+    >
+      {icon ? (
+        <span className="contents" dangerouslySetInnerHTML={{ __html: icon }} />
+      ) : (
+        <span className="truncate">{program}</span>
+      )}
+    </span>
+  );
+}
+
+/** Blocked work in diff notation — `+124 -18 ?3 ↑2`. Only `+` and `-` take
+ * colour; the spelled-out breakdown survives as the tooltip. */
+function BlockedFragment({ blockers }: { blockers: InTheWay }) {
+  const stats = blockerStats(blockers);
+  return (
+    <span
+      className="leaf-blocked flex flex-none items-center gap-[4px] text-faint"
+      title={`Kill will be refused unless forced — ${formatInTheWay(blockers)}`}
+    >
+      {stats.map((st) => (
+        <span
+          key={st.kind}
+          data-stat={st.kind}
+          className={
+            st.kind === "add" ? "text-live" : st.kind === "del" ? "text-danger" : "text-muted"
+          }
+        >
+          {st.text}
+        </span>
+      ))}
+    </span>
+  );
+}
+
+/** Inline rename (#125): Enter commits, Escape and blur cancel, an emptied
+ * field clears the name so the command fallback resumes. It starts from the
+ * session's own name, never from the command it falls back to. */
+function RenameField({
+  session: s,
+  onCommit,
+  onCancel,
+}: {
+  session: Session;
+  onCommit(name: string): void;
+  onCancel(): void;
+}) {
+  const ref = useRef<HTMLInputElement>(null);
+  const settled = useRef(false);
+
+  useEffect(() => {
+    ref.current?.focus();
+    ref.current?.select();
+  }, []);
+
+  return (
+    <input
+      ref={ref}
+      type="text"
+      className="leaf-rename min-w-0 flex-1 bg-surface-2 text-fs-13 text-ink"
+      defaultValue={customSessionName(s) ?? ""}
+      maxLength={MAX_SESSION_NAME_LEN}
+      aria-label={`Rename ${sessionName(s)}`}
+      // The card is an <a> the tree also drags from: without these, clicking
+      // into the field navigates away or starts a drag.
+      onClick={(e) => e.stopPropagation()}
+      onPointerDown={(e) => e.stopPropagation()}
+      onKeyDown={(e) => {
+        e.stopPropagation();
+        if (e.key === "Enter") {
+          e.preventDefault();
+          if (settled.current) return;
+          settled.current = true;
+          onCommit(normalizeSessionName(e.currentTarget.value));
+        } else if (e.key === "Escape") {
+          e.preventDefault();
+          if (settled.current) return;
+          settled.current = true;
+          onCancel();
+        }
+      }}
+      onBlur={() => {
+        if (settled.current) return;
+        settled.current = true;
+        onCancel();
+      }}
+    />
+  );
+}

web/src/components/sidebar/Sidebar.test.tsx

@@ -0,0 +1,227 @@
+// @vitest-environment happy-dom
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import type { Session } from "../../types.js";
+import { Sidebar } from "./Sidebar.js";
+
+afterEach(() => {
+  cleanup();
+  vi.useRealTimers();
+});
+
+function session(id: string, over: Partial<Session> = {}): Session {
+  return {
+    id,
+    cwd: "/home/n/alpha",
+    command: "hx src/",
+    env: {},
+    metadata: { name: id },
+    status: "Running",
+    created_at: "2026-08-24T10:00:00Z",
+    ...over,
+  } as Session;
+}
+
+/** The card element for a session, by the `data-session-id` the row carries. */
+function card(id: string): HTMLElement {
+  const el = document.querySelector<HTMLElement>(`[data-session-id="${id}"]`);
+  if (!el) throw new Error(`no card for ${id}`);
+  return el;
+}
+
+function tree(): HTMLElement {
+  return document.querySelector<HTMLElement>(".tree")!;
+}
+
+describe("SessionCard layout", () => {
+  it("renders two lines: the name, then a meta line naming the program", () => {
+    render(<Sidebar sessions={[session("alpha")]} />);
+
+    const row = card("alpha");
+    expect(row.textContent).toContain("alpha");
+    const meta = row.querySelector(".card-line2")!;
+    // The program only — never its arguments.
+    expect(meta.textContent).toContain("hx");
+    expect(meta.textContent).not.toContain("src/");
+  });
+
+  it("shows no duration under the 30s hold, and one above it", () => {
+    const now = Date.parse("2026-08-24T10:00:00Z");
+    vi.setSystemTime(now);
+    const fresh = session("fresh", { activity: "Active", activity_since: "2026-08-24T09:59:50Z" });
+    const held = session("held", { activity: "Active", activity_since: "2026-08-24T09:56:00Z" });
+
+    render(<Sidebar sessions={[fresh, held]} />);
+
+    expect(card("fresh").querySelector(".activity-duration")).toBeNull();
+    expect(card("held").querySelector(".activity-duration")!.textContent).toBe("4m");
+  });
+
+  it("paints a rail for every state, blinking on AwaitingInput and flashing on Error", () => {
+    render(
+      <Sidebar
+        sessions={[
+          session("idle"),
+          session("await", { activity: "AwaitingInput" }),
+          session("err", { activity: "Error" }),
+        ]}
+      />,
+    );
+
+    const rail = (id: string) => card(id).querySelector<HTMLElement>("[data-activity]")!;
+    expect(rail("idle").dataset.activity).toBe("idle");
+    expect(rail("idle").className).not.toContain("rail-");
+    expect(rail("await").className).toContain("rail-blink");
+    expect(rail("err").className).toContain("rail-flash");
+    // Status never rests on colour alone.
+    expect(rail("await").getAttribute("aria-label")).toBe("Awaiting input");
+  });
+
+  it("renders blocked work as diff notation with the spelled-out tooltip", () => {
+    render(
+      <Sidebar
+        sessions={[
+          session("alpha", {
+            blocked_work: { uncommitted_files: 2, insertions: 124, deletions: 18, untracked_files: 3 },
+          }),
+        ]}
+      />,
+    );
+
+    const blocked = card("alpha").querySelector<HTMLElement>(".leaf-blocked")!;
+    expect(blocked.textContent).toBe("+124-18?3");
+    expect(blocked.title).toContain("2 uncommitted files");
+  });
+
+  it("dims a provisional name and leaves a settled one alone", () => {
+    render(
+      <Sidebar
+        sessions={[
+          session("gen", { metadata: { name: "gen", name_source: "Generated" } }),
+          session("user", { metadata: { name: "user", name_source: "User" } }),
+        ]}
+      />,
+    );
+
+    expect(card("gen").querySelector(".text-muted")).not.toBeNull();
+    expect(card("user").textContent).toContain("user");
+  });
+});
+
+describe("keyboard walk", () => {
+  const two = [session("a", { cwd: "/one" }), session("b", { cwd: "/two" })];
+
+  it("j and k step the highlight through the cards", () => {
+    render(<Sidebar sessions={two} />);
+
+    fireEvent.keyDown(tree(), { key: "j" });
+    expect(card("a").dataset.highlighted).toBe("true");
+    fireEvent.keyDown(tree(), { key: "j" });
+    expect(card("b").dataset.highlighted).toBe("true");
+    fireEvent.keyDown(tree(), { key: "k" });
+    expect(card("a").dataset.highlighted).toBe("true");
+  });
+
+  it("stops on a collapsed folder header and Enter expands onto its first card", () => {
+    render(<Sidebar sessions={two} />);
+
+    const header = document.querySelector<HTMLElement>('[data-nav-key="folder:one"]')!;
+    fireEvent.click(header);
+    expect(header.getAttribute("aria-expanded")).toBe("false");
+
+    fireEvent.keyDown(tree(), { key: "j" });
+    expect(
+      document.querySelector<HTMLElement>('[data-nav-key="folder:one"]')!.dataset.highlighted,
+    ).toBe("true");
+
+    fireEvent.keyDown(tree(), { key: "Enter" });
+    expect(card("a").dataset.highlighted).toBe("true");
+  });
+
+  it("Enter on a card opens it, and Tab hands the keyboard to the pane", () => {
+    const onSelect = vi.fn();
+    const onFocusPane = vi.fn();
+    render(<Sidebar sessions={two} onSelect={onSelect} onFocusPane={onFocusPane} />);
+
+    fireEvent.keyDown(tree(), { key: "j" });
+    fireEvent.keyDown(tree(), { key: "Enter" });
+    expect(onSelect).toHaveBeenCalledWith("a");
+
+    fireEvent.keyDown(tree(), { key: "Tab" });
+    expect(onFocusPane).toHaveBeenCalled();
+  });
+
+  it("previews the session the walk lands on", () => {
+    const onPreview = vi.fn();
+    render(<Sidebar sessions={two} onPreview={onPreview} />);
+
+    fireEvent.keyDown(tree(), { key: "j" });
+    expect(onPreview).toHaveBeenCalledWith("a");
+  });
+
+  it("x asks to kill the highlighted session and r renames it", () => {
+    const onKill = vi.fn();
+    render(<Sidebar sessions={two} onKill={onKill} />);
+
+    fireEvent.keyDown(tree(), { key: "j" });
+    fireEvent.keyDown(tree(), { key: "x" });
+    expect(onKill).toHaveBeenCalledWith(expect.objectContaining({ id: "a" }));
+
+    fireEvent.keyDown(tree(), { key: "r" });
+    expect(card("a").querySelector(".leaf-rename")).not.toBeNull();
+  });
+});
+
+describe("context menu", () => {
+  it("offers rename, spawn similar and kill", () => {
+    const onSpawnSimilar = vi.fn();
+    const onKill = vi.fn();
+    render(
+      <Sidebar sessions={[session("alpha")]} onSpawnSimilar={onSpawnSimilar} onKill={onKill} />,
+    );
+
+    fireEvent.contextMenu(card("alpha"));
+    const labels = [...document.querySelectorAll('[role="menuitem"]')].map((n) => n.textContent);
+    expect(labels).toEqual(["Rename…", "Spawn similar", "Kill session"]);
+
+    fireEvent.click(screen.getByText("Spawn similar"));
+    expect(onSpawnSimilar).toHaveBeenCalledWith(expect.objectContaining({ id: "alpha" }));
+  });
+
+  it("renames in place: Enter commits the field, Escape cancels", () => {
+    const onRename = vi.fn();
+    render(<Sidebar sessions={[session("alpha")]} onRename={onRename} />);
+
+    fireEvent.contextMenu(card("alpha"));
+    fireEvent.click(screen.getByText("Rename…"));
+
+    const input = card("alpha").querySelector<HTMLInputElement>(".leaf-rename")!;
+    expect(input.value).toBe("alpha");
+    fireEvent.change(input, { target: { value: "  renamed  " } });
+    fireEvent.keyDown(input, { key: "Enter" });
+    expect(onRename).toHaveBeenCalledWith("alpha", "renamed");
+    expect(card("alpha").querySelector(".leaf-rename")).toBeNull();
+  });
+});
+
+describe("search", () => {
+  it("filters the tree down to matching sessions", () => {
+    render(<Sidebar sessions={[session("alpha"), session("beta", { cwd: "/home/n/beta" })]} />);
+
+    fireEvent.change(screen.getByLabelText("Search sessions"), { target: { value: "beta" } });
+
+    expect(document.querySelector('[data-session-id="alpha"]')).toBeNull();
+    expect(document.querySelector('[data-session-id="beta"]')).not.toBeNull();
+  });
+});
+
+describe("empty state", () => {
+  it("offers a spawn when there are no sessions at all", () => {
+    const onSpawn = vi.fn();
+    render(<Sidebar sessions={[]} onSpawn={onSpawn} />);
+
+    fireEvent.click(screen.getByText("+ Spawn session"));
+    expect(onSpawn).toHaveBeenCalled();
+  });
+});

web/src/components/sidebar/Sidebar.tsx

@@ -0,0 +1,368 @@
+// React port of the sidebar tree (catalog.ts). The contract it renders is
+// docs/SIDEBAR.md: two-line cards behind an activity rail, folder-grouped by
+// repository, walked with j/k.
+
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
+import { useStore } from "zustand";
+
+import { ApiRequestError, killSession, renameSession } from "../../api.js";
+import type { CatalogStore, CatalogStoreApi } from "../../stores/catalogStore.js";
+import type { InTheWay, Session } from "../../types.js";
+import { sessionBlockers, sessionName } from "../../types.js";
+import { buildTree, type TreeNode } from "../../tree.js";
+import { ContextMenu, type ContextMenuItem } from "./ContextMenu.js";
+import { FolderNode } from "./FolderNode.js";
+import { KillConfirm } from "./KillConfirm.js";
+import { SessionCard } from "./SessionCard.js";
+import { SidebarSearch } from "./SidebarSearch.js";
+import { filterSessions, firstRowUnder, navRows, sessionKey } from "./model.js";
+import { useNow } from "./useNow.js";
+import "./sidebar.css";
+
+export interface SidebarProps {
+  /** Live catalog. Either this or `sessions` supplies the tree. */
+  store?: CatalogStoreApi;
+  /** Static session list — what tests and the design kit render from. */
+  sessions?: Session[];
+  /** The daemon's home dir, so cwds abbreviate to `~/…`. */
+  homeDir?: string;
+  /** Showing in the focused pane. */
+  activeId?: string | null;
+  /** Open in some pane, focused one included. */
+  openIds?: ReadonlySet<string>;
+  /** Previewing (docs/PREVIEW.md) — a view, never durable state. */
+  previewId?: string | null;
+  onSelect?(id: string): void;
+  /** The highlight moved onto a session, or off every session. */
+  onPreview?(id: string | null): void;
+  onSpawnSimilar?(session: Session): void;
+  onSpawn?(): void;
+  /** Fast-forward spawn (`N`). */
+  onSpawnDefaults?(): void;
+  /** Tab: hand the keyboard back to the pane. */
+  onFocusPane?(): void;
+  onHelp?(): void;
+  /** Overrides the built-in `DELETE /api/sessions/:id` flow (tests, kit). */
+  onKill?(session: Session): void;
+  /** Overrides the built-in `PATCH /api/sessions/:id` (tests, kit). */
+  onRename?(id: string, name: string): void;
+}
+
+interface MenuState {
+  x: number;
+  y: number;
+  session: Session;
+}
+
+interface KillState {
+  session: Session;
+  blockers: InTheWay | null;
+  force: boolean;
+}
+
+export function Sidebar(props: SidebarProps) {
+  const sessions = useSessions(props);
+  const now = useNow();
+
+  const [query, setQuery] = useState("");
+  const [collapsed, setCollapsed] = useState<ReadonlySet<string>>(() => new Set<string>());
+  const [navKey, setNavKey] = useState<string | null>(null);
+  const [renamingId, setRenamingId] = useState<string | null>(null);
+  const [menu, setMenu] = useState<MenuState | null>(null);
+  const [kill, setKill] = useState<KillState | null>(null);
+  const treeRef = useRef<HTMLDivElement>(null);
+
+  const tree = useMemo(
+    () => buildTree(filterSessions(sessions, query), props.homeDir),
+    [sessions, query, props.homeDir],
+  );
+  const rows = useMemo(() => navRows(tree, collapsed), [tree, collapsed]);
+
+  // A row that went away — session killed, folder collapsed over it — drops
+  // the highlight rather than leaving it pointing at nothing.
+  useEffect(() => {
+    if (navKey !== null && !rows.some((r) => r.key === navKey)) setNavKey(null);
+  }, [rows, navKey]);
+
+  const preview = props.onPreview;
+  const previewOf = useCallback(
+    (key: string | null) => {
+      preview?.(key?.startsWith("session:") ? key.slice("session:".length) : null);
+    },
+    [preview],
+  );
+
+  const moveNav = useCallback(
+    (delta: number) => {
+      if (rows.length === 0) return;
+      const cur = rows.findIndex((r) => r.key === navKey);
+      // Nothing highlighted: start one off the end being walked from, so the
+      // first step lands on the first (or last) row.
+      const from = cur === -1 ? (delta > 0 ? -1 : 0) : cur;
+      const next = rows[(((from + delta) % rows.length) + rows.length) % rows.length];
+      setNavKey(next.key);
+      previewOf(next.key);
+    },
+    [rows, navKey, previewOf],
+  );
+
+  const toggleFolder = useCallback((path: string) => {
+    setCollapsed((prev) => {
+      const next = new Set(prev);
+      if (next.has(path)) next.delete(path);
+      else next.add(path);
+      return next;
+    });
+  }, []);
+
+  /** Enter: open the highlighted session, or expand the highlighted folder and
+   * land on the first row it was hiding. */
+  const activateNav = useCallback(() => {
+    const row = rows.find((r) => r.key === navKey);
+    if (!row) return;
+    if (row.kind === "session") {
+      props.onSelect?.(row.id);
+      return;
+    }
+    const expanded = new Set(collapsed);
+    expanded.delete(row.path);
+    setCollapsed(expanded);
+    const revealed = firstRowUnder(tree, expanded, row.path);
+    setNavKey(revealed?.key ?? null);
+  }, [rows, navKey, collapsed, tree, props]);
+
+  const beginKill = useCallback(
+    (s: Session) => {
+      if (props.onKill) {
+        props.onKill(s);
+        return;
+      }
+      setKill({ session: s, blockers: sessionBlockers(s), force: false });
+    },
+    [props],
+  );
+
+  const commitRename = useCallback(
+    (id: string, name: string) => {
+      setRenamingId(null);
+      if (props.onRename) props.onRename(id, name);
+      else void renameSession(id, name).catch(() => {});
+    },
+    [props],
+  );
+
+  /** The session behind the highlighted row, when the highlight is on a card. */
+  const highlightedSession = useCallback((): Session | undefined => {
+    const row = rows.find((r) => r.key === navKey);
+    if (row?.kind !== "session") return undefined;
+    return sessions.find((s) => s.id === row.id);
+  }, [rows, navKey, sessions]);
+
+  const onKeyDown = (e: React.KeyboardEvent) => {
+    // The inline rename field owns its own keys; the walk stays out of it.
+    if (e.target instanceof HTMLInputElement) return;
+    switch (e.key) {
+      case "j":
+      case "ArrowDown":
+        e.preventDefault();
+        moveNav(1);
+        return;
+      case "k":
+      case "ArrowUp":
+        e.preventDefault();
+        moveNav(-1);
+        return;
+      case "Enter":
+        e.preventDefault();
+        activateNav();
+        return;
+      case "Tab":
+        e.preventDefault();
+        props.onFocusPane?.();
+        return;
+      case "c": {
+        const row = rows.find((r) => r.key === navKey);
+        if (row?.kind !== "folder") return;
+        e.preventDefault();
+        toggleFolder(row.path);
+        return;
+      }
+      case "r": {
+        const s = highlightedSession();
+        if (!s) return;
+        e.preventDefault();
+        setRenamingId(s.id);
+        return;
+      }
+      case "x": {
+        const s = highlightedSession();
+        if (!s) return;
+        e.preventDefault();
+        beginKill(s);
+        return;
+      }
+      case "n":
+        e.preventDefault();
+        props.onSpawn?.();
+        return;
+      case "N":
+        e.preventDefault();
+        props.onSpawnDefaults?.();
+        return;
+      case "?":
+        e.preventDefault();
+        props.onHelp?.();
+        return;
+    }
+  };
+
+  const menuItems = (s: Session): ContextMenuItem[] => [
+    { label: "Rename…", onSelect: () => setRenamingId(s.id) },
+    { label: "Spawn similar", onSelect: () => props.onSpawnSimilar?.(s) },
+    { label: "Kill session", danger: true, onSelect: () => beginKill(s) },
+  ];
+
+  const renderNode = (node: TreeNode, depth: number): React.ReactNode => {
+    if (node.kind === "leaf") {
+      const s = node.session;
+      return (
+        <SessionCard
+          key={s.id}
+          session={s}
+          depth={depth}
+          now={now}
+          highlighted={navKey === sessionKey(s.id)}
+          active={props.activeId === s.id}
+          open={(props.openIds?.has(s.id) ?? false) && props.activeId !== s.id}
+          previewing={props.previewId === s.id && props.activeId !== s.id}
+          renaming={renamingId === s.id}
+          onSelect={() => props.onSelect?.(s.id)}
+          onOpenMenu={(x, y) => setMenu({ x, y, session: s })}
+          onSpawnSimilar={() => props.onSpawnSimilar?.(s)}
+          onKill={() => beginKill(s)}
+          onRenameCommit={(name) => commitRename(s.id, name)}
+          onRenameCancel={() => setRenamingId(null)}
+        />
+      );
+    }
+    if (!node.name) {
+      return node.children.map((c) => renderNode(c, depth));
+    }
+    return (
+      <FolderNode
+        key={node.path}
+        name={node.name}
+        path={node.path}
+        depth={depth}
+        collapsed={collapsed.has(node.path)}
+        highlighted={navKey === `folder:${node.path}`}
+        onToggle={() => toggleFolder(node.path)}
+      >
+        {node.children.map((c) => renderNode(c, depth + 1))}
+      </FolderNode>
+    );
+  };
+
+  return (
+    <aside className="sidebar flex h-full min-h-0 flex-col bg-surface">
+      <SidebarSearch
+        value={query}
+        onChange={setQuery}
+        onDismiss={() => treeRef.current?.focus()}
+      />
+      <div
+        ref={treeRef}
+        className="tree min-h-0 flex-1 overflow-y-auto outline-none"
+        tabIndex={-1}
+        role="tree"
+        aria-label="Sessions"
+        onKeyDown={onKeyDown}
+        // The keyboard walk's preview belongs to the list holding the
+        // keyboard: once it doesn't, the pane goes back to what was opened.
+        onBlur={() => preview?.(null)}
+      >
+        {sessions.length === 0 ? (
+          <EmptyState onSpawn={() => props.onSpawn?.()} />
+        ) : (
+          renderNode(tree, 0)
+        )}
+      </div>
+      {menu && (
+        <ContextMenu
+          x={menu.x}
+          y={menu.y}
+          items={menuItems(menu.session)}
+          onClose={() => setMenu(null)}
+        />
+      )}
+      {kill && (
+        <KillConfirm
+          name={sessionName(kill.session)}
+          blockers={kill.blockers}
+          force={kill.force}
+          onCancel={() => setKill(null)}
+          onConfirm={() => {
+            const { session: s, force } = kill;
+            setKill(null);
+            void killSession(s.id, force).catch((e: unknown) => {
+              // The daemon refuses an unforced kill over a worktree holding
+              // unsaved work; that refusal needs its own prompt
+              // (docs/WORKTREES.md).
+              if (e instanceof ApiRequestError && e.code === "kill_guarded") {
+                setKill({
+                  session: s,
+                  blockers: e.unsavedWork ?? sessionBlockers(s),
+                  force: true,
+                });
+              }
+            });
+          }}
+        />
+      )}
+    </aside>
+  );
+}
+
+/** The tree's one empty state: no sessions at all. */
+function EmptyState({ onSpawn }: { onSpawn(): void }) {
+  return (
+    <div className="empty flex flex-col items-center gap-sp-2 p-sp-6 text-center">
+      <div aria-hidden="true" className="text-fs-20 text-faint">
+        +
+      </div>
+      <div className="text-fs-13 text-ink">No sessions yet</div>
+      <p className="text-fs-12 text-muted">Start your first session — it'll show up here.</p>
+      <button
+        type="button"
+        className="rounded-r-1 bg-accent px-sp-3 py-sp-1 text-fs-12 text-accent-ink"
+        onClick={onSpawn}
+      >
+        + Spawn session
+      </button>
+    </div>
+  );
+}
+
+/** Sessions from the store when one is wired, else the static prop. */
+function useSessions(props: SidebarProps): Session[] {
+  const fromStore = useStore(
+    // `useStore` needs a store every render; the no-store case is served by a
+    // stable empty stand-in whose result is thrown away below.
+    props.store ?? EMPTY_STORE,
+    (s: CatalogStore) => s.sessions,
+  );
+  return useMemo(
+    () => (props.store ? [...fromStore.values()] : (props.sessions ?? [])),
+    [props.store, props.sessions, fromStore],
+  );
+}
+
+// One frozen state object, not a fresh one per call: `useStore` reads the
+// snapshot on every render and a new Map each time would never settle.
+const EMPTY_STATE = { sessions: new Map<string, Session>() };
+const EMPTY_STORE = {
+  getState: () => EMPTY_STATE,
+  getInitialState: () => EMPTY_STATE,
+  setState: () => {},
+  subscribe: () => () => {},
+} as unknown as CatalogStoreApi;

web/src/components/sidebar/SidebarSearch.tsx

@@ -0,0 +1,34 @@
+// The sidebar's search field: a substring filter over the tree (name, command
+// and cwd). Escape clears it and hands the keyboard back to the list.
+
+export interface SidebarSearchProps {
+  value: string;
+  onChange(value: string): void;
+  /** Escape on an already-empty field — the list wants the keyboard back. */
+  onDismiss?(): void;
+}
+
+export function SidebarSearch({ value, onChange, onDismiss }: SidebarSearchProps) {
+  return (
+    <header className="sidebar-search p-sp-2">
+      <input
+        type="search"
+        className="search w-full rounded-r-1 border border-border bg-surface-2 px-sp-2 py-sp-1 text-fs-12 text-ink"
+        placeholder="Search sessions…"
+        aria-label="Search sessions"
+        autoComplete="off"
+        autoCorrect="off"
+        autoCapitalize="off"
+        spellCheck={false}
+        value={value}
+        onChange={(e) => onChange(e.currentTarget.value)}
+        onKeyDown={(e) => {
+          if (e.key !== "Escape") return;
+          e.preventDefault();
+          if (value) onChange("");
+          else onDismiss?.();
+        }}
+      />
+    </header>
+  );
+}

web/src/components/sidebar/index.ts

@@ -0,0 +1,8 @@
+export { Sidebar, type SidebarProps } from "./Sidebar.js";
+export { SessionCard, type SessionCardProps } from "./SessionCard.js";
+export { FolderNode, type FolderNodeProps } from "./FolderNode.js";
+export { SidebarSearch, type SidebarSearchProps } from "./SidebarSearch.js";
+export { ActivityRail } from "./ActivityRail.js";
+export { ContextMenu, type ContextMenuItem } from "./ContextMenu.js";
+export { KillConfirm } from "./KillConfirm.js";
+export * from "./model.js";

web/src/components/sidebar/model.test.ts

@@ -0,0 +1,62 @@
+import { describe, expect, it } from "vitest";
+
+import { buildTree } from "../../tree.js";
+import type { Session } from "../../types.js";
+import { filterSessions, firstRowUnder, navRows, splitFolderLabel } from "./model.js";
+
+function session(id: string, cwd: string, command = "claude"): Session {
+  return {
+    id,
+    cwd,
+    command,
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-08-24T10:00:00Z",
+  } as Session;
+}
+
+describe("navRows", () => {
+  const tree = buildTree([session("a", "/one"), session("b", "/two")], undefined);
+
+  it("stops on every card and skips expanded folder headers", () => {
+    expect(navRows(tree, new Set()).map((r) => r.key)).toEqual(["session:a", "session:b"]);
+  });
+
+  it("stops on a collapsed folder header instead of the cards it hides", () => {
+    expect(navRows(tree, new Set(["one"])).map((r) => r.key)).toEqual([
+      "folder:one",
+      "session:b",
+    ]);
+  });
+
+  it("names the first row an expanded folder reveals", () => {
+    expect(firstRowUnder(tree, new Set(), "one")?.key).toBe("session:a");
+  });
+});
+
+describe("splitFolderLabel", () => {
+  it("keeps a shallow path whole", () => {
+    expect(splitFolderLabel("~/maestro")).toEqual({ stem: null, last: "~/maestro" });
+  });
+
+  it("initials the leading segments of a deep path", () => {
+    expect(splitFolderLabel("~/git.naps.pt/naps62/maestro")).toEqual({
+      stem: "~/g/n",
+      last: "maestro",
+    });
+  });
+});
+
+describe("filterSessions", () => {
+  const all = [session("a", "/home/n/alpha", "claude"), session("b", "/home/n/beta", "bash")];
+
+  it("returns everything for a blank query", () => {
+    expect(filterSessions(all, "  ")).toHaveLength(2);
+  });
+
+  it("matches the cwd and the command, case-insensitively", () => {
+    expect(filterSessions(all, "ALPHA").map((s) => s.id)).toEqual(["a"]);
+    expect(filterSessions(all, "bash").map((s) => s.id)).toEqual(["b"]);
+  });
+});

web/src/components/sidebar/model.ts

@@ -0,0 +1,90 @@
+// Pure model helpers behind the React sidebar. Kept out of the components so
+// the walk order and the folder label can be tested without a DOM.
+
+import type { Session } from "../../types.js";
+import { sessionCwd, sessionName } from "../../types.js";
+import type { TreeNode } from "../../tree.js";
+
+/** A row the keyboard walk can land on (docs/SIDEBAR.md "Keyboard walk"):
+ * every session card, and a folder header only while it is collapsed. */
+export type NavRow =
+  | { key: string; kind: "folder"; path: string }
+  | { key: string; kind: "session"; id: string };
+
+export function folderKey(path: string): string {
+  return `folder:${path}`;
+}
+
+export function sessionKey(id: string): string {
+  return `session:${id}`;
+}
+
+/** The walkable rows in visual order. An expanded folder contributes nothing
+ * itself — its cards are one row away — while a collapsed one is the only row
+ * it has, so skipping it would leave the folder unreachable. */
+export function navRows(root: TreeNode, collapsed: ReadonlySet<string>): NavRow[] {
+  const out: NavRow[] = [];
+  const walk = (node: TreeNode): void => {
+    if (node.kind === "leaf") {
+      out.push({ key: sessionKey(node.session.id), kind: "session", id: node.session.id });
+      return;
+    }
+    if (node.name && collapsed.has(node.path)) {
+      out.push({ key: folderKey(node.path), kind: "folder", path: node.path });
+      return;
+    }
+    for (const child of node.children) walk(child);
+  };
+  for (const child of root.kind === "folder" ? root.children : [root]) walk(child);
+  return out;
+}
+
+/** The first walkable row inside `path`, i.e. where the highlight lands when
+ * Enter expands that folder. */
+export function firstRowUnder(
+  root: TreeNode,
+  collapsed: ReadonlySet<string>,
+  path: string,
+): NavRow | undefined {
+  const found = findFolder(root, path);
+  if (!found) return undefined;
+  return navRows({ ...found, name: "" }, collapsed)[0];
+}
+
+function findFolder(node: TreeNode, path: string): Extract<TreeNode, { kind: "folder" }> | null {
+  if (node.kind === "leaf") return null;
+  if (node.path === path && node.name) return node;
+  for (const child of node.children) {
+    const hit = findFolder(child, path);
+    if (hit) return hit;
+  }
+  return null;
+}
+
+/** Structured form of `abbreviateFolderName`: a deep path shows its leading
+ * segments as initials so the tail stays readable in a narrow sidebar. */
+export function splitFolderLabel(name: string): { stem: string | null; last: string } {
+  const parts = name.split("/");
+  if (parts.length <= 2) return { stem: null, last: name };
+  const last = parts[parts.length - 1];
+  const stem = parts
+    .slice(0, -1)
+    .map((p) => (p === "~" ? "~" : (Array.from(p)[0] ?? "")))
+    .join("/");
+  return { stem, last };
+}
+
+/** Case-insensitive substring filter over a session's name, command and cwd —
+ * what the sidebar's own search field narrows the tree with. */
+export function filterSessions(sessions: Session[], query: string): Session[] {
+  const q = query.trim().toLowerCase();
+  if (!q) return sessions;
+  return sessions.filter((s) => {
+    const cwd = sessionCwd(s) ?? "";
+    return (
+      sessionName(s).toLowerCase().includes(q) ||
+      s.command.toLowerCase().includes(q) ||
+      cwd.toLowerCase().includes(q)
+    );
+  });
+}

web/src/components/sidebar/sidebar.css

@@ -0,0 +1,49 @@
+/* Motion for the activity rail (docs/SIDEBAR.md): a hard blink while
+   AwaitingInput, a fast flash while Error. Active and Idle are solid and
+   still — colour alone is the signal. Kept as real CSS rather than Tailwind
+   utilities because both need @keyframes of their own. */
+
+@keyframes maestro-rail-blink {
+  0%,
+  50% {
+    opacity: 1;
+  }
+  50.01%,
+  100% {
+    opacity: 0;
+  }
+}
+
+@keyframes maestro-rail-flash {
+  0%,
+  100% {
+    opacity: 1;
+  }
+  15% {
+    opacity: 0.25;
+  }
+  30% {
+    opacity: 1;
+  }
+  45% {
+    opacity: 0.25;
+  }
+  60% {
+    opacity: 1;
+  }
+}
+
+.rail-blink {
+  animation: maestro-rail-blink 1.2s steps(1) infinite;
+}
+
+.rail-flash {
+  animation: maestro-rail-flash 1.4s ease-out infinite;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .rail-blink,
+  .rail-flash {
+    animation: none;
+  }
+}

web/src/components/sidebar/useNow.ts

@@ -0,0 +1,16 @@
+import { useEffect, useState } from "react";
+
+/** A clock that ticks at least every `intervalMs` while the page is visible.
+ * docs/SIDEBAR.md asks for a re-render at least every 30s so the duration's
+ * cutover points land within one tick. */
+export function useNow(intervalMs = 30_000): number {
+  const [now, setNow] = useState(() => Date.now());
+  useEffect(() => {
+    const id = setInterval(() => {
+      if (document.visibilityState !== "visible") return;
+      setNow(Date.now());
+    }, intervalMs);
+    return () => clearInterval(id);
+  }, [intervalMs]);
+  return now;
+}

web/src/components/spawn/BranchPicker.test.tsx

@@ -0,0 +1,79 @@
+// @vitest-environment happy-dom
+import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import type { BranchInfo } from "../../types.js";
+import { BranchPicker, type BranchPickerProps } from "./BranchPicker.js";
+
+afterEach(cleanup);
+
+function props(over: Partial<BranchPickerProps> = {}): BranchPickerProps {
+  return {
+    enabled: true,
+    onToggleEnabled: vi.fn(),
+    hint: null,
+    baseRepo: "/repo",
+    mode: "new",
+    onModeChange: vi.fn(),
+    newBranch: "",
+    onNewBranchChange: vi.fn(),
+    branches: undefined,
+    existingBranch: "",
+    onExistingBranchChange: vi.fn(),
+    ...over,
+  };
+}
+
+describe("BranchPicker", () => {
+  it("shows the hint instead of the body while unresolved", () => {
+    render(<BranchPicker {...props({ hint: "Choose a working directory first." })} />);
+    expect(screen.getByText("Choose a working directory first.")).not.toBeNull();
+    expect(screen.queryByText("New branch name")).toBeNull();
+  });
+
+  it("shows the new-branch field by default and the repo line once resolved", () => {
+    render(<BranchPicker {...props()} />);
+    expect(screen.getByText("repo: /repo")).not.toBeNull();
+    expect(screen.getByPlaceholderText("feat/foo")).not.toBeNull();
+    expect(screen.queryByText("Pick a branch")).toBeNull();
+  });
+
+  it("switches to the existing-branch select and reports the mode change", () => {
+    const onModeChange = vi.fn();
+    render(<BranchPicker {...props({ onModeChange })} />);
+
+    fireEvent.click(screen.getByLabelText("Existing branch"));
+
+    expect(onModeChange).toHaveBeenCalledWith("existing");
+  });
+
+  it("disables a branch already held by another worktree, and the main checkout's HEAD", () => {
+    const branches: BranchInfo[] = [
+      { name: "main", is_head: true },
+      { name: "feat/a", is_head: false, worktree: "/repos/a" },
+      { name: "feat/b", is_head: false },
+    ];
+    render(<BranchPicker {...props({ mode: "existing", branches })} />);
+
+    const main = screen.getByRole("option", { name: /main — held by the main checkout/ }) as HTMLOptionElement;
+    const a = screen.getByRole("option", { name: /feat\/a — held by \/repos\/a/ }) as HTMLOptionElement;
+    const b = screen.getByRole("option", { name: "feat/b" }) as HTMLOptionElement;
+    expect(main.disabled).toBe(true);
+    expect(a.disabled).toBe(true);
+    expect(b.disabled).toBe(false);
+  });
+
+  it("shows a placeholder option when no local branches were found", () => {
+    render(<BranchPicker {...props({ mode: "existing", branches: [] })} />);
+    expect(screen.getByText("No local branches found.")).not.toBeNull();
+  });
+
+  it("toggles the worktree checkbox", () => {
+    const onToggleEnabled = vi.fn();
+    render(<BranchPicker {...props({ onToggleEnabled })} />);
+
+    fireEvent.click(screen.getByLabelText("Create git worktree"));
+
+    expect(onToggleEnabled).toHaveBeenCalledWith(false);
+  });
+});

web/src/components/spawn/BranchPicker.tsx

@@ -0,0 +1,119 @@
+// The spawn form's worktree section (#61): create-worktree toggle, then
+// (once a base repo is known) new-branch-vs-existing-branch, mirroring
+// spawnForm.ts's `.adv-group`/`.wt-body`/`.wt-mode` markup.
+
+import type { BranchInfo } from "../../types.js";
+import type { WorktreeBranchMode } from "../../spawnForm.js";
+
+export interface BranchPickerProps {
+  enabled: boolean;
+  onToggleEnabled(enabled: boolean): void;
+  /** Status line shown in place of the body — "Checking…", "not a repo",
+   * "choose a directory first". `null` once the body itself can render. */
+  hint: string | null;
+  /** The repo a worktree would branch from, once resolved. */
+  baseRepo: string | null;
+  mode: WorktreeBranchMode;
+  onModeChange(mode: WorktreeBranchMode): void;
+  newBranch: string;
+  onNewBranchChange(value: string): void;
+  /** This cwd's local branches, or `undefined` while unknown/not yet loaded. */
+  branches: BranchInfo[] | undefined;
+  existingBranch: string;
+  onExistingBranchChange(value: string): void;
+}
+
+export function BranchPicker(props: BranchPickerProps) {
+  return (
+    <div
+      className={`flex flex-col gap-sp-3 border-l-2 pl-sp-3 ${
+        props.enabled ? "border-accent" : "border-border"
+      }`}
+    >
+      <label className="flex cursor-pointer items-center gap-sp-2 text-fs-14 text-ink">
+        <input
+          type="checkbox"
+          data-role="toggle"
+          className="size-[18px] accent-accent"
+          checked={props.enabled}
+          onChange={(e) => props.onToggleEnabled(e.currentTarget.checked)}
+        />
+        Create git worktree
+      </label>
+
+      {props.hint && <p className="m-0 text-fs-12 text-muted">{props.hint}</p>}
+
+      {props.enabled && !props.hint && (
+        <div className="flex flex-col gap-sp-3">
+          {props.baseRepo && (
+            <p className="m-0 font-mono text-fs-12 text-muted">repo: {props.baseRepo}</p>
+          )}
+          <div role="radiogroup" aria-label="Branch source" className="flex gap-sp-4">
+            <label className="flex cursor-pointer items-center gap-sp-2 text-fs-14 text-ink">
+              <input
+                type="radio"
+                name="worktree_branch_mode"
+                checked={props.mode === "new"}
+                onChange={() => props.onModeChange("new")}
+              />
+              New branch
+            </label>
+            <label className="flex cursor-pointer items-center gap-sp-2 text-fs-14 text-ink">
+              <input
+                type="radio"
+                name="worktree_branch_mode"
+                checked={props.mode === "existing"}
+                onChange={() => props.onModeChange("existing")}
+              />
+              Existing branch
+            </label>
+          </div>
+
+          {props.mode === "new" ? (
+            <label className="flex flex-col gap-1 text-fs-12 text-muted">
+              New branch name
+              <input
+                name="worktree_branch"
+                type="text"
+                autoComplete="off"
+                placeholder="feat/foo"
+                className="w-full rounded-r-2 border border-border bg-surface-2 px-sp-3 py-2 font-mono text-fs-15 text-ink"
+                value={props.newBranch}
+                onChange={(e) => props.onNewBranchChange(e.currentTarget.value)}
+              />
+            </label>
+          ) : (
+            <label className="flex flex-col gap-1 text-fs-12 text-muted">
+              Pick a branch
+              <select
+                className="w-full rounded-r-2 border border-border bg-surface-2 px-sp-3 py-2 font-mono text-fs-15 text-ink"
+                value={props.existingBranch}
+                onChange={(e) => props.onExistingBranchChange(e.currentTarget.value)}
+              >
+                {branchOptions(props.branches)}
+              </select>
+            </label>
+          )}
+        </div>
+      )}
+    </div>
+  );
+}
+
+function branchOptions(branches: BranchInfo[] | undefined) {
+  if (!branches || branches.length === 0) {
+    return <option value="">No local branches found.</option>;
+  }
+  return branches.map((b) => {
+    // A branch already checked out anywhere stays visible but unpickable —
+    // git refuses a second checkout. That includes the main checkout's own
+    // HEAD, which is commonly `main` and would otherwise be the default pick,
+    // making every existing-branch spawn fail (#54 review).
+    const held = b.worktree ?? (b.is_head ? "the main checkout" : null);
+    return (
+      <option key={b.name} value={b.name} disabled={held !== null} title={held ?? ""}>
+        {held ? `${b.name} — held by ${held}` : b.name}
+      </option>
+    );
+  });
+}

web/src/components/spawn/DirAutocomplete.test.tsx

@@ -0,0 +1,109 @@
+// @vitest-environment happy-dom
+import { act, cleanup, fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { useState } from "react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { DirAutocomplete } from "./DirAutocomplete.js";
+
+vi.mock("../../api.js", () => ({
+  listDir: vi.fn(),
+}));
+
+import { listDir } from "../../api.js";
+
+const mockListDir = vi.mocked(listDir);
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+function Harness({ initial = "" }: { initial?: string }) {
+  const [value, setValue] = useState(initial);
+  return <DirAutocomplete value={value} onChange={setValue} placeholder="cwd" />;
+}
+
+// `fireEvent.focus`/`.blur` dispatch the event without moving the browser's
+// real focus, so `document.activeElement` (which the dropdown's fetch guards
+// against) never changes — calling the DOM method directly does both.
+function focus(el: HTMLElement): void {
+  act(() => el.focus());
+}
+function blur(el: HTMLElement): void {
+  act(() => el.blur());
+}
+
+describe("DirAutocomplete", () => {
+  it("lists entries matching the trailing segment on focus", async () => {
+    mockListDir.mockResolvedValue({ path: "/home/n", entries: ["alpha", "beta"] });
+    render(<Harness initial="/home/n/al" />);
+
+    focus(screen.getByPlaceholderText("cwd"));
+
+    expect(await screen.findByRole("option", { name: "alpha/" })).not.toBeNull();
+    expect(screen.queryByRole("option", { name: "beta/" })).toBeNull();
+  });
+
+  it("Tab commits the highlighted entry and does not close the field", async () => {
+    mockListDir.mockResolvedValue({ path: "/home/n", entries: ["alpha"] });
+    render(<Harness initial="/home/n/a" />);
+    const input = screen.getByPlaceholderText("cwd") as HTMLInputElement;
+    focus(input);
+    await screen.findByRole("option", { name: "alpha/" });
+
+    fireEvent.keyDown(input, { key: "Tab" });
+
+    expect(input.value).toBe("/home/n/alpha/");
+  });
+
+  it("arrows move the highlight and Enter accepts it without submitting", async () => {
+    mockListDir.mockResolvedValue({ path: "/home/n", entries: ["alpha", "beta"] });
+    render(<Harness initial="/home/n/" />);
+    const input = screen.getByPlaceholderText("cwd") as HTMLInputElement;
+    focus(input);
+    await screen.findByRole("option", { name: "alpha/" });
+
+    fireEvent.keyDown(input, { key: "ArrowDown" });
+    const notPrevented = fireEvent.keyDown(input, { key: "Enter" });
+
+    expect(input.value).toBe("/home/n/beta/");
+    expect(notPrevented).toBe(false); // preventDefault called -> event "processed"
+  });
+
+  it("Escape closes the dropdown and stops the key from bubbling", async () => {
+    mockListDir.mockResolvedValue({ path: "/home/n", entries: ["alpha"] });
+    const onKeyDown = vi.fn();
+    render(
+      <div onKeyDown={onKeyDown}>
+        <Harness initial="/home/n/a" />
+      </div>,
+    );
+    const input = screen.getByPlaceholderText("cwd");
+    focus(input);
+    await screen.findByRole("option", { name: "alpha/" });
+
+    fireEvent.keyDown(input, { key: "Escape" });
+
+    await waitFor(() => expect(screen.queryByRole("option")).toBeNull());
+    expect(onKeyDown).not.toHaveBeenCalled();
+  });
+
+  it("does not reopen on refocus until the operator types again", async () => {
+    mockListDir.mockResolvedValue({ path: "/home/n", entries: ["alpha"] });
+    render(<Harness initial="/home/n/a" />);
+    const input = screen.getByPlaceholderText("cwd");
+    focus(input);
+    await screen.findByRole("option", { name: "alpha/" });
+    fireEvent.keyDown(input, { key: "Escape" });
+    await waitFor(() => expect(screen.queryByRole("option")).toBeNull());
+
+    blur(input);
+    focus(input);
+
+    await new Promise((r) => setTimeout(r, 10));
+    expect(screen.queryByRole("option")).toBeNull();
+
+    fireEvent.change(input, { target: { value: "/home/n/al" } });
+    expect(await screen.findByRole("option", { name: "alpha/" })).not.toBeNull();
+  });
+});