fix(maestro): satisfy field_reassign_with_default lint

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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.toml

@@ -10,6 +10,7 @@ repository = "https://git.naps.pt/naps62/maestro"
 publish = false
 
 [workspace.dependencies]
+agent-client-protocol = { version = "2.1", features = ["unstable_tool_call_name"] }
 axum = { version = "0.7", features = ["ws"] }
 chrono = { version = "0.4", default-features = false, features = ["clock", "serde"] }
 clap = { version = "4.5", features = ["derive", "env"] }
@@ -17,6 +18,7 @@ crossterm = { version = "0.28", features = ["event-stream"] }
 dirs = "5"
 futures-util = { version = "0.3", default-features = false, features = ["sink", "std"] }
 libc = "0.2"
+maestro-acp = { path = "crates/maestro-acp" }
 maestro-config = { path = "crates/maestro-config" }
 # `default-features = false` so each consumer opts into `haiku-autoname`
 # through its own feature of the same name (#131); a workspace entry that
@@ -38,9 +40,11 @@ tempfile = "3"
 thiserror = "1"
 tokio = { version = "1", features = ["macros", "rt-multi-thread", "sync", "time", "net", "io-util", "fs", "signal", "process"] }
 tokio-tungstenite = "0.21"
+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

@@ -0,0 +1,21 @@
+[package]
+name = "maestro-acp"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+publish.workspace = true
+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
+tokio-util.workspace = true
+tracing.workspace = true
+
+[dev-dependencies]
+tempfile.workspace = true

crates/maestro-acp/tests/fake_acp_agent.py

@@ -0,0 +1,262 @@
+#!/usr/bin/env python3
+"""A deterministic stand-in for `claude-code-acp` (#134).
+
+Speaks just enough JSON-RPC over stdio for the daemon's handshake:
+answers `initialize` and `session/new`, logs every method it receives, and
+exits on SIGTERM. Tests point `PATH` at a directory holding this file under
+the adapter's name, so the real adapter (which needs Claude auth and is
+slow) never runs in the deterministic suite.
+
+Environment knobs, all optional:
+
+  FAKE_ACP_LOG            append one line per event to this file:
+                            start pid=<pid> cwd=<cwd>
+                            env <NAME>=<value>       (for FAKE_ACP_ECHO_ENV)
+                            caps <json of clientCapabilities>
+                            recv <method>
+                            signal SIGTERM
+  FAKE_ACP_ECHO_ENV       name of one env var to log at start
+  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)
+  FAKE_ACP_IGNORE_EOF=1      keep running after stdin closes, until signalled
+  FAKE_ACP_EMIT_ON_CANCEL=1  emit a final notification before handling cancel
+  FAKE_ACP_CANCEL_SETTLES=1  complete the outstanding prompt on cancel
+  FAKE_ACP_NO_LOAD=1      advertise `loadSession: false`
+  FAKE_ACP_LOAD_REPLAY=n  on `session/load`, replay n `agent_message_chunk`
+                            notifications ("replayed <i>") before answering,
+                            the way a real agent streams history back
+  FAKE_ACP_LOAD_FAIL=1    answer `session/load` with a JSON-RPC error
+  FAKE_ACP_DELAY_PROMPT_MS=n  wait before answering `session/prompt`
+  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
+
+Signals: SIGUSR1 emits one `agent_message_chunk` notification ("tick <n>",
+counting from 1) and logs `emit tick <n>`, so a test can make the agent
+speak on demand (#135).
+"""
+import json
+import os
+import signal
+import sys
+import time
+
+LOG = os.environ.get("FAKE_ACP_LOG")
+
+
+def log(line):
+    if not LOG:
+        return
+    with open(LOG, "a") as f:
+        f.write(line + "\n")
+        f.flush()
+
+
+def send(obj):
+    sys.stdout.write(json.dumps(obj) + "\n")
+    sys.stdout.flush()
+
+
+def on_sigterm(_signum, _frame):
+    log("signal SIGTERM")
+    sys.exit(0)
+
+
+signal.signal(signal.SIGTERM, on_sigterm)
+
+session_id = f"fake-{os.getpid()}"
+ticks = 0
+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):
+    return {"jsonrpc": "2.0", "method": "session/update", "params": {
+        "sessionId": session_id,
+        "update": {"sessionUpdate": "agent_message_chunk",
+                   "content": {"type": "text", "text": text}},
+    }}
+
+
+def on_sigusr1(_signum, _frame):
+    global ticks
+    ticks += 1
+    send(chunk(f"tick {ticks}"))
+    log(f"emit tick {ticks}")
+
+
+signal.signal(signal.SIGUSR1, on_sigusr1)
+
+log(f"start pid={os.getpid()} cwd={os.getcwd()}")
+echo = os.environ.get("FAKE_ACP_ECHO_ENV")
+if echo:
+    log(f"env {echo}={os.environ.get(echo, '')}")
+
+for raw in sys.stdin:
+    raw = raw.strip()
+    if not raw:
+        continue
+    msg = json.loads(raw)
+    method = msg.get("method")
+    if method is None:
+        # A response to something we sent; nothing to do.
+        if msg.get("id") == pending_permission_id:
+            log("permission response " + json.dumps(msg.get("result"), sort_keys=True))
+            send({"jsonrpc": "2.0", "id": pending_prompt_id,
+                  "result": {"stopReason": "end_turn"}})
+            pending_prompt_id = None
+            pending_permission_id = None
+        continue
+    log(f"recv {method}")
+    rid = msg.get("id")
+    params = msg.get("params") or {}
+
+    if method == "initialize":
+        log("caps " + json.dumps(params.get("clientCapabilities", {}), sort_keys=True))
+        if os.environ.get("FAKE_ACP_INIT_FAIL") == "1":
+            send({"jsonrpc": "2.0", "id": rid,
+                  "error": {"code": -32000, "message": "fake init failure"}})
+            continue
+        send({"jsonrpc": "2.0", "id": rid, "result": {
+            "protocolVersion": params.get("protocolVersion", 1),
+            "agentCapabilities": {
+                "loadSession": os.environ.get("FAKE_ACP_NO_LOAD") != "1"},
+            "agentInfo": {"name": "fake-acp-agent", "version": "0.0.0"},
+            "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": settings_response(True)})
+        send(chunk("hello from fake"))
+        if os.environ.get("FAKE_ACP_EXIT_AFTER_NEW") == "1":
+            sys.exit(0)
+    elif method == "session/load":
+        session_id = params.get("sessionId")
+        log(f"recv session/load sessionId={session_id}")
+        if os.environ.get("FAKE_ACP_LOAD_FAIL") == "1":
+            send({"jsonrpc": "2.0", "id": rid,
+                  "error": {"code": -32000, "message": "fake load failure"}})
+            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": 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"))
+        if (os.environ.get("FAKE_ACP_CANCEL_SETTLES") == "1"
+                and pending_prompt_id is not None):
+            send({"jsonrpc": "2.0", "id": pending_prompt_id,
+                  "result": {"stopReason": "cancelled"}})
+            pending_prompt_id = None
+            pending_permission_id = None
+        if os.environ.get("FAKE_ACP_EXIT_ON_CANCEL") == "1":
+            sys.exit(0)
+    elif method == "session/prompt":
+        if os.environ.get("FAKE_ACP_PERMISSION_AFTER_CANCEL") == "1":
+            if pending_prompt_id is None:
+                pending_prompt_id = rid
+                delayed_permission = True
+                continue
+            if delayed_permission:
+                delayed_permission = False
+                pending_permission_id = "permission-1"
+                send({"jsonrpc": "2.0", "id": pending_permission_id,
+                      "method": "session/request_permission", "params": {
+                          "sessionId": session_id,
+                          "toolCall": {"toolCallId": "tool-1", "fields": {}},
+                          "options": [
+                              {"optionId": "once", "name": "Allow once", "kind": "allow_once"},
+                              {"optionId": "deny", "name": "Deny", "kind": "reject_once"}
+                          ]
+                      }})
+                continue
+        if os.environ.get("FAKE_ACP_REQUEST_PERMISSION") == "1":
+            pending_prompt_id = rid
+            pending_permission_id = "permission-1"
+            send({"jsonrpc": "2.0", "id": pending_permission_id,
+                  "method": "session/request_permission", "params": {
+                      "sessionId": session_id,
+                      "toolCall": {"toolCallId": "tool-1", "fields": {}},
+                      "options": [
+                          {"optionId": "once", "name": "Allow once", "kind": "allow_once"},
+                          {"optionId": "session", "name": "Allow session", "kind": "allow_always"},
+                          {"optionId": "deny", "name": "Deny", "kind": "reject_once"}
+                      ]
+                  }})
+            continue
+        time.sleep(int(os.environ.get("FAKE_ACP_DELAY_PROMPT_MS", "0")) / 1000)
+        fail_once = os.environ.get("FAKE_ACP_PROMPT_FAIL_ONCE") == "1"
+        if os.environ.get("FAKE_ACP_PROMPT_FAIL") == "1" or (fail_once and prompt_failures == 0):
+            prompt_failures += 1
+            send({"jsonrpc": "2.0", "id": rid,
+                  "error": {"code": -32000, "message": "fake prompt failure"}})
+        else:
+            send({"jsonrpc": "2.0", "id": rid,
+                  "result": {"stopReason": "end_turn"}})
+    elif rid is not None:
+        send({"jsonrpc": "2.0", "id": rid,
+              "error": {"code": -32601, "message": f"method not found: {method}"}})
+
+if os.environ.get("FAKE_ACP_IGNORE_EOF") == "1":
+    while True:
+        signal.pause()

crates/maestro-acp/tests/spawn.rs

@@ -0,0 +1,505 @@
+//! `maestro-acp` against the fake adapter in `tests/fake_acp_agent.py`, plus
+//! 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::{AcpAdapter, AcpError, SpawnConfig, ADAPTER_BIN, INSTALL_COMMAND};
+use tempfile::TempDir;
+
+fn fake_agent() -> PathBuf {
+    Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/fake_acp_agent.py")
+}
+
+/// A temp `bin/` holding the fake agent under the adapter's name, plus a
+/// log file the agent appends to. `PATH` for the spawn is just that dir.
+struct Fake {
+    dir: TempDir,
+}
+
+impl Fake {
+    fn new() -> Self {
+        let dir = TempDir::new().unwrap();
+        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 }
+    }
+
+    fn log_path(&self) -> PathBuf {
+        self.dir.path().join("agent.log")
+    }
+
+    fn log(&self) -> String {
+        std::fs::read_to_string(self.log_path()).unwrap_or_default()
+    }
+
+    /// The fake's `bin/` first, so it shadows any real adapter, then the
+    /// process `PATH` so the script's `python3` still resolves.
+    fn env(&self) -> HashMap<String, String> {
+        let path = format!(
+            "{}:{}",
+            self.dir.path().join("bin").display(),
+            std::env::var("PATH").unwrap_or_default()
+        );
+        HashMap::from([
+            ("PATH".to_string(), path),
+            (
+                "FAKE_ACP_LOG".to_string(),
+                self.log_path().to_string_lossy().into_owned(),
+            ),
+        ])
+    }
+
+    fn config(&self, cwd: &Path) -> SpawnConfig {
+        let mut config = SpawnConfig::new(cwd, self.env());
+        config.handshake_timeout = Duration::from_secs(10);
+        config
+    }
+
+    async fn wait_for_log(&self, needle: &str) {
+        let deadline = Instant::now() + Duration::from_secs(5);
+        while Instant::now() < deadline {
+            if self.log().contains(needle) {
+                return;
+            }
+            tokio::time::sleep(Duration::from_millis(20)).await;
+        }
+        panic!("log never contained {needle:?}:\n{}", self.log());
+    }
+
+    fn pid(&self) -> u32 {
+        self.log()
+            .lines()
+            .find_map(|line| line.strip_prefix("start pid="))
+            .and_then(|rest| rest.split(' ').next())
+            .and_then(|pid| pid.parse().ok())
+            .expect("pid in log")
+    }
+
+    async fn wait_for_exit(&self) {
+        let pid = self.pid();
+        let deadline = Instant::now() + Duration::from_secs(5);
+        while pid_alive(pid) && Instant::now() < deadline {
+            tokio::time::sleep(Duration::from_millis(20)).await;
+        }
+        assert!(!pid_alive(pid), "child {pid} still alive");
+    }
+}
+
+fn pid_alive(pid: u32) -> bool {
+    Path::new(&format!("/proc/{pid}")).exists()
+        && std::fs::read_to_string(format!("/proc/{pid}/stat"))
+            .map(|s| !s.contains(") Z "))
+            .unwrap_or(false)
+}
+
+#[tokio::test]
+async fn spawn_runs_adapter_in_cwd_with_env_and_restrictive_caps() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut config = fake.config(cwd.path());
+    config
+        .env
+        .insert("FAKE_ACP_ECHO_ENV".into(), "MAESTRO_SESSION_ID".into());
+    config
+        .env
+        .insert("MAESTRO_SESSION_ID".into(), "sess-123".into());
+
+    let session = maestro_acp::spawn(config).await.expect("spawn");
+    assert!(session.session_id().starts_with("fake-"));
+    assert!(pid_alive(session.pid()));
+
+    let log = fake.log();
+    let cwd_canon = cwd.path().canonicalize().unwrap();
+    assert!(
+        log.contains(&format!("cwd={}", cwd_canon.display())),
+        "child cwd missing from log:\n{log}"
+    );
+    assert!(log.contains("env MAESTRO_SESSION_ID=sess-123"), "{log}");
+    assert!(log.contains("recv initialize"), "{log}");
+    assert!(log.contains("recv session/new"), "{log}");
+    let caps = log
+        .lines()
+        .find_map(|l| l.strip_prefix("caps "))
+        .expect("caps line");
+    let caps: serde_json::Value = serde_json::from_str(caps).unwrap();
+    assert_eq!(caps["fs"]["readTextFile"], false);
+    assert_eq!(caps["fs"]["writeTextFile"], false);
+    assert_eq!(caps["terminal"], false);
+
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .await;
+}
+
+#[tokio::test]
+async fn missing_adapter_names_the_install_command() {
+    let empty = TempDir::new().unwrap();
+    let cwd = TempDir::new().unwrap();
+    let env = HashMap::from([(
+        "PATH".to_string(),
+        empty.path().to_string_lossy().into_owned(),
+    )]);
+    let err = maestro_acp::spawn(SpawnConfig::new(cwd.path(), env))
+        .await
+        .expect_err("no adapter on PATH");
+    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();
+    let cwd = TempDir::new().unwrap();
+    let session = maestro_acp::spawn(fake.config(cwd.path()))
+        .await
+        .expect("spawn");
+
+    let mut updates = session.take_updates().expect("first take");
+    assert!(session.take_updates().is_none(), "handed out once");
+    let first = tokio::time::timeout(Duration::from_secs(5), updates.recv())
+        .await
+        .expect("update within 5s")
+        .expect("channel open");
+    assert_eq!(first.session_id.0.as_ref(), session.session_id());
+    match first.update {
+        SessionUpdate::AgentMessageChunk(chunk) => match chunk.content {
+            ContentBlock::Text(t) => assert_eq!(t.text, "hello from fake"),
+            other => panic!("unexpected content {other:?}"),
+        },
+        other => panic!("unexpected update {other:?}"),
+    }
+
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .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()).adapter(AcpAdapter::Codex))
+        .await
+        .expect("spawn");
+    let pid = session.pid();
+
+    session
+        .terminate(Duration::from_millis(200), Duration::from_secs(2))
+        .await;
+    assert!(session.has_exited());
+    fake.wait_for_log("signal SIGTERM").await;
+
+    let log = fake.log();
+    let cancel = log.find("recv session/cancel").expect("cancel logged");
+    let term = log.find("signal SIGTERM").expect("SIGTERM logged");
+    assert!(cancel < term, "cancel must precede SIGTERM:\n{log}");
+    assert!(!pid_alive(pid), "child {pid} still alive");
+}
+
+#[tokio::test]
+async fn terminate_is_satisfied_by_an_exit_on_cancel() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut config = fake.config(cwd.path());
+    config
+        .env
+        .insert("FAKE_ACP_EXIT_ON_CANCEL".into(), "1".into());
+    let session = maestro_acp::spawn(config).await.expect("spawn");
+
+    session
+        .terminate(Duration::from_secs(2), Duration::from_secs(2))
+        .await;
+    assert!(session.has_exited());
+    let log = fake.log();
+    assert!(log.contains("recv session/cancel"), "{log}");
+    assert!(!log.contains("signal SIGTERM"), "cancel was enough:\n{log}");
+}
+
+#[tokio::test]
+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()).adapter(AcpAdapter::Codex);
+    config.env.insert("FAKE_ACP_INIT_FAIL".into(), "1".into());
+
+    let err = maestro_acp::spawn(config).await.expect_err("init fails");
+    assert!(matches!(err, AcpError::Handshake(_)), "{err}");
+    assert!(err.to_string().contains("fake init failure"), "{err}");
+    // Closing the connection gives the fake EOF on stdin; the SIGTERM that
+    // follows may find it already gone. Either way it must not survive.
+    let pid: u32 = fake
+        .log()
+        .lines()
+        .find_map(|l| l.strip_prefix("start pid="))
+        .and_then(|rest| rest.split(' ').next())
+        .and_then(|p| p.parse().ok())
+        .expect("pid in log");
+    let deadline = Instant::now() + Duration::from_secs(5);
+    while pid_alive(pid) && Instant::now() < deadline {
+        tokio::time::sleep(Duration::from_millis(20)).await;
+    }
+    assert!(!pid_alive(pid), "child {pid} outlived the failed spawn");
+}
+
+#[tokio::test]
+async fn early_exit_is_observed_after_a_successful_handshake() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut config = fake.config(cwd.path());
+    config
+        .env
+        .insert("FAKE_ACP_EXIT_AFTER_NEW".into(), "1".into());
+    let session = maestro_acp::spawn(config).await.expect("spawn");
+
+    let status = tokio::time::timeout(Duration::from_secs(5), session.wait())
+        .await
+        .expect("exit within 5s")
+        .expect("status");
+    assert!(status.success(), "{status}");
+    assert!(session.has_exited());
+}
+
+#[tokio::test]
+async fn child_exit_before_handshake_reports_exited_early() {
+    // A "adapter" that dies before answering anything.
+    let dir = TempDir::new().unwrap();
+    let bin = dir.path().join("bin");
+    std::fs::create_dir_all(&bin).unwrap();
+    let script = bin.join(ADAPTER_BIN);
+    std::fs::write(&script, "#!/bin/sh\necho 'not logged in' >&2\nexit 3\n").unwrap();
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::set_permissions(&script, std::fs::Permissions::from_mode(0o755)).unwrap();
+    }
+    let cwd = TempDir::new().unwrap();
+    let env = HashMap::from([("PATH".to_string(), bin.to_string_lossy().into_owned())]);
+    let mut config = SpawnConfig::new(cwd.path(), env);
+    config.handshake_timeout = Duration::from_secs(10);
+
+    let err = maestro_acp::spawn(config).await.expect_err("child died");
+    match &err {
+        AcpError::ExitedEarly { status, stderr, .. } => {
+            assert!(status.contains('3'), "{status}");
+            assert!(stderr.contains("not logged in"), "{stderr}");
+        }
+        other => panic!("unexpected {other:?}"),
+    }
+}
+
+#[tokio::test]
+async fn drop_terminates_and_reaps_the_child() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let mut config = fake.config(cwd.path());
+    config.env.insert("FAKE_ACP_IGNORE_EOF".into(), "1".into());
+    let session = maestro_acp::spawn(config).await.expect("spawn");
+
+    drop(session);
+
+    fake.wait_for_log("signal SIGTERM").await;
+    fake.wait_for_exit().await;
+}
+
+fn chunk_text(n: &maestro_acp::schema::SessionNotification) -> String {
+    match &n.update {
+        SessionUpdate::AgentMessageChunk(chunk) => match &chunk.content {
+            ContentBlock::Text(t) => t.text.clone(),
+            other => panic!("unexpected content {other:?}"),
+        },
+        other => panic!("unexpected update {other:?}"),
+    }
+}
+
+#[tokio::test]
+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())
+        .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");
+    assert_eq!(session.session_id(), "fake-old");
+    let log = fake.log();
+    assert!(
+        log.contains("recv session/load sessionId=fake-old"),
+        "{log}"
+    );
+    assert!(!log.contains("recv session/new"), "{log}");
+
+    // The three replayed chunks never reach the receiver: the event log
+    // already holds them. The first notification after the response does.
+    let mut updates = session.take_updates().expect("updates");
+    let first = tokio::time::timeout(Duration::from_secs(5), updates.recv())
+        .await
+        .expect("update within 5s")
+        .expect("channel open");
+    assert_eq!(chunk_text(&first), "hello after load");
+    // Nothing queued behind it either.
+    tokio::time::sleep(Duration::from_millis(100)).await;
+    assert!(updates.try_recv().is_err(), "replay leaked through");
+
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .await;
+}
+
+#[tokio::test]
+async fn load_session_requires_the_load_capability() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    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)
+        .await
+        .expect_err("no loadSession");
+    assert!(matches!(err, AcpError::Handshake(_)), "{err}");
+    assert!(err.to_string().contains("loadSession"), "{err}");
+    assert!(!fake.log().contains("recv session/load"), "{}", fake.log());
+}
+
+#[tokio::test]
+async fn load_session_error_fails_the_spawn() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    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");
+    assert!(matches!(err, AcpError::Handshake(_)), "{err}");
+    assert!(err.to_string().contains("fake load failure"), "{err}");
+}
+
+/// End to end against the installed `claude-code-acp`. Needs Claude auth,
+/// takes seconds, so it is opt-in: `cargo test -p maestro-acp -- --ignored`.
+#[tokio::test]
+#[ignore]
+async fn real_adapter_handshake() {
+    let cwd = TempDir::new().unwrap();
+    let session = maestro_acp::spawn(SpawnConfig::new(cwd.path(), HashMap::new()))
+        .await
+        .expect("real claude-code-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());
+}
+
+/// 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

@@ -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;
 
@@ -51,7 +51,7 @@ 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,
@@ -61,6 +61,22 @@ pub async fn run_spawn(client: &DaemonClient, args: SpawnArgs) -> Result<Session
     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.
@@ -179,8 +195,8 @@ 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 {
@@ -190,6 +206,10 @@ 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",
@@ -207,8 +227,8 @@ 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 +250,67 @@ 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(),
@@ -254,6 +330,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         }
     }
 
@@ -285,6 +362,22 @@ 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-daemon/Cargo.toml

@@ -28,6 +28,7 @@ dirs.workspace = true
 futures-util.workspace = true
 include_dir = { workspace = true, optional = true }
 libc.workspace = true
+maestro-acp.workspace = true
 mime_guess = { workspace = true, optional = true }
 maestro-config.workspace = true
 maestro-hooks = { workspace = true, default-features = false }
@@ -42,6 +43,7 @@ tracing-subscriber.workspace = true
 uuid.workspace = true
 
 [dev-dependencies]
+libc.workspace = true
 reqwest.workspace = true
 tokio-tungstenite.workspace = true
 urlencoding = "2"

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/cli.rs

@@ -106,7 +106,7 @@ async fn run(config_override: Option<PathBuf>) -> Result<(), Box<dyn Error>> {
     projects.start_background_refresh();
 
     let router = local_api::router(local_api::state_for(
-        manager,
+        manager.clone(),
         config.hostname.clone(),
         config.home_dir.clone(),
         config.spawn_presets.clone(),
@@ -118,9 +118,22 @@ async fn run(config_override: Option<PathBuf>) -> Result<(), Box<dyn Error>> {
     let bound = listener.local_addr()?;
     tracing::info!(addr = %bound, "API listening");
 
-    let shutdown = async {
-        let _ = tokio::signal::ctrl_c().await;
-        tracing::info!("ctrl-c received — shutting down");
+    // Ctrl-C at a terminal or SIGTERM from systemd: either one is a
+    // shutdown, and both must reach the adapter children below (#134). The
+    // unit's `KillMode=process` signals only the daemon, so nothing else
+    // would end them.
+    let shutdown_manager = manager.clone();
+    let shutdown = async move {
+        let mut sigterm = tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())
+            .expect("install SIGTERM handler");
+        tokio::select! {
+            _ = tokio::signal::ctrl_c() => tracing::info!("ctrl-c received — shutting down"),
+            _ = sigterm.recv() => tracing::info!("SIGTERM received — shutting down"),
+        }
+        // Axum waits for upgraded WebSockets to drain. Structured children
+        // must be settled before that wait, while the signal path still owns
+        // the shutdown order (#179).
+        shutdown_manager.shutdown().await;
     };
 
     axum::serve(listener, router)

crates/maestro-daemon/src/lib.rs

@@ -21,6 +21,7 @@ pub mod hooks;
 pub mod local_api;
 pub mod panes;
 pub mod proc;
+pub mod projection;
 pub mod projects;
 pub mod pty;
 pub mod release;

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 +22,14 @@ use maestro_config::SpawnPreset;
 use maestro_protocol::{
     routes, ApiError, CatalogEvent, CreateSessionRequest, DaemonInfo, GitRoot, NameBatch,
     RenameSessionRequest, ReportActivityRequest, SendInputRequest, Session, SetFocusRequest,
+    StructuredApprovalDecision, StructuredConfigRequest, StructuredEvent, StructuredPromptRequest,
     PROTOCOL_VERSION,
 };
 use serde::Deserialize;
 use uuid::Uuid;
 
-use crate::session::SessionManager;
+use crate::session::{QueueAcpPrompt, SessionError, SessionManager, SetAcpConfig};
+use crate::sidecar::EventCursor;
 
 #[derive(Debug, Clone)]
 pub struct LocalApiState {
@@ -64,7 +67,20 @@ pub fn router(state: LocalApiState) -> Router {
         .route(routes::NAMES, get(names))
         .route(routes::INFO, get(daemon_info))
         .route(routes::EVENTS, any(events_ws))
-        .route(routes::patterns::ATTACH, any(attach_ws));
+        .route(routes::patterns::ATTACH, any(attach_ws))
+        .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),
+        );
     #[cfg(feature = "haiku-autoname")]
     {
         router = router.route(routes::patterns::SESSION_PROMPT, post(session_prompt));
@@ -170,6 +186,8 @@ fn session_error_status(code: &str) -> StatusCode {
         // 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,
     }
 }
@@ -297,11 +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>,
@@ -368,6 +385,197 @@ fn error_response(status: StatusCode, code: &str, message: &str) -> Response {
     (status, Json(ApiError::new(code, message))).into_response()
 }
 
+#[derive(Debug, Deserialize)]
+struct ReplayQuery {
+    since: Option<u64>,
+    before: Option<u64>,
+    limit: Option<usize>,
+}
+
+const MAX_STRUCTURED_REPLAY_LIMIT: usize = 500;
+
+async fn structured_replay(
+    State(s): State<LocalApiState>,
+    Path(id): Path<Uuid>,
+    Query(query): Query<ReplayQuery>,
+) -> Response {
+    if query.since.is_some() && query.before.is_some() {
+        return error_response(
+            StatusCode::BAD_REQUEST,
+            "invalid_cursor",
+            "use either since or before, not both",
+        );
+    }
+    let cursor = match query.before {
+        Some(before) => EventCursor::Before(Some(before)),
+        None => EventCursor::Since(query.since.unwrap_or(0)),
+    };
+    match s
+        .manager
+        .read_acp_projection_replay(
+            id,
+            cursor,
+            query
+                .limit
+                .unwrap_or(100)
+                .clamp(1, MAX_STRUCTURED_REPLAY_LIMIT),
+        )
+        .await
+    {
+        Ok(Some(events)) => Json(events).into_response(),
+        // A terminal session, or a structured session whose adapter is no
+        // longer live, cannot provide a coherent replay continuation.
+        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)
+        }
+    }
+}
+
+#[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::InFlight) => error_response(
+            StatusCode::CONFLICT,
+            "turn_in_flight",
+            "the structured session already has an active turn",
+        ),
+        Ok(QueueAcpPrompt::Unavailable) => error_response(
+            StatusCode::CONFLICT,
+            "not_structured",
+            "session is not a live structured session",
+        ),
+        Ok(QueueAcpPrompt::Failed(message)) => {
+            error_response(StatusCode::BAD_GATEWAY, "acp_prompt_failed", &message)
+        }
+        Err(e) => {
+            let info = e.to_error_info();
+            error_response(session_error_status(&info.code), &info.code, &info.message)
+        }
+    }
+}
+
+async fn structured_cancel(State(s): State<LocalApiState>, Path(id): Path<Uuid>) -> Response {
+    match s.manager.cancel_acp_turn(id).await {
+        Ok(true) => StatusCode::NO_CONTENT.into_response(),
+        Ok(false) => 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_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)>,
+    Json(decision): Json<StructuredApprovalDecision>,
+) -> Response {
+    let decision = match decision {
+        StructuredApprovalDecision::AllowOnce => crate::session::ApprovalDecision::AllowOnce,
+        StructuredApprovalDecision::AllowForSession => {
+            crate::session::ApprovalDecision::AllowForSession
+        }
+        StructuredApprovalDecision::Deny => crate::session::ApprovalDecision::Deny,
+    };
+    match s.manager.resolve_acp_approval(id, &nonce, decision).await {
+        Ok(Some(())) => StatusCode::NO_CONTENT.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)
+        }
+    }
+}
+
 /// Convenience constructor — pulls the bits `LocalApiState` needs from
 /// `DaemonConfig` so callers don't have to assemble it by hand. The project
 /// scanner starts with its cache cold; wire
@@ -405,12 +613,23 @@ 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 {
@@ -418,6 +637,75 @@ async fn attach_ws(
     }))
 }
 
+#[allow(clippy::result_large_err)]
+async fn structured_ws(
+    Path(id): Path<Uuid>,
+    State(s): State<LocalApiState>,
+    ws: axum::extract::WebSocketUpgrade,
+) -> Result<Response, Response> {
+    let Some((snapshot, state, rx)) = s
+        .manager
+        .subscribe_acp_projection(id, EventCursor::Since(0))
+        .await
+        .map_err(|e| {
+            let info = e.to_error_info();
+            error_response(session_error_status(&info.code), &info.code, &info.message)
+        })?
+    else {
+        return Err(error_response(
+            StatusCode::CONFLICT,
+            "not_structured",
+            "session is not a live structured session",
+        ));
+    };
+    Ok(ws.on_upgrade(move |socket| async move {
+        let _ = pump_structured(socket, snapshot, state, rx).await;
+    }))
+}
+
+async fn pump_structured(
+    socket: axum::extract::ws::WebSocket,
+    snapshot: maestro_protocol::TranscriptSnapshot,
+    state: maestro_protocol::ReducedState,
+    mut rx: tokio::sync::broadcast::Receiver<crate::projection::ProjectionUpdate>,
+) -> Result<(), axum::Error> {
+    use axum::extract::ws::Message;
+    use futures_util::{SinkExt, StreamExt};
+
+    let (mut sink, mut stream) = socket.split();
+    for event in [
+        StructuredEvent::TranscriptSnapshot { snapshot },
+        StructuredEvent::ReducedState { state },
+    ] {
+        if sink
+            .send(Message::Text(
+                serde_json::to_string(&event).expect("structured event encode"),
+            ))
+            .await
+            .is_err()
+        {
+            return Ok(());
+        }
+    }
+    loop {
+        tokio::select! {
+            update = rx.recv() => match update {
+                Ok(update) => {
+                    let event = StructuredEvent::ProjectionUpdate { transcript: update.transcript, state: update.state };
+                    if sink.send(Message::Text(serde_json::to_string(&event).expect("structured event encode"))).await.is_err() { break; }
+                }
+                Err(tokio::sync::broadcast::error::RecvError::Lagged(_)) => break,
+                Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
+            },
+            frame = stream.next() => match frame {
+                None | Some(Err(_)) | Some(Ok(Message::Close(_))) => break,
+                Some(Ok(_)) => {},
+            },
+        }
+    }
+    Ok(())
+}
+
 // ---------------------------------------------------------------------------
 // WS /api/events — live catalog deltas for browser/TUI subscribers (NAP-248)
 // ---------------------------------------------------------------------------

crates/maestro-daemon/src/sidecar.rs

@@ -5,10 +5,23 @@
 //! original `cwd`, command, env, metadata, etc. Files are deleted on
 //! `KillSession`. Sessions whose sidecar is missing at recovery time are still
 //! advertised but with empty metadata (handled by the caller, not here).
+//!
+//! A structured session (#135) also owns `<id>.events.jsonl` next to its
+//! sidecar: every `session/update` notification and daemon approval row is one
+//! JSON object, appended before it is broadcast. The log is the source of
+//! truth for the transcript; `seq` is the line's 1-based position, so a
+//! client that holds seq `n` asks for [`EventCursor::Since`]`(n)`. A line
+//! that does not parse — including the partial line a hard kill leaves at
+//! the end — keeps its seq and is skipped on read. `delete` removes the log
+//! with the sidecar; `load_all` never reads one as a sidecar.
 
+use std::collections::VecDeque;
+use std::fs::{File, OpenOptions};
+use std::io::{BufRead, BufReader, Read, Seek, SeekFrom, Write};
 use std::path::{Path, PathBuf};
 
-use maestro_protocol::Session;
+use maestro_acp::schema::SessionNotification;
+use maestro_protocol::{Session, TranscriptRow};
 use uuid::Uuid;
 
 #[derive(Debug, thiserror::Error)]
@@ -38,6 +51,120 @@ impl SidecarStore {
         self.dir.join(format!("{id}.json"))
     }
 
+    /// Where the per-session event log lives (#135).
+    pub fn events_path_for(&self, id: Uuid) -> PathBuf {
+        self.dir.join(format!("{id}.events.jsonl"))
+    }
+
+    /// Durable evidence that graceful daemon shutdown ended this structured
+    /// session and the next daemon may resume it.
+    pub fn recovery_path_for(&self, id: Uuid) -> PathBuf {
+        self.dir.join(format!("{id}.recover"))
+    }
+
+    /// Mark `id` as eligible for one structured-session recovery attempt.
+    pub fn mark_for_recovery(&self, id: Uuid) -> Result<(), SidecarError> {
+        std::fs::create_dir_all(&self.dir)?;
+        std::fs::write(self.recovery_path_for(id), [])?;
+        Ok(())
+    }
+
+    /// Consume the graceful-shutdown recovery marker for `id`.
+    pub fn take_recovery_marker(&self, id: Uuid) -> Result<bool, SidecarError> {
+        match std::fs::remove_file(self.recovery_path_for(id)) {
+            Ok(()) => Ok(true),
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => Ok(false),
+            Err(error) => Err(error.into()),
+        }
+    }
+
+    /// Open the event log for `id` for appending, creating it (and the
+    /// directory) when missing. One handle per live session: the caller
+    /// keeps it for the session's lifetime rather than reopening per
+    /// notification.
+    ///
+    /// A log whose last line has no newline — what a hard kill mid-write
+    /// leaves behind — is terminated first, so the next append starts a
+    /// fresh line instead of gluing onto the fragment. The fragment keeps
+    /// the seq of its line and reads as malformed.
+    pub fn open_events(&self, id: Uuid) -> Result<EventLog, SidecarError> {
+        std::fs::create_dir_all(&self.dir)?;
+        let mut file = OpenOptions::new()
+            .create(true)
+            .read(true)
+            .append(true)
+            .open(self.events_path_for(id))?;
+        let mut lines = 0u64;
+        let mut last = None;
+        let mut reader = BufReader::new(&mut file);
+        let mut buf = [0u8; 64 * 1024];
+        loop {
+            let n = reader.read(&mut buf)?;
+            if n == 0 {
+                break;
+            }
+            lines += buf[..n].iter().filter(|&&b| b == b'\n').count() as u64;
+            last = Some(buf[n - 1]);
+        }
+        if last.is_some_and(|b| b != b'\n') {
+            file.write_all(b"\n")?;
+            lines += 1;
+        }
+        file.seek(SeekFrom::End(0))?;
+        Ok(EventLog {
+            file: Box::new(file),
+            last_seq: lines,
+        })
+    }
+
+    /// Read events from the log for `id`, at most `limit`, in ascending seq
+    /// order. A missing log is an empty log. Lines that fail to parse are
+    /// skipped but still consume a seq, so cursors stay stable.
+    pub fn read_events(
+        &self,
+        id: Uuid,
+        cursor: EventCursor,
+        limit: usize,
+    ) -> Result<Vec<LoggedEvent>, SidecarError> {
+        let file = match File::open(self.events_path_for(id)) {
+            Ok(f) => f,
+            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(Vec::new()),
+            Err(e) => return Err(e.into()),
+        };
+        if limit == 0 {
+            return Ok(Vec::new());
+        }
+        let mut out: VecDeque<LoggedEvent> = VecDeque::new();
+        let mut seq = 0u64;
+        for line in BufReader::new(file).split(b'\n') {
+            let line = line?;
+            seq += 1;
+            let keep = match cursor {
+                EventCursor::Since(since) => seq > since,
+                EventCursor::Before(Some(before)) => seq < before,
+                EventCursor::Before(None) => true,
+            };
+            if !keep {
+                if matches!(cursor, EventCursor::Before(Some(_))) {
+                    break;
+                }
+                continue;
+            }
+            let Ok(event) = PersistedEvent::decode(&line) else {
+                continue;
+            };
+            out.push_back(LoggedEvent { seq, event });
+            match cursor {
+                EventCursor::Since(_) if out.len() >= limit => break,
+                EventCursor::Before(_) if out.len() > limit => {
+                    out.pop_front();
+                }
+                _ => {}
+            }
+        }
+        Ok(out.into())
+    }
+
     /// Atomically write `session` to `<dir>/<id>.json`. Creates the directory
     /// if it does not exist.
     pub fn write(&self, session: &Session) -> Result<(), SidecarError> {
@@ -59,13 +186,13 @@ impl SidecarStore {
         }
     }
 
-    /// Delete the sidecar for `id`. No-op if it does not exist.
+    /// Delete the sidecar, event log, and recovery marker for `id`. No-op for
+    /// whichever does not exist.
     pub fn delete(&self, id: Uuid) -> Result<(), SidecarError> {
-        match std::fs::remove_file(self.path_for(id)) {
-            Ok(()) => Ok(()),
-            Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
-            Err(e) => Err(e.into()),
-        }
+        remove_if_present(&self.events_path_for(id))?;
+        remove_if_present(&self.dir.join(format!("{id}.approvals.jsonl")))?;
+        remove_if_present(&self.recovery_path_for(id))?;
+        remove_if_present(&self.path_for(id))
     }
 
     /// Read every sidecar JSON in the directory. Files that fail to parse are
@@ -81,6 +208,8 @@ impl SidecarStore {
         for entry in entries {
             let entry = entry?;
             let path = entry.path();
+            // `.events.jsonl` logs (#135) sit in the same directory and are
+            // never sidecars.
             if path.extension().and_then(|s| s.to_str()) != Some("json") {
                 continue;
             }
@@ -95,3 +224,425 @@ impl SidecarStore {
         Ok(out)
     }
 }
+
+fn remove_if_present(path: &Path) -> Result<(), SidecarError> {
+    match std::fs::remove_file(path) {
+        Ok(()) => Ok(()),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        Err(e) => Err(e.into()),
+    }
+}
+
+/// Which slice of a session's event log to read.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EventCursor {
+    /// Forward: events with `seq` strictly greater than the cursor, the
+    /// first `limit` of them. `Since(0)` is the whole log from the start.
+    /// What a client catching up after a reconnect asks for.
+    Since(u64),
+    /// Backward: events with `seq` strictly less than the cursor, the last
+    /// `limit` of them, still returned in ascending order. `None` means the
+    /// tail of the log, for a first paint. The next page passes the smallest
+    /// seq it received.
+    Before(Option<u64>),
+}
+
+/// One line of a session's event log.
+#[derive(Debug, Clone, PartialEq)]
+pub struct LoggedEvent {
+    /// 1-based line position in the log; the cursor for [`EventCursor`].
+    pub seq: u64,
+    pub event: PersistedEvent,
+}
+
+/// A single entry in the structured event history.
+///
+/// ACP notifications retain their original JSON representation, so existing
+/// event logs remain readable. Daemon-generated rows use an envelope so they
+/// can share the same cursor sequence without pretending to be ACP traffic.
+#[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>),
+}
+
+impl PersistedEvent {
+    fn decode(line: &[u8]) -> Result<Self, serde_json::Error> {
+        serde_json::from_slice::<SessionNotification>(line)
+            .map(|notification| Self::Notification(Box::new(notification)))
+            .or_else(|_| serde_json::from_slice(line))
+    }
+}
+
+impl From<SessionNotification> for PersistedEvent {
+    fn from(notification: SessionNotification) -> Self {
+        Self::Notification(Box::new(notification))
+    }
+}
+
+impl From<&SessionNotification> for PersistedEvent {
+    fn from(notification: &SessionNotification) -> Self {
+        Self::Notification(Box::new(notification.clone()))
+    }
+}
+
+impl From<&PersistedEvent> for PersistedEvent {
+    fn from(event: &PersistedEvent) -> Self {
+        event.clone()
+    }
+}
+
+/// 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.
+pub struct EventLog {
+    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
+    }
+
+    /// Append one notification as a line and return its seq. The line is
+    /// 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.
+    ///
+    /// 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)
+                .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');
+
+        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/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

@@ -4,12 +4,17 @@ mod common;
 
 use std::collections::HashMap;
 use std::net::{Ipv4Addr, SocketAddr};
+use std::path::Path;
 use std::time::Duration;
 
 use common::DaemonFixture;
 use futures_util::{SinkExt, StreamExt};
 use maestro_daemon::local_api;
-use maestro_protocol::{ApiError, CreateSessionRequest, Session, WorktreeSpec};
+use maestro_protocol::{
+    ActivityState, ApiError, CreateSessionRequest, Session, SessionStatus, SessionView,
+    WorktreeSpec,
+};
+use tempfile::TempDir;
 use tokio::net::TcpListener;
 use tokio::sync::oneshot;
 use tokio_tungstenite::tungstenite::Message as WsMessage;
@@ -86,6 +91,643 @@ fn ws_url(addr: SocketAddr, path: &str) -> String {
     format!("ws://{addr}{path}")
 }
 
+struct FakeAcp {
+    dir: TempDir,
+}
+
+impl FakeAcp {
+    fn new() -> Self {
+        use std::os::unix::fs::PermissionsExt;
+
+        let dir = TempDir::new().unwrap();
+        let bin = dir.path().join("bin");
+        std::fs::create_dir_all(&bin).unwrap();
+        let adapter = bin.join("claude-code-acp");
+        std::fs::copy(
+            Path::new(env!("CARGO_MANIFEST_DIR")).join("../maestro-acp/tests/fake_acp_agent.py"),
+            &adapter,
+        )
+        .unwrap();
+        std::fs::set_permissions(&adapter, std::fs::Permissions::from_mode(0o755)).unwrap();
+        Self { dir }
+    }
+
+    fn env(&self) -> HashMap<String, String> {
+        HashMap::from([
+            (
+                "PATH".into(),
+                format!(
+                    "{}:{}",
+                    self.dir.path().join("bin").display(),
+                    std::env::var("PATH").unwrap()
+                ),
+            ),
+            (
+                "FAKE_ACP_LOG".into(),
+                self.dir.path().join("agent.log").display().to_string(),
+            ),
+        ])
+    }
+
+    fn pid(&self) -> u32 {
+        std::fs::read_to_string(self.dir.path().join("agent.log"))
+            .unwrap_or_default()
+            .lines()
+            .filter_map(|line| {
+                line.strip_prefix("start pid=")?
+                    .split(' ')
+                    .next()?
+                    .parse()
+                    .ok()
+            })
+            .next_back()
+            .expect("fake ACP started")
+    }
+
+    fn log(&self) -> String {
+        std::fs::read_to_string(self.dir.path().join("agent.log")).unwrap_or_default()
+    }
+}
+
+async fn structured_session(h: &Harness, fake: &FakeAcp) -> Uuid {
+    structured_session_with_env(h, fake.env()).await
+}
+
+async fn structured_session_with_env(h: &Harness, env: HashMap<String, String>) -> Uuid {
+    h.manager
+        .create(CreateSessionRequest {
+            view: SessionView::Structured,
+            cwd: "/tmp".into(),
+            command: "claude".into(),
+            env,
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .unwrap()
+        .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]
+async fn structured_ws_sends_snapshot_then_live_projection() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+    let (mut ws, _) = connect_async(ws_url(h.addr, &format!("/api/structured/{id}")))
+        .await
+        .unwrap();
+
+    let first = ws.next().await.unwrap().unwrap().into_text().unwrap();
+    let second = ws.next().await.unwrap().unwrap().into_text().unwrap();
+    assert_eq!(
+        serde_json::from_str::<serde_json::Value>(&first).unwrap()["type"],
+        "transcript_snapshot"
+    );
+    assert_eq!(
+        serde_json::from_str::<serde_json::Value>(&second).unwrap()["type"],
+        "reduced_state"
+    );
+
+    let response = reqwest::Client::new()
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/prompt"),
+        ))
+        .json(&serde_json::json!({"prompt": "hello"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), reqwest::StatusCode::NO_CONTENT);
+    let live = tokio::time::timeout(Duration::from_secs(1), ws.next())
+        .await
+        .expect("projection update arrives on the subscribed stream")
+        .unwrap()
+        .unwrap()
+        .into_text()
+        .unwrap();
+    assert_eq!(
+        serde_json::from_str::<serde_json::Value>(&live).unwrap()["type"],
+        "projection_update"
+    );
+}
+
+#[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;
+    let fake = FakeAcp::new();
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_DELAY_PROMPT_MS".into(), "200".into());
+    let id = structured_session_with_env(&h, env).await;
+    let client = reqwest::Client::new();
+    let first = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/prompt"),
+        ))
+        .json(&serde_json::json!({"prompt": "first"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(first.status(), reqwest::StatusCode::NO_CONTENT);
+    let second = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/prompt"),
+        ))
+        .json(&serde_json::json!({"prompt": "second"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(second.status(), reqwest::StatusCode::CONFLICT);
+    let error: ApiError = second.json().await.unwrap();
+    assert_eq!(error.error.code, "turn_in_flight");
+
+    let cancel = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/cancel"),
+        ))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(cancel.status(), reqwest::StatusCode::NO_CONTENT);
+    let next = client
+        .post(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/prompt"),
+        ))
+        .json(&serde_json::json!({"prompt": "next"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(next.status(), reqwest::StatusCode::NO_CONTENT);
+    tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            if fake.log().matches("recv session/prompt").count() == 2 {
+                break;
+            }
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+    })
+    .await
+    .expect("both prompt commands reach ACP");
+    let log = fake.log();
+    let first_prompt = log.find("recv session/prompt").unwrap();
+    let cancel = log.find("recv session/cancel").unwrap();
+    let second_prompt = log.rfind("recv session/prompt").unwrap();
+    assert!(first_prompt < cancel && cancel < second_prompt, "{log}");
+}
+
+#[tokio::test]
+async fn structured_approval_is_secret_single_use_and_race_safe() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_REQUEST_PERMISSION".into(), "1".into());
+    let id = structured_session_with_env(&h, env).await;
+    let client = reqwest::Client::new();
+    let (mut ws, _) = connect_async(ws_url(h.addr, &format!("/api/structured/{id}")))
+        .await
+        .unwrap();
+    ws.next().await.unwrap().unwrap();
+    ws.next().await.unwrap().unwrap();
+    assert_eq!(
+        client
+            .post(url(
+                h.addr,
+                &format!("/api/sessions/{id}/structured/prompt")
+            ))
+            .json(&serde_json::json!({"prompt":"needs permission"}))
+            .send()
+            .await
+            .unwrap()
+            .status(),
+        reqwest::StatusCode::NO_CONTENT
+    );
+
+    let nonce = tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            let event: serde_json::Value =
+                serde_json::from_str(&ws.next().await.unwrap().unwrap().into_text().unwrap())
+                    .unwrap();
+            if let Some(nonce) = event["state"]["pending_approval"]["nonce"].as_str() {
+                assert_eq!(event["transcript"]["row"]["kind"], "approval");
+                assert!(event["transcript"]["row"]["data"].get("nonce").is_none());
+                break nonce.to_owned();
+            }
+        }
+    })
+    .await
+    .unwrap();
+    wait_for_session_activity(&h, id, ActivityState::AwaitingInput).await;
+    assert!(
+        !fake.log().contains(&nonce),
+        "daemon nonce leaked to ACP agent"
+    );
+
+    let path = format!("/api/sessions/{id}/structured/approvals/{nonce}");
+    let (a, b) = tokio::join!(
+        client
+            .post(url(h.addr, &path))
+            .json(&serde_json::json!("allow_once"))
+            .send(),
+        client
+            .post(url(h.addr, &path))
+            .json(&serde_json::json!("deny"))
+            .send(),
+    );
+    assert_eq!(a.unwrap().status(), reqwest::StatusCode::NO_CONTENT);
+    assert_eq!(b.unwrap().status(), reqwest::StatusCode::NO_CONTENT);
+    assert_eq!(
+        client
+            .post(url(h.addr, &path))
+            .json(&serde_json::json!("deny"))
+            .send()
+            .await
+            .unwrap()
+            .status(),
+        reqwest::StatusCode::NO_CONTENT
+    );
+    tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            if fake.log().contains("permission response") {
+                break;
+            }
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+    })
+    .await
+    .unwrap();
+    let log = fake.log();
+    assert!(
+        log.contains("\"optionId\": \"once\"") || log.contains("\"optionId\": \"deny\""),
+        "{log}"
+    );
+    tokio::time::timeout(Duration::from_secs(1), async {
+        loop {
+            let event: serde_json::Value =
+                serde_json::from_str(&ws.next().await.unwrap().unwrap().into_text().unwrap())
+                    .unwrap();
+            if event["state"]["pending_approval"].is_null() {
+                break;
+            }
+        }
+    })
+    .await
+    .expect("resolved approval clears the reduced state");
+    wait_for_session_activity(&h, id, ActivityState::Idle).await;
+    assert_eq!(
+        client
+            .post(url(
+                h.addr,
+                &format!(
+                    "/api/sessions/{}/structured/approvals/{nonce}",
+                    Uuid::new_v4()
+                )
+            ))
+            .json(&serde_json::json!("deny"))
+            .send()
+            .await
+            .unwrap()
+            .status(),
+        reqwest::StatusCode::NOT_FOUND
+    );
+}
+
+#[tokio::test]
+async fn structured_prompt_failure_clears_the_turn() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let mut env = fake.env();
+    env.insert("FAKE_ACP_PROMPT_FAIL_ONCE".into(), "1".into());
+    let id = structured_session_with_env(&h, env).await;
+    let client = reqwest::Client::new();
+    let path = format!("/api/sessions/{id}/structured/prompt");
+    let (mut ws, _) = connect_async(ws_url(h.addr, &format!("/api/structured/{id}")))
+        .await
+        .unwrap();
+    ws.next().await.unwrap().unwrap();
+    ws.next().await.unwrap().unwrap();
+    let first = client
+        .post(url(h.addr, &path))
+        .json(&serde_json::json!({"prompt":"fails"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(first.status(), reqwest::StatusCode::NO_CONTENT);
+    let mut saw_active_turn = false;
+    tokio::time::timeout(Duration::from_secs(1), async {
+        while let Some(Ok(message)) = ws.next().await {
+            let event: serde_json::Value =
+                serde_json::from_str(&message.into_text().unwrap()).unwrap();
+            let turn = &event["state"]["turn"];
+            if turn["responding"] == true {
+                saw_active_turn = true;
+            }
+            if saw_active_turn && turn["responding"] == false && turn["thinking"] == false {
+                return;
+            }
+        }
+        panic!("structured websocket closed before the failed turn cleared");
+    })
+    .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"}))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(second.status(), reqwest::StatusCode::NO_CONTENT);
+    assert!(second.bytes().await.unwrap().is_empty());
+}
+
+#[tokio::test]
+async fn structured_prompt_rejects_unknown_and_unavailable_sessions() {
+    let h = spawn("naps-laptop").await;
+    let client = reqwest::Client::new();
+    let prompt = |id| {
+        client
+            .post(url(
+                h.addr,
+                &format!("/api/sessions/{id}/structured/prompt"),
+            ))
+            .json(&serde_json::json!({"prompt": "hello"}))
+    };
+
+    let unknown = prompt(Uuid::new_v4()).send().await.unwrap();
+    assert_eq!(unknown.status(), reqwest::StatusCode::NOT_FOUND);
+    let error: ApiError = unknown.json().await.unwrap();
+    assert_eq!(error.error.code, "not_found");
+
+    let terminal = h
+        .manager
+        .create(CreateSessionRequest {
+            view: SessionView::Terminal,
+            cwd: "/tmp".into(),
+            command: "sh".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .unwrap();
+    let non_structured = prompt(terminal.id).send().await.unwrap();
+    assert_eq!(non_structured.status(), reqwest::StatusCode::CONFLICT);
+    let error: ApiError = non_structured.json().await.unwrap();
+    assert_eq!(error.error.code, "not_structured");
+
+    let fake = FakeAcp::new();
+    let dead = structured_session(&h, &fake).await;
+    h.manager.shutdown().await;
+    assert_eq!(h.manager.status(dead).await, Some(SessionStatus::Dead));
+    let unavailable = prompt(dead).send().await.unwrap();
+    assert_eq!(unavailable.status(), reqwest::StatusCode::CONFLICT);
+    let error: ApiError = unavailable.json().await.unwrap();
+    assert_eq!(error.error.code, "not_structured");
+}
+
+#[tokio::test]
+async fn structured_replay_honors_cursors_and_limit() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+    let client = reqwest::Client::new();
+
+    let events: Vec<serde_json::Value> = tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            let events: Vec<serde_json::Value> = client
+                .get(url(
+                    h.addr,
+                    &format!("/api/sessions/{id}/structured/replay?since=0&limit=1"),
+                ))
+                .send()
+                .await
+                .unwrap()
+                .json()
+                .await
+                .unwrap();
+            if !events.is_empty() {
+                return events;
+            }
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+    })
+    .await
+    .unwrap();
+    assert_eq!(events.len(), 1);
+    assert_eq!(events[0]["cursor"], 1);
+    assert!(events[0].get("notification").is_none());
+
+    let invalid = client
+        .get(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/replay?since=0&before=2"),
+        ))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(invalid.status(), reqwest::StatusCode::BAD_REQUEST);
+}
+
+#[tokio::test]
+async fn structured_replay_pages_projected_events_in_cursor_order() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+    let client = reqwest::Client::new();
+    unsafe { libc::kill(fake.pid() as libc::pid_t, libc::SIGUSR1) };
+    let events: Vec<serde_json::Value> = tokio::time::timeout(Duration::from_secs(2), async {
+        loop {
+            let events: Vec<serde_json::Value> = client
+                .get(url(
+                    h.addr,
+                    &format!("/api/sessions/{id}/structured/replay?before=99&limit=2"),
+                ))
+                .send()
+                .await
+                .unwrap()
+                .json()
+                .await
+                .unwrap();
+            if events.len() == 2 {
+                return events;
+            }
+            tokio::time::sleep(Duration::from_millis(10)).await;
+        }
+    })
+    .await
+    .unwrap();
+    assert_eq!(
+        events
+            .iter()
+            .map(|event| event["cursor"].as_u64().unwrap())
+            .collect::<Vec<_>>(),
+        vec![1, 2]
+    );
+    let boundary: Vec<serde_json::Value> = client
+        .get(url(
+            h.addr,
+            &format!("/api/sessions/{id}/structured/replay?before=2&limit=10"),
+        ))
+        .send()
+        .await
+        .unwrap()
+        .json()
+        .await
+        .unwrap();
+    assert_eq!(boundary.len(), 1);
+    assert_eq!(boundary[0]["cursor"], 1);
+}
+
+#[tokio::test]
+async fn structured_replay_rejects_unknown_terminal_and_dead_sessions() {
+    let h = spawn("naps-laptop").await;
+    let client = reqwest::Client::new();
+    let unknown = client
+        .get(url(
+            h.addr,
+            &format!("/api/sessions/{}/structured/replay", Uuid::new_v4()),
+        ))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(unknown.status(), reqwest::StatusCode::NOT_FOUND);
+    let terminal = h
+        .manager
+        .create(CreateSessionRequest {
+            view: SessionView::Terminal,
+            cwd: "/tmp".into(),
+            command: "sh".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .unwrap();
+    let response = client
+        .get(url(
+            h.addr,
+            &format!("/api/sessions/{}/structured/replay", terminal.id),
+        ))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), reqwest::StatusCode::CONFLICT);
+
+    let fake = FakeAcp::new();
+    let dead = structured_session(&h, &fake).await;
+    h.manager.shutdown().await;
+    assert_eq!(h.manager.status(dead).await, Some(SessionStatus::Dead));
+    let response = client
+        .get(url(
+            h.addr,
+            &format!("/api/sessions/{dead}/structured/replay"),
+        ))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(response.status(), reqwest::StatusCode::CONFLICT);
+    let error: ApiError = response.json().await.unwrap();
+    assert_eq!(error.error.code, "not_structured");
+}
+
+#[tokio::test]
+async fn structured_ws_rejects_a_dead_session() {
+    let h = spawn("naps-laptop").await;
+    let fake = FakeAcp::new();
+    let id = structured_session(&h, &fake).await;
+    h.manager.shutdown().await;
+    assert_eq!(h.manager.status(id).await, Some(SessionStatus::Dead));
+
+    let err = connect_async(ws_url(h.addr, &format!("/api/structured/{id}")))
+        .await
+        .expect_err("dead structured session must not upgrade");
+    let message = err.to_string();
+    assert!(
+        message.contains("409") || message.to_lowercase().contains("conflict"),
+        "{message}"
+    );
+}
+
 #[tokio::test]
 async fn info_returns_daemon_identity() {
     let h = spawn("naps-laptop").await;
@@ -723,6 +1365,39 @@ 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;
@@ -789,6 +1464,73 @@ 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::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]

crates/maestro-daemon/tests/sidecar.rs

@@ -6,8 +6,8 @@ use std::collections::HashMap;
 use std::path::PathBuf;
 
 use chrono::{DateTime, Utc};
-use maestro_daemon::sidecar::SidecarStore;
-use maestro_protocol::{Session, SessionStatus, SessionView};
+use maestro_daemon::sidecar::{PersistedEvent, SidecarStore};
+use maestro_protocol::{Session, SessionStatus, SessionView, TranscriptRow, TranscriptRowKind};
 use serde_json::Value;
 use tempfile::TempDir;
 use uuid::Uuid;
@@ -32,6 +32,7 @@ fn sample(id: Uuid) -> Session {
         current_cwd: Some(PathBuf::from("/tmp/work/crates")),
         blocked_work: None,
         last_focused_at: None,
+        acp_session_id: None,
         view: SessionView::Terminal,
     }
 }
@@ -67,15 +68,30 @@ fn delete_removes_file_and_is_idempotent() {
     let s = sample(id);
 
     store.write(&s).unwrap();
+    store.mark_for_recovery(id).unwrap();
     assert!(store.path_for(id).exists());
+    assert!(store.recovery_path_for(id).exists());
 
     store.delete(id).unwrap();
     assert!(!store.path_for(id).exists());
+    assert!(!store.recovery_path_for(id).exists());
 
     // second delete is a no-op
     store.delete(id).unwrap();
 }
 
+#[test]
+fn recovery_marker_is_consumed_once() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+
+    assert!(!store.take_recovery_marker(id).unwrap());
+    store.mark_for_recovery(id).unwrap();
+    assert!(store.take_recovery_marker(id).unwrap());
+    assert!(!store.take_recovery_marker(id).unwrap());
+}
+
 #[test]
 fn load_all_recovers_every_sidecar_and_skips_garbage() {
     let dir = TempDir::new().unwrap();
@@ -145,3 +161,237 @@ fn write_creates_parent_directory() {
     assert!(nested.exists());
     assert!(store.path_for(s.id).exists());
 }
+
+// ---- per-session event log (#135) ----
+
+use maestro_acp::schema::{ContentBlock, SessionNotification, SessionUpdate, TextContent};
+use maestro_daemon::sidecar::EventCursor;
+
+fn note(text: &str) -> SessionNotification {
+    SessionNotification::new(
+        "acp-1",
+        SessionUpdate::AgentMessageChunk(maestro_acp::schema::ContentChunk::new(
+            ContentBlock::Text(TextContent::new(text)),
+        )),
+    )
+}
+
+fn text_of(n: &SessionNotification) -> &str {
+    match &n.update {
+        SessionUpdate::AgentMessageChunk(chunk) => match &chunk.content {
+            ContentBlock::Text(t) => &t.text,
+            other => panic!("unexpected content {other:?}"),
+        },
+        other => panic!("unexpected update {other:?}"),
+    }
+}
+
+fn event_text(event: &maestro_daemon::sidecar::LoggedEvent) -> &str {
+    let maestro_daemon::sidecar::PersistedEvent::Notification(notification) = &event.event else {
+        panic!("expected ACP notification")
+    };
+    text_of(notification)
+}
+
+#[test]
+fn append_assigns_line_position_as_seq_and_reads_back() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+
+    let mut log = store.open_events(id).expect("open");
+    assert_eq!(log.last_seq(), 0);
+    assert_eq!(log.append(note("a")).unwrap(), 1);
+    assert_eq!(log.append(note("b")).unwrap(), 2);
+    assert_eq!(log.append(note("c")).unwrap(), 3);
+    assert_eq!(log.last_seq(), 3);
+
+    let path = store.events_path_for(id);
+    assert!(path.ends_with(format!("{id}.events.jsonl")), "{path:?}");
+    let raw = std::fs::read_to_string(&path).unwrap();
+    assert_eq!(raw.lines().count(), 3, "one object per line:\n{raw}");
+    for line in raw.lines() {
+        let v: Value = serde_json::from_str(line).expect("each line is one JSON object");
+        assert_eq!(v["sessionId"], "acp-1");
+    }
+
+    let all = store.read_events(id, EventCursor::Since(0), 100).unwrap();
+    assert_eq!(all.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![1, 2, 3]);
+    assert_eq!(
+        all.iter().map(event_text).collect::<Vec<_>>(),
+        vec!["a", "b", "c"]
+    );
+}
+
+#[test]
+fn since_reads_forward_and_before_reads_backward_with_limit() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    let mut log = store.open_events(id).unwrap();
+    for i in 1..=6 {
+        log.append(note(&format!("n{i}"))).unwrap();
+    }
+
+    // `since` is exclusive: what a client that already holds seq 2 needs.
+    let fwd = store.read_events(id, EventCursor::Since(2), 3).unwrap();
+    assert_eq!(fwd.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![3, 4, 5]);
+    // Past the end: nothing, not an error.
+    assert!(store
+        .read_events(id, EventCursor::Since(6), 3)
+        .unwrap()
+        .is_empty());
+
+    // `before` is exclusive and pages backward: the `limit` events closest
+    // to the cursor, still in ascending seq order.
+    let back = store
+        .read_events(id, EventCursor::Before(Some(5)), 2)
+        .unwrap();
+    assert_eq!(back.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![3, 4]);
+    // No cursor: the tail of the log, for a first paint.
+    let tail = store.read_events(id, EventCursor::Before(None), 2).unwrap();
+    assert_eq!(tail.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![5, 6]);
+    // Paging past the start runs out cleanly.
+    let start = store
+        .read_events(id, EventCursor::Before(Some(2)), 10)
+        .unwrap();
+    assert_eq!(start.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![1]);
+    assert!(store
+        .read_events(id, EventCursor::Before(Some(1)), 10)
+        .unwrap()
+        .is_empty());
+}
+
+#[test]
+fn missing_log_reads_as_empty() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    assert!(store
+        .read_events(id, EventCursor::Since(0), 10)
+        .unwrap()
+        .is_empty());
+    assert!(store
+        .read_events(id, EventCursor::Before(None), 10)
+        .unwrap()
+        .is_empty());
+}
+
+#[test]
+fn malformed_lines_are_skipped_but_keep_their_seq() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    let mut log = store.open_events(id).unwrap();
+    log.append(note("first")).unwrap();
+    drop(log);
+
+    // Garbage in the middle and a line that is JSON but not a notification.
+    let path = store.events_path_for(id);
+    let mut raw = std::fs::read_to_string(&path).unwrap();
+    raw.push_str("{not json\n");
+    raw.push_str("{\"unrelated\": true}\n");
+    std::fs::write(&path, raw).unwrap();
+    let mut log = store.open_events(id).unwrap();
+    assert_eq!(log.last_seq(), 3);
+    assert_eq!(log.append(note("fourth")).unwrap(), 4);
+
+    let all = store.read_events(id, EventCursor::Since(0), 10).unwrap();
+    assert_eq!(all.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![1, 4]);
+    assert_eq!(event_text(&all[1]), "fourth");
+}
+
+#[test]
+fn truncated_last_line_still_opens_and_the_next_append_starts_a_fresh_line() {
+    // A hard kill mid-write leaves a partial line with no newline.
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    let mut log = store.open_events(id).unwrap();
+    log.append(note("whole")).unwrap();
+    drop(log);
+
+    let path = store.events_path_for(id);
+    let mut raw = std::fs::read(&path).unwrap();
+    raw.extend_from_slice(br#"{"sessionId":"acp-1","update":{"sessionUpd"#);
+    std::fs::write(&path, &raw).unwrap();
+
+    // Reads: the partial line is skipped, nothing else is lost.
+    let all = store.read_events(id, EventCursor::Since(0), 10).unwrap();
+    assert_eq!(all.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![1]);
+
+    // Reopening terminates the partial line so the next append does not
+    // glue onto it; the partial keeps a seq of its own.
+    let mut log = store.open_events(id).unwrap();
+    assert_eq!(log.last_seq(), 2);
+    assert_eq!(log.append(note("after")).unwrap(), 3);
+    let all = store.read_events(id, EventCursor::Since(0), 10).unwrap();
+    assert_eq!(all.iter().map(|e| e.seq).collect::<Vec<_>>(), vec![1, 3]);
+    assert_eq!(event_text(&all[1]), "after");
+    let raw = std::fs::read_to_string(&path).unwrap();
+    assert_eq!(raw.lines().count(), 3, "{raw}");
+}
+
+#[test]
+fn delete_removes_the_event_log_and_load_all_ignores_it() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    store.write(&sample(id)).unwrap();
+    let mut log = store.open_events(id).unwrap();
+    log.append(note("x")).unwrap();
+    drop(log);
+    let legacy_approvals = dir.path().join(format!("{id}.approvals.jsonl"));
+    std::fs::write(&legacy_approvals, b"obsolete").unwrap();
+    assert!(store.events_path_for(id).exists());
+
+    let loaded = store.load_all().unwrap();
+    assert_eq!(loaded.len(), 1, "the .jsonl must not be read as a sidecar");
+
+    store.delete(id).unwrap();
+    assert!(!store.path_for(id).exists());
+    assert!(!store.events_path_for(id).exists());
+    assert!(!legacy_approvals.exists());
+    // Idempotent with the log already gone.
+    store.delete(id).unwrap();
+}
+
+#[test]
+fn approval_rows_share_event_cursors_with_legacy_acp_lines() {
+    let dir = TempDir::new().unwrap();
+    let store = SidecarStore::new(dir.path());
+    let id = Uuid::new_v4();
+    let legacy = serde_json::to_vec(&note("before")).unwrap();
+    std::fs::create_dir_all(dir.path()).unwrap();
+    std::fs::write(store.events_path_for(id), [legacy, b"\n".to_vec()].concat()).unwrap();
+
+    let mut log = store.open_events(id).unwrap();
+    assert_eq!(
+        log.append(PersistedEvent::Approval {
+            row: TranscriptRow {
+                id: "approval:secret".into(),
+                kind: TranscriptRowKind::Approval,
+                data: serde_json::json!({"tool": "bash"}),
+            },
+        })
+        .unwrap(),
+        2
+    );
+    assert_eq!(log.append(note("after")).unwrap(), 3);
+
+    let all = store.read_events(id, EventCursor::Since(0), 10).unwrap();
+    assert_eq!(
+        all.iter().map(|event| event.seq).collect::<Vec<_>>(),
+        [1, 2, 3]
+    );
+    assert!(matches!(all[1].event, PersistedEvent::Approval { .. }));
+    assert_eq!(event_text(&all[0]), "before");
+    assert_eq!(event_text(&all[2]), "after");
+
+    let since = store.read_events(id, EventCursor::Since(1), 1).unwrap();
+    assert_eq!(since[0].seq, 2);
+    let before = store
+        .read_events(id, EventCursor::Before(Some(3)), 1)
+        .unwrap();
+    assert_eq!(before[0].seq, 2);
+}

crates/maestro-daemon/tests/worktree.rs

@@ -405,13 +405,17 @@ fn run_git(dir: &std::path::Path, args: &[&str]) {
     );
 }
 
+/// `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_fails_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)
@@ -423,9 +427,17 @@ fn add_fails_when_branch_already_exists() {
     let wt_root = TempDir::new().unwrap();
     let mgr = WorktreeManager::new(Some(wt_root.path().to_path_buf()));
 
-    let err = mgr.add_new(&repo, "feat/dup").unwrap_err();
-    let msg = format!("{err}");
-    assert!(msg.contains("git exited"), "{msg}");
+    let path = mgr
+        .add_new(&repo, "feat/dup")
+        .expect("sidesteps the branch collision");
+    assert!(path.ends_with("feat/dup-2"), "{}", path.display());
+    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/Cargo.toml

@@ -13,6 +13,7 @@ path = "src/lib.rs"
 [dependencies]
 chrono.workspace = true
 futures-util.workspace = true
+libc.workspace = true
 maestro-protocol = { workspace = true, features = ["client"] }
 maestro-testing.workspace = true
 serde.workspace = true

crates/maestro-e2e/src/daemon.rs

@@ -87,6 +87,14 @@ impl Daemon {
         }
     }
 
+    /// Send the daemon the same SIGTERM systemd uses, without waiting for its
+    /// graceful HTTP shutdown to finish.
+    pub fn send_sigterm(&self) {
+        let child = self.child.as_ref().expect("daemon is running");
+        let result = unsafe { libc::kill(child.id() as libc::pid_t, libc::SIGTERM) };
+        assert_eq!(result, 0, "send SIGTERM to daemon");
+    }
+
     /// Re-spawn the daemon on the same port + state. The previous tmux
     /// server (under `TMUX_TMPDIR`) is left running so `recover()` can adopt
     /// its sessions.

crates/maestro-e2e/tests/e2e.rs

@@ -15,7 +15,7 @@ use std::time::{Duration, Instant};
 use futures_util::{SinkExt, StreamExt};
 use maestro_e2e::util::wait_for_async;
 use maestro_e2e::{Daemon, TestClient};
-use maestro_protocol::{CreateSessionRequest, WorktreeSpec};
+use maestro_protocol::{CreateSessionRequest, SessionStatus, SessionView, WorktreeSpec};
 use tempfile::TempDir;
 use tokio_tungstenite::tungstenite::Message as WsMessage;
 
@@ -36,6 +36,61 @@ fn create_req(cwd: &std::path::Path, command: &str) -> CreateSessionRequest {
     }
 }
 
+struct FakeAcp {
+    _dir: TempDir,
+    env: HashMap<String, String>,
+}
+
+fn fake_acp(log: &std::path::Path) -> FakeAcp {
+    let dir = tempfile::tempdir().expect("fake adapter dir");
+    let adapter = dir.path().join("claude-code-acp");
+    std::fs::copy(
+        concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/../maestro-acp/tests/fake_acp_agent.py"
+        ),
+        &adapter,
+    )
+    .expect("copy fake adapter");
+    let mut permissions = std::fs::metadata(&adapter)
+        .expect("adapter metadata")
+        .permissions();
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        permissions.set_mode(0o755);
+    }
+    std::fs::set_permissions(&adapter, permissions).expect("make fake adapter executable");
+    let env = HashMap::from([
+        (
+            "PATH".into(),
+            format!(
+                "{}:{}",
+                dir.path().display(),
+                std::env::var("PATH").unwrap_or_default()
+            ),
+        ),
+        ("FAKE_ACP_LOG".into(), log.to_string_lossy().into_owned()),
+    ]);
+    FakeAcp { _dir: dir, env }
+}
+
+fn fake_acp_pid(log: &std::path::Path) -> Option<u32> {
+    std::fs::read_to_string(log).ok()?.lines().find_map(|line| {
+        line.strip_prefix("start pid=")?
+            .split(' ')
+            .next()?
+            .parse()
+            .ok()
+    })
+}
+
+fn pid_alive(pid: u32) -> bool {
+    std::fs::read_to_string(format!("/proc/{pid}/stat"))
+        .map(|stat| !stat.contains(") Z "))
+        .unwrap_or(false)
+}
+
 /// A worktree spec built through its wire shape. The daemon and clients ship
 /// together (#87 dropped `cleanup_on_kill` from the struct), so the JSON
 /// object carries only the fields the lifecycle actually honours.
@@ -328,10 +383,11 @@ async fn spawn_new_branch_creates_worktree_and_runs_in_it() {
     client.kill_session(s.id).await.expect("kill");
 }
 
-/// #66: a second spawn onto a branch that already has a worktree is rejected
-/// with a structured worktree error; the first worktree stays intact.
+/// #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();
@@ -341,28 +397,33 @@ 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
+    let second = client
         .spawn_session(&worktree_req(base.path(), "feature/dup", true))
-        .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:?}"),
-    }
+        .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")
@@ -373,7 +434,8 @@ 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
@@ -992,6 +1054,66 @@ async fn daemon_restart_recovers_session() {
     client.kill_session(s.id).await.expect("kill");
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn sigterm_stops_structured_child_before_events_ws_drains() {
+    let (mut daemon, client) = bring_up().await;
+    let cwd = TempDir::new().unwrap();
+    let log = cwd.path().join("fake-acp.log");
+    let fake = fake_acp(&log);
+    let session = client
+        .spawn_session(&CreateSessionRequest {
+            view: SessionView::Structured,
+            cwd: cwd.path().to_path_buf(),
+            command: "claude".into(),
+            env: fake.env.clone(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .expect("spawn structured session");
+    let ws_url = daemon.client().events_url().expect("events URL");
+    let (_events_ws, _) = tokio_tungstenite::connect_async(ws_url)
+        .await
+        .expect("events WS handshake");
+    wait_for_async("fake ACP starts", Duration::from_secs(5), || {
+        let log = log.clone();
+        async move { fake_acp_pid(&log).is_some() }
+    })
+    .await;
+    let pid = fake_acp_pid(&log).expect("fake ACP pid");
+
+    daemon.send_sigterm();
+
+    wait_for_async(
+        "fake ACP exits after SIGTERM",
+        Duration::from_secs(5),
+        || async { !pid_alive(pid) },
+    )
+    .await;
+    let sidecar_path = daemon
+        .state_dir()
+        .join("sessions")
+        .join(format!("{}.json", session.id));
+    wait_for_async(
+        "dead structured session sidecar",
+        Duration::from_secs(5),
+        || {
+            let sidecar_path = sidecar_path.clone();
+            async move {
+                std::fs::read(&sidecar_path)
+                    .ok()
+                    .and_then(|json| {
+                        serde_json::from_slice::<maestro_protocol::Session>(&json).ok()
+                    })
+                    .is_some_and(|saved| saved.status == SessionStatus::Dead)
+            }
+        },
+    )
+    .await;
+
+    daemon.stop();
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn concurrent_spawns_each_get_unique_ids() {
     let (_daemon, client) = bring_up().await;

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 {
@@ -285,6 +743,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         }
     }
 
@@ -496,38 +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

@@ -123,6 +123,15 @@ pub struct Session {
     /// daemon that predates the field keeps working untouched.
     #[serde(default)]
     pub view: SessionView,
+    /// 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
+    /// the hook-reported Claude Code conversation id (#161): that one is what
+    /// `claude --resume` takes, this one is what the ACP adapter takes, and
+    /// the two are minted by different processes with different lifetimes.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub acp_session_id: Option<String>,
 }
 
 /// A session's process shape (#133): a plain terminal, or a structured agent
@@ -147,9 +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
@@ -157,15 +166,14 @@ 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,
 }
 
@@ -746,6 +754,150 @@ pub enum CatalogEvent {
     },
 }
 
+// ---------------------------------------------------------------------------
+// Structured-session projections
+// ---------------------------------------------------------------------------
+
+/// One client-neutral item in a structured session transcript.
+///
+/// `data` preserves the ACP payload without committing clients to an ACP
+/// dependency. Rendering choices, including markdown and tool-card treatment,
+/// stay with the client.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct TranscriptRow {
+    /// Stable within one session, so later deltas can address this row.
+    pub id: String,
+    pub kind: TranscriptRowKind,
+    pub data: Value,
+}
+
+/// The semantic shape of a [`TranscriptRow`].
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum TranscriptRowKind {
+    User,
+    AgentText,
+    AgentThought,
+    ToolCall,
+    ToolDiff,
+    Approval,
+    Plan,
+    Notice,
+}
+
+/// A complete transcript at a durable event-log position.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct TranscriptSnapshot {
+    pub cursor: u64,
+    #[serde(default)]
+    pub rows: Vec<TranscriptRow>,
+}
+
+/// One durable, client-neutral replay step from a structured session.
+///
+/// Results are ordered by increasing `cursor`. `since` returns the first
+/// matching steps; `before` returns the final matching steps, still increasing.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct StructuredReplayEvent {
+    /// Durable ACP-log position represented by this projected step.
+    pub cursor: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub transcript: Option<TranscriptDelta>,
+    pub state: ReducedState,
+}
+
+/// A change to a transcript row.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum TranscriptDelta {
+    Append { row: TranscriptRow },
+    Patch { row: TranscriptRow },
+    Remove { id: String },
+}
+
+/// Per-turn indicators derived from the ACP stream.
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+pub struct TurnState {
+    #[serde(default)]
+    pub responding: bool,
+    #[serde(default)]
+    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.
+///
+/// Values whose shape ACP owns are carried as JSON so this wire protocol stays
+/// forward-compatible when ACP adds fields or variants.
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+pub struct ReducedState {
+    #[serde(default)]
+    pub turn: TurnState,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub pending_approval: Option<Value>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub plan: Option<Value>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub usage: Option<Value>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub context: Option<Value>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    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.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum StructuredEvent {
+    TranscriptSnapshot {
+        snapshot: TranscriptSnapshot,
+    },
+    ReducedState {
+        state: ReducedState,
+    },
+    ProjectionUpdate {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        transcript: Option<TranscriptDelta>,
+        state: ReducedState,
+    },
+}
+
+/// HTTP body for `POST /api/sessions/:id/structured/prompt`.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+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")]
+pub enum StructuredApprovalDecision {
+    AllowOnce,
+    AllowForSession,
+    Deny,
+}
+
 // ---------------------------------------------------------------------------
 // Client ↔ Daemon control messages (text frames on the attach WS)
 // ---------------------------------------------------------------------------
@@ -886,6 +1038,7 @@ mod tests {
             blocked_work: None,
             last_focused_at: None,
             view: SessionView::Terminal,
+            acp_session_id: None,
         }
     }
 
@@ -1134,6 +1287,54 @@ mod tests {
         assert_eq!(structured, round_trip(&structured));
     }
 
+    #[test]
+    fn structured_projection_types_round_trip_and_default() {
+        let row = TranscriptRow {
+            id: "tool:read-1".into(),
+            kind: TranscriptRowKind::ToolCall,
+            data: serde_json::json!({"name": "vendor.read", "title": "Read"}),
+        };
+        let snapshot = TranscriptSnapshot {
+            cursor: 7,
+            rows: vec![row.clone()],
+        };
+        assert_eq!(snapshot, round_trip(&snapshot));
+        assert_eq!(
+            TranscriptDelta::Patch { row: row.clone() },
+            round_trip(&TranscriptDelta::Patch { row })
+        );
+
+        let state: ReducedState = serde_json::from_value(serde_json::json!({})).unwrap();
+        assert_eq!(state, ReducedState::default());
+        assert_eq!(
+            serde_json::to_value(TranscriptRowKind::AgentThought).unwrap(),
+            serde_json::json!("agent_thought")
+        );
+    }
+
+    #[test]
+    fn acp_session_id_defaults_to_none_and_round_trips() {
+        // A payload from before #134 carries no `acp_session_id`; it must
+        // read as `None`, stay off the wire while unset, and round-trip
+        // once the adapter has handed one back.
+        let json = serde_json::json!({
+            "id": Uuid::from_u128(1),
+            "cwd": "/tmp",
+            "command": "bash",
+            "status": "Running",
+            "created_at": "2026-05-24T12:00:00Z"
+        });
+        let s: Session = serde_json::from_value(json).unwrap();
+        assert_eq!(s.acp_session_id, None);
+        let serialized = serde_json::to_value(&s).unwrap();
+        assert!(serialized.get("acp_session_id").is_none());
+
+        let mut structured = sample_session();
+        structured.view = SessionView::Structured;
+        structured.acp_session_id = Some("sess_01HZX".into());
+        assert_eq!(structured, round_trip(&structured));
+    }
+
     /// A client that predates the new/existing discriminator sends no
     /// `create_branch`; the daemon must read that as "create a new branch" —
     /// exactly what every payload meant before the field existed (#56).

crates/maestro-protocol/src/routes.rs

@@ -71,6 +71,41 @@ pub fn attach(id: Uuid) -> String {
     format!("{API_PREFIX}/attach/{id}")
 }
 
+/// `WS /api/structured/:id` — transcript/state snapshots and live deltas.
+pub fn structured(id: Uuid) -> String {
+    format!("{API_PREFIX}/structured/{id}")
+}
+
+/// `GET /api/sessions/:id/structured/replay` — cursor-bounded ACP history.
+pub fn structured_replay(id: Uuid) -> String {
+    format!("{SESSIONS}/{id}/structured/replay")
+}
+
+/// `POST /api/sessions/:id/structured/prompt` — send an ACP prompt.
+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}")
+}
+
 /// Axum-style patterns for the two parameterised routes, so the server
 /// registers the same paths [`session`] and [`attach`] build.
 pub mod patterns {
@@ -80,6 +115,13 @@ pub mod patterns {
     pub const SESSION_PROMPT: &str = "/api/sessions/:id/prompt";
     pub const SESSION_FOCUS: &str = "/api/sessions/:id/focus";
     pub const ATTACH: &str = "/api/attach/:id";
+    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";
 }
 
 /// A daemon base URL that could not be turned into a WebSocket base.
@@ -129,6 +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::*;
@@ -178,6 +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]
@@ -206,6 +257,22 @@ mod tests {
             attach(id()),
             "/api/attach/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50"
         );
+        assert_eq!(
+            structured(id()),
+            "/api/structured/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50"
+        );
+        assert_eq!(
+            structured_replay(id()),
+            "/api/sessions/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50/structured/replay"
+        );
+        assert_eq!(
+            structured_prompt(id()),
+            "/api/sessions/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50/structured/prompt"
+        );
+        assert_eq!(
+            structured_cancel(id()),
+            "/api/sessions/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50/structured/cancel"
+        );
         assert_eq!(
             attach_url("https://laptop.lan:7070", id()).unwrap(),
             "wss://laptop.lan:7070/api/attach/6f1a7c0e-0f5e-4a2b-9a3d-6b1c2d3e4f50"
@@ -240,6 +307,22 @@ mod tests {
             patterns::ATTACH.trim_end_matches(":id"),
             attach(id()).trim_end_matches(&id().to_string())
         );
+        assert_eq!(
+            patterns::STRUCTURED.trim_end_matches(":id"),
+            structured(id()).trim_end_matches(&id().to_string())
+        );
+        assert_eq!(
+            patterns::STRUCTURED_REPLAY.trim_end_matches(":id/structured/replay"),
+            session(id()).trim_end_matches(&id().to_string())
+        );
+        assert_eq!(
+            patterns::STRUCTURED_PROMPT.trim_end_matches(":id/structured/prompt"),
+            session(id()).trim_end_matches(&id().to_string())
+        );
+        assert_eq!(
+            patterns::STRUCTURED_CANCEL.trim_end_matches(":id/structured/cancel"),
+            session(id()).trim_end_matches(&id().to_string())
+        );
     }
 
     #[test]
@@ -258,5 +341,9 @@ mod tests {
             assert!(path.starts_with(API_PREFIX), "{path} escapes {API_PREFIX}");
         }
         assert!(attach(id()).starts_with(API_PREFIX));
+        assert!(structured(id()).starts_with(API_PREFIX));
+        assert!(structured_replay(id()).starts_with(API_PREFIX));
+        assert!(structured_prompt(id()).starts_with(API_PREFIX));
+        assert!(structured_cancel(id()).starts_with(API_PREFIX));
     }
 }

crates/maestro-testing/src/lib.rs

@@ -48,6 +48,7 @@ pub fn session(id: Uuid, cwd: &str, command: &str) -> Session {
         current_cwd: None,
         blocked_work: None,
         last_focused_at: None,
+        acp_session_id: None,
     }
 }
 

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;
@@ -1899,6 +2215,7 @@ mod tests {
                     current_cwd: None,
                     blocked_work: None,
                     last_focused_at: None,
+                    acp_session_id: None,
                 })
                 .collect(),
         });
@@ -2081,6 +2398,7 @@ mod tests {
                 current_cwd: None,
                 blocked_work: None,
                 last_focused_at: None,
+                acp_session_id: None,
             }],
         });
         app.dispatch(Action::SidebarNext);
@@ -2109,6 +2427,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         }
     }
 
@@ -2802,6 +3121,55 @@ 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,
+        };
+
+        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.
@@ -3219,6 +3587,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: focused,
+            acp_session_id: None,
         };
         let older = Utc::now() - chrono::Duration::seconds(60);
         app.catalog.apply_event(CatalogEvent::Snapshot {
@@ -3498,6 +3867,7 @@ mod tests {
                 current_cwd: None,
                 blocked_work: None,
                 last_focused_at: None,
+                acp_session_id: None,
             }],
         });
         app.dispatch(Action::KillHighlighted);
@@ -3534,6 +3904,7 @@ mod tests {
                 current_cwd: None,
                 blocked_work: None,
                 last_focused_at: None,
+                acp_session_id: None,
             }],
         });
     }
@@ -3691,4 +4062,112 @@ 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/catalog.rs

@@ -224,6 +224,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         }
     }
 

crates/maestro-tui/src/command_bar.rs

@@ -810,6 +810,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: 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> {
@@ -694,7 +735,11 @@ impl DraftPane {
         }
         let worktree = self.build_worktree()?;
         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(),
@@ -754,6 +799,9 @@ 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 +843,7 @@ 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 +1050,9 @@ 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 +1072,10 @@ 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 +1093,14 @@ 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 +1144,10 @@ 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 +1185,9 @@ 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 +1206,7 @@ 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 +1226,9 @@ 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 +1427,24 @@ 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.
@@ -1817,6 +1903,272 @@ 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(),
+            },
+            SpawnPreset {
+                id: "codex".into(),
+                label: "Codex".into(),
+                command: "codex".into(),
+            },
+            SpawnPreset {
+                id: "opencode".into(),
+                label: "OpenCode".into(),
+                command: "opencode".into(),
+            },
+        ]);
+        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(),
+            },
+            SpawnPreset {
+                id: "codex-wrapped".into(),
+                label: "Codex (npx)".into(),
+                command: "npx codex exec".into(),
+            },
+            SpawnPreset {
+                id: "aider".into(),
+                label: "Aider".into(),
+                command: "aider".into(),
+            },
+        ]);
+
+        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(),
+            },
+            SpawnPreset {
+                id: "codex".into(),
+                label: "Codex".into(),
+                command: "codex".into(),
+            },
+        ]);
+        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/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/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

@@ -501,6 +501,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         }
     }
 
@@ -1268,6 +1269,7 @@ mod tests {
             current_cwd: None,
             blocked_work: None,
             last_focused_at: None,
+            acp_session_id: None,
         };
         let sb = Sidebar {
             sessions: vec![s],

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
 
@@ -188,6 +195,37 @@ 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: ACP adapters
+
+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
+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` 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
+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 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. 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
 
 The daemon serves the SPA off its own listener. Open

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

@@ -231,7 +231,24 @@ 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 +298,10 @@ 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 +1,448 @@
+# 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. Opening it reveals independently
+  expandable tool calls, including any raw command, input, output, and diff
+  content the adapter supplied.
+- 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."
+
+- A 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 — one active turn per session, never a hidden 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/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",
@@ -16,7 +16,8 @@
     "@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",

web/pnpm-lock.yaml

@@ -20,6 +20,9 @@ importers:
       '@xterm/xterm':
         specifier: ^5.5.0
         version: 5.5.0
+      marked:
+        specifier: ^18.0.11
+        version: 18.0.11
     devDependencies:
       happy-dom:
         specifier: ^20.11.6
@@ -424,6 +427,11 @@ packages:
   magic-string@0.30.21:
     resolution: {integrity: sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ==}
 
+  marked@18.0.11:
+    resolution: {integrity: sha512-HnslJfsZkRPBDJRHvVtAaWlZHEpSu7u8LgQuJCELjRKuWR+hpq4A7sLq3p8HaI9ypVoXDXxV34CsQJEe1+J5Aw==}
+    engines: {node: '>= 20'}
+    hasBin: true
+
   ms@2.1.3:
     resolution: {integrity: sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==}
 
@@ -864,6 +872,8 @@ snapshots:
     dependencies:
       '@jridgewell/sourcemap-codec': 1.5.5
 
+  marked@18.0.11: {}
+
   ms@2.1.3: {}
 
   nanoid@3.3.12: {}

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/connections.test.ts

@@ -2,28 +2,84 @@
 import { afterEach, describe, expect, it, vi } from "vitest";
 
 import { ConnectionPool } from "./connections.js";
+import { CatalogStore } from "./events.js";
+import type { Session } from "./types.js";
 
 // The pane's own bytes-out path, stubbed: the escape hatch only needs to know
 // the pool reaches the focused connection with them.
 const sent: { id: string; data: string }[] = [];
-vi.mock("./attach.js", () => ({
-  createAttachConnection: (id: string) => ({
+const disposed: string[] = [];
+const mounts: { id: string; focus: boolean | undefined }[] = [];
+function fakeConn(kind: string, id: string) {
+  const el = document.createElement("div");
+  el.tabIndex = -1; // focusable via .focus(), like a real input/terminal
+  el.dataset.kind = kind;
+  el.dataset.session = id;
+  return {
     sessionId: id,
-    el: document.createElement("div"),
-    onMount() {},
+    kind,
+    el,
+    onMount(opts?: { focus?: boolean }) {
+      mounts.push({ id, focus: opts?.focus });
+    },
     onUnmount() {},
     focusTerminal() {},
     sendInput(data: string) {
       sent.push({ id, data });
     },
-    dispose() {},
-  }),
+    updateInfo() {},
+    dispose() {
+      disposed.push(`${kind}:${id}`);
+    },
+  };
+}
+vi.mock("./attach.js", () => ({
+  createAttachConnection: (id: string) => fakeConn("attach", id),
+}));
+vi.mock("./structured.js", () => ({
+  createStructuredConnection: (id: string) => fakeConn("structured", id),
 }));
 
 afterEach(() => {
   vi.unstubAllGlobals();
+  sent.length = 0;
+  disposed.length = 0;
+  mounts.length = 0;
 });
 
+/** Minimal fixture for the `CatalogState` a `CatalogStore` broadcasts. */
+function session(id: string, view?: "Terminal" | "Structured"): Session {
+  return {
+    id,
+    cwd: "/repo",
+    command: "claude",
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    view,
+  };
+}
+
+/** A `CatalogStore` an id can be pushed into on demand, mirroring
+ *  events.test.ts's own injectable-socket pattern. */
+class FakeCatalogSocket {
+  onmessage: ((ev: { data: string }) => void) | null = null;
+  onopen: (() => void) | null = null;
+  onclose: (() => void) | null = null;
+  onerror: (() => void) | null = null;
+  close(): void {}
+  push(sessions: Session[]): void {
+    this.onmessage?.({ data: JSON.stringify({ type: "Snapshot", sessions }) });
+  }
+}
+function fakeStore(): { store: CatalogStore; socket: FakeCatalogSocket } {
+  const socket = new FakeCatalogSocket();
+  const store = new CatalogStore({ socket: () => socket as unknown as WebSocket });
+  store.start();
+  return { store, socket };
+}
+
 const A = "aaaaaaaa-0000-0000-0000-0000000000ff";
 const B = "bbbbbbbb-0000-0000-0000-0000000000ff";
 
@@ -125,3 +181,203 @@ describe("ConnectionPool.sendToFocused", () => {
     expect(sent).toEqual([]);
   });
 });
+
+// A deep link or restored layout can `mount()` a session before the catalog
+// snapshot names its view — the daemon defaults an absent `view` to
+// `"Terminal"`, but so does an *unknown* session, and only one of those is
+// actually resolved (#140 review).
+describe("ConnectionPool: view resolution races", () => {
+  it("replaces a wrongly-typed connection once the catalog resolves it, without waiting for another mount()", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+
+    pool.mount(A, pane); // no info: deep-link-before-snapshot race
+    expect(disposed).toEqual([]);
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    // The fresh connection landed in the same pane nothing re-mounted it into.
+    expect(pane.children).toHaveLength(1);
+  });
+
+  it("also repairs a wrongly-typed connection that is parked, not mounted, without evicting its other parked siblings", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const hidden = document.body.lastElementChild as HTMLElement; // this pool's own cache
+    pool.mount(A, document.createElement("div"));
+    pool.mount(B, document.createElement("div"));
+    pool.unmount(A);
+    pool.unmount(B);
+    disposed.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    // B's own element is still parked — A's repair didn't wipe its siblings
+    // out of the shared hidden cache.
+    expect(hidden.querySelector(`[data-session="${B}"]`)).not.toBeNull();
+    expect((hidden.querySelector(`[data-session="${A}"]`) as HTMLElement | null)?.dataset.kind).toBe("structured");
+  });
+
+  it("does not replace a connection whose resolved view already matches", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    pool.mount(A, pane, { name: "a", command: "claude", view: "Structured" });
+    disposed.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual([]);
+  });
+
+  it("does not downgrade an already-resolved connection when a later mount() call has no info", () => {
+    mockFetch();
+    const pool = new ConnectionPool();
+    const pane = document.createElement("div");
+    pool.mount(A, pane, { name: "a", command: "claude", view: "Structured" });
+    disposed.length = 0;
+
+    pool.mount(A, pane); // e.g. a re-render before the catalog answers again
+
+    expect(disposed).toEqual([]);
+  });
+
+  it("does not treat a session missing from the catalog as Terminal and churn a live connection", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    pool.mount(A, pane, { name: "a", command: "claude", view: "Structured" });
+    disposed.length = 0;
+
+    // `A` is absent from this snapshot — main.ts's own subscription handles
+    // closing the pane; the pool must not race it by "fixing" the view first.
+    socket.push([session(B, "Terminal")]);
+
+    expect(disposed).toEqual([]);
+  });
+
+  it("re-focuses the fresh connection when the keyboard was actually inside the replaced pane", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    document.body.appendChild(pane);
+    pool.mount(A, pane);
+    pool.setFocus(A);
+    (pane.firstElementChild as HTMLElement).focus();
+    expect(document.activeElement).toBe(pane.firstElementChild);
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    expect(mounts).toEqual([{ id: A, focus: true }]);
+    pane.remove();
+  });
+
+  it("does not steal focus from a same-tab sidebar preview even though focusedId still names the previous pane", () => {
+    // docs/PREVIEW.md: previewing a session already open in the current tab
+    // moves the keyboard into the sidebar without ever calling setFocus, so
+    // `focusedId` keeps naming the pane the operator was in before — but the
+    // DOM disagrees, and the DOM is what must decide.
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    document.body.appendChild(pane);
+    pool.mount(A, pane);
+    pool.setFocus(A);
+    (pane.firstElementChild as HTMLElement).focus();
+
+    const sidebarInput = document.createElement("input");
+    document.body.appendChild(sidebarInput);
+    sidebarInput.focus();
+    expect(document.activeElement).toBe(sidebarInput);
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    expect(mounts).toEqual([{ id: A, focus: false }]);
+    pane.remove();
+    sidebarInput.remove();
+  });
+
+  it("counts focus on a descendant of the pane's element, not just the element itself", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    document.body.appendChild(pane);
+    pool.mount(A, pane);
+    pool.setFocus(A);
+    const textarea = document.createElement("textarea");
+    (pane.firstElementChild as HTMLElement).appendChild(textarea);
+    textarea.focus();
+    expect(document.activeElement).toBe(textarea);
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(mounts).toEqual([{ id: A, focus: true }]);
+    pane.remove();
+  });
+
+  it("treats document.body (nothing meaningfully focused) as no active descendant", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    document.body.appendChild(pane);
+    pool.mount(A, pane);
+    pool.setFocus(A);
+    (document.activeElement as HTMLElement | null)?.blur();
+    expect(document.activeElement).toBe(document.body);
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(mounts).toEqual([{ id: A, focus: false }]);
+    pane.remove();
+  });
+
+  it("does not steal focus for a merely-visible pane that was never actually focused", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const paneA = document.createElement("div");
+    const paneB = document.createElement("div");
+    pool.mount(A, paneA);
+    pool.mount(B, paneB);
+    pool.setFocus(B); // B is the real keyboard focus; A is only visible
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    expect(mounts).toEqual([{ id: A, focus: false }]);
+  });
+
+  it("does not focus a parked (unmounted) connection it repairs", () => {
+    mockFetch();
+    const { store, socket } = fakeStore();
+    const pool = new ConnectionPool({ store });
+    const pane = document.createElement("div");
+    pool.mount(A, pane);
+    pool.setFocus(A);
+    pool.unmount(A); // parked — no longer visible, `focusedId` still names it
+    mounts.length = 0;
+
+    socket.push([session(A, "Structured")]);
+
+    expect(disposed).toEqual(["attach:" + A]);
+    expect(mounts).toEqual([]); // parked repair calls onUnmount, never onMount
+  });
+});

web/src/connections.ts

@@ -1,10 +1,10 @@
-import {
-  createAttachConnection,
-  type AttachConnection,
-  type AttachInfo,
-} from "./attach.js";
+import { createAttachConnection } from "./attach.js";
+import type { AttachInfo } from "./paneTitle.js";
+import type { PaneConnection } from "./pane.js";
+import { createStructuredConnection } from "./structured.js";
 import { setSessionFocus } from "./api.js";
-import type { Uuid } from "./types.js";
+import type { CatalogState, CatalogStore } from "./events.js";
+import { sessionName, type SessionView, type Uuid } from "./types.js";
 
 /**
  * How many *parked* (off-screen but still-connected) sessions to keep warm
@@ -16,6 +16,15 @@ import type { Uuid } from "./types.js";
  */
 const MAX_PARKED = 6;
 
+/** A session's view defaults to `"Terminal"` wherever it isn't carried —
+ *  matching the wire default (`SessionView`'s `#[default]`, types.ts). Only
+ *  meaningful once the session itself is known; an altogether-unknown
+ *  session (no `AttachInfo`/`Session` at all) is a distinct, un-resolved
+ *  state callers must check for separately, not "Terminal". */
+function resolveView(view: SessionView | undefined): SessionView {
+  return view ?? "Terminal";
+}
+
 export interface PoolOptions {
   /** Fired when the focused session changes (drives sidebar highlight + HUD). */
   onFocusChange?: (id: Uuid | null) => void;
@@ -27,6 +36,9 @@ export interface PoolOptions {
   onClosed?: (id: Uuid) => void;
   /** Forwarded to each connection: should a dropped socket be retried? */
   shouldReconnect?: (id: Uuid, code: number) => boolean;
+  /** Threaded through to a structured connection so its rail can read live
+   *  worktree/git-status data (#140). Terminal connections don't need it. */
+  store?: CatalogStore;
 }
 
 /**
@@ -40,12 +52,19 @@ export interface PoolOptions {
  */
 export class ConnectionPool {
   /** All live connections. Insertion order doubles as LRU: oldest first. */
-  private readonly cache = new Map<Uuid, AttachConnection>();
+  private readonly cache = new Map<Uuid, PaneConnection>();
+  /** The view each cached connection was actually created for — a deep link
+   *  or a restored layout can `mount()` a session before the catalog
+   *  snapshot names its view, defaulting it to `"Terminal"`; this is what
+   *  lets a later reconciliation notice the resolved view disagrees (#140
+   *  review). */
+  private readonly connViews = new Map<Uuid, SessionView>();
   /** Sessions currently mounted into a visible pane (never evicted). */
   private readonly mounted = new Set<Uuid>();
   private readonly hidden: HTMLElement;
   private focusedId: Uuid | null = null;
   private readonly opts: PoolOptions;
+  private readonly unsubscribeStore?: () => void;
 
   constructor(opts: PoolOptions = {}) {
     this.opts = opts;
@@ -54,6 +73,11 @@ export class ConnectionPool {
     this.hidden.className = "conn-cache";
     this.hidden.setAttribute("aria-hidden", "true");
     document.body.appendChild(this.hidden);
+    // A session `mount()`ed before its catalog entry exists gets a
+    // `"Terminal"` connection by default; once the snapshot actually names
+    // the view, fix any connection that guessed wrong — nothing else
+    // re-`mount()`s an already-open pane just because the catalog updated.
+    this.unsubscribeStore = opts.store?.subscribe((state) => this.reconcileViews(state));
   }
 
   /** The focused session, or null when nothing is focused (welcome pane). */
@@ -77,18 +101,19 @@ export class ConnectionPool {
   mount(id: Uuid, pane: HTMLElement, info?: AttachInfo, opts?: { focus?: boolean }): void {
     let conn = this.cache.get(id);
     if (conn) {
-      this.cache.delete(id);
-      this.cache.set(id, conn);
+      // `info === undefined` means "session not known yet", not "Terminal" —
+      // never downgrade a resolved connection just because a later caller
+      // couldn't resolve the session. Only a *resolved* view that disagrees
+      // with what this connection was built for forces a replace.
+      if (info !== undefined && resolveView(info.view) !== this.connViews.get(id)) {
+        conn = this.replace(id, info);
+      } else {
+        this.cache.delete(id);
+        this.cache.set(id, conn); // LRU refresh
+        if (info) conn.updateInfo(info);
+      }
     } else {
-      conn = createAttachConnection(
-        id,
-        {
-          onRequestClose: (sid) => this.opts.onRequestClose?.(sid),
-          onClosed: (sid) => this.opts.onClosed?.(sid),
-          shouldReconnect: (sid, code) => this.opts.shouldReconnect?.(sid, code) ?? false,
-        },
-        info,
-      );
+      conn = this.create(id, info);
       this.cache.set(id, conn);
     }
     if (conn.el.parentElement !== pane) {
@@ -101,6 +126,71 @@ export class ConnectionPool {
     this.evict();
   }
 
+  private create(id: Uuid, info?: AttachInfo): PaneConnection {
+    const view = resolveView(info?.view);
+    this.connViews.set(id, view);
+    const connOpts = {
+      onRequestClose: (sid: Uuid) => this.opts.onRequestClose?.(sid),
+      onClosed: (sid: Uuid) => this.opts.onClosed?.(sid),
+      shouldReconnect: (sid: Uuid, code: number) => this.opts.shouldReconnect?.(sid, code) ?? false,
+    };
+    return view === "Structured"
+      ? createStructuredConnection(id, connOpts, info, this.opts.store)
+      : createAttachConnection(id, connOpts, info);
+  }
+
+  /** Dispose whatever is cached for `id` and cache a freshly created
+   *  connection in its place. Does not touch the DOM or `mounted` — callers
+   *  place the new element themselves. */
+  private replace(id: Uuid, info?: AttachInfo): PaneConnection {
+    this.cache.get(id)?.dispose();
+    const fresh = this.create(id, info);
+    this.cache.set(id, fresh);
+    return fresh;
+  }
+
+  /** Proactively fix any cached connection whose view no longer matches the
+   *  catalog — the only path that repairs a pane nothing will `mount()`
+   *  again on its own (parked, or mounted but not currently being
+   *  re-rendered by anything else). A session absent from `state` (not yet
+   *  known, or removed) is left alone — that's `main.ts`'s
+   *  `closePane`/eviction concern, not a view mismatch. */
+  private reconcileViews(state: CatalogState): void {
+    for (const id of [...this.cache.keys()]) {
+      const session = state.sessions.get(id);
+      if (session === undefined || resolveView(session.view) === this.connViews.get(id)) continue;
+      const existing = this.cache.get(id)!;
+      const parent = existing.el.parentElement;
+      const wasMounted = this.mounted.has(id);
+      // Capture before anything below touches the DOM: dispose()/el.remove()
+      // detach `existing.el`, and once a focused descendant is detached the
+      // browser moves `document.activeElement` to `<body>` — too late to
+      // tell whether the keyboard was actually in this pane.
+      const hadDomFocus = existing.el.contains(document.activeElement);
+      const info: AttachInfo = { name: sessionName(session), command: session.command, view: session.view };
+      const fresh = this.replace(id, info);
+      existing.el.remove(); // don't rely on dispose() to clear the DOM
+      if (parent && parent !== this.hidden) {
+        parent.replaceChildren(fresh.el);
+      } else {
+        // Parked: `this.hidden` holds every parked connection's element as
+        // siblings — append, never replaceChildren, or they'd all vanish.
+        this.hidden.appendChild(fresh.el);
+      }
+      if (wasMounted) {
+        // `focusedId` names the session the pool was last told to focus —
+        // but a same-tab sidebar preview moves the keyboard into the
+        // sidebar without clearing it (multiview.ts skips `setFocus` while
+        // previewing), so `focusedId` alone can point at a pane the
+        // keyboard already left. Only re-focus when the DOM agrees it
+        // never did.
+        fresh.onMount({ focus: this.focusedId === id && hadDomFocus });
+      } else {
+        fresh.onUnmount();
+      }
+    }
+  }
+
   /** Park `id` back into the hidden cache (still connected) and stop showing it. */
   unmount(id: Uuid): void {
     if (!this.mounted.delete(id)) return;
@@ -177,13 +267,16 @@ export class ConnectionPool {
     if (!conn) return;
     conn.dispose();
     this.cache.delete(id);
+    this.connViews.delete(id);
     this.mounted.delete(id);
     if (this.focusedId === id) this.setFocus(null);
   }
 
   dispose(): void {
+    this.unsubscribeStore?.();
     for (const conn of this.cache.values()) conn.dispose();
     this.cache.clear();
+    this.connViews.clear();
     this.mounted.clear();
     this.hidden.remove();
   }

web/src/daemonLink.test.ts

@@ -130,6 +130,31 @@ describe("DaemonLink", () => {
     expect(link.status().state).toBe("online");
   });
 
+  it("rechecks immediately when the browser returns from the background", async () => {
+    const sched = manual();
+    let reply: DaemonInfo | null = info("aaa", "i1");
+    const link = new DaemonLink({
+      fetchInfo: async () => {
+        if (!reply) throw new Error("down");
+        return reply;
+      },
+      scheduler: sched,
+      reload: () => {},
+    });
+    await link.start();
+
+    reply = null;
+    link.noteDisconnected();
+    sched.run();
+    await Promise.resolve();
+    expect(link.status().state).toBe("down");
+
+    reply = info("aaa", "i1");
+    link.recover();
+    await Promise.resolve();
+    expect(link.status().state).toBe("online");
+  });
+
   it("reloads the page when the daemon comes back on a new commit", async () => {
     const sched = manual();
     const reload = vi.fn();

web/src/daemonLink.ts

@@ -148,6 +148,17 @@ export class DaemonLink {
     void this.probe();
   }
 
+  /**
+   * Recheck liveness after the browser resumes from the background. Mobile
+   * browsers may suspend both WebSocket events and timers while a PWA is
+   * hidden, leaving a stale `down` state after the daemon is already back.
+   */
+  recover(): void {
+    if (this.state === "updating") return;
+    this.noteDisconnected();
+    void this.probe();
+  }
+
   /**
    * One `/api/info` round-trip. Resolves `true` when the daemon answered.
    *

web/src/events.test.ts

@@ -132,6 +132,21 @@ describe("CatalogStore reducer", () => {
 });
 
 describe("CatalogStore reconnect", () => {
+  it("replaces a suspended socket immediately", () => {
+    const first = new FakeSocket();
+    const second = new FakeSocket();
+    const { store } = storeWith([first, second]);
+    store.start();
+
+    store.reconnect();
+
+    expect(first.closed).toBe(true);
+    second.open();
+    // A late close from the old socket is deliberately ignored.
+    first.drop();
+    expect(store.backoff()).toBe(INITIAL_BACKOFF_MS);
+  });
+
   it("doubles the delay per attempt and caps it", () => {
     const sockets = Array.from({ length: 8 }, () => new FakeSocket());
     const { store, scheduler } = storeWith(sockets);

web/src/events.ts

@@ -59,6 +59,23 @@ export class CatalogStore {
     this.connect();
   }
 
+  /** Replace a socket that may have gone stale while the browser was suspended. */
+  reconnect(): void {
+    if (this.reconnectTimer !== null) {
+      this.scheduler.clearTimer(this.reconnectTimer);
+      this.reconnectTimer = null;
+    }
+    if (this.ws) {
+      // A close event from the superseded socket must not schedule a second
+      // connection alongside the new one.
+      this.ws.onclose = null;
+      this.ws.onerror = null;
+      this.ws.close();
+      this.ws = null;
+    }
+    this.connect();
+  }
+
   /** Current reconnect delay, for tests asserting the backoff schedule. */
   backoff(): number {
     return this.backoffMs;

web/src/main.ts

@@ -107,6 +107,19 @@ void link.start();
 
 store.start();
 
+// Installed mobile browsers suspend timers and WebSockets in the background.
+// Replacing the socket on return avoids leaving the restart overlay up after a
+// transient lost connection has already recovered.
+function recoverFromBackground(): void {
+  if (document.visibilityState !== "visible") return;
+  link.recover();
+  store.reconnect();
+}
+
+document.addEventListener("visibilitychange", recoverFromBackground);
+window.addEventListener("pageshow", recoverFromBackground);
+window.addEventListener("online", recoverFromBackground);
+
 // Dev-only: `?mock` seeds a representative catalog so the UI can be reviewed
 // without a running daemon. Stripped from production builds by Vite.
 if (import.meta.env.DEV && location.search.includes("mock")) {
@@ -172,6 +185,7 @@ const pool = new ConnectionPool({
   onRequestClose: (id) => closePane(id),
   onClosed: (id) => closePane(id),
   shouldReconnect: (id, code) => shouldRetryClose(id, code, store.snapshot().sessions),
+  store,
 });
 
 // Session death used to reach the UI on two uncoordinated channels — the row
@@ -209,7 +223,7 @@ function scheduleSave(): void {
 
 function infoFor(sessionId: string) {
   const s = store.snapshot().sessions.get(sessionId);
-  return s ? { name: sessionName(s), command: s.command } : undefined;
+  return s ? { name: sessionName(s), command: s.command, view: s.view } : undefined;
 }
 
 /** Drive the shell's responsive layout off whether any pane is open. */

web/src/pane.ts

@@ -0,0 +1,29 @@
+// Shared shape a mounted pane connection satisfies, whatever session view is
+// behind it — what ConnectionPool needs to mount/park/dispose a pane without
+// caring whether it holds an xterm attach (attach.ts) or a structured
+// transcript (structured.ts).
+
+import type { Uuid } from "./types.js";
+import type { AttachInfo } from "./paneTitle.js";
+
+export interface PaneConnection {
+  readonly sessionId: Uuid;
+  /** The element to mount into a pane. */
+  readonly el: HTMLElement;
+  /** Becomes the visible view: fit/focus/sync as the connection needs.
+   *  `focus: false` mounts without taking the keyboard (a sidebar preview). */
+  onMount(opts?: { focus?: boolean }): void;
+  /** Parked into the hidden cache: keep streaming, stop driving focus/sizing. */
+  onUnmount(): void;
+  /** Put the keyboard into this pane's primary input — the terminal for an
+   *  attach connection, the composer for a structured one. */
+  focusTerminal(): void;
+  /** Raw bytes into a PTY, bypassing normal key handling (the leader's
+   *  literal-byte escape hatch, docs/COMMAND-BAR.md). A structured connection
+   *  has no PTY, so this is a no-op there. */
+  sendInput(data: string): void;
+  /** Refresh the pane header after the catalog renames a live session. */
+  updateInfo(info: AttachInfo): void;
+  /** Fully disconnect and remove the element. */
+  dispose(): void;
+}

web/src/paneTitle.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+
+import { paneTitleAttr, paneTitleHtml } from "./paneTitle.js";
+
+describe("paneTitleHtml", () => {
+  it("falls back to a short session id when there is no info yet", () => {
+    expect(paneTitleHtml("abcdef12-3456-7890-abcd-ef1234567890")).toContain("abcdef12");
+  });
+
+  it("shows the name alone when command matches it", () => {
+    const html = paneTitleHtml("s1", { name: "claude", command: "claude" });
+    expect(html).toContain("claude");
+    expect(html).not.toContain("at-cmd");
+  });
+
+  it("escapes a name that looks like markup", () => {
+    const html = paneTitleHtml("s1", { name: "<img onerror=x>", command: "claude" });
+    expect(html).not.toContain("<img");
+  });
+});
+
+describe("paneTitleAttr", () => {
+  it("escapes the attribute form too", () => {
+    const attr = paneTitleAttr("s1", { name: '"quoted"', command: "claude" });
+    expect(attr).not.toContain('"quoted"');
+    expect(attr).toContain("&quot;quoted&quot;");
+  });
+});

web/src/paneTitle.ts

@@ -0,0 +1,36 @@
+// Pane header title: name/command echoing the sidebar card, shared by the
+// xterm attach view (attach.ts) and the structured transcript view
+// (structured.ts) so both panes read identically.
+
+import { escapeHtml } from "./html.js";
+import { splitCommand, toolIconSvg } from "./toolIcon.js";
+import type { SessionView, Uuid } from "./types.js";
+
+/** What a pane header shows about its session. Falls back to a short session
+ * id when the session isn't known yet. */
+export interface AttachInfo {
+  name: string;
+  command: string;
+  /** Which connection kind to mount (#140). Absent/`"Terminal"` mounts the
+   * xterm attach; `"Structured"` mounts the transcript view. */
+  view?: SessionView;
+}
+
+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 paneTitleHtml(sessionId: Uuid, info?: AttachInfo): string {
+  return 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>`;
+}
+
+/** Attribute-safe (`title="..."`) form of the same identity. */
+export function paneTitleAttr(sessionId: Uuid, info?: AttachInfo): string {
+  return escapeHtml(info ? `${info.name} · ${info.command}  (${sessionId})` : sessionId);
+}

web/src/routes.ts

@@ -37,6 +37,36 @@ export function sessionFocus(id: Uuid): string {
   return `${session(id)}/focus`;
 }
 
+/** `WS /api/structured/:id` — transcript/state snapshots and live deltas. */
+export function structured(id: Uuid): string {
+  return `${API_PREFIX}/structured/${encodeURIComponent(id)}`;
+}
+
+/** `POST /api/sessions/:id/structured/prompt` — send an ACP prompt. */
+export function structuredPrompt(id: Uuid): string {
+  return `${session(id)}/structured/prompt`;
+}
+
+export function structuredAttachment(id: Uuid): string {
+  return `${session(id)}/structured/attachments`;
+}
+
+/** `POST /api/sessions/:id/structured/cancel` — cancel an ACP turn. */
+export function structuredCancel(id: Uuid): string {
+  return `${session(id)}/structured/cancel`;
+}
+
+/** `POST /api/sessions/:id/structured/config` — change an ACP session option. */
+export function structuredConfig(id: Uuid): string {
+  return `${session(id)}/structured/config`;
+}
+
+/** `POST /api/sessions/:id/structured/approvals/:nonce` — answer a permission
+ * request. */
+export function structuredApproval(id: Uuid, nonce: string): string {
+  return `${session(id)}/structured/approvals/${encodeURIComponent(nonce)}`;
+}
+
 /** Append the `path` query parameter `DIRS` and `GITROOT` accept. */
 export function withPathQuery(route: string, value: string): string {
   return `${route}?${PATH_QUERY}=${encodeURIComponent(value)}`;
@@ -55,3 +85,7 @@ export function eventsWsUrl(): string {
 export function attachWsUrl(id: Uuid): string {
   return `${wsBase()}${attach(id)}`;
 }
+
+export function structuredWsUrl(id: Uuid): string {
+  return `${wsBase()}${structured(id)}`;
+}

web/src/spawnForm.test.ts

@@ -6,6 +6,7 @@ const base: SpawnFormValues = {
   command: "claude",
   cwd: "/home/user/project",
   name: "amber-fox",
+  structuredView: false,
   worktreeEnabled: false,
   worktreeBranch: "",
   worktreeBranchMode: "new",
@@ -25,6 +26,28 @@ describe("buildSpawnRequest", () => {
     expect(res).toEqual({ req: { cwd: base.cwd, command: base.command, metadata: {} } });
   });
 
+  it.each(["claude", "FOO=1 /usr/local/bin/codex", "env -i codex"])(
+    "requests structured view for resolved %s commands",
+    (command) => {
+      expect(buildSpawnRequest({ ...base, command, structuredView: true }, null)).toEqual({
+        req: {
+          cwd: base.cwd,
+          command,
+          metadata: { name: "amber-fox" },
+          view: "Structured",
+        },
+      });
+    },
+  );
+
+  it("does not request structured view for unsupported commands", () => {
+    expect(
+      buildSpawnRequest({ ...base, command: "opencode", structuredView: true }, null),
+    ).toEqual({
+      req: { cwd: base.cwd, command: "opencode", metadata: { name: "amber-fox" } },
+    });
+  });
+
   it("attaches a trimmed branch when worktree is enabled, and always cleans up", () => {
     const res = buildSpawnRequest(
       { ...base, worktreeEnabled: true, worktreeBranch: "  feat/foo  " },

web/src/spawnForm.ts

@@ -11,9 +11,17 @@ import { attachDirAutocomplete } from "./dirAutocomplete.js";
 import { parentDir } from "./paths.js";
 import { filterProjects, groupProjects, isStale, sortProjects } from "./projectList.js";
 import type { ProjectGroup } from "./projectList.js";
+import { splitCommand } from "./toolIcon.js";
 import { abbreviateCwd } from "./types.js";
 import type { BranchInfo, CreateSessionRequest, Project, Session, SpawnPreset } from "./types.js";
 
+const STRUCTURED_VIEW_TOOLS = new Set(["claude", "codex"]);
+
+function supportsStructuredView(command: string): boolean {
+  const tool = splitCommand(command).tool;
+  return tool !== null && STRUCTURED_VIEW_TOOLS.has(tool);
+}
+
 /** Where a worktree's branch comes from: freshly created (default) or picked
  * from the repository's existing branches (#61). */
 export type WorktreeBranchMode = "new" | "existing";
@@ -40,6 +48,7 @@ export interface SpawnFormValues {
   command: string;
   cwd: string;
   name: string;
+  structuredView: boolean;
   worktreeEnabled: boolean;
   worktreeBranch: string;
   worktreeBranchEdited: boolean;
@@ -66,6 +75,10 @@ export function buildSpawnRequest(
     metadata,
   };
 
+  if (values.structuredView && supportsStructuredView(values.command)) {
+    req.view = "Structured";
+  }
+
   if (values.worktreeEnabled) {
     const mode = values.worktreeBranchMode ?? "new";
     const branch = values.worktreeBranch.trim();
@@ -153,6 +166,10 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
         <span class="wt-summary"></span>
       </button>
       <div class="wt-collapsible" hidden>
+        <label class="row-inline structured-view" hidden>
+          <input type="checkbox" name="structured_view" />
+          Structured view
+        </label>
         <div class="field wt-step" hidden>
           <span class="field-label">Worktree</span>
           <div class="picker wt-choices"></div>
@@ -203,6 +220,8 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
   const wtChoices = form.querySelector(".wt-choices") as HTMLElement;
   const cwdRawWrap = form.querySelector(".cwd-raw-wrap") as HTMLElement;
   const cwdRaw = form.querySelector(".cwd-raw") as HTMLInputElement;
+  const structuredWrap = form.querySelector(".structured-view") as HTMLElement;
+  const structuredView = form.querySelector("input[name=structured_view]") as HTMLInputElement;
   const wtEnabled = form.querySelector("input[name=worktree_enabled]") as HTMLInputElement;
   const wtToggle = form.querySelector(".wt-toggle") as HTMLButtonElement;
   const wtCollapsible = form.querySelector(".wt-collapsible") as HTMLElement;
@@ -248,6 +267,7 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
       command,
       cwd,
       name: nameInput.value,
+      structuredView: structuredView.checked,
       worktreeEnabled: wtEnabled.checked,
       worktreeBranch: branchValue(),
       worktreeBranchEdited: branchEdited,
@@ -317,6 +337,7 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
     } else {
       command = preset!.command;
     }
+    updateStructuredAvailability();
     for (const tile of cmdTiles.querySelectorAll(".tile")) {
       tile.classList.toggle("is-active", (tile as HTMLElement).dataset.id === id);
     }
@@ -354,10 +375,29 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
   // operator has already touched (#76).
   let commandTouched = false;
 
+  // Set once the operator works the checkbox themselves. Until then every
+  // command change re-derives the default (on for Claude Code and Codex, off
+  // for everything else); afterwards their choice outranks it, the same guard
+  // `commandTouched` gives the command field.
+  let structuredTouched = false;
+
+  function updateStructuredAvailability(): void {
+    const supported = supportsStructuredView(command);
+    structuredWrap.hidden = !supported;
+    if (!supported) structuredView.checked = false;
+    else if (!structuredTouched) structuredView.checked = true;
+  }
+
+  structuredView.addEventListener("change", () => {
+    structuredTouched = true;
+    emit();
+  });
+
   cmdRaw.addEventListener("input", () => {
     if (selectedPresetId === "custom" || presets.find((p) => p.id === selectedPresetId)?.command === "") {
       commandTouched = true;
       command = cmdRaw.value.trim();
+      updateStructuredAvailability();
       emit();
     }
   });
@@ -844,10 +884,11 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
     if (e.key !== "Enter" || e.defaultPrevented) return;
     const target = e.target as HTMLElement;
 
-    if (target === wtEnabled) {
+    if (target === wtEnabled || target === structuredView) {
       e.preventDefault();
-      wtEnabled.checked = !wtEnabled.checked;
-      wtEnabled.dispatchEvent(new Event("change"));
+      const checkbox = target as HTMLInputElement;
+      checkbox.checked = !checkbox.checked;
+      checkbox.dispatchEvent(new Event("change"));
       return;
     }
 
@@ -885,6 +926,7 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
         command,
         cwd,
         name: nameInput.value,
+        structuredView: structuredView.checked,
         worktreeEnabled: wtEnabled.checked,
         worktreeBranch: branchValue(),
         worktreeBranchEdited: branchEdited,

web/src/spawnFormStructured.test.ts

@@ -0,0 +1,158 @@
+// @vitest-environment happy-dom
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { createSpawnForm, type SpawnFormHandle } from "./spawnForm.js";
+
+function stubApi(): RequestInit[] {
+  const sessionRequests: RequestInit[] = [];
+  vi.stubGlobal(
+    "fetch",
+    vi.fn(async (input: RequestInfo | URL, init?: RequestInit) => {
+      const url = String(input);
+      if (url.includes("/api/sessions") && init?.method === "POST") {
+        sessionRequests.push(init);
+        return new Response(JSON.stringify({ id: "s1", command: "claude", cwd: "/srv/work" }), {
+          status: 200,
+        });
+      }
+      if (url.includes("/api/info")) {
+        return new Response(
+          JSON.stringify({ hostname: "h", version: "0", home_dir: "/home/user" }),
+          { status: 200 },
+        );
+      }
+      if (url.includes("/api/names")) {
+        return new Response(JSON.stringify({ names: ["amber-fox"] }), { status: 200 });
+      }
+      return new Response(JSON.stringify([]), { status: 200 });
+    }),
+  );
+  return sessionRequests;
+}
+
+describe("spawn form structured view", () => {
+  let handle: SpawnFormHandle | null = null;
+
+  async function drain(): Promise<void> {
+    for (let i = 0; i < 20; i++) await Promise.resolve();
+  }
+
+  afterEach(async () => {
+    handle?.destroy();
+    handle = null;
+    await drain();
+    vi.unstubAllGlobals();
+  });
+
+  it("is default-on and shown for resolved Claude Code and Codex commands", async () => {
+    stubApi();
+    handle = createSpawnForm({ onSuccess() {} });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    const wrap = handle.el.querySelector<HTMLElement>(".structured-view")!;
+    const checkbox = wrap.querySelector<HTMLInputElement>("input")!;
+    const disclosure = handle.el.querySelector<HTMLElement>(".wt-collapsible")!;
+    expect(disclosure.hidden).toBe(true);
+    handle.el.querySelector<HTMLButtonElement>(".wt-toggle")!.click();
+    expect(disclosure.hidden).toBe(false);
+    expect(wrap.hidden).toBe(false);
+    expect(checkbox.checked).toBe(true);
+
+    const custom = handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!;
+    custom.click();
+    const command = handle.el.querySelector<HTMLInputElement>(".cmd-raw")!;
+    command.value = "FOO=1 /usr/local/bin/codex";
+    command.dispatchEvent(new Event("input"));
+    expect(wrap.hidden).toBe(false);
+    expect(checkbox.checked).toBe(true);
+
+    command.value = "opencode";
+    command.dispatchEvent(new Event("input"));
+    expect(wrap.hidden).toBe(true);
+    expect(checkbox.checked).toBe(false);
+  });
+
+  it("keeps an unchecked box unchecked across a command change", async () => {
+    stubApi();
+    handle = createSpawnForm({ onSuccess() {} });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    const checkbox = handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!;
+    expect(checkbox.checked).toBe(true);
+    checkbox.click();
+    expect(checkbox.checked).toBe(false);
+
+    handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!.click();
+    const command = handle.el.querySelector<HTMLInputElement>(".cmd-raw")!;
+    command.value = "codex";
+    command.dispatchEvent(new Event("input"));
+
+    expect(checkbox.checked).toBe(false);
+  });
+
+  it("clears the checked default when Codex changes to an unsupported command", async () => {
+    stubApi();
+    handle = createSpawnForm({ onSuccess() {} });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!.click();
+    const command = handle.el.querySelector<HTMLInputElement>(".cmd-raw")!;
+    command.value = "env -i codex";
+    command.dispatchEvent(new Event("input"));
+
+    const checkbox = handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!;
+    expect(checkbox.checked).toBe(true);
+
+    command.value = "opencode";
+    command.dispatchEvent(new Event("input"));
+
+    expect(checkbox.closest<HTMLElement>(".structured-view")!.hidden).toBe(true);
+    expect(checkbox.checked).toBe(false);
+  });
+
+  it.each(["claude", "codex"])("emits Structured for a %s command by default", async (tool) => {
+    const requests = stubApi();
+    handle = createSpawnForm({
+      seed: { cwd: "/srv/work", cwdRawVisible: true, worktreeEnabled: false },
+      onSuccess() {},
+    });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    if (tool === "codex") {
+      handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!.click();
+      const command = handle.el.querySelector<HTMLInputElement>(".cmd-raw")!;
+      command.value = "codex";
+      command.dispatchEvent(new Event("input"));
+    }
+
+    handle.el.requestSubmit();
+    await drain();
+
+    expect(requests).toHaveLength(1);
+    expect(JSON.parse(String(requests[0].body))).toMatchObject({
+      command: tool,
+      view: "Structured",
+    });
+  });
+
+  it("emits no view once the operator unticks the box", async () => {
+    const requests = stubApi();
+    handle = createSpawnForm({
+      seed: { cwd: "/srv/work", cwdRawVisible: true, worktreeEnabled: false },
+      onSuccess() {},
+    });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!.click();
+    handle.el.requestSubmit();
+    await drain();
+
+    expect(requests).toHaveLength(1);
+    expect(JSON.parse(String(requests[0].body)).view).toBeUndefined();
+  });
+});

web/src/structuredDiff.test.ts

@@ -0,0 +1,187 @@
+import { describe, expect, it } from "vitest";
+
+import { computeDiffLines, diffStats, type DiffLine } from "./structuredDiff.js";
+
+function texts(lines: DiffLine[]): Array<[string, string]> {
+  return lines.map((l) => [l.kind, l.text]);
+}
+
+describe("computeDiffLines", () => {
+  it("renders a brand new file (no oldText) as all additions", () => {
+    const lines = computeDiffLines(null, "a\nb\n");
+    expect(texts(lines)).toEqual([
+      ["add", "a"],
+      ["add", "b"],
+    ]);
+  });
+
+  it("renders a full deletion as all removals", () => {
+    const lines = computeDiffLines("a\nb\n", "");
+    expect(texts(lines)).toEqual([
+      ["del", "a"],
+      ["del", "b"],
+    ]);
+  });
+
+  it("shows a small replace as context around del/add", () => {
+    const lines = computeDiffLines("one\ntwo\nthree\n", "one\ntwx\nthree\n");
+    expect(texts(lines)).toEqual([
+      ["ctx", "one"],
+      ["del", "two"],
+      ["add", "twx"],
+      ["ctx", "three"],
+    ]);
+  });
+
+  it("leaves identical text as pure context, uncollapsed when short", () => {
+    const lines = computeDiffLines("a\nb\nc\n", "a\nb\nc\n");
+    expect(texts(lines)).toEqual([
+      ["ctx", "a"],
+      ["ctx", "b"],
+      ["ctx", "c"],
+    ]);
+  });
+
+  it("handles an insertion without changing surrounding lines", () => {
+    expect(texts(computeDiffLines("a\nc\n", "a\nb\nc\n"))).toEqual([
+      ["ctx", "a"],
+      ["add", "b"],
+      ["ctx", "c"],
+    ]);
+  });
+
+  it("handles a deletion without changing surrounding lines", () => {
+    expect(texts(computeDiffLines("a\nb\nc\n", "a\nc\n"))).toEqual([
+      ["ctx", "a"],
+      ["del", "b"],
+      ["ctx", "c"],
+    ]);
+  });
+
+  it("renders two empty files without invented lines", () => {
+    expect(computeDiffLines("", "")).toEqual([]);
+  });
+
+  it("shows when a final newline is added", () => {
+    expect(texts(computeDiffLines("a", "a\n"))).toEqual([
+      ["del", "a"],
+      ["eof", "\\ No newline at end of file"],
+      ["add", "a"],
+    ]);
+  });
+
+  it("shows when a final newline is removed", () => {
+    expect(texts(computeDiffLines("a\n", "a"))).toEqual([
+      ["del", "a"],
+      ["add", "a"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+  });
+
+  it("marks an unchanged unterminated final context line", () => {
+    expect(texts(computeDiffLines("a\nb\nc", "a\nX\nc"))).toEqual([
+      ["ctx", "a"],
+      ["del", "b"],
+      ["add", "X"],
+      ["ctx", "c"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+  });
+
+  it("marks an unterminated new file only once", () => {
+    const lines = computeDiffLines(null, "a");
+    expect(texts(lines)).toEqual([
+      ["add", "a"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+    expect(lines.filter((line) => line.kind === "eof")).toHaveLength(1);
+  });
+
+  it("collapses a long unchanged interior run, keeping 3 lines of context each side", () => {
+    const common = Array.from({ length: 20 }, (_, i) => `line${i}`);
+    const oldText = [...common.slice(0, 10), "OLD", ...common.slice(10)].join("\n");
+    const newText = [...common.slice(0, 10), "NEW", ...common.slice(10)].join("\n");
+    const lines = computeDiffLines(oldText, newText);
+    // The leading run keeps only its last 3 lines (adjacent to the change),
+    // behind a marker for the rest; the trailing run mirrors that.
+    expect(lines[0].kind).toBe("hunk");
+    expect(lines[1]).toEqual({ kind: "ctx", text: "line7" });
+    expect(lines[2]).toEqual({ kind: "ctx", text: "line8" });
+    expect(lines[3]).toEqual({ kind: "ctx", text: "line9" });
+    expect(lines[4].kind).toBe("del");
+    expect(lines[5].kind).toBe("add");
+    expect(lines[6]).toEqual({ kind: "ctx", text: "line10" });
+    expect(lines.filter((l) => l.kind === "hunk")).toHaveLength(2);
+  });
+
+  it("preserves the EOF marker when a long unterminated trailing run collapses", () => {
+    const trailing = Array.from({ length: 10 }, (_, i) => `t${i}`);
+    const oldText = ["OLD", ...trailing].join("\n");
+    const newText = ["NEW", ...trailing].join("\n");
+
+    expect(texts(computeDiffLines(oldText, newText))).toEqual([
+      ["del", "OLD"],
+      ["add", "NEW"],
+      ["ctx", "t0"],
+      ["ctx", "t1"],
+      ["ctx", "t2"],
+      ["hunk", "⋯ 7 unchanged lines ⋯"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+  });
+
+  it("produces one hunk for the long middle run, none for the short edges", () => {
+    // Edge runs (2 lines) fit within their one-sided 3-line context budget;
+    // only the interior run (10 lines, budgeted 3+3=6) needs to collapse.
+    const middle = Array.from({ length: 10 }, (_, i) => `c${i}`);
+    const oldText = ["lead0", "lead1", "OLD1", ...middle, "OLD2", "trail0", "trail1"].join("\n");
+    const newText = ["lead0", "lead1", "NEW1", ...middle, "NEW2", "trail0", "trail1"].join("\n");
+    const lines = computeDiffLines(oldText, newText);
+    const dels = lines.filter((l) => l.kind === "del").map((l) => l.text);
+    const adds = lines.filter((l) => l.kind === "add").map((l) => l.text);
+    expect(dels).toEqual(["OLD1", "OLD2"]);
+    expect(adds).toEqual(["NEW1", "NEW2"]);
+    expect(lines.filter((l) => l.kind === "hunk")).toHaveLength(1);
+    expect(texts(lines).slice(0, 2)).toEqual([
+      ["ctx", "lead0"],
+      ["ctx", "lead1"],
+    ]);
+    expect(texts(lines).slice(-3)).toEqual([
+      ["ctx", "trail0"],
+      ["ctx", "trail1"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+  });
+
+  it("handles an old file with no trailing newline", () => {
+    const lines = computeDiffLines("a\nb", "a\nb\nc");
+    expect(texts(lines)).toEqual([
+      ["ctx", "a"],
+      ["del", "b"],
+      ["eof", "\\ No newline at end of file"],
+      ["add", "b"],
+      ["add", "c"],
+      ["eof", "\\ No newline at end of file"],
+    ]);
+  });
+
+  it("falls back to a bounded coarse diff for a pathological changed middle", () => {
+    const oldLines = Array.from({ length: 501 }, (_, index) => `line${index}`);
+    const newLines = [...oldLines.slice(1), oldLines[0]];
+    const lines = computeDiffLines(`${oldLines.join("\n")}\n`, `${newLines.join("\n")}\n`);
+    expect(lines).toHaveLength(1_002);
+    expect(lines.slice(0, 501).every((line) => line.kind === "del")).toBe(true);
+    expect(lines.slice(501).every((line) => line.kind === "add")).toBe(true);
+  });
+});
+
+describe("diffStats", () => {
+  it("counts add/del lines, ignoring context and hunk markers", () => {
+    const lines = computeDiffLines("a\nb\nc\n", "a\nx\ny\nc\n");
+    expect(diffStats(lines)).toEqual({ added: 2, removed: 1 });
+  });
+
+  it("is zero for identical text", () => {
+    expect(diffStats(computeDiffLines("same\n", "same\n"))).toEqual({ added: 0, removed: 0 });
+  });
+});

web/src/structuredDiff.ts

@@ -0,0 +1,167 @@
+// Line-level diff for a `ToolDiff` row's `Diff` content block (#140). ACP
+// hands over full `oldText`/`newText`, not a unified-diff patch, so the
+// coloured hunks the design calls for have to be computed here.
+
+export type DiffLineKind = "add" | "del" | "ctx" | "hunk" | "eof";
+
+export interface DiffLine {
+  kind: DiffLineKind;
+  /** The line's text (a `hunk` line is a human summary, not source text). */
+  text: string;
+}
+
+/** Interior unchanged runs longer than this collapse to a summary line
+ *  flanked by this many lines of real context on each side. */
+const CONTEXT = 3;
+
+/** Bounds the O(n·m) LCS table: above this cell count, the changed middle is
+ *  shown as one coarse del-then-add block instead of a fine-grained diff —
+ *  still correct, just not minimal. */
+const LCS_CELL_LIMIT = 250_000;
+
+interface SourceLine {
+  text: string;
+  terminated: boolean;
+}
+
+function splitLines(text: string): SourceLine[] {
+  if (text === "") return [];
+  const parts = text.split("\n");
+  const hasFinalNewline = text.endsWith("\n");
+  if (hasFinalNewline) parts.pop();
+  return parts.map((line, index) => ({
+    text: line,
+    terminated: index < parts.length - 1 || hasFinalNewline,
+  }));
+}
+
+type Op = { kind: "add" | "del" | "ctx"; line: SourceLine };
+
+function sameLine(a: SourceLine, b: SourceLine): boolean {
+  return a.text === b.text && a.terminated === b.terminated;
+}
+
+/** Longest-common-subsequence diff of two line arrays, already trimmed of any
+ *  shared prefix/suffix by the caller. */
+function lcsDiff(a: SourceLine[], b: SourceLine[]): Op[] {
+  const n = a.length;
+  const m = b.length;
+  if (n === 0) return b.map((line) => ({ kind: "add", line }));
+  if (m === 0) return a.map((line) => ({ kind: "del", line }));
+  if (n * m > LCS_CELL_LIMIT) {
+    return [...a.map((line) => ({ kind: "del" as const, line })), ...b.map((line) => ({ kind: "add" as const, line }))];
+  }
+  // dp[i][j] = length of the LCS of a[i:] and b[j:].
+  const columns = m + 1;
+  const dp = new Uint32Array((n + 1) * columns);
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      dp[i * columns + j] = sameLine(a[i], b[j])
+        ? dp[(i + 1) * columns + j + 1] + 1
+        : Math.max(dp[(i + 1) * columns + j], dp[i * columns + j + 1]);
+    }
+  }
+  const ops: Op[] = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (sameLine(a[i], b[j])) {
+      ops.push({ kind: "ctx", line: a[i] });
+      i++;
+      j++;
+    } else if (dp[(i + 1) * columns + j] >= dp[i * columns + j + 1]) {
+      ops.push({ kind: "del", line: a[i] });
+      i++;
+    } else {
+      ops.push({ kind: "add", line: b[j] });
+      j++;
+    }
+  }
+  while (i < n) ops.push({ kind: "del", line: a[i++] });
+  while (j < m) ops.push({ kind: "add", line: b[j++] });
+  return ops;
+}
+
+function diffLines(a: SourceLine[], b: SourceLine[]): Op[] {
+  let pre = 0;
+  while (pre < a.length && pre < b.length && sameLine(a[pre], b[pre])) pre++;
+  let suf = 0;
+  while (
+    suf < a.length - pre &&
+    suf < b.length - pre &&
+    sameLine(a[a.length - 1 - suf], b[b.length - 1 - suf])
+  ) {
+    suf++;
+  }
+  const prefixCtx: Op[] = a.slice(0, pre).map((line) => ({ kind: "ctx", line }));
+  const suffixCtx: Op[] = a.slice(a.length - suf).map((line) => ({ kind: "ctx", line }));
+  const middle = lcsDiff(a.slice(pre, a.length - suf), b.slice(pre, b.length - suf));
+  return [...prefixCtx, ...middle, ...suffixCtx];
+}
+
+/** Collapse a long run of unchanged lines to a summary, keeping up to
+ *  {@link CONTEXT} real lines adjacent to each neighbouring change — same
+ *  shape a unified diff gives a reader, without claiming line numbers this
+ *  module never tracked. A run touching the start/end of the whole diff has
+ *  no change to be adjacent to on that side, so it keeps no context there
+ *  (unless it is the *only* run, i.e. nothing changed at all). */
+function hunk(ops: Op[]): DiffLine[] {
+  const out: DiffLine[] = [];
+  const push = (op: Op) => {
+    out.push({ kind: op.kind, text: op.line.text });
+    if (!op.line.terminated) {
+      out.push({ kind: "eof", text: "\\ No newline at end of file" });
+    }
+  };
+  let i = 0;
+  while (i < ops.length) {
+    if (ops[i].kind !== "ctx") {
+      push(ops[i]);
+      i++;
+      continue;
+    }
+    let j = i;
+    while (j < ops.length && ops[j].kind === "ctx") j++;
+    const run = ops.slice(i, j);
+    const wholeDiff = i === 0 && j === ops.length;
+    const keepHead = wholeDiff || i > 0 ? CONTEXT : 0;
+    const keepTail = wholeDiff || j < ops.length ? CONTEXT : 0;
+    if (run.length <= keepHead + keepTail) {
+      run.forEach(push);
+    } else {
+      if (keepHead) run.slice(0, keepHead).forEach(push);
+      const collapsed = run.slice(keepHead, run.length - keepTail);
+      out.push({
+        kind: "hunk",
+        text: `⋯ ${collapsed.length} unchanged lines ⋯`,
+      });
+      if (collapsed.some((op) => !op.line.terminated)) {
+        out.push({ kind: "eof", text: "\\ No newline at end of file" });
+      }
+      if (keepTail) run.slice(run.length - keepTail).forEach(push);
+    }
+    i = j;
+  }
+  return out;
+}
+
+/** Coloured, hunked diff lines for a `Diff` content block. `oldText` absent
+ *  (a new file) renders every line of `newText` as added. */
+export function computeDiffLines(oldText: string | null | undefined, newText: string): DiffLine[] {
+  const newLines = splitLines(newText);
+  if (oldText == null) return hunk(newLines.map((line) => ({ kind: "add", line })));
+  const ops = diffLines(splitLines(oldText), newLines);
+  return hunk(ops);
+}
+
+/** `+added -removed` counts straight off the diff — real derived data, not a
+ *  fabricated duration or line count. */
+export function diffStats(lines: DiffLine[]): { added: number; removed: number } {
+  let added = 0;
+  let removed = 0;
+  for (const line of lines) {
+    if (line.kind === "add") added++;
+    else if (line.kind === "del") removed++;
+  }
+  return { added, removed };
+}

web/src/structuredRender.test.ts

@@ -0,0 +1,490 @@
+// @vitest-environment happy-dom
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  buildToolGroup,
+  buildTranscriptRow,
+  renderInlineMarkdown,
+  renderMarkdown,
+} from "./structuredRender.js";
+import type { TranscriptRow } from "./types.js";
+
+function row<K extends TranscriptRow["kind"]>(
+  kind: K,
+  data: unknown,
+  id = "r1",
+): TranscriptRow & { kind: K } {
+  return { id, kind, data };
+}
+
+describe("buildTranscriptRow: user/agent/thought", () => {
+  it("renders a user row with the text content and no markdown", () => {
+    const el = buildTranscriptRow(
+      row("user", { content: { type: "text", text: "hi <b>there</b>" } }),
+    );
+    expect(el.className).toContain("st-row-user");
+    expect(el.textContent).toContain("hi <b>there</b>");
+    expect(el.querySelector(".st-who")).toBeNull();
+    // never actual markup from user input
+    expect(el.querySelector("b")).toBeNull();
+  });
+
+  it("renders agent prose as paragraphs with inline markdown", () => {
+    const el = buildTranscriptRow(
+      row("agent_text", { content: { type: "text", text: "one **two** `three`\n\nfour" } }),
+    );
+    expect(el.className).toContain("st-row-agent");
+    const ps = el.querySelectorAll("p");
+    expect(ps).toHaveLength(2);
+    expect(ps[0].innerHTML).toContain("<strong>two</strong>");
+    expect(ps[0].innerHTML).toContain("<code>three</code>");
+  });
+
+  it("trims ACP framing whitespace and renders thought-row inline markdown", () => {
+    const el = buildTranscriptRow(
+      row("agent_thought", {
+        content: { type: "text", text: "\n\n**Planning comply tool commentary update**\n" },
+      }),
+    );
+    expect(el.className).toContain("st-row-thought");
+    expect(el.textContent).toBe("Planning comply tool commentary update");
+    expect(el.querySelector("strong")?.textContent).toBe("Planning comply tool commentary update");
+  });
+
+  it("falls back to a labelled placeholder for non-text content, never crashing", () => {
+    const el = buildTranscriptRow(row("user", { content: { type: "image" } }));
+    expect(el.textContent).toContain("[image]");
+  });
+
+  it("never clips text: a very long user message is not truncated", () => {
+    const long = "x".repeat(5000);
+    const el = buildTranscriptRow(row("user", { content: { type: "text", text: long } }));
+    expect(el.textContent).toContain(long);
+  });
+
+  it("copies message blocks on click and supports keyboard activation", async () => {
+    const writeText = vi.fn().mockResolvedValue(undefined);
+    Object.defineProperty(navigator, "clipboard", { configurable: true, value: { writeText } });
+    const el = buildTranscriptRow(
+      row("agent_text", { content: { type: "text", text: "copy **this** exactly" } }),
+    );
+    expect(el.getAttribute("role")).toBe("button");
+    el.click();
+    await Promise.resolve();
+    expect(writeText).toHaveBeenCalledWith("copy **this** exactly");
+    el.dispatchEvent(new KeyboardEvent("keydown", { key: "Enter", bubbles: true }));
+    await Promise.resolve();
+    expect(writeText).toHaveBeenCalledTimes(2);
+  });
+});
+
+describe("renderInlineMarkdown", () => {
+  it("escapes raw HTML before applying markdown", () => {
+    expect(renderInlineMarkdown("<script>alert(1)</script>")).not.toContain("<script>");
+  });
+
+  it("does not treat a single asterisk pair meant as bold as nested italics", () => {
+    expect(renderInlineMarkdown("**bold**")).toBe("<strong>bold</strong>");
+  });
+});
+
+describe("renderMarkdown", () => {
+  it("renders GFM tables as semantic table markup", () => {
+    const html = renderMarkdown("| Model | State |\n| --- | --- |\n| Opus | ready |");
+    expect(html).toContain("<table>");
+    expect(html).toContain("<th>Model</th>");
+    expect(html).toContain("<td>Opus</td>");
+  });
+
+  it("removes executable HTML and unsafe URLs", () => {
+    const html = renderMarkdown(
+      '<img src=x onerror="alert(1)"><script>alert(2)</script>[bad](javascript:alert(3))',
+    );
+    expect(html).not.toContain("<img");
+    expect(html).not.toContain("<script");
+    expect(html).not.toContain('href="javascript:');
+  });
+});
+
+describe("buildTranscriptRow: tool calls", () => {
+  it("shows glyph, name, argument and no meta for a completed non-diff call", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        toolCallId: "t1",
+        title: "Read(src/lib.rs)",
+        kind: "read",
+        status: "completed",
+      }),
+    );
+    const head = el.querySelector(".st-tool-head") as HTMLButtonElement;
+    expect(head.querySelector(".st-tool-name")!.textContent).toBe("Read");
+    expect(head.querySelector(".st-tool-arg")!.textContent).toBe("src/lib.rs");
+    expect(head.querySelector(".st-tool-meta")).toBeNull();
+  });
+
+  it("falls back to the kind label and full title when the title has no Name(arg) shape", () => {
+    const el = buildTranscriptRow(row("tool_call", { title: "does something odd", kind: "execute" }));
+    const head = el.querySelector(".st-tool-head")!;
+    expect(head.querySelector(".st-tool-name")!.textContent).toBe("Execute");
+    expect(head.querySelector(".st-tool-arg")!.textContent).toBe("does something odd");
+  });
+
+  it("shows a running badge for an in-progress call", () => {
+    const el = buildTranscriptRow(row("tool_call", { title: "Bash(sleep 1)", status: "in_progress" }));
+    const meta = el.querySelector(".st-tool-meta")!;
+    expect(meta.textContent).toBe("running");
+    expect(meta.className).toContain("st-tool-meta-running");
+  });
+
+  it("shows a failed badge for a failed call", () => {
+    const el = buildTranscriptRow(row("tool_call", { title: "Bash(false)", status: "failed" }));
+    expect(el.querySelector(".st-tool-meta")!.textContent).toBe("failed");
+  });
+
+  it("starts collapsed and expands its text output on click", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "Grep(x)",
+        status: "completed",
+        content: [{ type: "content", content: { type: "text", text: "match found" } }],
+      }),
+    );
+    const head = el.querySelector(".st-tool-head") as HTMLButtonElement;
+    const out = el.querySelector(".st-tool-out") as HTMLElement;
+    expect(out.hidden).toBe(true);
+    expect(head.getAttribute("aria-expanded")).toBe("false");
+    head.click();
+    expect(out.hidden).toBe(false);
+    expect(head.getAttribute("aria-expanded")).toBe("true");
+    expect(out.textContent).toContain("match found");
+    head.click();
+    expect(out.hidden).toBe(false);
+    expect(out.getAttribute("aria-hidden")).toBe("true");
+    expect(out.inert).toBe(true);
+    expect(out.classList.contains("is-expanded")).toBe(false);
+  });
+
+  it("does not expand when there is nothing to show", () => {
+    const el = buildTranscriptRow(row("tool_call", { title: "Read(x)", status: "completed" }));
+    const head = el.querySelector(".st-tool-head") as HTMLButtonElement;
+    head.click();
+    expect(head.getAttribute("aria-expanded")).toBe("false");
+  });
+
+  it("renders command fields and keeps the exact JSON available", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "Bash(test)",
+        rawInput: { command: "printf ok", cwd: "/workspace", timeout_ms: 1000 },
+        rawOutput: { formatted_output: "ok", exit_code: 0 },
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    expect(el.querySelector(".st-tool-detail pre")!.textContent).toBe("printf ok");
+    expect(el.querySelector(".st-tool-fact")!.textContent).toBe("Exit code0");
+    const raw = el.querySelector(".st-tool-raw") as HTMLDetailsElement;
+    expect(raw.open).toBe(false);
+    expect(raw.textContent).toContain('"timeout_ms": 1000');
+    expect(raw.textContent).toContain('"exit_code": 0');
+  });
+
+  it("renders MCP arguments and results without hiding the source payload", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "mcp.github.search",
+        rawInput: { server: "github", tool: "search", arguments: { query: "ACP" } },
+        rawOutput: { result: { count: 2 }, error: null },
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    const labels = [
+      ...el.querySelectorAll(
+        ".st-tool-out > .st-disclosure-clip > .st-disclosure-inner > .st-tool-detail",
+      ),
+    ].map((node) => node.querySelector(".st-tool-detail-label")?.textContent);
+    expect(labels).toEqual(["Arguments", "Result"]);
+    expect(el.querySelector(".st-tool-raw")!.textContent).toContain('"server": "github"');
+  });
+
+  it("renders a recognized web search query", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "Search the web",
+        rawInput: { type: "webSearch", query: "Agent Client Protocol", action: { type: "search" } },
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    expect(el.querySelector(".st-tool-detail-label")!.textContent).toBe("Query");
+    expect(el.querySelector(".st-tool-detail pre")!.textContent).toBe("Agent Client Protocol");
+  });
+
+  it("falls back to raw JSON for an unknown provider shape", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", { title: "Custom", rawInput: { peculiar: [1, 2] }, rawOutput: "done" }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    expect(
+      el.querySelectorAll(
+        ".st-tool-out > .st-disclosure-clip > .st-disclosure-inner > .st-tool-detail",
+      ),
+    ).toHaveLength(0);
+    expect(el.querySelector(".st-tool-raw")!.textContent).toContain('"peculiar"');
+    expect(el.querySelector(".st-tool-raw")!.textContent).toContain('"done"');
+  });
+
+  it("renders standardized content before provider-specific and raw data", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "Bash(test)",
+        content: [
+          { type: "content", content: { type: "text", text: "typed result" } },
+          { type: "content", content: { type: "resource_link", name: "report", uri: "file:///tmp/report" } },
+          { type: "terminal", terminalId: "term-1" },
+        ],
+        rawInput: { command: "test" },
+        rawOutput: { formatted_output: "typed result", exit_code: 0 },
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    const inner = el.querySelector(".st-tool-out > .st-disclosure-clip > .st-disclosure-inner")!;
+    expect([...inner.children].map((node) => node.className)).toEqual([
+      "st-tool-text st-copyable",
+      "st-tool-resource",
+      "st-tool-terminal",
+      "st-tool-detail",
+      "st-tool-fact",
+      "st-tool-raw",
+    ]);
+    expect(el.querySelector(".st-tool-resource")!.textContent).toContain("file:///tmp/report");
+    expect(el.querySelector(".st-tool-terminal")!.textContent).toBe("Terminal · term-1");
+  });
+
+  it("renders safe typed image and audio blocks as media controls", () => {
+    const el = buildTranscriptRow(
+      row("tool_call", {
+        title: "Media",
+        content: [
+          { type: "content", content: { type: "image", mimeType: "image/png", data: "aW1hZ2U=" } },
+          { type: "content", content: { type: "audio", mimeType: "audio/mpeg", data: "YXVkaW8=" } },
+        ],
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    expect((el.querySelector(".st-tool-image") as HTMLImageElement).src).toBe("data:image/png;base64,aW1hZ2U=");
+    expect((el.querySelector(".st-tool-audio") as HTMLAudioElement).src).toBe("data:audio/mpeg;base64,YXVkaW8=");
+  });
+});
+
+describe("buildToolGroup", () => {
+  it("starts collapsed, then reveals independently expandable tool calls", () => {
+    const rows = [
+      row("tool_call", { title: "Read(a.ts)", content: [{ type: "content", content: { type: "text", text: "a" } }] }, "t1"),
+      row("tool_call", { title: "Bash(test)", content: [{ type: "content", content: { type: "text", text: "ok" } }] }, "t2"),
+    ];
+    const children = rows.map((tool) => buildTranscriptRow(tool));
+    const onExpanded = vi.fn();
+    const group = buildToolGroup("turn:u1", rows, children, false, onExpanded);
+    const head = group.querySelector<HTMLButtonElement>(".st-tool-group-head")!;
+    const body = group.querySelector<HTMLElement>(".st-tool-group-body")!;
+    expect(head.textContent).toContain("2 tool calls");
+    expect(body.getAttribute("aria-hidden")).toBe("true");
+    expect(body.inert).toBe(true);
+    head.click();
+    expect(body.getAttribute("aria-hidden")).toBe("false");
+    expect(body.classList.contains("is-expanded")).toBe(true);
+    expect(onExpanded).toHaveBeenCalledWith(true);
+    const toolHeads = group.querySelectorAll<HTMLButtonElement>(".st-tool-head");
+    toolHeads[1].click();
+    expect(toolHeads[0].getAttribute("aria-expanded")).toBe("false");
+    expect(toolHeads[1].getAttribute("aria-expanded")).toBe("true");
+  });
+});
+
+describe("buildTranscriptRow: tool diffs", () => {
+  it("shows +added -removed derived from the diff, and renders coloured hunks on expand", () => {
+    const el = buildTranscriptRow(
+      row("tool_diff", {
+        title: "Edit(x.rs)",
+        status: "completed",
+        content: [{ type: "diff", path: "/repo/x.rs", oldText: "a\nb\n", newText: "a\nc\n" }],
+      }),
+    );
+    const meta = el.querySelector(".st-tool-meta")!;
+    expect(meta.textContent).toContain("+1");
+    expect(meta.textContent).toContain("−1");
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    const diff = el.querySelector(".st-diff") as HTMLElement;
+    expect(diff).not.toBeNull();
+    expect(diff.querySelector(".st-ln-add")!.textContent).toBe("c");
+    expect(diff.querySelector(".st-ln-del")!.textContent).toBe("b");
+  });
+
+  it("gives the diff its own horizontally-scrolling container", () => {
+    const el = buildTranscriptRow(
+      row("tool_diff", {
+        title: "Edit(x.rs)",
+        content: [{ type: "diff", path: "/repo/x.rs", newText: "new file\n" }],
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    // jsdom/happy-dom doesn't compute layout CSS, so assert the class the
+    // stylesheet keys `overflow-x: auto` off, not a computed style.
+    expect(el.querySelector(".st-diff")!.classList).toContain("st-diff");
+  });
+
+  it("renders a visible marker for a removed final newline", () => {
+    const el = buildTranscriptRow(
+      row("tool_diff", {
+        title: "Edit(x.rs)",
+        content: [{ type: "diff", path: "/repo/x.rs", oldText: "same\n", newText: "same" }],
+      }),
+    );
+    (el.querySelector(".st-tool-head") as HTMLButtonElement).click();
+    expect(el.querySelector(".st-ln-eof")!.textContent).toBe("\\ No newline at end of file");
+  });
+});
+
+describe("buildTranscriptRow: approval", () => {
+  const approvalRow = (options: Array<{ optionId: string; name: string; kind: string }>) =>
+    row("approval", {
+      sessionId: "s1",
+      toolCall: { toolCallId: "t1", title: "Write outside worktree", locations: [{ path: "/etc/x" }] },
+      options,
+    });
+
+  const allThreeOptions = [
+    { optionId: "a1", name: "Allow once", kind: "allow_once" },
+    { optionId: "a2", name: "Allow always", kind: "allow_always" },
+    { optionId: "r1", name: "Reject once", kind: "reject_once" },
+  ];
+
+  it("shows the three decision buttons only when the request offers all three option kinds", () => {
+    const el = buildTranscriptRow(approvalRow(allThreeOptions), {
+      pending: true,
+      onDecide: () => Promise.resolve(),
+    });
+    const buttons = el.querySelectorAll(".st-approval-acts button");
+    expect(buttons).toHaveLength(3);
+    expect(el.querySelector(".st-approval-path")!.textContent).toBe("/etc/x");
+  });
+
+  it("hides the buttons and shows an answered note once resolved", () => {
+    const el = buildTranscriptRow(approvalRow(allThreeOptions), {
+      pending: false,
+      onDecide: () => Promise.resolve(),
+    });
+    expect(el.querySelector(".st-approval-acts")).toBeNull();
+    expect(el.querySelector(".st-approval-resolved")!.textContent).toBe("answered");
+  });
+
+  it("invokes onDecide with the clicked decision and disables the buttons", () => {
+    const onDecide = vi.fn().mockResolvedValue(undefined);
+    const el = buildTranscriptRow(approvalRow(allThreeOptions), { pending: true, onDecide });
+    const buttons = el.querySelectorAll<HTMLButtonElement>(".st-approval-acts button");
+    buttons[2].click();
+    expect(onDecide).toHaveBeenCalledWith("deny");
+    expect(buttons[0].disabled).toBe(true);
+  });
+
+  it("treats a row with no approval state as not pending, defensively", () => {
+    const el = buildTranscriptRow(approvalRow(allThreeOptions));
+    expect(el.querySelector(".st-approval-acts")).toBeNull();
+  });
+
+  it("omits Allow for session when the request offers no allow_always option", () => {
+    const el = buildTranscriptRow(
+      approvalRow([
+        { optionId: "a1", name: "Allow once", kind: "allow_once" },
+        { optionId: "r1", name: "Reject once", kind: "reject_once" },
+      ]),
+      { pending: true, onDecide: () => Promise.resolve() },
+    );
+    const labels = [...el.querySelectorAll(".st-approval-acts button")].map((b) => b.textContent);
+    expect(labels).toEqual(["Allow once", "Deny"]);
+  });
+
+  it("offers Deny for either reject_once or reject_always, never for neither", () => {
+    const rejectAlwaysOnly = buildTranscriptRow(
+      approvalRow([{ optionId: "r2", name: "Reject always", kind: "reject_always" }]),
+      { pending: true, onDecide: () => Promise.resolve() },
+    );
+    expect([...rejectAlwaysOnly.querySelectorAll(".st-approval-acts button")].map((b) => b.textContent)).toEqual([
+      "Deny",
+    ]);
+  });
+
+  it("shows a 'no decision offered' note instead of an empty action row when nothing matches", () => {
+    const el = buildTranscriptRow(approvalRow([{ optionId: "x", name: "Something else", kind: "allow_once" }]), {
+      pending: true,
+      onDecide: () => Promise.resolve(),
+    });
+    // allow_once is offered, so this specific case still shows a button —
+    // use a kind the client doesn't map to any decision at all.
+    expect(el.querySelectorAll(".st-approval-acts button")).toHaveLength(1);
+
+    const none = buildTranscriptRow(approvalRow([]), { pending: true, onDecide: () => Promise.resolve() });
+    expect(none.querySelector(".st-approval-acts")).toBeNull();
+    expect(none.querySelector(".st-approval-resolved")!.textContent).toBe("no decision offered");
+  });
+
+  it("re-enables the buttons when onDecide rejects", async () => {
+    const onDecide = vi.fn().mockRejectedValue(new Error("network down"));
+    const el = buildTranscriptRow(approvalRow(allThreeOptions), { pending: true, onDecide });
+    const buttons = el.querySelectorAll<HTMLButtonElement>(".st-approval-acts button");
+    buttons[0].click();
+    expect(buttons[0].disabled).toBe(true);
+    await Promise.resolve().then(() => Promise.resolve());
+    expect(buttons[0].disabled).toBe(false);
+    expect(buttons[1].disabled).toBe(false);
+  });
+
+  it("leaves the buttons disabled when onDecide resolves", async () => {
+    const onDecide = vi.fn().mockResolvedValue(undefined);
+    const el = buildTranscriptRow(approvalRow(allThreeOptions), { pending: true, onDecide });
+    const buttons = el.querySelectorAll<HTMLButtonElement>(".st-approval-acts button");
+    buttons[0].click();
+    await Promise.resolve().then(() => Promise.resolve());
+    expect(buttons[0].disabled).toBe(true);
+  });
+});
+
+describe("buildTranscriptRow: notice / unknown kinds", () => {
+  it("renders durable per-turn duration and context usage", () => {
+    const el = buildTranscriptRow(
+      row("notice", {
+        maestroTurnMeta: {
+          elapsedMs: 72_000,
+          contextTokens: 18_400,
+          contextDelta: 2_350,
+          outcome: "completed",
+          model: "opus",
+        },
+      }, "turn:1"),
+    )!;
+
+    expect(el.classList.contains("st-turn-meta")).toBe(true);
+    expect(el.textContent).toContain("1m 12s · +2.4k context tokens · opus");
+    expect(el.getAttribute("aria-label")).toBe("Copy turn details");
+  });
+
+  it("renders notice and unknown row kinds safely", () => {
+    expect(buildTranscriptRow(row("notice", { sessionUpdate: "future" }))?.textContent).toBe(
+      "[notice]",
+    );
+    const unknown = { id: "r1", kind: "future_kind", data: {} } as unknown as TranscriptRow;
+    expect(buildTranscriptRow(unknown)?.textContent).toBe("[future_kind]");
+  });
+
+  it("omits command-catalog and session-info notices used only as UI state", () => {
+    expect(
+      buildTranscriptRow(
+        row("notice", { sessionUpdate: "available_commands_update", availableCommands: [] }),
+      ),
+    ).toBeNull();
+    expect(buildTranscriptRow(row("notice", { sessionUpdate: "session_info_update" }))).toBeNull();
+  });
+
+  it("returns no transcript element for a plan row", () => {
+    expect(buildTranscriptRow(row("plan", { entries: [] }))).toBeNull();
+  });
+});

web/src/structuredRender.ts

@@ -0,0 +1,831 @@
+// Pure per-row and rail DOM builders for the structured transcript (#140).
+// No socket, no daemon calls — structured.ts owns the connection and calls
+// into here with data already in hand, so every rendering decision here is
+// unit-testable without a WebSocket.
+
+import { escapeHtml } from "./html.js";
+import { marked, Renderer } from "marked";
+import { computeDiffLines, diffStats } from "./structuredDiff.js";
+import type {
+  AcpContentBlock,
+  AcpPermissionOption,
+  AcpToolCallContent,
+  AcpToolCallLike,
+  StructuredApprovalDecision,
+  TranscriptRow,
+  TurnMeta,
+} from "./types.js";
+
+// ---------------------------------------------------------------------------
+// row taxonomy
+// ---------------------------------------------------------------------------
+
+/** Glyph shown in a tool row's head, by `ToolKind`. Unrecognised/absent kinds
+ *  fall back to the generic bullet — never a blank glyph column. */
+const KIND_GLYPH: Record<string, string> = {
+  read: "≡",
+  edit: "±",
+  delete: "✕",
+  move: "→",
+  search: "⌕",
+  execute: "$",
+  think: "…",
+  fetch: "⇣",
+  switch_mode: "⇄",
+};
+
+const KIND_LABEL: Record<string, string> = {
+  read: "Read",
+  edit: "Edit",
+  delete: "Delete",
+  move: "Move",
+  search: "Search",
+  execute: "Execute",
+  think: "Think",
+  fetch: "Fetch",
+  switch_mode: "Switch mode",
+};
+
+function toolGlyph(kind: string | undefined): string {
+  return (kind && KIND_GLYPH[kind]) || "•";
+}
+
+function toolKindLabel(kind: string | undefined): string {
+  return (kind && KIND_LABEL[kind]) || "Tool";
+}
+
+/** Split a title into `{label, arg}` when it follows the adapter's own
+ *  `Name(argument)` convention; otherwise the whole title is the arg and the
+ *  tool's `kind` supplies a generic label. Never guesses at a shape the data
+ *  doesn't actually show. */
+function splitToolTitle(
+  title: string | undefined,
+  name: string | null | undefined,
+  kind: string | undefined,
+): { label: string; arg: string } {
+  const label = name ?? toolKindLabel(kind);
+  if (!title) return { label, arg: "" };
+  const m = /^(\S+)\(([\s\S]*)\)$/.exec(title);
+  if (m) return { label: name ?? m[1], arg: m[2] };
+  return { label, arg: title };
+}
+
+function el(tag: string, className?: string): HTMLElement {
+  const node = document.createElement(tag);
+  if (className) node.className = className;
+  return node;
+}
+
+/** Content-block text, or a labelled placeholder for anything that isn't
+ *  text — never dropped silently, never fabricated. */
+function contentBlockText(block: AcpContentBlock | undefined): string {
+  if (!block) return "";
+  switch (block.type) {
+    case "text":
+      return block.text;
+    case "image":
+      return "[image]";
+    case "audio":
+      return "[audio]";
+    case "resource_link":
+      return `[resource: ${block.name ?? block.uri ?? "linked"}]`;
+    case "resource":
+      return "[resource]";
+    default:
+      return "";
+  }
+}
+
+/** Small inline renderer retained for compact labels and focused tests. */
+export function renderInlineMarkdown(text: string): string {
+  const escaped = escapeHtml(text);
+  return escaped
+    .replace(/`([^`]+)`/g, "<code>$1</code>")
+    .replace(/\*\*([^*]+)\*\*/g, "<strong>$1</strong>")
+    .replace(/(?<!\*)\*([^*]+)\*(?!\*)/g, "<em>$1</em>");
+}
+
+/** Render assistant output as GFM, then sanitize the complete result before it
+ * enters the DOM. This gives transcripts proper tables, lists, code blocks and
+ * links without trusting model-authored HTML or URL attributes. */
+export function renderMarkdown(text: string): string {
+  const renderer = new Renderer();
+  renderer.html = ({ text: raw }) => escapeHtml(raw);
+  renderer.image = ({ text: alt }) => escapeHtml(alt ? `[image: ${alt}]` : "[image]");
+  renderer.link = ({ href, title, tokens }) => {
+    const label = renderer.parser.parseInline(tokens);
+    const scheme = /^([a-z][a-z\d+.-]*):/i.exec(href.trim())?.[1]?.toLowerCase();
+    if (scheme && !["http", "https", "mailto"].includes(scheme)) return label;
+    const safeTitle = title ? ` title="${escapeHtml(title)}"` : "";
+    return `<a href="${escapeHtml(href)}"${safeTitle}>${label}</a>`;
+  };
+
+  return marked.parse(text, { async: false, gfm: true, renderer });
+}
+
+function renderProse(container: HTMLElement, text: string): void {
+  container.innerHTML = renderMarkdown(text);
+
+  for (const table of Array.from(container.querySelectorAll("table"))) {
+    const scroller = el("div", "st-markdown-table-wrap");
+    table.replaceWith(scroller);
+    scroller.appendChild(table);
+  }
+
+  for (const link of container.querySelectorAll("a")) {
+    link.target = "_blank";
+    link.rel = "noopener noreferrer";
+  }
+}
+
+async function writeClipboard(text: string): Promise<void> {
+  try {
+    await navigator.clipboard.writeText(text);
+    return;
+  } catch {
+    const textarea = document.createElement("textarea");
+    textarea.value = text;
+    textarea.style.position = "fixed";
+    textarea.style.opacity = "0";
+    document.body.appendChild(textarea);
+    textarea.select();
+    const copied = document.execCommand?.("copy") ?? false;
+    textarea.remove();
+    if (!copied) throw new Error("clipboard unavailable");
+  }
+}
+
+function makeCopyable(node: HTMLElement, text: string, label: string): void {
+  if (!text) return;
+  node.classList.add("st-copyable");
+  node.tabIndex = 0;
+  node.setAttribute("role", "button");
+  node.setAttribute("aria-label", `Copy ${label}`);
+  node.title = `Copy ${label}`;
+
+  const copy = () => {
+    void writeClipboard(text).then(
+      () => {
+        node.dataset.copyState = "copied";
+        node.setAttribute("aria-label", `${label} copied`);
+        window.setTimeout(() => {
+          delete node.dataset.copyState;
+          node.setAttribute("aria-label", `Copy ${label}`);
+        }, 1200);
+      },
+      () => {
+        node.dataset.copyState = "error";
+      },
+    );
+  };
+  node.addEventListener("click", (event) => {
+    if ((event.target as Element | null)?.closest("a")) return;
+    copy();
+  });
+  node.addEventListener("keydown", (event) => {
+    if (event.key !== "Enter" && event.key !== " ") return;
+    event.preventDefault();
+    copy();
+  });
+}
+
+// ---------------------------------------------------------------------------
+// row builders
+// ---------------------------------------------------------------------------
+
+function buildContentRow(row: TranscriptRow, variant: "user" | "agent" | "thought"): HTMLElement {
+  const data = row.data as { content?: AcpContentBlock; messageId?: string } | undefined;
+  const text = contentBlockText(data?.content);
+  const displayText = variant === "thought" ? text.trim() : text;
+  const wrap = el("div", `st-row st-row-${variant}`);
+  const body = el("div", "st-body");
+  if (variant === "user") {
+    const line = el("div", "st-user-text");
+    line.textContent = displayText;
+    body.appendChild(line);
+  } else if (variant === "agent") {
+    renderProse(body, displayText);
+  } else {
+    body.innerHTML = renderInlineMarkdown(displayText);
+  }
+  wrap.appendChild(body);
+  const label = variant === "user" ? "message" : variant === "agent" ? "response" : "thought";
+  makeCopyable(wrap, displayText, label);
+  return wrap;
+}
+
+function buildDiffBlock(diff: { path: string; oldText?: string | null; newText: string }): HTMLElement {
+  const wrap = el("div", "st-diff-block");
+  const label = el("div", "st-diff-path");
+  label.textContent = diff.path;
+  label.title = diff.path;
+  makeCopyable(label, diff.path, "path");
+  wrap.appendChild(label);
+  const scroller = el("div", "st-diff");
+  const pre = document.createElement("pre");
+  for (const line of computeDiffLines(diff.oldText, diff.newText)) {
+    const span = document.createElement("span");
+    span.className = `st-ln st-ln-${line.kind}`;
+    span.textContent = line.text;
+    pre.appendChild(span);
+    pre.appendChild(document.createTextNode("\n"));
+  }
+  scroller.appendChild(pre);
+  makeCopyable(scroller, pre.textContent ?? "", "diff");
+  wrap.appendChild(scroller);
+  return wrap;
+}
+
+function printable(value: unknown): string | null {
+  if (value === undefined || value === null) return null;
+  if (typeof value === "string") return value;
+  try {
+    return JSON.stringify(value, null, 2);
+  } catch {
+    return String(value);
+  }
+}
+
+function jsonPrintable(value: unknown): string | null {
+  if (value === undefined) return null;
+  try {
+    return JSON.stringify(value, null, 2) ?? null;
+  } catch {
+    return printable(value);
+  }
+}
+
+function record(value: unknown): Record<string, unknown> | null {
+  if (!value || typeof value !== "object" || Array.isArray(value)) return null;
+  return value as Record<string, unknown>;
+}
+
+function appendToolDetail(container: HTMLElement, label: string, text: string): void {
+  const detail = el("div", "st-tool-detail");
+  const heading = el("div", "st-tool-detail-label");
+  heading.textContent = label;
+  const value = document.createElement("pre");
+  value.textContent = text;
+  makeCopyable(value, text, label.toLowerCase());
+  detail.append(heading, value);
+  container.appendChild(detail);
+}
+
+function appendToolValue(container: HTMLElement, label: string, value: unknown, duplicates?: Set<string>): void {
+  const text = printable(value);
+  if (text !== null && text !== "" && !duplicates?.has(text)) appendToolDetail(container, label, text);
+}
+
+function appendExitCode(container: HTMLElement, value: unknown): void {
+  if (typeof value !== "number") return;
+  const line = el("div", "st-tool-fact");
+  const label = el("span", "st-tool-fact-label");
+  label.textContent = "Exit code";
+  const code = el("code", value === 0 ? "st-tool-exit-ok" : "st-tool-exit-failed");
+  code.textContent = String(value);
+  line.append(label, code);
+  container.appendChild(line);
+}
+
+function appendCommandPayload(
+  container: HTMLElement,
+  input: Record<string, unknown>,
+  output: unknown,
+  contentText: Set<string>,
+): boolean {
+  if (typeof input.command !== "string") return false;
+  appendToolDetail(container, "Command", input.command);
+  appendToolValue(container, "Working directory", input.cwd);
+
+  const result = record(output);
+  if (result) {
+    appendToolValue(container, "Output", result.formatted_output ?? result.stdout ?? result.output, contentText);
+    appendExitCode(container, result.exit_code);
+  }
+  return true;
+}
+
+function appendMcpPayload(
+  container: HTMLElement,
+  input: Record<string, unknown>,
+  output: unknown,
+  contentText: Set<string>,
+): boolean {
+  if (typeof input.server !== "string" || typeof input.tool !== "string" || !("arguments" in input)) return false;
+  appendToolValue(container, "Arguments", input.arguments);
+  const result = record(output);
+  if (result) {
+    appendToolValue(container, "Result", result.result, contentText);
+    appendToolValue(container, "Error", result.error);
+  }
+  return true;
+}
+
+function appendSearchPayload(
+  container: HTMLElement,
+  input: Record<string, unknown>,
+  tool: AcpToolCallLike,
+): boolean {
+  if (typeof input.query !== "string" || (tool.kind !== "search" && input.type !== "webSearch")) return false;
+  appendToolDetail(container, "Query", input.query);
+  appendToolValue(container, "Action", input.action);
+  return true;
+}
+
+function appendFunctionPayload(
+  container: HTMLElement,
+  input: Record<string, unknown>,
+  output: unknown,
+  contentText: Set<string>,
+): boolean {
+  if (!("arguments" in input)) return false;
+  appendToolValue(container, "Arguments", input.arguments);
+  const result = record(output);
+  if (result) appendToolValue(container, "Result", result.output, contentText);
+  return true;
+}
+
+function appendKnownToolPayload(
+  container: HTMLElement,
+  tool: AcpToolCallLike,
+  content: AcpToolCallContent[],
+): void {
+  const input = record(tool.rawInput);
+  if (!input) return;
+  const contentText = new Set(
+    content
+      .filter((block): block is Extract<AcpToolCallContent, { type: "content" }> => block.type === "content")
+      .filter((block) => block.content.type === "text")
+      .map((block) => (block.content as Extract<AcpContentBlock, { type: "text" }>).text),
+  );
+  if (appendCommandPayload(container, input, tool.rawOutput, contentText)) return;
+  if (appendMcpPayload(container, input, tool.rawOutput, contentText)) return;
+  if (appendSearchPayload(container, input, tool)) return;
+  appendFunctionPayload(container, input, tool.rawOutput, contentText);
+}
+
+function safeMediaSource(
+  mimeType: string | undefined,
+  data: string | undefined,
+  family: "image" | "audio",
+): string | null {
+  if (!mimeType || !data || !new RegExp(`^${family}/[a-z0-9.+-]+$`, "i").test(mimeType)) return null;
+  return `data:${mimeType};base64,${data}`;
+}
+
+function appendContentBlock(container: HTMLElement, block: AcpContentBlock): void {
+  if (block.type === "text") {
+    if (!block.text) return;
+    const text = el("div", "st-tool-text");
+    text.textContent = block.text;
+    makeCopyable(text, block.text, "output");
+    container.appendChild(text);
+    return;
+  }
+  if (block.type === "image") {
+    const source = safeMediaSource(block.mimeType, block.data, "image");
+    if (source) {
+      const image = document.createElement("img");
+      image.className = "st-tool-image";
+      image.src = source;
+      image.alt = "Tool output";
+      image.loading = "lazy";
+      container.appendChild(image);
+      return;
+    }
+    appendToolValue(container, "Image", block.uri ?? block.mimeType ?? "Unavailable");
+    return;
+  }
+  if (block.type === "audio") {
+    const source = safeMediaSource(block.mimeType, block.data, "audio");
+    if (source) {
+      const audio = document.createElement("audio");
+      audio.className = "st-tool-audio";
+      audio.controls = true;
+      audio.src = source;
+      container.appendChild(audio);
+      return;
+    }
+    appendToolValue(container, "Audio", block.mimeType ?? "Unavailable");
+    return;
+  }
+  if (block.type === "resource_link") {
+    const resource = el("div", "st-tool-resource");
+    const name = el("span", "st-tool-resource-name");
+    name.textContent = block.title ?? block.name ?? "Resource";
+    resource.appendChild(name);
+    if (block.uri) {
+      const uri = el("code", "st-tool-resource-uri");
+      uri.textContent = block.uri;
+      makeCopyable(uri, block.uri, "resource URI");
+      resource.appendChild(uri);
+    }
+    if (block.description) {
+      const description = el("span", "st-tool-resource-description");
+      description.textContent = block.description;
+      resource.appendChild(description);
+    }
+    container.appendChild(resource);
+    return;
+  }
+  const resource = block.resource;
+  if (typeof resource?.text === "string") {
+    appendToolDetail(container, resource.uri ? `Resource · ${resource.uri}` : "Resource", resource.text);
+  } else {
+    appendToolValue(container, "Resource", resource);
+  }
+}
+
+function appendStandardContent(container: HTMLElement, content: AcpToolCallContent[]): void {
+  for (const block of content) {
+    if (block.type === "content") appendContentBlock(container, block.content);
+    if (block.type === "diff") container.appendChild(buildDiffBlock(block));
+    if (block.type === "terminal") {
+      const note = el("div", "st-tool-terminal");
+      note.textContent = block.terminalId ? `Terminal · ${block.terminalId}` : "Embedded terminal";
+      container.appendChild(note);
+    }
+  }
+}
+
+function appendRawPayload(container: HTMLElement, tool: AcpToolCallLike): void {
+  const input = jsonPrintable(tool.rawInput);
+  const output = jsonPrintable(tool.rawOutput);
+  if (input === null && output === null) return;
+
+  const disclosure = document.createElement("details");
+  disclosure.className = "st-tool-raw";
+  const summary = document.createElement("summary");
+  summary.textContent = "Raw JSON";
+  disclosure.appendChild(summary);
+  const body = el("div", "st-tool-raw-body");
+  if (input !== null) appendToolDetail(body, "Input", input);
+  if (output !== null) appendToolDetail(body, "Output", output);
+  disclosure.appendChild(body);
+  container.appendChild(disclosure);
+}
+
+function setDisclosure(element: HTMLElement, expanded: boolean, animate = false): void {
+  element.hidden = false;
+  if (animate && expanded && !element.classList.contains("is-expanded")) {
+    // Establish the collapsed grid track before opening it in the same event
+    // turn. Without this read, a freshly lazy-built tool body has no painted
+    // starting state and the browser quite reasonably skips the transition.
+    void element.offsetHeight;
+  }
+  element.classList.toggle("is-expanded", expanded);
+  element.setAttribute("aria-hidden", String(!expanded));
+  element.inert = !expanded;
+}
+
+/** `+added -removed` across every diff block in a tool call's content —
+ *  real derived data, never a fabricated duration. */
+function toolDiffMeta(content: AcpToolCallContent[]): string {
+  let added = 0;
+  let removed = 0;
+  for (const block of content) {
+    if (block.type !== "diff") continue;
+    const stats = diffStats(computeDiffLines(block.oldText, block.newText));
+    added += stats.added;
+    removed += stats.removed;
+  }
+  return `+${added} −${removed}`;
+}
+
+function statusMeta(status: string | undefined, hasDiff: boolean): { text: string; kind: string } | null {
+  if (status === "in_progress") return { text: "running", kind: "running" };
+  if (status === "failed") return { text: "failed", kind: "failed" };
+  if (status === "pending" && !hasDiff) return { text: "pending", kind: "pending" };
+  return null;
+}
+
+function buildToolRow(
+  row: TranscriptRow,
+  expanded: boolean,
+  onExpandedChange?: (expanded: boolean) => void,
+): HTMLElement {
+  const tool = (row.data ?? {}) as AcpToolCallLike;
+  const content = tool.content ?? [];
+  const hasDiff = content.some((c) => c.type === "diff");
+  const { label, arg } = splitToolTitle(tool.title, tool.name, tool.kind);
+
+  const wrap = el("div", "st-row st-row-tool");
+  const card = el("div", "st-tool");
+  wrap.appendChild(card);
+
+  const head = document.createElement("button");
+  head.type = "button";
+  head.className = "st-tool-head";
+  head.setAttribute("aria-expanded", "false");
+
+  const glyph = el("span", "st-tool-glyph");
+  glyph.textContent = toolGlyph(tool.kind);
+  glyph.setAttribute("aria-hidden", "true");
+  const name = el("span", "st-tool-name");
+  name.textContent = label;
+  const argEl = el("span", "st-tool-arg");
+  argEl.textContent = arg;
+  argEl.title = arg;
+  head.append(glyph, name, argEl);
+
+  const metaParts: string[] = [];
+  if (hasDiff) metaParts.push(toolDiffMeta(content));
+  const meta = statusMeta(tool.status, hasDiff);
+  if (meta) metaParts.push(meta.text);
+  if (metaParts.length > 0) {
+    const metaEl = el("span", "st-tool-meta");
+    if (meta) metaEl.classList.add(`st-tool-meta-${meta.kind}`);
+    metaEl.textContent = metaParts.join(" · ");
+    head.appendChild(metaEl);
+  }
+  card.appendChild(head);
+
+  const out = el("div", "st-tool-out st-disclosure");
+  const outClip = el("div", "st-disclosure-clip");
+  const outInner = el("div", "st-disclosure-inner");
+  outClip.appendChild(outInner);
+  out.appendChild(outClip);
+  out.hidden = true;
+  let outBuilt = false;
+  const buildOut = () => {
+    if (outBuilt) return;
+    outBuilt = true;
+    appendStandardContent(outInner, content);
+    appendKnownToolPayload(outInner, tool, content);
+    appendRawPayload(outInner, tool);
+  };
+  card.appendChild(out);
+
+  const setExpanded = (nextExpanded: boolean, animate = false) => {
+    if (nextExpanded) buildOut();
+    if (outInner.children.length === 0) nextExpanded = false;
+    head.setAttribute("aria-expanded", String(nextExpanded));
+    if (outInner.children.length === 0) {
+      out.hidden = true;
+    } else {
+      setDisclosure(out, nextExpanded, animate);
+    }
+  };
+  head.addEventListener("click", () => {
+    setExpanded(head.getAttribute("aria-expanded") !== "true", true);
+    onExpandedChange?.(head.getAttribute("aria-expanded") === "true");
+  });
+  setExpanded(expanded);
+
+  return wrap;
+}
+
+export function buildToolGroup(
+  id: string,
+  rows: TranscriptRow[],
+  children: HTMLElement[],
+  expanded: boolean,
+  onExpandedChange?: (expanded: boolean) => void,
+): HTMLElement {
+  const wrap = el("div", "st-tool-group");
+  wrap.dataset.toolGroupId = id;
+  const head = document.createElement("button");
+  head.type = "button";
+  head.className = "st-tool-group-head";
+  head.setAttribute("aria-expanded", String(expanded));
+
+  const glyph = el("span", "st-tool-group-glyph");
+  glyph.textContent = "›";
+  glyph.setAttribute("aria-hidden", "true");
+  const title = el("span", "st-tool-group-title");
+  title.textContent = `${rows.length} tool calls`;
+  head.append(glyph, title);
+
+  const body = el("div", "st-tool-group-body st-disclosure");
+  const bodyClip = el("div", "st-disclosure-clip");
+  const bodyInner = el("div", "st-disclosure-inner");
+  bodyInner.append(...children);
+  bodyClip.appendChild(bodyInner);
+  body.appendChild(bodyClip);
+  setDisclosure(body, expanded);
+  head.addEventListener("click", () => {
+    expanded = !expanded;
+    head.setAttribute("aria-expanded", String(expanded));
+    setDisclosure(body, expanded, true);
+    onExpandedChange?.(expanded);
+  });
+  wrap.append(head, body);
+  return wrap;
+}
+
+function buildPlainRow(row: TranscriptRow): HTMLElement {
+  const wrap = el("div", "st-row st-row-notice");
+  const body = el("div", "st-body");
+  body.textContent = `[${row.kind}]`;
+  wrap.appendChild(body);
+  makeCopyable(wrap, body.textContent, "notice");
+  return wrap;
+}
+
+function compactNumber(value: number): string {
+  if (Math.abs(value) < 1_000) return String(value);
+  if (Math.abs(value) < 1_000_000) return `${(value / 1_000).toFixed(value % 1_000 === 0 ? 0 : 1)}k`;
+  return `${(value / 1_000_000).toFixed(value % 1_000_000 === 0 ? 0 : 1)}m`;
+}
+
+export function formatElapsed(milliseconds: number): string {
+  const seconds = Math.max(0, Math.floor(milliseconds / 1_000));
+  if (seconds < 60) return `${seconds}s`;
+  const minutes = Math.floor(seconds / 60);
+  const remainder = seconds % 60;
+  return remainder === 0 ? `${minutes}m` : `${minutes}m ${remainder}s`;
+}
+
+export function formatContextTokens(value: number): string {
+  return `${compactNumber(value)} context`;
+}
+
+function buildTurnMetaRow(meta: TurnMeta): HTMLElement {
+  const wrap = el("div", `st-turn-meta st-turn-meta-${meta.outcome}`);
+  wrap.setAttribute("aria-label", `Turn ${meta.outcome}`);
+  const parts = [formatElapsed(meta.elapsedMs)];
+  if (typeof meta.contextDelta === "number") {
+    const sign = meta.contextDelta > 0 ? "+" : "";
+    parts.push(`${sign}${compactNumber(meta.contextDelta)} context tokens`);
+  } else if (typeof meta.contextTokens === "number") {
+    parts.push(formatContextTokens(meta.contextTokens));
+  }
+  if (meta.model) parts.push(meta.model);
+  if (meta.outcome !== "completed") parts.push(meta.outcome);
+  const dot = el("span", "st-turn-meta-dot");
+  dot.setAttribute("aria-hidden", "true");
+  const text = el("span");
+  text.textContent = parts.join(" · ");
+  wrap.append(dot, text);
+  makeCopyable(wrap, text.textContent, "turn details");
+  return wrap;
+}
+
+function turnMeta(row: TranscriptRow): TurnMeta | null {
+  if (row.kind !== "notice" || !row.data || typeof row.data !== "object") return null;
+  const value = (row.data as { maestroTurnMeta?: unknown }).maestroTurnMeta;
+  if (!value || typeof value !== "object") return null;
+  const meta = value as Partial<TurnMeta>;
+  if (typeof meta.elapsedMs !== "number" || typeof meta.outcome !== "string") return null;
+  return meta as TurnMeta;
+}
+
+function isStateOnlyNotice(row: TranscriptRow): boolean {
+  if (row.kind !== "notice" || !row.data || typeof row.data !== "object") return false;
+  const update = (row.data as { sessionUpdate?: string }).sessionUpdate;
+  return update === "available_commands_update" || update === "session_info_update";
+}
+
+export interface ApprovalRowState {
+  pending: boolean;
+  /** Resolves once the decision has been submitted; rejects when the POST
+   *  failed and this approval is still the one awaiting a decision, so the
+   *  caller knows to restore its controls. Never rejects for a stale click
+   *  (the approval already moved on) — there is nothing to restore then. */
+  onDecide: (decision: StructuredApprovalDecision) => Promise<void>;
+}
+
+/** Which decisions a permission request actually backs, by the
+ *  `PermissionOptionKind` values it offers (docs/STRUCTURED-VIEW.md's
+ *  "Decision mapping"). A decision with no matching option resolves
+ *  `Cancelled` server-side regardless of what the client sent — offering its
+ *  button would let the operator "allow" something that silently no-ops. */
+function offeredDecisions(options: AcpPermissionOption[]): StructuredApprovalDecision[] {
+  const kinds = new Set(options.map((o) => o.kind));
+  const decisions: StructuredApprovalDecision[] = [];
+  if (kinds.has("allow_once")) decisions.push("allow_once");
+  if (kinds.has("allow_always")) decisions.push("allow_for_session");
+  if (kinds.has("reject_once") || kinds.has("reject_always")) decisions.push("deny");
+  return decisions;
+}
+
+function buildApprovalRow(row: TranscriptRow, approval: ApprovalRowState): HTMLElement {
+  const request = (row.data ?? {}) as { toolCall?: AcpToolCallLike; options?: AcpPermissionOption[] };
+  const toolCall = request.toolCall ?? {};
+  const wrap = el("div", "st-row st-row-approval");
+  const card = el("div", "st-approval");
+  wrap.appendChild(card);
+
+  const title = el("div", "st-approval-title");
+  title.innerHTML = `<span aria-hidden="true">⚠</span> permission requested`;
+  card.appendChild(title);
+
+  const what = el("div", "st-approval-what");
+  what.textContent = toolCall.title ?? toolKindLabel(toolCall.kind);
+  card.appendChild(what);
+
+  const path = toolCall.locations?.[0]?.path;
+  if (path) {
+    const pathEl = el("div", "st-approval-path");
+    pathEl.textContent = path;
+    card.appendChild(pathEl);
+  }
+
+  if (approval.pending) {
+    const acts = el("div", "st-approval-acts");
+    const mk = (label: string, decision: StructuredApprovalDecision, cls: string) => {
+      const btn = document.createElement("button");
+      btn.type = "button";
+      btn.className = cls ? `act ${cls}` : "act";
+      btn.textContent = label;
+      btn.addEventListener("click", () => {
+        const buttons = [...acts.querySelectorAll<HTMLButtonElement>("button")];
+        buttons.forEach((b) => (b.disabled = true));
+        approval.onDecide(decision).catch(() => {
+          // Rejects only when this approval is still pending (see
+          // ApprovalRowState) — restore the controls so the operator can
+          // retry; the error itself is surfaced by the connection.
+          buttons.forEach((b) => (b.disabled = false));
+        });
+      });
+      return btn;
+    };
+    const offered = offeredDecisions(request.options ?? []);
+    const specs: [StructuredApprovalDecision, string, string][] = [
+      ["allow_once", "Allow once", "primary"],
+      ["allow_for_session", "Allow for session", ""],
+      ["deny", "Deny", "deny"],
+    ];
+    for (const [decision, label, cls] of specs) {
+      if (offered.includes(decision)) acts.appendChild(mk(label, decision, cls));
+    }
+    if (acts.children.length > 0) {
+      card.appendChild(acts);
+    } else {
+      const none = el("div", "st-approval-resolved");
+      none.textContent = "no decision offered";
+      card.appendChild(none);
+    }
+  } else {
+    const resolved = el("div", "st-approval-resolved");
+    resolved.textContent = "answered";
+    card.appendChild(resolved);
+  }
+
+  return wrap;
+}
+
+/** Build the DOM for one transcript row, or `null` for state-only plan rows.
+ *  `approval` is consulted only for an `approval` row; tool
+ *  expansion is supplied and reported explicitly. */
+export function buildTranscriptRow(
+  row: TranscriptRow & { kind: "plan" },
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): null;
+export function buildTranscriptRow(
+  row: TranscriptRow & { kind: "notice" },
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement | null;
+export function buildTranscriptRow(
+  row: TranscriptRow & { kind: Exclude<TranscriptRow["kind"], "plan" | "notice"> },
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement;
+export function buildTranscriptRow(
+  row: TranscriptRow,
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement | null;
+export function buildTranscriptRow(
+  row: TranscriptRow,
+  approval?: ApprovalRowState,
+  toolExpanded = false,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement | null {
+  let built: HTMLElement;
+  switch (row.kind) {
+    case "user":
+      built = buildContentRow(row, "user");
+      break;
+    case "agent_text":
+      built = buildContentRow(row, "agent");
+      break;
+    case "agent_thought":
+      built = buildContentRow(row, "thought");
+      break;
+    case "tool_call":
+    case "tool_diff":
+      built = buildToolRow(row, toolExpanded, onToolExpandedChange);
+      break;
+    case "approval":
+      built = buildApprovalRow(row, approval ?? { pending: false, onDecide: () => Promise.resolve() });
+      break;
+    case "plan":
+      return null;
+    case "notice":
+      if (isStateOnlyNotice(row)) return null;
+      built = turnMeta(row) ? buildTurnMetaRow(turnMeta(row)!) : buildPlainRow(row);
+      break;
+    default:
+      built = buildPlainRow(row);
+      break;
+  }
+  built.dataset.rowId = row.id;
+  return built;
+}

web/src/toolIcon.test.ts

@@ -1,5 +1,12 @@
 import { describe, expect, it } from "vitest";
 import { splitCommand, toolIconSvg } from "./toolIcon.js";
+import commandResolutionFixture from "../../fixtures/command-resolution.json";
+
+interface CommandResolutionCase {
+  command: string;
+  program: string;
+  tool: string | null;
+}
 
 describe("tool icons on the command fragment (docs/SIDEBAR.md)", () => {
   it("recognises the agents and shells sessions are spawned with", () => {
@@ -46,6 +53,14 @@ describe("tool icons on the command fragment (docs/SIDEBAR.md)", () => {
     expect(splitCommand("").tool).toBeNull();
   });
 
+  it("resolves every case in the shared command-resolution fixture (#199)", () => {
+    const cases = commandResolutionFixture.cases as CommandResolutionCase[];
+    expect(cases.length).toBeGreaterThan(0);
+    for (const { command, program, tool } of cases) {
+      expect(splitCommand(command), command).toEqual({ tool, program });
+    }
+  });
+
   it("gives every recognised tool a labelled mark", () => {
     for (const tool of ["claude", "codex", "opencode", "gemini", "aider", "cursor", "pi", "shell"]) {
       const svg = toolIconSvg(tool);

web/src/toolIcon.ts

@@ -9,10 +9,11 @@
  * as text, so the fragment never renders a mark that stands for the wrong tool.
  */
 
-/** Command wrappers that run another program: the tool is what follows. */
-const WRAPPERS = new Set(["sudo", "env", "npx", "bunx", "uvx", "pnpm", "yarn", "command"]);
-
-/** Program name (already basenamed and lowercased) → icon id. */
+/** Program name (already basenamed and lowercased) → icon id.
+ *
+ * `claude-code-acp` — the daemon's actual structured-session child — is
+ * deliberately absent: the daemon launches it directly and ignores the
+ * session's command, so it is never itself a valid user-facing launch form. */
 const BY_PROGRAM: Record<string, string> = {
   claude: "claude",
   "claude-code": "claude",
@@ -53,39 +54,443 @@ export interface CommandParts {
   program: string;
 }
 
-/** Split a command line into the tool its icon stands for and the program name.
+/** Split a command line into the tool its icon stands for and the program
+ * name — basenamed and stripped of its arguments. Leading `FOO=bar`
+ * assignments and wrapper forms (`sudo`, `env -i`, `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 Rust `command_program`/
+ * `command_tool` in `crates/maestro-protocol/src/display.rs`.
  *
  * `claude --resume` → `{tool: "claude", program: "claude"}`; an unrecognised
  * `hx src/` keeps `hx` as the program with no tool. */
 export function splitCommand(command: string): CommandParts {
-  const words = command.trim().split(/\s+/).filter(Boolean);
-  let i = 0;
-  // Leading `FOO=bar` assignments and wrappers stand in front of the real
-  // program; `pnpm dlx x` / `yarn dlx x` need one more word skipped.
-  while (i < words.length) {
-    const word = words[i];
-    if (/^[A-Za-z_][A-Za-z0-9_]*=/.test(word)) {
-      i += 1;
-      continue;
-    }
-    const wrapper = basename(word).toLowerCase();
-    if (WRAPPERS.has(wrapper)) {
-      i += 1;
-      if ((wrapper === "pnpm" || wrapper === "yarn") && words[i] === "dlx") i += 1;
-      continue;
-    }
-    break;
+  const words = tokenize(command);
+  if (words === null) {
+    const program = legacyFirstWord(command);
+    return { tool: null, program };
   }
+  const i = programIndex(words);
   if (i >= words.length) return { tool: null, program: command.trim() };
-  const program = basename(words[i]);
+  const program = basename(words[i].text);
   return { tool: BY_PROGRAM[program.toLowerCase()] ?? null, program };
 }
 
+/** The naive "first whitespace word, basenamed" reading used only when
+ * {@link tokenize} rejects the line outright — still something sane to
+ * show, never a wrapper/tool match to act on. */
+function legacyFirstWord(command: string): string {
+  const first = command.trim().split(/\s+/).filter(Boolean)[0];
+  return first === undefined ? command.trim() : basename(first);
+}
+
+/** One token from {@link tokenize}: its dequoted text, and — when both the
+ * name and `=` were entirely unquoted/unescaped in the source — the index 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). */
+interface Word {
+  text: string;
+  plainEq: number | null;
+}
+
+/** `FOO=bar`, the shell's own prefix for one command's environment —
+ * recognised only when the `=` came from plain, unquoted/unescaped source
+ * text (#199). */
+function isEnvAssignment(word: Word): boolean {
+  if (word.plainEq === null) return false;
+  return /^[A-Za-z_][A-Za-z0-9_]*$/.test(word.text.slice(0, word.plainEq));
+}
+
+/** Walk `words` past leading `FOO=bar` assignments and known wrapper forms
+ * (interleaved in any order/count) to the index of the actual 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 ({@link Wrapper.acceptsAssignment}) —
+ * `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). */
+function programIndex(words: Word[]): number {
+  const texts = words.map((w) => w.text);
+  let i = 0;
+  let assignmentAllowed = true;
+  for (;;) {
+    if (assignmentAllowed) {
+      while (i < words.length && isEnvAssignment(words[i])) {
+        i += 1;
+      }
+    }
+    if (i >= words.length) break;
+    const wrapper = basename(texts[i]).toLowerCase();
+    const w = WRAPPER_RESOLVERS[wrapper];
+    if (!w) break;
+    const next = w.resolve(texts, i);
+    // 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.
+    if (next === null || next <= i) break;
+    i = next;
+    assignmentAllowed = w.acceptsAssignment;
+  }
+  return i;
+}
+
 function basename(word: string): string {
   const cut = word.lastIndexOf("/");
   return cut >= 0 ? word.slice(cut + 1) : word;
 }
 
+/** Word-split `command` the way a shell would (honouring `'…'`, `"…"` and
+ * `\` quoting/escaping — POSIX quote *removal*, not evaluation) and return
+ * `null` 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). */
+function tokenize(command: string): Word[] | null {
+  const words: Word[] = [];
+  let current = "";
+  let hasCurrent = false;
+  let plainEq: number | null = null;
+  let assignmentNameIsPlain = true;
+  let i = 0;
+  const n = command.length;
+
+  while (i < n) {
+    const c = command[i];
+    if (c === " " || c === "\t" || c === "\r") {
+      if (hasCurrent) {
+        words.push({ text: current, plainEq });
+        current = "";
+        hasCurrent = false;
+        plainEq = null;
+        assignmentNameIsPlain = true;
+      }
+      i += 1;
+    } else if (c === "\n") {
+      return null;
+    } else if ("|&;<>()`".includes(c)) {
+      return null;
+    } else if (c === "$" && command[i + 1] === "(") {
+      return null;
+    } else if (c === "'") {
+      hasCurrent = true;
+      if (plainEq === null) assignmentNameIsPlain = false;
+      i += 1;
+      const close = command.indexOf("'", i);
+      if (close === -1) return null; // unterminated single quote
+      current += command.slice(i, close);
+      i = close + 1;
+    } else if (c === '"') {
+      hasCurrent = true;
+      if (plainEq === null) assignmentNameIsPlain = false;
+      i += 1;
+      for (;;) {
+        if (i >= n) return null; // unterminated double quote
+        const c2 = command[i];
+        if (c2 === '"') {
+          i += 1;
+          break;
+        }
+        if (c2 === "\\") {
+          const escaped = command[i + 1];
+          if (escaped === undefined) return null; // trailing backslash
+          if (escaped === "\n") {
+            i += 2; // line continuation, removed entirely
+            continue;
+          }
+          current += '"\\$`'.includes(escaped) ? escaped : "\\" + escaped;
+          i += 2;
+        } else {
+          current += c2;
+          i += 1;
+        }
+      }
+    } else if (c === "\\") {
+      const escaped = command[i + 1];
+      if (escaped === undefined) return null; // trailing backslash
+      if (escaped === "\n") {
+        i += 2; // line continuation, removed entirely
+        continue;
+      }
+      hasCurrent = true;
+      if (plainEq === null) assignmentNameIsPlain = false;
+      current += escaped;
+      i += 2;
+    } else {
+      hasCurrent = true;
+      if (c === "=" && plainEq === null && assignmentNameIsPlain) {
+        plainEq = current.length;
+      }
+      current += c;
+      i += 1;
+    }
+  }
+  if (hasCurrent) words.push({ text: current, plainEq });
+  return 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 {@link consumeOptions}
+ * returning `null`. */
+interface OptionTable {
+  flags: Set<string>;
+  valued: Set<string>;
+  /** 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. */
+  bundlesShortOptions: boolean;
+}
+
+/** `-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). */
+function matchesShortCluster(opts: OptionTable, word: string): boolean {
+  let idx = 1;
+  while (idx < word.length) {
+    const short = "-" + word[idx];
+    if (opts.flags.has(short)) {
+      idx += 1;
+      continue;
+    }
+    if (opts.valued.has(short)) {
+      return idx + 1 < word.length;
+    }
+    return false;
+  }
+  return true;
+}
+
+/** Consume `opts`'s options starting at `words[i]`, returning the index just
+ * past them (which may equal `i` if there are none) — or `null` on an
+ * option this table doesn't recognise, or a valued option missing its
+ * operand. */
+function consumeOptions(opts: OptionTable, words: string[], i: number): number | null {
+  for (;;) {
+    const word = words[i];
+    if (word === undefined) return i;
+    if (word === "--") return i + 1;
+    if (word === "-" || !word.startsWith("-")) return i;
+    const eq = word.indexOf("=");
+    if (eq >= 0) {
+      if (opts.valued.has(word.slice(0, eq)) && word.slice(eq + 1).length > 0) {
+        i += 1;
+        continue;
+      }
+      return null;
+    }
+    if (opts.flags.has(word)) {
+      i += 1;
+      continue;
+    }
+    if (opts.valued.has(word)) {
+      const value = words[i + 1];
+      if (value === undefined || value.length === 0 || value.startsWith("-")) return null;
+      i += 2;
+      continue;
+    }
+    if (
+      opts.bundlesShortOptions &&
+      !word.startsWith("--") &&
+      word.length > 2 &&
+      matchesShortCluster(opts, word)
+    ) {
+      i += 1;
+      continue;
+    }
+    return null;
+  }
+}
+
+const NO_OPTIONS: OptionTable = { flags: new Set(), valued: new Set(), bundlesShortOptions: false };
+
+const ENV_OPTS: OptionTable = {
+  flags: new Set(["-i", "--ignore-environment", "-0", "--null", "-v", "--debug"]),
+  valued: new Set(["-u", "--unset", "-C", "--chdir"]),
+  bundlesShortOptions: true,
+};
+
+const SUDO_OPTS: OptionTable = {
+  flags: new Set([
+    "-i",
+    "--login",
+    "-n",
+    "--non-interactive",
+    "-E",
+    "--preserve-env",
+    "-H",
+    "--set-home",
+    "-A",
+    "--askpass",
+    "-b",
+    "--background",
+    "-k",
+    "--reset-timestamp",
+    "-K",
+    "--remove-timestamp",
+    "-S",
+    "--stdin",
+  ]),
+  valued: new Set(["-u", "--user", "-g", "--group"]),
+  bundlesShortOptions: 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 = {
+  flags: new Set(["-p"]),
+  valued: new Set(),
+  bundlesShortOptions: 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). */
+function resolveTime(words: string[], i: number): number | null {
+  let next = i + 1;
+  if (words[next] === "-p") next += 1;
+  if (words[next] === "--") next += 1;
+  const command = words[next];
+  return command?.startsWith("-") ? null : 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 = {
+  flags: new Set(["-y", "--yes", "--no", "-q", "--quiet", "--ignore-existing"]),
+  valued: new Set(["-p", "--package", "--shell"]),
+  bundlesShortOptions: false,
+};
+
+const PNPM_OPTS: OptionTable = {
+  flags: new Set(["--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: new Set(["-C", "--dir", "--filter", "--package"]),
+  bundlesShortOptions: false,
+};
+
+const YARN_OPTS: OptionTable = {
+  flags: new Set(["--silent", "-s", "--no-progress", "--non-interactive"]),
+  valued: new Set(["--cwd"]),
+  bundlesShortOptions: false,
+};
+
+const PNPM_DLX_OPTS: OptionTable = {
+  flags: new Set(["-s", "--silent"]),
+  valued: new Set(["--package"]),
+  bundlesShortOptions: false,
+};
+
+const YARN_DLX_OPTS: OptionTable = {
+  flags: new Set(["-q", "--quiet"]),
+  valued: new Set(["-p", "--package"]),
+  bundlesShortOptions: false,
+};
+
+const BUN_X_OPTS: OptionTable = {
+  flags: new Set(["--bun", "--no-install", "--verbose", "--silent"]),
+  valued: new Set(["-p", "--package"]),
+  bundlesShortOptions: false,
+};
+
+/** `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. */
+function resolveDlx(
+  opts: OptionTable,
+  dlxOpts: OptionTable,
+  words: string[],
+  i: number,
+): number | null {
+  const j = consumeOptions(opts, words, i + 1);
+  if (j === null) return null;
+  if (words[j] !== "dlx") return null;
+  return consumeOptions(dlxOpts, 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. */
+function resolveBun(words: string[], i: number): number | null {
+  if (words[i + 1] !== "x") return null;
+  return consumeOptions(BUN_X_OPTS, words, i + 2);
+}
+
+/** 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 `null` if this occurrence
+ * isn't a form we resolve through. */
+type WrapperResolver = (words: string[], i: number) => number | null;
+
+/** 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. */
+interface 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). */
+  acceptsAssignment: boolean;
+}
+
+const WRAPPER_RESOLVERS: Record<string, Wrapper> = {
+  env: { resolve: (words, i) => consumeOptions(ENV_OPTS, words, i + 1), acceptsAssignment: true },
+  sudo: {
+    resolve: (words, i) => consumeOptions(SUDO_OPTS, words, i + 1),
+    acceptsAssignment: true,
+  },
+  command: {
+    resolve: (words, i) => consumeOptions(COMMAND_BUILTIN_OPTS, words, i + 1),
+    acceptsAssignment: false,
+  },
+  nohup: {
+    resolve: (words, i) => consumeOptions(NO_OPTIONS, words, i + 1),
+    acceptsAssignment: false,
+  },
+  time: { resolve: resolveTime, acceptsAssignment: true },
+  npx: {
+    resolve: (words, i) => consumeOptions(NPX_OPTS, words, i + 1),
+    acceptsAssignment: false,
+  },
+  pnpm: {
+    resolve: (words, i) => resolveDlx(PNPM_OPTS, PNPM_DLX_OPTS, words, i),
+    acceptsAssignment: false,
+  },
+  yarn: {
+    resolve: (words, i) => resolveDlx(YARN_OPTS, YARN_DLX_OPTS, words, i),
+    acceptsAssignment: false,
+  },
+  bun: { resolve: resolveBun, acceptsAssignment: false },
+  bunx: {
+    resolve: (words, i) => consumeOptions(BUN_X_OPTS, words, i + 1),
+    acceptsAssignment: false,
+  },
+  uvx: { resolve: (_words, i) => i + 1, acceptsAssignment: false },
+};
+
 /** Anthropic's burst: tapered rays around a centre, long ones on the axes. */
 function burst(): string {
   const rays = Array.from({ length: 8 }, (_, k) => {

web/src/types.ts

@@ -56,8 +56,19 @@ export interface Session {
    * how the command bar's empty query sorts a never-focused session after every
    * session that has one (`docs/COMMAND-BAR.md`). */
   last_focused_at?: IsoTimestamp | null;
+  /** The ACP session id the selected provider adapter returned from
+   * `session/new` (#134). Only a `Structured` session whose handshake
+   * succeeded has one; a respawn passes it to `session/load` (#135). */
+  acp_session_id?: string | null;
+  /** Terminal (PTY bytes) or structured (ACP rows) (#133). Fixed at spawn and
+   * immutable for the session's life. Defaults to `"Terminal"` on the wire, so
+   * absent means terminal. */
+  view?: SessionView;
 }
 
+/** A session's process shape (#133): mirrors `maestro_protocol::SessionView`. */
+export type SessionView = "Terminal" | "Structured";
+
 /** A session's daemon-created worktree (`SessionWorktree` on the wire). */
 export interface SessionWorktree {
   path: string;
@@ -265,6 +276,7 @@ export interface CreateSessionRequest {
   env?: Record<string, string>;
   metadata?: Record<string, unknown>;
   worktree?: WorktreeSpec;
+  view?: SessionView;
 }
 
 export type CatalogEvent =
@@ -363,6 +375,244 @@ export function abbreviateCwd(cwd: string, home?: string): string {
   return cwd;
 }
 
+// ---------------------------------------------------------------------------
+// Structured-session projections (#133/#140). Mirror of
+// `maestro_protocol`'s "Structured-session projections" section. `data`,
+// `ReducedState.plan/usage/context/pending_approval` and every `Acp*` type
+// below are the daemon's opaque ACP payloads (`serde_json::Value` on the
+// wire) — shaped to `claude-code-acp`'s ACP v1 schema, not covered by
+// maestro-protocol's own compatibility guarantee. Treat every field as
+// optional and degrade gracefully rather than trust this shape exactly.
+// ---------------------------------------------------------------------------
+
+/** `maestro_protocol::TranscriptRowKind`, snake_case on the wire. */
+export type TranscriptRowKind =
+  | "user"
+  | "agent_text"
+  | "agent_thought"
+  | "tool_call"
+  | "tool_diff"
+  | "approval"
+  | "plan"
+  | "notice";
+
+/** One row of a structured session's transcript. */
+export interface TranscriptRow {
+  id: string;
+  kind: TranscriptRowKind;
+  data: unknown;
+}
+
+/** The complete transcript at a durable event-log position (`WS
+ * /api/structured/:id`'s first message, and every replay page). */
+export interface TranscriptSnapshot {
+  cursor: number;
+  rows: TranscriptRow[];
+}
+
+/** A change to one transcript row, addressed by `id`. */
+export type TranscriptDelta =
+  | { type: "append"; row: TranscriptRow }
+  | { type: "patch"; row: TranscriptRow }
+  | { type: "remove"; id: string };
+
+/** Per-turn indicators derived from the ACP stream — read verbatim, never
+ * re-derived client-side (docs/STRUCTURED-VIEW.md). */
+export interface TurnState {
+  responding: boolean;
+  thinking: boolean;
+  active_tool_calls: string[];
+  started_at?: string | null;
+  started_context_tokens?: number | null;
+}
+
+/** A whole-session view derived from ACP notifications. `plan`/`usage`/
+ * `context`/`pending_approval` are opaque ACP JSON — see the module note
+ * above. `pending_approval` is `{nonce, request: AcpRequestPermissionRequest}`
+ * while a permission request is live, absent otherwise. */
+export interface ReducedState {
+  turn: TurnState;
+  pending_approval?: { nonce: string; request: AcpRequestPermissionRequest } | null;
+  plan?: AcpPlan | null;
+  usage?: AcpUsage | null;
+  context?: AcpUsage | null;
+  model?: string | null;
+  mode?: string | null;
+  config_options?: { configOptions: AcpSessionConfigOption[] } | null;
+}
+
+/** Server messages on `WS /api/structured/:id`. */
+export type StructuredEvent =
+  | { type: "transcript_snapshot"; snapshot: TranscriptSnapshot }
+  | { type: "reduced_state"; state: ReducedState }
+  | { type: "projection_update"; transcript?: TranscriptDelta | null; state: ReducedState };
+
+/** `POST /api/sessions/:id/structured/prompt` body. */
+export interface StructuredPromptRequest {
+  prompt: string;
+}
+
+export interface StructuredConfigRequest {
+  config_id: string;
+  value: string | boolean;
+}
+
+export interface AcpSessionConfigChoice {
+  value: string;
+  name: string;
+  description?: string | null;
+}
+
+export interface AcpSessionConfigGroup {
+  group: string;
+  name: string;
+  options: AcpSessionConfigChoice[];
+}
+
+export interface AcpSessionConfigOption {
+  id: string;
+  name: string;
+  description?: string | null;
+  category?: string | null;
+  type: "select" | "boolean" | string;
+  currentValue: string | boolean;
+  options?: Array<AcpSessionConfigChoice | AcpSessionConfigGroup>;
+}
+
+/** `POST /api/sessions/:id/structured/approvals/:nonce` body — a bare JSON
+ * string (a bracketless Rust enum), not `{decision: ...}`. */
+export type StructuredApprovalDecision = "allow_once" | "allow_for_session" | "deny";
+
+// ---- ACP v1 payload shapes (agent-client-protocol schema, camelCase) ----
+
+export interface AcpEmbeddedResource {
+  uri?: string;
+  mimeType?: string;
+  text?: string;
+  blob?: string;
+}
+
+/** `ContentBlock`, including the fields needed to render typed tool output. */
+export type AcpContentBlock =
+  | { type: "text"; text: string }
+  | { type: "image"; data?: string; mimeType?: string; uri?: string | null }
+  | { type: "audio"; data?: string; mimeType?: string }
+  | {
+      type: "resource_link";
+      uri?: string;
+      name?: string;
+      title?: string | null;
+      description?: string | null;
+      mimeType?: string | null;
+      size?: number | null;
+    }
+  | { type: "resource"; resource?: AcpEmbeddedResource };
+
+/** `ContentChunk` — the payload of a `User`/`AgentText`/`AgentThought` row. */
+export interface AcpContentChunk {
+  content: AcpContentBlock;
+  messageId?: string | null;
+}
+
+/** `ToolKind`, snake_case on the wire. */
+export type AcpToolKind =
+  | "read"
+  | "edit"
+  | "delete"
+  | "move"
+  | "search"
+  | "execute"
+  | "think"
+  | "fetch"
+  | "switch_mode"
+  | "other";
+
+/** `ToolCallStatus`, snake_case on the wire. */
+export type AcpToolCallStatus = "pending" | "in_progress" | "completed" | "failed";
+
+/** `Diff` — a file modification. `oldText` absent means a new file. */
+export interface AcpDiff {
+  path: string;
+  oldText?: string | null;
+  newText: string;
+}
+
+/** `ToolCallContent`. */
+export type AcpToolCallContent =
+  | { type: "content"; content: AcpContentBlock }
+  | ({ type: "diff" } & AcpDiff)
+  | { type: "terminal"; terminalId?: string };
+
+export interface AcpToolCallLocation {
+  path: string;
+  line?: number | null;
+}
+
+/** `ToolCall` (a `ToolCall`/`ToolDiff` row's `data`) and, loosely, the
+ * flattened `ToolCallUpdate` an approval's `toolCall` field carries — the
+ * two share every field below, just with different subsets required. */
+export interface AcpToolCallLike {
+  toolCallId?: string;
+  title?: string;
+  /** Unstable ACP capability; absent when the adapter doesn't send one. */
+  name?: string | null;
+  kind?: AcpToolKind;
+  status?: AcpToolCallStatus;
+  content?: AcpToolCallContent[];
+  locations?: AcpToolCallLocation[];
+  rawInput?: unknown;
+  rawOutput?: unknown;
+}
+
+/** `PlanEntryPriority` / `PlanEntryStatus`, snake_case on the wire. */
+export type AcpPlanPriority = "high" | "medium" | "low";
+export type AcpPlanEntryStatus = "pending" | "in_progress" | "completed";
+
+export interface AcpPlanEntry {
+  content: string;
+  priority: AcpPlanPriority;
+  status: AcpPlanEntryStatus;
+}
+
+/** `Plan` — `ReducedState.plan`. */
+export interface AcpPlan {
+  entries: AcpPlanEntry[];
+}
+
+/** `UsageUpdate` — `ReducedState.usage`/`.context` (the daemon folds one
+ * update into both fields). */
+export interface AcpUsage {
+  used: number;
+  size: number;
+  cost?: { amount: number; currency: string } | null;
+}
+
+/** Daemon-owned durable footer appended when one prompt turn settles. ACP
+ * only reports context occupancy, so `contextDelta` is not a billing-token
+ * count and may be negative when the provider compacts the context. */
+export interface TurnMeta {
+  elapsedMs: number;
+  contextTokens?: number | null;
+  contextDelta?: number | null;
+  outcome: "completed" | "cancelled" | "failed" | string;
+  model?: string | null;
+}
+
+export interface AcpPermissionOption {
+  optionId: string;
+  name: string;
+  kind: "allow_once" | "allow_always" | "reject_once" | "reject_always";
+}
+
+/** `RequestPermissionRequest`, serialized without its nonce (the nonce lives
+ * only in `ReducedState.pending_approval.nonce`) — an `Approval` row's `data`,
+ * and `ReducedState.pending_approval.request`. */
+export interface AcpRequestPermissionRequest {
+  sessionId: string;
+  toolCall: AcpToolCallLike;
+  options: AcpPermissionOption[];
+}
+
 /** `~/git.naps.pt/naps62/maestro` → `~/g/n/maestro`: keep the last segment
  * verbatim, collapse every earlier one to its first character. Two-or-fewer
  * segments are left alone (nothing to gain). Returns escaped HTML with the

web/tsconfig.build.json

@@ -0,0 +1,8 @@
+{
+  // The nix derivation's src is `./web`, so the shared fixtures/ directory at
+  // the repo root does not exist there and `*.test.ts` cannot resolve its
+  // imports. Tests are not part of the shipped bundle; `pnpm typecheck` still
+  // checks them from a full checkout.
+  "extends": "./tsconfig.json",
+  "exclude": ["src/**/*.test.ts", "src/**/*.test.tsx"]
+}