feat(maestro): select ACP adapter by command

crates/maestro-acp/src/lib.rs

@@ -58,11 +58,40 @@ use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
 
 pub use agent_client_protocol::schema::v1 as schema;
 
-/// The adapter binary, resolved on `PATH`.
-pub const ADAPTER_BIN: &str = "claude-code-acp";
+/// ACP adapter selected from the structured session's resolved command.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AcpAdapter {
+    ClaudeCode,
+    Codex,
+}
 
-/// How to install the adapter when it is missing. Named in the error so an
-/// operator staring at a failed session knows what to run.
+impl AcpAdapter {
+    pub const fn binary(self) -> &'static str {
+        match self {
+            Self::ClaudeCode => "claude-code-acp",
+            Self::Codex => "codex-acp",
+        }
+    }
+
+    pub const fn install_command(self) -> &'static str {
+        match self {
+            Self::ClaudeCode => "npm install -g --prefix ~/.local @zed-industries/claude-code-acp",
+            Self::Codex => "npm install -g --prefix ~/.local @agentclientprotocol/codex-acp",
+        }
+    }
+}
+
+impl std::fmt::Display for AcpAdapter {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::ClaudeCode => "Claude Code",
+            Self::Codex => "Codex",
+        })
+    }
+}
+
+/// Compatibility aliases for Claude Code callers.
+pub const ADAPTER_BIN: &str = "claude-code-acp";
 pub const INSTALL_COMMAND: &str =
     "npm install -g --prefix ~/.local @zed-industries/claude-code-acp";
 
@@ -166,6 +195,8 @@ pub struct SpawnConfig {
     /// instead of opening a fresh one. The adapter must advertise
     /// `loadSession`; the handshake fails otherwise.
     pub load_session: Option<String>,
+    /// The provider-specific adapter to launch.
+    pub adapter: AcpAdapter,
 }
 
 impl SpawnConfig {
@@ -175,6 +206,7 @@ impl SpawnConfig {
             env,
             handshake_timeout: HANDSHAKE_TIMEOUT,
             load_session: None,
+            adapter: AcpAdapter::ClaudeCode,
         }
     }
 
@@ -183,6 +215,11 @@ impl SpawnConfig {
         self.load_session = Some(session_id.into());
         self
     }
+
+    pub fn adapter(mut self, adapter: AcpAdapter) -> Self {
+        self.adapter = adapter;
+        self
+    }
 }
 
 /// A blocked ACP permission request delivered to the daemon.
@@ -198,31 +235,39 @@ pub struct PermissionRequest {
 pub enum AcpError {
     /// The adapter is not on `PATH`. The message names the install command
     /// so the failed session is actionable rather than silently dead.
-    #[error("{ADAPTER_BIN} not found on PATH; install it with: {INSTALL_COMMAND}")]
-    AdapterMissing,
-    #[error("failed to start {ADAPTER_BIN}: {0}")]
-    Spawn(#[source] std::io::Error),
+    #[error("{adapter} ACP adapter ({bin}) not found on PATH; install it with: {install_command}", bin = adapter.binary(), install_command = adapter.install_command())]
+    AdapterMissing { adapter: AcpAdapter },
+    #[error("failed to start {adapter} ACP adapter ({bin}): {source}", bin = adapter.binary())]
+    Spawn {
+        adapter: AcpAdapter,
+        #[source]
+        source: std::io::Error,
+    },
     /// The adapter answered the handshake with an error.
     #[error("ACP handshake failed: {0}")]
     Handshake(String),
     /// The adapter went away before the handshake finished. Carries the
     /// tail of its stderr, which is where a missing Claude login shows up.
-    #[error("{ADAPTER_BIN} exited during the ACP handshake ({status}){stderr}")]
-    ExitedEarly { status: String, stderr: String },
+    #[error("{adapter} ACP adapter ({bin}) exited during the ACP handshake ({status}){stderr}", bin = adapter.binary())]
+    ExitedEarly {
+        adapter: AcpAdapter,
+        status: String,
+        stderr: String,
+    },
     #[error("ACP handshake timed out after {0:?}")]
     HandshakeTimeout(Duration),
 }
 
 /// Resolve [`ADAPTER_BIN`] against the `PATH` the child would run with: the
 /// session env's `PATH` when it sets one, the daemon's own otherwise.
-pub fn resolve_adapter(env: &HashMap<String, String>) -> Option<PathBuf> {
+pub fn resolve_adapter(adapter: AcpAdapter, env: &HashMap<String, String>) -> Option<PathBuf> {
     let path: OsString = match env.get("PATH") {
         Some(p) => OsString::from(p),
         None => std::env::var_os("PATH")?,
     };
     std::env::split_paths(&path)
         .filter(|dir| !dir.as_os_str().is_empty())
-        .map(|dir| dir.join(ADAPTER_BIN))
+        .map(|dir| dir.join(adapter.binary()))
         .find(|candidate| is_executable(candidate))
 }
 
@@ -248,6 +293,12 @@ enum Command {
     Close,
 }
 
+struct ConnectionConfig {
+    cwd: PathBuf,
+    load_session: Option<String>,
+    adapter: AcpAdapter,
+}
+
 enum ChildCommand {
     Signal(libc::c_int),
     Reap(oneshot::Sender<bool>),
@@ -435,7 +486,9 @@ impl Drop for AcpSession {
 /// Fails without a running child: on any error the process is already
 /// signalled, so a failed session never leaves a stray adapter behind.
 pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
-    let adapter = resolve_adapter(&config.env).ok_or(AcpError::AdapterMissing)?;
+    let provider = config.adapter;
+    let adapter = resolve_adapter(provider, &config.env)
+        .ok_or(AcpError::AdapterMissing { adapter: provider })?;
 
     let mut cmd = tokio::process::Command::new(&adapter);
     cmd.current_dir(&config.cwd)
@@ -463,18 +516,27 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
             });
         }
     }
-    let mut child = cmd.spawn().map_err(AcpError::Spawn)?;
+    let mut child = cmd.spawn().map_err(|source| AcpError::Spawn {
+        adapter: provider,
+        source,
+    })?;
     let pid = child.id().expect("child pid is known before wait");
     let stdin = child.stdin.take().expect("piped stdin");
     let stdout = child.stdout.take().expect("piped stdout");
     let stderr = child.stderr.take().expect("piped stderr");
 
     let stderr_tail = Arc::new(Mutex::new(VecDeque::<u8>::new()));
-    tokio::spawn(drain_stderr(stderr, pid, stderr_tail.clone()));
+    tokio::spawn(drain_stderr(stderr, pid, stderr_tail.clone(), provider));
 
     let (exit_tx, exit_rx) = watch::channel(None);
     let (child_commands_tx, child_commands_rx) = mpsc::unbounded_channel();
-    tokio::spawn(supervise_child(child, pid, child_commands_rx, exit_tx));
+    tokio::spawn(supervise_child(
+        child,
+        pid,
+        child_commands_rx,
+        exit_tx,
+        provider,
+    ));
 
     let (updates_tx, updates_rx) = mpsc::unbounded_channel();
     let (permission_tx, permission_rx) = mpsc::unbounded_channel();
@@ -483,8 +545,11 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
     let transport = ByteStreams::new(stdin.compat_write(), stdout.compat());
     tokio::spawn(run_connection(
         transport,
-        config.cwd.clone(),
-        config.load_session.clone(),
+        ConnectionConfig {
+            cwd: config.cwd.clone(),
+            load_session: config.load_session.clone(),
+            adapter: provider,
+        },
         updates_tx,
         permission_tx,
         commands_rx,
@@ -517,6 +582,7 @@ pub async fn spawn(config: SpawnConfig) -> Result<AcpSession, AcpError> {
                     .to_string()
             };
             AcpError::ExitedEarly {
+                adapter: provider,
                 status: status.map_or_else(|| "unknown status".into(), |s| s.to_string()),
                 stderr: if stderr.is_empty() {
                     String::new()
@@ -551,12 +617,13 @@ async fn supervise_child(
     pid: u32,
     mut commands: mpsc::UnboundedReceiver<ChildCommand>,
     exit_tx: watch::Sender<Option<ExitStatus>>,
+    adapter: AcpAdapter,
 ) {
     loop {
         tokio::select! {
             status = child.wait() => {
                 let status = status.ok();
-                tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                 let _ = exit_tx.send(status);
                 return;
             }
@@ -570,7 +637,7 @@ async fn supervise_child(
                 Some(ChildCommand::Reap(done)) => match child.try_wait() {
                     Ok(Some(status)) => {
                         let _ = done.send(true);
-                        tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                        tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                         let _ = exit_tx.send(Some(status));
                         return;
                     }
@@ -578,7 +645,7 @@ async fn supervise_child(
                         let _ = done.send(false);
                     }
                     Err(error) => {
-                        tracing::warn!(pid, %error, "could not reap {ADAPTER_BIN}");
+                        tracing::warn!(pid, %error, provider = %adapter, "could not reap ACP adapter");
                         let _ = done.send(false);
                     }
                 },
@@ -588,7 +655,7 @@ async fn supervise_child(
                     // a reused PID.
                     unsafe { libc::kill(pid as libc::pid_t, libc::SIGTERM) };
                     let status = child.wait().await.ok();
-                    tracing::debug!(pid, ?status, "{ADAPTER_BIN} exited");
+                    tracing::debug!(pid, ?status, provider = %adapter, "ACP adapter exited");
                     let _ = exit_tx.send(status);
                     return;
                 }
@@ -704,8 +771,7 @@ fn config_notification(session_id: &str, options: Vec<SessionConfigOption>) -> S
 
 async fn run_connection<T>(
     transport: T,
-    cwd: PathBuf,
-    load_session: Option<String>,
+    config: ConnectionConfig,
     updates_tx: mpsc::UnboundedSender<SessionNotification>,
     permission_requests: mpsc::UnboundedSender<PermissionRequest>,
     mut commands_rx: mpsc::UnboundedReceiver<Command>,
@@ -779,11 +845,13 @@ async fn run_connection<T>(
                     return Ok(());
                 }
             };
-            let (session_id, modes, initial_options, models) = match load_session {
+            let (session_id, modes, initial_options, models) = match config.load_session {
                 Some(existing) => {
                     if !initialized.agent_capabilities.load_session {
                         let _ = ready_tx.send(Err(ReadyError::Handshake(format!(
-                            "{ADAPTER_BIN} does not advertise loadSession; cannot resume session {existing}"
+                            "{} ACP adapter ({}) does not advertise loadSession; cannot resume session {existing}",
+                            config.adapter,
+                            config.adapter.binary()
                         ))));
                         return Ok(());
                     }
@@ -793,7 +861,7 @@ async fn run_connection<T>(
                     if let Err(e) = cx
                         .send_request(ExtendedLoadSessionRequest {
                             session_id: SessionId::new(existing.as_str()),
-                            cwd,
+                            cwd: config.cwd,
                             mcp_servers: vec![],
                         })
                         .on_receiving_result(move |result| {
@@ -824,7 +892,7 @@ async fn run_connection<T>(
                 }
                 None => match cx
                     .send_request(ExtendedNewSessionRequest {
-                        cwd,
+                        cwd: config.cwd,
                         mcp_servers: vec![],
                     })
                     .block_task()
@@ -1004,10 +1072,11 @@ async fn drain_stderr(
     stderr: tokio::process::ChildStderr,
     pid: u32,
     tail: Arc<Mutex<VecDeque<u8>>>,
+    adapter: AcpAdapter,
 ) {
     let mut lines = tokio::io::BufReader::new(stderr).lines();
     while let Ok(Some(line)) = lines.next_line().await {
-        tracing::debug!(pid, "{ADAPTER_BIN}: {line}");
+        tracing::debug!(pid, provider = %adapter, "ACP adapter: {line}");
         let mut tail = tail.lock().expect("stderr tail");
         tail.extend(line.as_bytes());
         tail.push_back(b'\n');

crates/maestro-acp/tests/spawn.rs

@@ -6,7 +6,7 @@ use std::path::{Path, PathBuf};
 use std::time::{Duration, Instant};
 
 use maestro_acp::schema::{ContentBlock, SessionUpdate};
-use maestro_acp::{AcpError, SpawnConfig, ADAPTER_BIN, INSTALL_COMMAND};
+use maestro_acp::{AcpAdapter, AcpError, SpawnConfig, ADAPTER_BIN, INSTALL_COMMAND};
 use tempfile::TempDir;
 
 fn fake_agent() -> PathBuf {
@@ -25,6 +25,7 @@ impl Fake {
         let bin = dir.path().join("bin");
         std::fs::create_dir_all(&bin).unwrap();
         std::fs::copy(fake_agent(), bin.join(ADAPTER_BIN)).unwrap();
+        std::fs::copy(fake_agent(), bin.join(AcpAdapter::Codex.binary())).unwrap();
         Self { dir }
     }
 
@@ -146,12 +147,38 @@ async fn missing_adapter_names_the_install_command() {
     let err = maestro_acp::spawn(SpawnConfig::new(cwd.path(), env))
         .await
         .expect_err("no adapter on PATH");
-    assert!(matches!(err, AcpError::AdapterMissing));
+    assert!(matches!(
+        err,
+        AcpError::AdapterMissing {
+            adapter: AcpAdapter::ClaudeCode
+        }
+    ));
     let msg = err.to_string();
     assert!(msg.contains(ADAPTER_BIN), "{msg}");
     assert!(msg.contains(INSTALL_COMMAND), "{msg}");
 }
 
+#[test]
+fn codex_adapter_has_its_own_binary_and_install_guidance() {
+    assert_eq!(AcpAdapter::Codex.binary(), "codex-acp");
+    assert!(AcpAdapter::Codex
+        .install_command()
+        .contains("@agentclientprotocol/codex-acp"));
+}
+
+#[tokio::test]
+async fn spawn_selects_the_codex_adapter() {
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+    let session = maestro_acp::spawn(fake.config(cwd.path()).adapter(AcpAdapter::Codex))
+        .await
+        .expect("spawn Codex adapter");
+    assert!(fake.log().contains("recv session/new"));
+    session
+        .terminate(Duration::from_millis(100), Duration::from_secs(2))
+        .await;
+}
+
 #[tokio::test]
 async fn session_updates_reach_the_taken_receiver() {
     let fake = Fake::new();
@@ -341,7 +368,7 @@ async fn child_exit_before_handshake_reports_exited_early() {
 
     let err = maestro_acp::spawn(config).await.expect_err("child died");
     match &err {
-        AcpError::ExitedEarly { status, stderr } => {
+        AcpError::ExitedEarly { status, stderr, .. } => {
             assert!(status.contains('3'), "{status}");
             assert!(stderr.contains("not logged in"), "{stderr}");
         }

crates/maestro-daemon/src/session.rs

@@ -15,7 +15,8 @@ use std::task::{Context, Poll};
 use std::time::Duration;
 
 use chrono::Utc;
-use maestro_acp::{AcpSession, PermissionRequest, SpawnConfig};
+use maestro_acp::{AcpAdapter, AcpSession, PermissionRequest, SpawnConfig};
+use maestro_protocol::display::command_tool;
 use maestro_protocol::{
     ActivityState, CatalogEvent, CreateSessionRequest, ErrorInfo, NameSource, Session,
     SessionStatus, SessionView, StructuredReplayEvent, TranscriptDelta, TranscriptRow,
@@ -59,6 +60,16 @@ pub const DEFAULT_BLOCKED_WORK_INTERVAL: Duration = Duration::from_secs(15);
 /// actually go.
 const SUBMIT_DELAY: Duration = Duration::from_millis(150);
 
+fn structured_adapter(command: &str) -> Result<AcpAdapter, String> {
+    match command_tool(command) {
+        Some("claude") => Ok(AcpAdapter::ClaudeCode),
+        Some("codex") => Ok(AcpAdapter::Codex),
+        _ => Err(format!(
+            "structured view supports Claude Code or Codex commands; cannot select an ACP adapter for {command:?}"
+        )),
+    }
+}
+
 /// Per-session daemon-local bookkeeping that complements the public `Session`.
 #[derive(Debug)]
 pub struct SessionRecord {
@@ -1250,14 +1261,18 @@ impl SessionManager {
         // up still yields a session — Dead, with the reason on it — so the
         // operator sees what to fix instead of a silently missing session.
         let (acp, acp_failure) = match req.view {
-            SessionView::Structured => {
-                match maestro_acp::spawn(SpawnConfig::new(
-                    &effective_cwd,
-                    session_env
-                        .iter()
-                        .map(|(k, v)| (k.clone(), v.clone()))
-                        .collect(),
-                ))
+            SessionView::Structured => match structured_adapter(&req.command) {
+                Err(error) => (None, Some(error)),
+                Ok(adapter) => match maestro_acp::spawn(
+                    SpawnConfig::new(
+                        &effective_cwd,
+                        session_env
+                            .iter()
+                            .map(|(k, v)| (k.clone(), v.clone()))
+                            .collect(),
+                    )
+                    .adapter(adapter),
+                )
                 .await
                 {
                     Ok(acp) => (Some(Arc::new(acp)), None),
@@ -1265,8 +1280,8 @@ impl SessionManager {
                         tracing::warn!(%id, error = %e, "structured session: adapter failed to start");
                         (None, Some(e.to_string()))
                     }
-                }
-            }
+                },
+            },
             SessionView::Terminal => {
                 let spawned = {
                     let tmux = self.inner.tmux.clone();
@@ -1674,23 +1689,30 @@ impl SessionManager {
 
             let (acp, failure) = if recoverable {
                 match session.acp_session_id.clone() {
-                    Some(acp_session_id) => {
-                        let config = SpawnConfig::new(
-                            &session.cwd,
-                            session_env
-                                .iter()
-                                .map(|(key, value)| (key.clone(), value.clone()))
-                                .collect(),
-                        )
-                        .load_session(acp_session_id);
-                        match maestro_acp::spawn(config).await {
-                            Ok(acp) => (Some(Arc::new(acp)), None),
-                            Err(error) => {
-                                tracing::warn!(%id, %error, "structured session: adapter failed to resume");
-                                (None, Some(error.to_string()))
+                    Some(acp_session_id) => match structured_adapter(&session.command) {
+                        Err(error) => {
+                            tracing::warn!(%id, %error, "structured session: unsupported command during recovery");
+                            (None, Some(error))
+                        }
+                        Ok(adapter) => {
+                            let config = SpawnConfig::new(
+                                &session.cwd,
+                                session_env
+                                    .iter()
+                                    .map(|(key, value)| (key.clone(), value.clone()))
+                                    .collect(),
+                            )
+                            .load_session(acp_session_id)
+                            .adapter(adapter);
+                            match maestro_acp::spawn(config).await {
+                                Ok(acp) => (Some(Arc::new(acp)), None),
+                                Err(error) => {
+                                    tracing::warn!(%id, %error, "structured session: adapter failed to resume");
+                                    (None, Some(error.to_string()))
+                                }
                             }
                         }
-                    }
+                    },
                     None => (
                         None,
                         Some("structured session has no stored ACP session id".into()),
@@ -2969,15 +2991,18 @@ mod tests {
     use std::task::Poll;
     use std::time::Duration;
 
-    use maestro_acp::schema::{
-        PermissionOption, PermissionOptionKind, RequestPermissionOutcome, RequestPermissionRequest,
-        ToolCallUpdate, ToolCallUpdateFields,
+    use maestro_acp::{
+        schema::{
+            PermissionOption, PermissionOptionKind, RequestPermissionOutcome,
+            RequestPermissionRequest, ToolCallUpdate, ToolCallUpdateFields,
+        },
+        AcpAdapter,
     };
     use maestro_protocol::{ActivityState, CatalogEvent, CreateSessionRequest, SessionView};
 
     use super::{
         apply_structured_activity, cancel_pending_approvals, permission_outcome,
-        record_permission_request, run_structured_activity_pass,
+        record_permission_request, run_structured_activity_pass, structured_adapter,
         sync_structured_activity_from_stream, AcpDispatchState, AcpEventStream, ApprovalDecision,
         RecordOutcome, SessionManager,
     };
@@ -3001,6 +3026,17 @@ mod tests {
         )
     }
 
+    #[test]
+    fn structured_adapter_uses_the_shared_command_resolution() {
+        assert_eq!(structured_adapter("claude"), Ok(AcpAdapter::ClaudeCode));
+        assert_eq!(
+            structured_adapter("sudo -u agent -- /opt/bin/codex"),
+            Ok(AcpAdapter::Codex)
+        );
+        assert!(structured_adapter("opencode").is_err());
+        assert!(structured_adapter("claude && codex").is_err());
+    }
+
     fn stream(log: EventLog) -> AcpEventStream {
         let (live, _live_rx) = tokio::sync::broadcast::channel(16);
         let (projected_live, _projected_rx) = tokio::sync::broadcast::channel(16);

crates/maestro-daemon/tests/acp.rs

@@ -11,7 +11,7 @@ use std::time::{Duration, Instant};
 
 use common::{init_bare_repo, init_repo, push_all_to_origin, wait_for_async, DaemonFixture};
 use maestro_acp::schema::{ContentBlock, SessionUpdate};
-use maestro_acp::{ADAPTER_BIN, INSTALL_COMMAND};
+use maestro_acp::{AcpAdapter, ADAPTER_BIN};
 use maestro_daemon::projection::TurnLifecycle;
 use maestro_daemon::sidecar::{EventCursor, SidecarStore};
 use maestro_daemon::worktree::WorktreeManager;
@@ -38,6 +38,7 @@ impl Fake {
         let bin = dir.path().join("bin");
         std::fs::create_dir_all(&bin).unwrap();
         std::fs::copy(fake_agent(), bin.join(ADAPTER_BIN)).unwrap();
+        std::fs::copy(fake_agent(), bin.join(AcpAdapter::Codex.binary())).unwrap();
         Self { dir }
     }
 
@@ -96,10 +97,18 @@ fn event_text(event: &maestro_daemon::sidecar::LoggedEvent) -> &str {
 }
 
 fn structured(cwd: &Path, env: HashMap<String, String>) -> CreateSessionRequest {
+    structured_command(cwd, env, "claude")
+}
+
+fn structured_command(
+    cwd: &Path,
+    env: HashMap<String, String>,
+    command: &str,
+) -> CreateSessionRequest {
     CreateSessionRequest {
         view: SessionView::Structured,
         cwd: cwd.to_path_buf(),
-        command: "claude".into(),
+        command: command.into(),
         env,
         metadata: HashMap::new(),
         worktree: None,
@@ -130,7 +139,11 @@ async fn structured_spawn_starts_the_adapter_in_cwd_with_session_env() {
 
     let session = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(
+            cwd.path(),
+            env,
+            "codex --dangerously-bypass-approvals-and-sandbox",
+        ))
         .await
         .expect("create");
 
@@ -215,7 +228,7 @@ async fn structured_activity_tracks_turn_completion_and_failure() {
     env.insert("FAKE_ACP_PROMPT_FAIL_ONCE".into(), "1".into());
     let session = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(cwd.path(), env, "codex"))
         .await
         .unwrap();
 
@@ -570,7 +583,7 @@ async fn recovery_loads_the_acp_session_without_duplicating_history() {
 
     let session = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(cwd.path(), env, "codex"))
         .await
         .expect("create");
     let acp_id = session.acp_session_id.clone().expect("acp id");
@@ -684,7 +697,7 @@ async fn shutdown_preserves_a_pristine_structured_worktree_for_recovery() {
         .create(CreateSessionRequest {
             view: SessionView::Structured,
             cwd: repo.path().to_path_buf(),
-            command: "claude".into(),
+            command: "codex".into(),
             env: fake.env(),
             metadata: HashMap::new(),
             worktree: Some(WorktreeSpec {
@@ -779,15 +792,18 @@ async fn missing_adapter_yields_a_failed_session_naming_the_install_command() {
 
     let session = fx
         .manager
-        .create(structured(cwd.path(), env))
+        .create(structured_command(cwd.path(), env, "codex"))
         .await
         .expect("a failed session, not an error");
 
     assert_eq!(session.status, SessionStatus::Dead);
     assert_eq!(session.activity, ActivityState::Error);
     let detail = session.activity_detail.clone().expect("actionable detail");
-    assert!(detail.contains(ADAPTER_BIN), "{detail}");
-    assert!(detail.contains(INSTALL_COMMAND), "{detail}");
+    assert!(detail.contains(AcpAdapter::Codex.binary()), "{detail}");
+    assert!(
+        detail.contains(AcpAdapter::Codex.install_command()),
+        "{detail}"
+    );
     assert_eq!(session.acp_session_id, None);
 
     // It is a real session: listed, on disk, and dismissable like any other
@@ -801,6 +817,28 @@ async fn missing_adapter_yields_a_failed_session_naming_the_install_command() {
     assert!(!fx.manager.has(session.id).await);
 }
 
+#[tokio::test]
+async fn unsupported_structured_command_fails_without_launching_claude() {
+    let fx = DaemonFixture::new();
+    let fake = Fake::new();
+    let cwd = TempDir::new().unwrap();
+
+    let session = fx
+        .manager
+        .create(structured_command(cwd.path(), fake.env(), "opencode"))
+        .await
+        .expect("failed structured session is persisted");
+
+    assert_eq!(session.status, SessionStatus::Dead);
+    let detail = session.activity_detail.expect("selection error");
+    assert!(detail.contains("Claude Code or Codex"), "{detail}");
+    assert!(
+        fake.log().is_empty(),
+        "unsupported command launched an adapter"
+    );
+    fx.manager.kill(session.id, false).await.expect("dismiss");
+}
+
 #[tokio::test]
 async fn kill_sends_cancel_then_sigterm_and_removes_the_sidecar() {
     let fx = DaemonFixture::new();