feat(maestro): route maestro send through ACP for structured sessions

Structured sessions were rejected by `send_input` with NotTerminal.
Now `run_send` checks the session view and routes to
`send_structured_prompt` for structured sessions.

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

crates/maestro-cli/src/cli.rs

@@ -41,8 +41,8 @@ pub enum Command {
     Attach(AttachArgs),
     /// Kill a session by ID.
     Kill(KillArgs),
-    /// Type text into a running session, as if it had been typed on an
-    /// attached terminal.
+    /// Send text to a running session. Terminal sessions receive raw
+    /// keystrokes; structured sessions receive an ACP prompt.
     Send(SendArgs),
     /// Install or update the agent activity hook (#106).
     Hooks(HooksArgs),

crates/maestro-cli/src/sessions.rs

@@ -130,9 +130,12 @@ pub fn resolve_session(sessions: &[Session], needle: &str) -> Result<uuid::Uuid,
 /// `maestro send`. Answers with the session that was typed into, so the
 /// caller can name it once the daemon has accepted the text.
 ///
-/// A bare ID skips the catalog fetch; anything else needs the list to match
-/// against. Text comes from the arguments, or from stdin when there is none —
-/// the shape a heredoc or a pipe wants.
+/// Terminal sessions get raw keystrokes via `send_input`; structured sessions
+/// get an ACP prompt via `send_structured_prompt` (`--no-enter` is ignored
+/// there — ACP prompts are always complete messages).
+///
+/// Text comes from the arguments, or from stdin when there is none — the
+/// shape a heredoc or a pipe wants.
 #[allow(clippy::result_large_err)]
 pub async fn run_send(
     client: &DaemonClient,
@@ -155,19 +158,28 @@ pub async fn run_send(
         return Err(CliError::NothingToSend);
     }
 
-    let id = match uuid::Uuid::parse_str(args.session.trim()) {
-        Ok(id) => id,
-        Err(_) => {
-            let sessions = client.list_sessions().await?;
-            resolve_session(&sessions, &args.session)?
-        }
-    };
+    // We always need the session list: even a bare UUID needs the view field
+    // to decide which endpoint to hit.
+    let sessions = client.list_sessions().await?;
+    let id = resolve_session(&sessions, &args.session)?;
+    let view = sessions
+        .iter()
+        .find(|s| s.id == id)
+        .map(|s| s.view)
+        .unwrap_or(SessionView::Terminal);
 
-    let req = SendInputRequest {
-        text,
-        submit: !args.no_enter,
-    };
-    client.send_input(id, &req).await?;
+    match view {
+        SessionView::Structured => {
+            client.send_structured_prompt(id, &text).await?;
+        }
+        SessionView::Terminal => {
+            let req = SendInputRequest {
+                text,
+                submit: !args.no_enter,
+            };
+            client.send_input(id, &req).await?;
+        }
+    }
     Ok(id)
 }
 

crates/maestro-cli/tests/against_mock_daemon.rs

@@ -2,7 +2,7 @@
 //! was unit-tested, but nothing exercised the client, the error decoding, or
 //! the unreachable-daemon path without compiling and forking a real daemon.
 
-use maestro_protocol::{DaemonClient, DaemonInfo};
+use maestro_protocol::{DaemonClient, DaemonInfo, SessionView};
 use maestro_testing::{session, MockDaemon};
 use uuid::Uuid;
 
@@ -202,6 +202,35 @@ async fn send_resolves_a_session_by_name() {
     assert_eq!(sent, id);
 }
 
+/// A structured session routes through the ACP prompt endpoint, not the
+/// terminal input one — `--no-enter` is irrelevant (ACP prompts are
+/// complete messages).
+#[tokio::test]
+async fn send_to_structured_session_uses_acp_prompt() {
+    let mock = MockDaemon::start().await;
+    let id = Uuid::from_u128(13);
+    let mut s = session(id, "/tmp", "claude");
+    s.view = SessionView::Structured;
+    mock.add_session(s);
+
+    let args = maestro_cli::cli::SendArgs {
+        session: id.to_string(),
+        text: vec!["fix".into(), "the".into(), "tests".into()],
+        no_enter: false,
+    };
+    let sent = maestro_cli::sessions::run_send(&mock.client(), &args, &mut std::io::empty())
+        .await
+        .expect("send");
+
+    assert_eq!(sent, id);
+    // Terminal input must stay empty — the message went through ACP.
+    assert!(mock.inputs().is_empty());
+    let prompts = mock.structured_prompts();
+    assert_eq!(prompts.len(), 1);
+    assert_eq!(prompts[0].0, id);
+    assert_eq!(prompts[0].1.prompt, "fix the tests");
+}
+
 #[tokio::test]
 async fn send_to_an_unknown_session_fails_without_typing_anything() {
     let mock = MockDaemon::start().await;

crates/maestro-testing/src/lib.rs

@@ -22,7 +22,8 @@ use chrono::Utc;
 use futures_util::{SinkExt, StreamExt};
 use maestro_protocol::{
     routes, ApiError, CatalogEvent, CreateSessionRequest, DaemonClient, DaemonInfo, DirListing,
-    GitRoot, RecentDirs, SendInputRequest, Session, SessionStatus, PROTOCOL_VERSION,
+    GitRoot, RecentDirs, SendInputRequest, Session, SessionStatus, StructuredPromptRequest,
+    PROTOCOL_VERSION,
 };
 use tokio::net::TcpListener;
 use tokio::sync::{broadcast, oneshot};
@@ -60,6 +61,8 @@ struct Inner {
     forced_error: Option<(u16, ApiError)>,
     /// Everything `POST /api/sessions/:id/input` was asked to type, in order.
     inputs: Vec<(Uuid, SendInputRequest)>,
+    /// Every ACP prompt sent to a structured session, in order.
+    structured_prompts: Vec<(Uuid, StructuredPromptRequest)>,
 }
 
 #[derive(Clone)]
@@ -92,6 +95,10 @@ impl MockDaemon {
             .route(routes::SESSIONS, get(list_sessions).post(create_session))
             .route(routes::patterns::SESSION, delete(kill_session))
             .route(routes::patterns::SESSION_INPUT, post(send_input))
+            .route(
+                routes::patterns::STRUCTURED_PROMPT,
+                post(structured_prompt),
+            )
             .route(routes::INFO, get(daemon_info))
             .route(routes::DIRS, get(list_dir))
             .route(routes::RECENT_DIRS, get(recent_dirs))
@@ -178,6 +185,16 @@ impl MockDaemon {
         self.state.inner.lock().expect("poisoned").inputs.clone()
     }
 
+    /// Every ACP prompt this daemon received, oldest first.
+    pub fn structured_prompts(&self) -> Vec<(Uuid, StructuredPromptRequest)> {
+        self.state
+            .inner
+            .lock()
+            .expect("poisoned")
+            .structured_prompts
+            .clone()
+    }
+
     pub fn session_count(&self) -> usize {
         self.state.inner.lock().expect("poisoned").sessions.len()
     }
@@ -266,6 +283,26 @@ async fn send_input(
     StatusCode::NO_CONTENT.into_response()
 }
 
+async fn structured_prompt(
+    State(s): State<AppState>,
+    Path(id): Path<Uuid>,
+    Json(req): Json<StructuredPromptRequest>,
+) -> Response {
+    if let Some(r) = forced(&s) {
+        return r;
+    }
+    let mut guard = s.inner.lock().expect("poisoned");
+    if !guard.sessions.iter().any(|x| x.id == id) {
+        return (
+            StatusCode::NOT_FOUND,
+            Json(ApiError::new("not_found", "no such session on this daemon")),
+        )
+            .into_response();
+    }
+    guard.structured_prompts.push((id, req));
+    StatusCode::NO_CONTENT.into_response()
+}
+
 async fn daemon_info(State(s): State<AppState>) -> Response {
     if let Some(r) = forced(&s) {
         return r;