feat(maestro): optimistic session kill in sidebar

Close the kill dialog and remove the session card immediately on
confirm instead of waiting for the DELETE round-trip. Restores the
session if the daemon refuses with kill_guarded and re-opens the
dialog in force mode.

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

crates/maestro-acp/src/lib.rs

@@ -58,6 +58,24 @@ use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
 
 pub use agent_client_protocol::schema::v1 as schema;
 
+/// Item on the updates channel.  Notifications and turn-done markers share
+/// the same FIFO so the event pump processes every notification for a turn
+/// before seeing its done signal.
+#[derive(Debug)]
+pub enum AcpUpdate {
+    /// A raw `session/update` notification from the adapter.
+    Notification(Box<SessionNotification>),
+    /// The prompt response for `turn` arrived.  All notifications for this
+    /// turn precede this marker on the wire, and therefore in this channel.
+    /// The event pump must fire `done` after persisting every preceding
+    /// notification.
+    TurnDone {
+        turn: u64,
+        result: Result<(), String>,
+        done: oneshot::Sender<Result<(), String>>,
+    },
+}
+
 /// ACP adapter selected from the structured session's resolved command.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum AcpAdapter {
@@ -354,7 +372,7 @@ pub struct AcpSession {
     pid: u32,
     commands: mpsc::UnboundedSender<Command>,
     child_commands: mpsc::UnboundedSender<ChildCommand>,
-    updates: Mutex<Option<mpsc::UnboundedReceiver<SessionNotification>>>,
+    updates: Mutex<Option<mpsc::UnboundedReceiver<AcpUpdate>>>,
     permission_requests: Mutex<Option<mpsc::UnboundedReceiver<PermissionRequest>>>,
     exit: watch::Receiver<Option<ExitStatus>>,
 }
@@ -393,9 +411,9 @@ impl AcpSession {
         wait_exit(&self.exit).await
     }
 
-    /// The stream of raw `session/update` notifications, handed out once.
+    /// The stream of updates (notifications + turn-done markers), handed out
-    /// Notifications that arrived before the take are still queued on it.
+    /// once.  Items that arrived before the take are still queued.
-    pub fn take_updates(&self) -> Option<mpsc::UnboundedReceiver<SessionNotification>> {
+    pub fn take_updates(&self) -> Option<mpsc::UnboundedReceiver<AcpUpdate>> {
         self.updates.lock().expect("updates mutex").take()
     }
 
@@ -772,7 +790,7 @@ fn config_notification(session_id: &str, options: Vec<SessionConfigOption>) -> S
 async fn run_connection<T>(
     transport: T,
     config: ConnectionConfig,
-    updates_tx: mpsc::UnboundedSender<SessionNotification>,
+    updates_tx: mpsc::UnboundedSender<AcpUpdate>,
     permission_requests: mpsc::UnboundedSender<PermissionRequest>,
     mut commands_rx: mpsc::UnboundedReceiver<Command>,
     ready_tx: oneshot::Sender<Result<String, ReadyError>>,
@@ -800,7 +818,7 @@ async fn run_connection<T>(
                     return Ok(());
                 }
                 // A dropped receiver only means nobody wants updates any more.
-                let _ = received_updates.send(notification);
+                let _ = received_updates.send(AcpUpdate::Notification(Box::new(notification)));
                 Ok(())
             },
             agent_client_protocol::on_receive_notification!(),
@@ -916,18 +934,18 @@ async fn run_connection<T>(
                 models.as_ref(),
             )));
             if let Some(modes) = &modes {
-                let _ = updates_tx.send(SessionNotification::new(
+                let _ = updates_tx.send(AcpUpdate::Notification(Box::new(SessionNotification::new(
                     SessionId::new(session_id.as_str()),
                     SessionUpdate::CurrentModeUpdate(CurrentModeUpdate::new(
                         modes.current_mode_id.clone(),
                     )),
-                ));
+                ))));
             }
             if !config_options.lock().expect("config options").is_empty() {
-                let _ = updates_tx.send(config_notification(
+                let _ = updates_tx.send(AcpUpdate::Notification(Box::new(config_notification(
                     &session_id,
                     config_options.lock().expect("config options").clone(),
-                ));
+                ))));
             }
             let _ = ready_tx.send(Ok(session_id.clone()));
 
@@ -955,16 +973,23 @@ async fn run_connection<T>(
                             let done = Arc::new(Mutex::new(Some(done)));
                             let callback_done = done.clone();
                             let callback_turn = permission_turn.clone();
+                            let callback_updates = updates_tx.clone();
                             if let Err(error) = cx.send_request(request).on_receiving_result(move |result| {
                                 let callback_done = callback_done.clone();
                                 let callback_turn = callback_turn.clone();
+                                let callback_updates = callback_updates.clone();
                                 async move {
                                     callback_turn
                                         .lock()
                                         .expect("permission turn state")
                                         .finish(turn);
+                                    // Route through the same channel as notifications so the
+                                    // event pump sees this after every chunk for the turn.
+                                    let result = result.map(|_| ()).map_err(|e| e.to_string());
                                     if let Some(done) = callback_done.lock().expect("prompt sender").take() {
-                                        let _ = done.send(result.map(|_| ()).map_err(|e| e.to_string()));
+                                        if callback_updates.send(AcpUpdate::TurnDone { turn, result, done }).is_err() {
+                                            // Channel closed — nowhere left to signal.
+                                        }
                                     }
                                     Ok(())
                                 }
@@ -998,7 +1023,7 @@ async fn run_connection<T>(
                                 }).on_receiving_result(move |result| async move {
                                     if result.is_ok() {
                                         let options = replace_config_value(&callback_options, &callback_config_id, &callback_value);
-                                        let _ = callback_updates.send(config_notification(&callback_session, options));
+                                        let _ = callback_updates.send(AcpUpdate::Notification(Box::new(config_notification(&callback_session, options))));
                                     }
                                     if let Some(done) = callback_done.lock().expect("config sender").take() {
                                         let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));
@@ -1017,13 +1042,13 @@ async fn run_connection<T>(
                                 )).on_receiving_result(move |result| async move {
                                     if result.is_ok() {
                                         let options = replace_config_value(&callback_options, &callback_config_id, &callback_value);
-                                        let _ = callback_updates.send(config_notification(&callback_session, options));
+                                        let _ = callback_updates.send(AcpUpdate::Notification(Box::new(config_notification(&callback_session, options))));
-                                        let _ = callback_updates.send(SessionNotification::new(
+                                        let _ = callback_updates.send(AcpUpdate::Notification(Box::new(SessionNotification::new(
                                             SessionId::new(callback_session.as_str()),
                                             SessionUpdate::CurrentModeUpdate(CurrentModeUpdate::new(
                                                 callback_value.as_value_id().expect("checked mode value").0.clone(),
                                             )),
-                                        ));
+                                        ))));
                                     }
                                     if let Some(done) = callback_done.lock().expect("config sender").take() {
                                         let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));
@@ -1041,7 +1066,7 @@ async fn run_connection<T>(
                                             let mut current = callback_options.lock().expect("config options");
                                             current.retain(|option| option.id.0.as_ref().starts_with("__maestro_legacy_"));
                                             current.extend(response.config_options.clone());
-                                            let _ = callback_updates.send(config_notification(&callback_session, current.clone()));
+                                            let _ = callback_updates.send(AcpUpdate::Notification(Box::new(config_notification(&callback_session, current.clone()))));
                                         }
                                         if let Some(done) = callback_done.lock().expect("config sender").take() {
                                             let _ = done.send(result.map(|_| ()).map_err(|error| error.to_string()));

crates/maestro-acp/tests/spawn.rs

@@ -193,6 +193,9 @@ async fn session_updates_reach_the_taken_receiver() {
         .await
         .expect("update within 5s")
         .expect("channel open");
+    let maestro_acp::AcpUpdate::Notification(first) = first else {
+        panic!("expected Notification");
+    };
     assert_eq!(first.session_id.0.as_ref(), session.session_id());
     match first.update {
         SessionUpdate::AgentMessageChunk(chunk) => match chunk.content {
@@ -221,7 +224,10 @@ async fn advertised_settings_are_normalized_and_mutable() {
             .await
             .expect("settings update")
             .expect("channel open");
-        if let SessionUpdate::ConfigOptionUpdate(options) = update.update {
+        let maestro_acp::AcpUpdate::Notification(n) = update else {
+            continue;
+        };
+        if let SessionUpdate::ConfigOptionUpdate(options) = n.update {
             break options.config_options;
         }
     };
@@ -390,7 +396,10 @@ async fn drop_terminates_and_reaps_the_child() {
     fake.wait_for_exit().await;
 }
 
-fn chunk_text(n: &maestro_acp::schema::SessionNotification) -> String {
+fn chunk_text(update: &maestro_acp::AcpUpdate) -> String {
+    let maestro_acp::AcpUpdate::Notification(n) = update else {
+        panic!("expected Notification, got {update:?}");
+    };
     match &n.update {
         SessionUpdate::AgentMessageChunk(chunk) => match &chunk.content {
             ContentBlock::Text(t) => t.text.clone(),

crates/maestro-daemon/src/session.rs

@@ -2403,34 +2403,49 @@ fn start_acp_event_pump(
     let weak_inner = Arc::downgrade(inner);
     let weak_acp = Arc::downgrade(acp);
     tokio::spawn(async move {
-        while let Some(notification) = updates.recv().await {
+        while let Some(update) = updates.recv().await {
-            let append_error = {
+            match update {
-                let mut events = events.lock().await;
+                maestro_acp::AcpUpdate::Notification(notification) => {
-                let event = PersistedEvent::Notification(Box::new(notification));
+                    let append_error = {
-                match events.log.append(&event) {
+                        let mut events = events.lock().await;
-                    Ok(seq) => {
+                        let event = PersistedEvent::Notification(notification);
-                        let logged = LoggedEvent {
+                        match events.log.append(&event) {
-                            seq,
+                            Ok(seq) => {
-                            event: event.clone(),
+                                let logged = LoggedEvent {
-                        };
+                                    seq,
-                        let projected = apply_persisted_event(&mut events.projection, &logged);
+                                    event: event.clone(),
-                        let _ = events.live.send(logged);
+                                };
-                        events.broadcast(projected);
+                                let projected =
-                        None
+                                    apply_persisted_event(&mut events.projection, &logged);
+                                let _ = events.live.send(logged);
+                                events.broadcast(projected);
+                                None
+                            }
+                            Err(error) => Some(error),
+                        }
+                    };
+                    if let Some(error) = append_error {
+                        tracing::error!(%id, %error, "structured event log append failed");
+                        if let Some(acp) = weak_acp.upgrade() {
+                            acp.terminate(maestro_acp::CANCEL_GRACE, maestro_acp::TERM_GRACE)
+                                .await;
+                        }
+                        if let Some(inner) = weak_inner.upgrade() {
+                            mark_session_dead(&inner, id).await;
+                        }
+                        break;
                     }
-                    Err(error) => Some(error),
                 }
-            };
+                maestro_acp::AcpUpdate::TurnDone {
-            if let Some(error) = append_error {
+                    turn: _,
-                tracing::error!(%id, %error, "structured event log append failed");
+                    result,
-                if let Some(acp) = weak_acp.upgrade() {
+                    done,
-                    acp.terminate(maestro_acp::CANCEL_GRACE, maestro_acp::TERM_GRACE)
+                } => {
-                        .await;
+                    // Every notification for this turn has been persisted and
+                    // broadcast above.  Signal the done oneshot so
+                    // finish_queued_acp_turn runs with the transcript complete.
+                    let _ = done.send(result);
                 }
-                if let Some(inner) = weak_inner.upgrade() {
-                    mark_session_dead(&inner, id).await;
-                }
-                break;
             }
         }
         let _ = done_tx.send(true);

web/src/App.tsx

@@ -113,15 +113,23 @@ function Shell() {
   // a transient lost connection has already recovered.
   useEffect(() => {
     const recover = () => {
-      if (document.visibilityState !== "visible") return;
       void linkStore.getState().probe();
       catalogStore.getState().reconnect();
     };
-    document.addEventListener("visibilitychange", recover);
+    // visibilitychange fires reliably on tab/app switch; guard it so we don't
+    // probe while the page is being hidden.
+    const onVisibility = () => {
+      if (document.visibilityState !== "visible") return;
+      recover();
+    };
+    // pageshow (bfcache restore) and online (network back) indicate the page
+    // is active — fire unconditionally since visibilityState may lag behind on
+    // some mobile browsers.
+    document.addEventListener("visibilitychange", onVisibility);
     window.addEventListener("pageshow", recover);
     window.addEventListener("online", recover);
     return () => {
-      document.removeEventListener("visibilitychange", recover);
+      document.removeEventListener("visibilitychange", onVisibility);
       window.removeEventListener("pageshow", recover);
       window.removeEventListener("online", recover);
     };

web/src/components/sidebar/Sidebar.tsx

@@ -333,10 +333,25 @@ export function Sidebar(props: SidebarProps) {
           onCancel={() => setKill(null)}
           onConfirm={async () => {
             const { session: s, force } = kill;
+            // Close the dialog immediately and optimistically remove the
+            // session from the sidebar so the operator isn't staring at a
+            // spinner while the daemon tears down the tmux session.
+            setKill(null);
+            const store = props.store;
+            if (store) {
+              const next = new Map(store.getState().sessions);
+              next.delete(s.id);
+              store.setState({ sessions: next });
+            }
             try {
               await killSession(s.id, force);
-              setKill(null);
             } catch (e: unknown) {
+              // Restore the session so it reappears in the sidebar.
+              if (store) {
+                const restored = new Map(store.getState().sessions);
+                restored.set(s.id, s);
+                store.setState({ sessions: restored });
+              }
               // The daemon refuses an unforced kill over a worktree holding
               // unsaved work; that refusal needs its own prompt
               // (docs/WORKTREES.md).
@@ -349,7 +364,8 @@ export function Sidebar(props: SidebarProps) {
                 });
                 return;
               }
-              throw e;
+              // Nothing else we can usefully show — the session is back in
+              // the sidebar and the operator can retry.
             }
           }}
         />

web/src/components/structured/structured.css

@@ -481,6 +481,7 @@
 }
 
 .st-tool-arg {
+  flex: 1 1 0;
   color: var(--muted);
   overflow: hidden;
   text-overflow: ellipsis;

web/src/components/structured/useStructuredSession.ts

@@ -197,11 +197,12 @@ export function useStructuredSession(
     };
 
     // Mobile browsers suspend timers and silently kill WebSockets in the
-    // background. Kick a fresh connect when the page becomes visible again.
+    // background. The browser often still reports readyState === OPEN because
+    // TCP keepalive hasn't noticed the dead connection yet. Force-replace
+    // unconditionally — connect() closes the old socket first, and the server
+    // replays the full transcript on every reconnect so nothing is lost.
     const onVisibility = () => {
       if (document.visibilityState !== "visible" || disposed) return;
-      if (socket && (socket.readyState === WebSocket.OPEN || socket.readyState === WebSocket.CONNECTING)) return;
-      cancelTimer();
       setStatus("reconnecting");
       connect();
     };

web/src/components/terminal/TerminalPane.tsx

@@ -303,17 +303,22 @@ export const TerminalPane = forwardRef<TerminalPaneHandle, TerminalPaneProps>(
       ta?.addEventListener("blur", onTaBlur);
 
       // Mobile browsers (Android especially) suspend timers and silently kill
-      // WebSockets when the app goes to background. The backoff timer set by
+      // WebSockets when the app goes to background. The browser often still
-      // onclose is frozen too, so recovery stalls until visibility returns. Kick
+      // reports readyState === OPEN because TCP keepalive hasn't noticed the
-      // a fresh connect immediately when the page becomes visible again.
+      // dead connection yet. Force-replace the socket unconditionally —
+      // a genuinely alive server socket gets a clean close, and the reconnect
+      // replays the scrollback so nothing is lost.
       const onVisibility = () => {
         if (document.visibilityState !== "visible" || disposed) return;
-        if (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING) return;
-        // Cancel any pending backoff — we're reconnecting right now.
         if (reconnectTimer !== null) {
           window.clearTimeout(reconnectTimer);
           reconnectTimer = null;
         }
+        // Detach the old socket's handlers so its close event doesn't race
+        // with the fresh connection (same pattern as catalogStore.reconnect).
+        ws.onclose = null;
+        ws.onerror = null;
+        ws.close();
         reconnectMs = INITIAL_RECONNECT_MS;
         onStatusChange?.("reconnecting");
         connect();

web/src/styles.css

@@ -2648,6 +2648,7 @@ input.leaf-rename:focus {
 }
 
 .st-tool-arg {
+  flex: 1 1 0;
   color: var(--muted);
   overflow: hidden;
   text-overflow: ellipsis;
@@ -2893,7 +2894,11 @@ input.leaf-rename:focus {
 }
 
 .st-tool-group-title {
-  flex: 0 0 auto;
+  flex: 1 1 0;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
   font-weight: 500;
 }