feat(maestro): add the web ctrl-k command bar

The overlay, the query line and the session half of the results
(docs/COMMAND-BAR.md): an empty query lists sessions most recently
focused first, typing ranks through `matchAndRank` with the winning
field's ranges highlighted, and results render under kind headers
ordered by their best-scoring member.

Enter dispatches `SESSION_SELECT_EVENT`, the path the sidebar's click
and the hash router already share, so a bar attach cannot leave the
layout in a state a click could not produce.

The global key listener moves to the capture phase, which #148 left
alone: an attached xterm swallows every keystroke it is given, so
ctrl-k has to be seen ahead of the terminal.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

crates/maestro-cli/src/sessions.rs

@@ -251,6 +251,7 @@ mod tests {
             activity_since: chrono::Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 

crates/maestro-daemon/src/session.rs

@@ -285,33 +285,50 @@ impl SessionManager {
     /// Subscribe to a session's PTY broadcast and return the replay buffer
     /// (NAP-229). Callers send the buffer before pumping the live receiver
     /// so freshly-attached clients see the last screenful immediately.
+    ///
+    /// Opening an attach is focusing (#145): it stamps
+    /// [`Session::last_focused_at`], the same field `set_focused` stamps, so
+    /// a client that only ever attaches sorts identically to one that
+    /// reports focus explicitly.
     pub async fn subscribe_pty_with_replay(
         &self,
         id: Uuid,
     ) -> Option<(Vec<u8>, broadcast::Receiver<Vec<u8>>)> {
         let tmux = self.inner.tmux.clone();
-        let sessions = self.inner.sessions.lock().await;
-        let rec = sessions.get(&id)?;
-        // For a live session, tmux's own screen beats the byte tail: the tail
-        // starts mid-stream, so a full-screen program (an agent TUI) replayed
-        // from it renders as garbage until something forces a repaint. A dead
-        // session has no pane left to capture, so it keeps the byte tail.
-        let alive = rec.session.status == SessionStatus::Running;
-        // The capture shells out to tmux while the replay lock is held, which
-        // parks the reader for the length of one tmux round-trip. That only
-        // happens on attach, and the alternative is a seam in the stream.
-        Some(rec.bridge.subscribe_with_snapshot(|| {
-            if !alive {
-                return None;
-            }
-            match tmux.capture_pane(id) {
-                Ok(snapshot) => snapshot,
-                Err(e) => {
-                    tracing::warn!(error = ?e, %id, "capture-pane failed; replaying raw bytes");
-                    None
+        let (result, updated) = {
+            let mut sessions = self.inner.sessions.lock().await;
+            let rec = sessions.get_mut(&id)?;
+            rec.session.last_focused_at = Some(Utc::now());
+            let updated = rec.session.clone();
+            // For a live session, tmux's own screen beats the byte tail: the
+            // tail starts mid-stream, so a full-screen program (an agent TUI)
+            // replayed from it renders as garbage until something forces a
+            // repaint. A dead session has no pane left to capture, so it
+            // keeps the byte tail.
+            let alive = rec.session.status == SessionStatus::Running;
+            // The capture shells out to tmux while the replay lock is held,
+            // which parks the reader for the length of one tmux round-trip.
+            // That only happens on attach, and the alternative is a seam in
+            // the stream.
+            let result = rec.bridge.subscribe_with_snapshot(|| {
+                if !alive {
+                    return None;
                 }
-            }
-        }))
+                match tmux.capture_pane(id) {
+                    Ok(snapshot) => snapshot,
+                    Err(e) => {
+                        tracing::warn!(error = ?e, %id, "capture-pane failed; replaying raw bytes");
+                        None
+                    }
+                }
+            });
+            (result, updated)
+        };
+        let _ = self
+            .inner
+            .events
+            .send(CatalogEvent::SessionUpdated { session: updated });
+        Some(result)
     }
 
     pub async fn has(&self, id: Uuid) -> bool {
@@ -448,6 +465,7 @@ impl SessionManager {
             // The watcher fills this in on its first blocked-work pass; a
             // fresh tree has nothing in the way anyway.
             blocked_work: None,
+            last_focused_at: None,
         };
 
         if let Err(e) = self.inner.sidecar.write(&session) {
@@ -652,6 +670,7 @@ impl SessionManager {
 
                     current_cwd: None,
                     blocked_work: None,
+                    last_focused_at: None,
                 },
             };
             let fifo_path = self.inner.fifo_dir.join(format!("{id}.fifo"));
@@ -838,11 +857,26 @@ impl SessionManager {
     /// Record whether a client's pane is currently showing `id`. Read by the
     /// activity pass's next tick to decide whether an `AwaitingInput` glow
     /// has been looked at long enough to clear (`apply_focus_suppression`).
-    /// An unknown session is [`SessionError::NotFound`].
+    /// Gaining focus also stamps [`Session::last_focused_at`] (#145) — losing
+    /// it does not, since the command bar's ordering cares about the last
+    /// time the operator arrived, not when they left. An unknown session is
+    /// [`SessionError::NotFound`].
     pub async fn set_focused(&self, id: Uuid, focused: bool) -> Result<(), SessionError> {
-        let mut sessions = self.inner.sessions.lock().await;
-        let rec = sessions.get_mut(&id).ok_or(SessionError::NotFound(id))?;
-        rec.focused_since = focused.then(std::time::Instant::now);
+        let updated = {
+            let mut sessions = self.inner.sessions.lock().await;
+            let rec = sessions.get_mut(&id).ok_or(SessionError::NotFound(id))?;
+            rec.focused_since = focused.then(std::time::Instant::now);
+            if focused {
+                rec.session.last_focused_at = Some(Utc::now());
+            }
+            focused.then(|| rec.session.clone())
+        };
+        if let Some(session) = updated {
+            let _ = self
+                .inner
+                .events
+                .send(CatalogEvent::SessionUpdated { session });
+        }
         Ok(())
     }
 }

crates/maestro-daemon/tests/local_api.rs

@@ -383,6 +383,41 @@ async fn patch_unknown_session_returns_404() {
     assert_eq!(resp.status(), reqwest::StatusCode::NOT_FOUND);
 }
 
+/// #145: `POST /.../focus` with `focused: true` over HTTP stamps
+/// `last_focused_at`, observable on the next `GET /api/sessions`.
+#[tokio::test]
+async fn post_focus_stamps_last_focused_at() {
+    let h = spawn("naps-laptop").await;
+    let session = h
+        .manager
+        .create(CreateSessionRequest {
+            cwd: "/tmp".into(),
+            command: "sleep 60".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .unwrap();
+    assert_eq!(session.last_focused_at, None);
+
+    let resp = reqwest::Client::new()
+        .post(url(h.addr, &format!("/api/sessions/{}/focus", session.id)))
+        .json(&serde_json::json!({ "focused": true }))
+        .send()
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), reqwest::StatusCode::NO_CONTENT);
+
+    let sessions: Vec<Session> = reqwest::get(url(h.addr, "/api/sessions"))
+        .await
+        .unwrap()
+        .json()
+        .await
+        .unwrap();
+    assert!(sessions[0].last_focused_at.is_some());
+}
+
 #[tokio::test]
 async fn delete_owned_session_kills_it() {
     let h = spawn("naps-laptop").await;

crates/maestro-daemon/tests/session_manager.rs

@@ -1091,3 +1091,109 @@ async fn spawned_sessions_export_maestro_session_id_and_url() {
 
     fx.manager.kill(s.id, false).await.expect("kill");
 }
+
+/// docs/COMMAND-BAR.md, empty-query ordering: a session that has never been
+/// focused carries no `last_focused_at` at all, which is what lets a client
+/// sort it after every session that has one (#145).
+#[tokio::test]
+async fn a_freshly_created_session_has_never_been_focused() {
+    let fx = DaemonFixture::new();
+    let cwd = TempDir::new().unwrap();
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: cwd.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .expect("create");
+
+    assert_eq!(s.last_focused_at, None);
+    assert_eq!(fx.manager.snapshot().await[0].last_focused_at, None);
+}
+
+/// #145: `POST /.../focus` reporting `focused: true` stamps
+/// `last_focused_at` and announces it on the event stream; reporting
+/// `focused: false` (losing focus) leaves the stamp alone, since the bar
+/// orders by when the operator last arrived, not when they left.
+#[tokio::test]
+async fn set_focused_true_stamps_last_focused_at() {
+    let fx = DaemonFixture::new();
+    let cwd = TempDir::new().unwrap();
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: cwd.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .expect("create");
+
+    let mut events = fx.manager.events();
+    let before = chrono::Utc::now();
+    fx.manager.set_focused(s.id, true).await.expect("focus");
+
+    let updated = fx.manager.snapshot().await[0].clone();
+    let stamp = updated.last_focused_at.expect("stamped on focus");
+    assert!(stamp >= before);
+
+    let mut saw_update = false;
+    while let Ok(event) = tokio::time::timeout(Duration::from_millis(200), events.recv()).await {
+        if let Ok(CatalogEvent::SessionUpdated { session }) = event {
+            if session.id == s.id && session.last_focused_at == Some(stamp) {
+                saw_update = true;
+                break;
+            }
+        }
+    }
+    assert!(saw_update, "expected a SessionUpdated carrying the stamp");
+
+    fx.manager.set_focused(s.id, false).await.expect("unfocus");
+    let after_unfocus = fx.manager.snapshot().await[0].clone();
+    assert_eq!(
+        after_unfocus.last_focused_at,
+        Some(stamp),
+        "losing focus must not clear the last-focused stamp"
+    );
+}
+
+/// #145: opening `/api/attach/:id` is focusing too — it must stamp the same
+/// field `set_focused` does, so a client that only ever attaches sorts
+/// identically to one that reports focus explicitly.
+#[tokio::test]
+async fn attaching_stamps_last_focused_at() {
+    let fx = DaemonFixture::new();
+    let cwd = TempDir::new().unwrap();
+
+    let s = fx
+        .manager
+        .create(CreateSessionRequest {
+            cwd: cwd.path().to_path_buf(),
+            command: "sleep 30".into(),
+            env: HashMap::new(),
+            metadata: HashMap::new(),
+            worktree: None,
+        })
+        .await
+        .expect("create");
+    assert_eq!(s.last_focused_at, None);
+
+    let before = chrono::Utc::now();
+    let (_replay, _rx) = fx
+        .manager
+        .subscribe_pty_with_replay(s.id)
+        .await
+        .expect("known session");
+
+    let updated = fx.manager.snapshot().await[0].clone();
+    let stamp = updated.last_focused_at.expect("attach stamps focus");
+    assert!(stamp >= before);
+}

crates/maestro-daemon/tests/sidecar.rs

@@ -31,6 +31,7 @@ fn sample(id: Uuid) -> Session {
         activity_since: chrono::Utc::now(),
         current_cwd: Some(PathBuf::from("/tmp/work/crates")),
         blocked_work: None,
+        last_focused_at: None,
     }
 }
 

crates/maestro-protocol/src/display.rs

@@ -248,6 +248,7 @@ mod tests {
             activity_since: Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 

crates/maestro-protocol/src/lib.rs

@@ -108,6 +108,14 @@ pub struct Session {
     /// from daemons that predate the field stay forward-compatible.
     #[serde(default)]
     pub blocked_work: Option<InTheWay>,
+    /// Wall-clock time this session last became the pane a client was
+    /// showing (#145) — stamped by both `POST /.../focus` and opening
+    /// `/api/attach/:id`, since either one is the operator moving there.
+    /// `None` until the session has been focused at least once, which is
+    /// also how the command bar's empty-query ordering (`docs/COMMAND-BAR.md`)
+    /// sorts a never-focused session after every session that has one.
+    #[serde(default)]
+    pub last_focused_at: Option<DateTime<Utc>>,
 }
 
 /// Default for [`Session::last_activity_at`] when an older payload omits it.
@@ -847,6 +855,7 @@ mod tests {
                 .with_timezone(&Utc),
             current_cwd: Some(PathBuf::from("/home/naps62/projects/maestro/crates")),
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 
@@ -896,6 +905,28 @@ mod tests {
         );
     }
 
+    #[test]
+    fn last_focused_at_defaults_to_none_on_legacy_payload() {
+        // Pre-#145 payload omits the field; `None` means never-focused.
+        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.last_focused_at, None);
+
+        let mut focused = sample_session();
+        focused.last_focused_at = Some(
+            DateTime::parse_from_rfc3339("2026-05-24T12:06:00Z")
+                .unwrap()
+                .with_timezone(&Utc),
+        );
+        assert_eq!(focused, round_trip(&focused));
+    }
+
     #[test]
     fn activity_since_defaults_to_epoch_on_legacy_payload() {
         // A daemon predating #102 omits `activity_since`; it must deserialize

crates/maestro-testing/src/lib.rs

@@ -46,6 +46,7 @@ pub fn session(id: Uuid, cwd: &str, command: &str) -> Session {
         activity_since: chrono::Utc::now(),
         current_cwd: None,
         blocked_work: None,
+        last_focused_at: None,
     }
 }
 

crates/maestro-tui/src/app.rs

@@ -87,10 +87,13 @@ pub struct App {
     /// that can move `Focus::Pane` (attach, tab switch, sidebar toggle,
     /// mouse) is covered without each one remembering to report it.
     focused_session: Option<Uuid>,
-    /// A sidebar highlight waiting out its debounce before it becomes a
-    /// preview (`docs/PREVIEW.md`). Walking the list with `j` held down must
-    /// not open an attach per row it passes over.
+    /// A sidebar highlight waiting for the pane's minimum gap before it
+    /// becomes a preview (`docs/PREVIEW.md`). Walking the list with `j` held
+    /// down must not open an attach per row it passes over.
     pending_preview: Option<(Uuid, std::time::Instant)>,
+    /// When the pane last swapped what it previews. `None` until the first
+    /// one, which is why a highlight landing on a still sidebar shows at once.
+    last_preview_at: Option<std::time::Instant>,
     /// Sessions attached only because they were previewed, oldest first. Kept
     /// connected past the preview so stepping back onto a row is instant, and
     /// bounded so a long walk doesn't leave a socket per session behind.
@@ -125,10 +128,11 @@ struct FrameKey {
 /// else changed.
 const CLOCK_REFRESH: Duration = Duration::from_secs(1);
 
-/// How long a highlight has to stand still before the pane previews it
-/// (`docs/PREVIEW.md`). Long enough that a fast walk down the list doesn't
-/// attach to every row it crosses, short enough to read as immediate.
-const PREVIEW_DELAY: Duration = Duration::from_millis(120);
+/// Shortest gap between two pane swaps (`docs/PREVIEW.md`). The first
+/// highlight to land shows at once; this only bounds how often the pane may
+/// follow after that, so a fast walk down the list attaches to the row it
+/// started on and the row it stopped on rather than every row between.
+const PREVIEW_GAP: Duration = Duration::from_millis(120);
 
 /// How many preview-only attaches to keep connected behind the current one.
 const PREVIEW_BUDGET: usize = 3;
@@ -213,6 +217,7 @@ impl App {
             clicks: ClickTracker::default(),
             focused_session: None,
             pending_preview: None,
+            last_preview_at: None,
             preview_lru: Vec::new(),
             last_frame: None,
             last_drawn_at: std::time::Instant::now(),
@@ -526,9 +531,10 @@ impl App {
     }
 
     /// Recompute what the pane should be previewing. A session highlighted in
-    /// the sidebar is previewed after [`PREVIEW_DELAY`]; anything else — a
-    /// group row, the pane holding the keyboard, or the highlight already
-    /// sitting on the attached session — clears the preview at once.
+    /// the sidebar is previewed as soon as [`PREVIEW_GAP`] has passed since the
+    /// last swap — immediately, for a highlight landing on a still list.
+    /// Anything else — a group row, the pane holding the keyboard, or the
+    /// highlight already sitting on the attached session — clears at once.
     fn refresh_preview(&mut self) {
         let wanted = match (self.state.focus, &self.state.sidebar_highlight) {
             (Focus::Sidebar, Some(SidebarItem::Session(sid))) => Some(*sid),
@@ -537,7 +543,12 @@ impl App {
         match wanted {
             Some(sid) if self.state.active_session() != Some(sid) => {
                 if self.state.preview != Some(sid) {
-                    self.pending_preview = Some((sid, std::time::Instant::now() + PREVIEW_DELAY));
+                    let now = std::time::Instant::now();
+                    let due = match self.last_preview_at {
+                        Some(last) if now < last + PREVIEW_GAP => last + PREVIEW_GAP,
+                        _ => now,
+                    };
+                    self.pending_preview = Some((sid, due));
                 }
             }
             _ => {
@@ -547,8 +558,8 @@ impl App {
         }
     }
 
-    /// The debounce elapsed: show the highlighted session, attaching it if
-    /// nothing already is.
+    /// The pane is free to follow: show the highlighted session, attaching it
+    /// if nothing already is.
     fn poll_due_preview_at(&mut self, now: std::time::Instant) -> Vec<Effect> {
         let Some((sid, due)) = self.pending_preview else {
             return Vec::new();
@@ -560,6 +571,7 @@ impl App {
         if self.state.preview == Some(sid) {
             return Vec::new();
         }
+        self.last_preview_at = Some(now);
         self.state.preview = Some(sid);
         // Set outside the input path, so nothing else marks the frame stale.
         self.epoch = self.epoch.wrapping_add(1);
@@ -1653,6 +1665,7 @@ mod tests {
                     activity_since: chrono::Utc::now(),
                     current_cwd: None,
                     blocked_work: None,
+                    last_focused_at: None,
                 })
                 .collect(),
         });
@@ -1671,24 +1684,22 @@ mod tests {
         }
     }
 
-    fn after_debounce() -> std::time::Instant {
-        std::time::Instant::now() + PREVIEW_DELAY + Duration::from_millis(1)
+    fn after_gap() -> std::time::Instant {
+        std::time::Instant::now() + PREVIEW_GAP + Duration::from_millis(1)
     }
 
     /// docs/PREVIEW.md: the highlight shows a session in the pane without the
     /// tab taking it on.
     #[test]
-    fn highlighting_a_session_previews_it_once_the_debounce_elapses() {
+    fn highlighting_a_session_previews_it_without_waiting() {
         let a = Uuid::from_u128(1);
         let mut app = app_with_sessions(&[a]);
         app.dispatch(Action::SidebarNext);
 
-        // Nothing yet: the highlight has to stand still first.
-        assert_eq!(app.poll_due_preview_at(std::time::Instant::now()), vec![]);
-        assert_eq!(app.state.preview, None);
-
+        // The list was still, so the pane follows on the next poll — no gap to
+        // wait out first (docs/PREVIEW.md).
         assert_eq!(
-            app.poll_due_preview_at(after_debounce()),
+            app.poll_due_preview_at(std::time::Instant::now()),
             vec![Effect::Attach(a)]
         );
         assert_eq!(app.state.preview, Some(a));
@@ -1697,6 +1708,28 @@ mod tests {
         assert_eq!(app.state.active_tab().session(), None);
     }
 
+    /// The gap only bounds the *second* swap, so a burst costs two mounts.
+    #[test]
+    fn a_second_move_inside_the_gap_waits_for_it() {
+        let a = Uuid::from_u128(1);
+        let b = Uuid::from_u128(2);
+        let mut app = app_with_sessions(&[a, b]);
+
+        app.dispatch(Action::SidebarNext);
+        let now = std::time::Instant::now();
+        assert_eq!(app.poll_due_preview_at(now), vec![Effect::Attach(a)]);
+
+        app.dispatch(Action::SidebarNext);
+        assert_eq!(app.poll_due_preview_at(now), vec![]);
+        assert_eq!(app.state.preview, Some(a));
+
+        assert_eq!(
+            app.poll_due_preview_at(after_gap()),
+            vec![Effect::Attach(b)]
+        );
+        assert_eq!(app.state.preview, Some(b));
+    }
+
     /// A fast walk down the list attaches to where it stopped, not to every
     /// row it crossed.
     #[test]
@@ -1707,7 +1740,7 @@ mod tests {
         app.dispatch(Action::SidebarNext);
         app.dispatch(Action::SidebarNext);
 
-        let effects = app.poll_due_preview_at(after_debounce());
+        let effects = app.poll_due_preview_at(after_gap());
         assert_eq!(effects, vec![Effect::Attach(b)]);
         assert_eq!(app.state.preview, Some(b));
     }
@@ -1723,7 +1756,7 @@ mod tests {
 
         app.state.sidebar_highlight = Some(SidebarItem::Session(b));
         app.refresh_preview();
-        app.poll_due_preview_at(after_debounce());
+        app.poll_due_preview_at(after_gap());
         assert_eq!(app.state.preview, Some(b));
 
         app.state.sidebar_highlight = Some(SidebarItem::Session(a));
@@ -1743,7 +1776,7 @@ mod tests {
         app.state.focus = Focus::Sidebar;
         app.state.sidebar_highlight = Some(SidebarItem::Session(b));
         app.refresh_preview();
-        app.poll_due_preview_at(after_debounce());
+        app.poll_due_preview_at(after_gap());
 
         app.dispatch(Action::FocusPane(crate::action::Direction::Right));
         assert_eq!(app.state.preview, None);
@@ -1756,7 +1789,7 @@ mod tests {
         let a = Uuid::from_u128(1);
         let mut app = app_with_sessions(&[a]);
         app.dispatch(Action::SidebarNext);
-        app.poll_due_preview_at(after_debounce());
+        app.poll_due_preview_at(after_gap());
         // Stand in for the attach the effect would have opened.
         app.emulators.insert(a, fake_handle());
 
@@ -1775,10 +1808,13 @@ mod tests {
             .map(Uuid::from_u128)
             .collect();
         let mut app = app_with_sessions(&ids);
+        // Each row is previewed in its own gap window, so all of them land.
+        let mut clock = std::time::Instant::now();
         for id in &ids {
             app.state.sidebar_highlight = Some(SidebarItem::Session(*id));
             app.refresh_preview();
-            app.poll_due_preview_at(after_debounce());
+            clock += PREVIEW_GAP + Duration::from_millis(1);
+            app.poll_due_preview_at(clock);
             app.emulators.insert(*id, fake_handle());
         }
 
@@ -1810,6 +1846,7 @@ mod tests {
                 activity_since: chrono::Utc::now(),
                 current_cwd: None,
                 blocked_work: None,
+                last_focused_at: None,
             }],
         });
         app.dispatch(Action::SidebarNext);
@@ -1836,6 +1873,7 @@ mod tests {
             activity_since: Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 
@@ -2697,6 +2735,7 @@ mod tests {
 
                 current_cwd: None,
                 blocked_work: None,
+                last_focused_at: None,
             }],
         });
         app.dispatch(Action::KillHighlighted);
@@ -2731,6 +2770,7 @@ mod tests {
                 activity_since: Utc::now(),
                 current_cwd: None,
                 blocked_work: None,
+                last_focused_at: None,
             }],
         });
     }

crates/maestro-tui/src/catalog.rs

@@ -222,6 +222,7 @@ mod tests {
             activity_since: chrono::Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 

crates/maestro-tui/src/sidebar.rs

@@ -461,6 +461,7 @@ mod tests {
             activity_since: Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         }
     }
 
@@ -1123,6 +1124,7 @@ mod tests {
             activity_since: Utc::now(),
             current_cwd: None,
             blocked_work: None,
+            last_focused_at: None,
         };
         let sb = Sidebar {
             sessions: vec![s],

docs/PREVIEW.md

@@ -32,6 +32,33 @@ The throwaway tab never counts as an open session: the tab bar does not appear
 because of it, the mobile shell does not switch away from the session list for
 it, and the sidebar does not mark the session as open.
 
+## How a preview reads
+
+A preview is provisional, so it never wears the accent — the accent is what
+says "this is the one you picked". It has a hue of its own, and every surface
+involved in the preview carries that same hue, so the pane and the row it came
+from read as one thing rather than two unrelated highlights.
+
+Web client (`--preview` and friends in `web/src/styles.css`):
+
+| Surface | While previewing |
+|---|---|
+| The previewed pane's titlebar | Tinted in the preview hue, at full strength, in place of the focused pane's accent tint. |
+| The canvas | A `preview` chip, top right, and a dashed inset ring. |
+| A throwaway tab | Dashed border, italic label. |
+| The sidebar row being previewed | Filled with the preview hue, over whatever open/focused state the row already had. |
+| A hovered sidebar row, and the keyboard cursor on a session | A lighter wash of the same hue, because both are what previews a row. |
+
+Rows say it with fill, not with an edge: the only ring left in the session list
+is `.is-active`'s, which means "open in a pane". The dashed edges belong to the
+pane — the canvas ring and the throwaway tab.
+
+The hue is a palette token, not a fixed colour: a palette whose accent already
+sits on it moves it (`--preview-h`), so "previewing" and "picked" never collide.
+
+The TUI marks a preview in text only — the title bar reads `<name>  ·  preview`
+— and has no preview colour role yet.
+
 ## What ends a preview
 
 - The highlight moves to another session — that session is previewed instead.
@@ -50,15 +77,19 @@ Nothing moves a second time on commit.
 
 ## Timing
 
-A preview follows the highlight closely enough to be usable as a way to look
-around, and lags a pointer enough not to flash rows crossed on the way
-somewhere else.
+**A preview is never delayed.** Landing on a row — by pointer or by `j`/`k` —
+shows it on the next frame, and so does leaving every row. There is no
+settling period in front of the first preview, because that period would sit
+in front of the one preview the operator actually meant.
 
-| Trigger | Delay |
-|---|---|
-| Keyboard step (`j`/`k`, arrows) | 60 ms |
-| Pointer hover (web, mouse only — never touch) | 150 ms |
-| Clearing (highlight left every session) | same delay as the trigger that set it |
+What is bounded is how *often* the pane may swap: at most once per 120 ms.
+A burst inside one window — `j` held down, or the pointer sweeping the length
+of the sidebar — shows the row it started on, then the row it ended on, and
+none of the rows in between. So a walk costs a couple of pane mounts rather
+than one per row, without the operator ever waiting on one.
+
+The highlight itself is not bounded by any of this: the row lights up on the
+same frame as the input, whatever the pane behind it is doing.
 
 Touch has no hover, and a tap already opens a session, so touch never previews.
 

web/src/attach.ts

@@ -5,6 +5,7 @@ import "@xterm/xterm/css/xterm.css";
 
 import { attachWsUrl } from "./routes.js";
 import { FOCUS_SIDEBAR_EVENT } from "./catalog.js";
+import { CommandSet, defineCommands } from "./commands.js";
 import { escapeHtml } from "./html.js";
 import { INITIAL_RECONNECT_MS, MAX_RECONNECT_MS } from "./reconnect.js";
 import { applyModsToChar, cursorSeq, tildeSeq } from "./keys.js";
@@ -13,6 +14,15 @@ import { splitCommand, toolIconSvg } from "./toolIcon.js";
 import type { ClientControl, Uuid } from "./types.js";
 import { WebglPolicy } from "./webglRenderer.js";
 
+// The pane's half of the command registry (#148): plain Escape hands the
+// keyboard back to the session list, the pair to the list's Tab.
+const paneKeys = new CommandSet(
+  defineCommands({
+    "pane.focusList": () => document.dispatchEvent(new CustomEvent(FOCUS_SIDEBAR_EVENT)),
+  }),
+  { preventDefault: false },
+);
+
 /** One budget for the whole page — see webglRenderer.ts for why contexts are
  *  rationed rather than handed to every connection. */
 const webglPolicy = new WebglPolicy();
@@ -56,8 +66,6 @@ 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 {
@@ -210,12 +218,12 @@ export function createAttachConnection(
   }
 
   // Plain Escape hands the keyboard back to the session list instead of the
-  // shell/app. `false` tells xterm to skip its own handling of this event.
+  // shell/app. `false` tells xterm to skip its own handling of this event —
+  // which is also why the set doesn't `preventDefault`: swallowing here is
+  // xterm's return value, not the browser's.
   term.attachCustomKeyEventHandler((e) => {
-    if (e.type !== "keydown" || e.key !== "Escape") return true;
-    if (e.ctrlKey || e.altKey || e.metaKey || e.shiftKey) return true;
-    document.dispatchEvent(new CustomEvent(FOCUS_SIDEBAR_EVENT));
-    return false;
+    if (e.type !== "keydown") return true;
+    return !paneKeys.handle(e);
   });
 
   // Touch scrolling: xterm's built-in touch handling is jittery (drags crawl a

web/src/catalog.ts

@@ -2,7 +2,8 @@ import { escapeHtml } from "./html.js";
 import { ApiRequestError, getDaemonInfo, killSession, renameSession } from "./api.js";
 import { openForceKillDialog } from "./killDialog.js";
 import { openContextMenu } from "./contextMenu.js";
-import { isTypingTarget, toggleHelp } from "./help.js";
+import { toggleHelp } from "./help.js";
+import { CommandSet, defineCommands } from "./commands.js";
 import { CatalogStore } from "./events.js";
 import type { InTheWay, Session } from "./types.js";
 import {
@@ -164,6 +165,10 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
     return wrap;
   }
 
+  // The row outlives the snapshot it was built from: a refresh that changes
+  // nothing structural patches it in place rather than replacing it, so the
+  // handlers below have to read the current session, not the one captured here.
+  let cur = node.session;
   const s = node.session;
   const now = Date.now();
   const row = document.createElement("a");
@@ -197,33 +202,74 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
   similarBtn.addEventListener("click", (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
-    document.dispatchEvent(new CustomEvent(SPAWN_SIMILAR_EVENT, { detail: s }));
+    document.dispatchEvent(new CustomEvent(SPAWN_SIMILAR_EVENT, { detail: cur }));
   });
   const killBtn = row.querySelector(".leaf-kill") as HTMLButtonElement;
   killBtn.addEventListener("click", (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
-    void requestKill(s, name);
+    void requestKill(cur, sessionName(cur));
   });
   row.addEventListener("click", () => {
-    document.dispatchEvent(new CustomEvent(SESSION_SELECT_EVENT, { detail: s.id }));
+    document.dispatchEvent(new CustomEvent(SESSION_SELECT_EVENT, { detail: cur.id }));
   });
   row.addEventListener("contextmenu", (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
     openContextMenu(ev.clientX, ev.clientY, [
-      { label: "Rename…", onSelect: () => beginRename(row, s) },
+      { label: "Rename…", onSelect: () => beginRename(row, cur) },
       {
         label: "Spawn similar",
         onSelect: () =>
-          document.dispatchEvent(new CustomEvent(SPAWN_SIMILAR_EVENT, { detail: s })),
+          document.dispatchEvent(new CustomEvent(SPAWN_SIMILAR_EVENT, { detail: cur })),
+      },
+      {
+        label: "Kill session",
+        danger: true,
+        onSelect: () => void requestKill(cur, sessionName(cur)),
       },
-      { label: "Kill session", danger: true, onSelect: () => void requestKill(s, name) },
     ]);
   });
+  leafPatches.set(row, (next) => {
+    cur = next;
+    const nextSlug = activityColorSlug(next.activity ?? "Idle");
+    const nextWord = STATE_WORDS[nextSlug] ?? STATE_WORDS.idle;
+    row.setAttribute(
+      "aria-label",
+      `${sessionName(next)}, ${next.status === "Running" ? "running" : "exited"}, ${nextWord}`,
+    );
+    const rail = row.querySelector(".activity-rail");
+    if (rail) rail.outerHTML = activityRailMarkup(nextSlug, nextWord);
+    const meta = row.querySelector(".card-line2");
+    if (meta) meta.outerHTML = metaLine(next, Date.now());
+  });
   return row;
 }
 
+/** Refresh a standing card from a newer snapshot of its session, keeping the
+ *  element (and so the pointer's `:hover`) exactly where it is. Registered by
+ *  `renderNode`; only the bits `treeSignature` leaves out are rewritten. */
+const leafPatches = new WeakMap<HTMLElement, (s: Session) => void>();
+
+/**
+ * Everything about the tree that a patch cannot fix up.
+ *
+ * The daemon re-sends a session on every activity, foreground or cwd shift —
+ * a couple of times a minute per live session — and rebuilding the sidebar for
+ * each one drops `:hover` from the row under the pointer. Refreshes whose
+ * signature is unchanged are patched into the standing rows instead; anything
+ * that moves, renames, appears or dies changes the signature and rebuilds.
+ */
+function treeSignature(node: TreeNode): string {
+  if (node.kind === "folder") {
+    const head = `F:${node.name}:${node.path}:${collapsed.has(node.path)}`;
+    if (node.name && collapsed.has(node.path)) return head;
+    return `${head}(${node.children.map(treeSignature).join(",")})`;
+  }
+  const s = node.session;
+  return `L:${s.id}:${sessionName(s)}:${s.status}:${isProvisionalName(s)}`;
+}
+
 /**
  * Kill on the first click (#81): the daemon is the one that decides whether a
  * session may go, and it refuses over a worktree holding unsaved work. Only
@@ -342,6 +388,9 @@ export interface SidebarHandle {
   setActive(id: string | null): void;
   /** Apply the full open/focused highlight state. */
   setHighlights(h: SidebarHighlights): void;
+  /** Mark the row the content pane is previewing (docs/PREVIEW.md), or clear it
+   *  with `null`. A preview is a view, not state, so this only paints. */
+  setPreview(sessionId: string | null): void;
   /** Hand the keyboard to the session list, highlighting a row to walk from. */
   focusList(): void;
   /** Whether the session list currently holds DOM focus. */
@@ -368,7 +417,7 @@ export interface SidebarOptions {
    *  shell shows it in the content pane without opening it (docs/PREVIEW.md).
    *  `source` is there so a mouse sweep can be debounced differently from a
    *  keyboard step. */
-  onPreview?: (sessionId: string | null, source: "key" | "hover") => void;
+  onPreview?: (sessionId: string | null) => void;
 }
 
 export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): SidebarHandle {
@@ -501,6 +550,10 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
   });
 
   let highlights: SidebarHighlights = { open: new Set(), focused: null };
+  // The previewed row is painted alongside the open/focused tiers so a
+  // re-render can't drop it, but it is never part of `highlights`: a preview
+  // is a view, and nothing about it is durable (docs/PREVIEW.md).
+  let previewing: string | null = null;
   const applyHighlights = () => {
     for (const n of treeHost.querySelectorAll<HTMLElement>(".tree-leaf")) {
       const id = n.dataset.sessionId;
@@ -509,6 +562,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
       const open = highlights.open.has(id);
       n.classList.toggle("is-active", focused);
       n.classList.toggle("is-open", open && !focused);
+      n.classList.toggle("is-previewing", previewing === id);
     }
   };
 
@@ -547,7 +601,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     navKey = next.dataset.navKey ?? null;
     applyNav();
     next.scrollIntoView({ block: "nearest" });
-    opts.onPreview?.(sessionOf(navKey), "key");
+    opts.onPreview?.(sessionOf(navKey));
   };
 
   /** Enter: open the highlighted session, or expand the highlighted folder. */
@@ -578,7 +632,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
   const setHovered = (id: string | null) => {
     if (hovered === id) return;
     hovered = id;
-    opts.onPreview?.(id, "hover");
+    opts.onPreview?.(id);
   };
   treeHost.addEventListener("pointerover", (e) => {
     if (e.pointerType === "touch") return;
@@ -595,7 +649,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
   treeHost.tabIndex = -1;
   // The keyboard walk's preview belongs to the list having the keyboard: once
   // it doesn't, the content pane goes back to what the operator actually opened.
-  treeHost.addEventListener("blur", () => opts.onPreview?.(null, "key"));
+  treeHost.addEventListener("blur", () => opts.onPreview?.(null));
 
   /** The session behind the highlighted row, if the highlight is on a card. */
   const highlightedSession = (): { row: HTMLElement; session: Session } | undefined => {
@@ -616,24 +670,33 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     applyNav();
   };
 
-  treeHost.addEventListener("keydown", (e) => {
-    if (e.ctrlKey || e.altKey || e.metaKey) return;
-    // The inline rename field lives inside a row and owns its own keys.
-    if (isTypingTarget(e.target)) return;
-    if (e.key === "j" || e.key === "ArrowDown") moveNav(1);
-    else if (e.key === "k" || e.key === "ArrowUp") moveNav(-1);
-    else if (e.key === "Enter") activateNav();
-    else if (e.key === "Tab") document.dispatchEvent(new CustomEvent(FOCUS_PANE_EVENT));
-    else if (e.key === "c") toggleHighlightedFolder();
-    else if (e.key === "x") {
-      const hit = highlightedSession();
-      if (hit) void requestKill(hit.session, sessionName(hit.session));
-    } else if (e.key === "r") {
-      const hit = highlightedSession();
-      if (hit) beginRename(hit.row, hit.session);
-    } else return;
-    e.preventDefault();
-  });
+  // The session list's half of the command registry (#148). One set per
+  // sidebar, so a second sidebar (tests, hot reload) drives its own rows; the
+  // labels and chords still come from the one registry.
+  const listKeys = new CommandSet(
+    defineCommands({
+      "list.next": () => moveNav(1),
+      "list.prev": () => moveNav(-1),
+      "list.activate": () => activateNav(),
+      "list.toggleFolder": () => toggleHighlightedFolder(),
+      "list.rename": () => {
+        const hit = highlightedSession();
+        if (hit) beginRename(hit.row, hit.session);
+      },
+      "list.kill": () => {
+        const hit = highlightedSession();
+        if (hit) void requestKill(hit.session, sessionName(hit.session));
+      },
+      "list.focusPane": () => document.dispatchEvent(new CustomEvent(FOCUS_PANE_EVENT)),
+    }),
+  );
+
+  // The inline rename field lives inside a row and owns its own keys; the set's
+  // plain-key rule keeps this walk out of it.
+  treeHost.addEventListener("keydown", (e) => listKeys.handle(e));
+
+  /** Signature of what is currently on screen — see `treeSignature`. */
+  let renderedSignature: string | null = null;
 
   const refresh = () => {
     // Rebuilding the tree now would blow away the field being typed into.
@@ -641,6 +704,15 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
     const state = store.snapshot();
     const sessions = [...state.sessions.values()];
     const tree = buildTree(sessions, homeDir, filter);
+    const signature = sessions.length === 0 ? `EMPTY:${filter.trim()}` : treeSignature(tree);
+    if (signature === renderedSignature) {
+      for (const row of treeHost.querySelectorAll<HTMLElement>(".tree-leaf")) {
+        const s = row.dataset.sessionId ? state.sessions.get(row.dataset.sessionId) : undefined;
+        if (s) leafPatches.get(row)?.(s);
+      }
+      return;
+    }
+    renderedSignature = signature;
     treeHost.replaceChildren();
     if (sessions.length === 0) {
       treeHost.appendChild(
@@ -664,7 +736,13 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
       /* absolute paths are a fine fallback */
     });
 
-  const rerenderHandler = () => refresh();
+  // Dispatched when something outside the store changed what the tree should
+  // look like — a folder collapsed, a rename ended — none of which the store
+  // snapshot can show, so the signature check has to be bypassed.
+  const rerenderHandler = () => {
+    renderedSignature = null;
+    refresh();
+  };
   document.addEventListener("catalog-rerender", rerenderHandler);
 
   // "Spawn similar" (#28) is dispatched here and handled in main.ts, where the
@@ -692,6 +770,10 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
       highlights = h;
       applyHighlights();
     },
+    setPreview(sessionId: string | null) {
+      previewing = sessionId;
+      applyHighlights();
+    },
     focusList() {
       // Start from the session on screen — that is where the user's attention
       // already is — falling back to the standing highlight, then the top row.

web/src/catalogPatch.test.ts

@@ -0,0 +1,105 @@
+// @vitest-environment happy-dom
+import { beforeAll, describe, expect, it } from "vitest";
+
+import { renderSidebar } from "./catalog.js";
+import type { CatalogListener, CatalogStore } from "./events.js";
+import type { Session } from "./types.js";
+
+beforeAll(() => {
+  Object.defineProperty(window, "localStorage", {
+    value: { getItem: () => null, setItem: () => {} },
+  });
+  window.fetch = () => Promise.reject(new Error("offline"));
+});
+
+const ID = "11111111-2222-3333-4444-555555555555";
+
+function session(overrides: Partial<Session> = {}): Session {
+  return {
+    id: ID,
+    cwd: "/home/naps/tea/maestro",
+    command: "claude",
+    env: {},
+    metadata: {},
+    status: "Running",
+    created_at: "2026-08-24T10:00:00Z",
+    ...overrides,
+  };
+}
+
+/** A store whose updates actually reach subscribers, unlike the one-shot
+ *  harness in catalog.test.ts. */
+function liveStore(initial: Session[]) {
+  const state = { sessions: new Map(initial.map((s) => [s.id, s])) };
+  const listeners = new Set<CatalogListener>();
+  const store = {
+    snapshot: () => state,
+    subscribe: (fn: CatalogListener) => {
+      listeners.add(fn);
+      fn(state);
+      return () => listeners.delete(fn);
+    },
+  } as unknown as CatalogStore;
+  const push = (sessions: Session[]) => {
+    state.sessions = new Map(sessions.map((s) => [s.id, s]));
+    for (const fn of listeners) fn(state);
+  };
+  return { store, push };
+}
+
+const rowOf = (el: HTMLElement) => el.querySelector<HTMLElement>(".tree-leaf")!;
+
+describe("sidebar refresh keeps rows in place (docs/SIDEBAR.md)", () => {
+  it("patches an activity change into the standing row instead of rebuilding it", () => {
+    const { store, push } = liveStore([session({ activity: "Idle" })]);
+    const { el } = renderSidebar(store, {});
+    const before = rowOf(el);
+
+    push([session({ activity: "AwaitingInput" })]);
+
+    // Same element: a rebuild under the pointer would drop `:hover` and restart
+    // the row's transitions, which is the flicker this avoids.
+    expect(rowOf(el)).toBe(before);
+    // …and the card still tells the truth about the session.
+    expect(before.querySelector(".activity-rail")?.getAttribute("data-activity")).toBe(
+      "awaiting-input",
+    );
+    expect(before.querySelector(".card-line2")?.getAttribute("data-activity")).toBe(
+      "awaiting-input",
+    );
+    expect(before.getAttribute("aria-label")).toContain("Awaiting input");
+  });
+
+  it("rebuilds when the row set changes", () => {
+    const { store, push } = liveStore([session()]);
+    const { el } = renderSidebar(store, {});
+    const before = rowOf(el);
+
+    push([session(), session({ id: "99999999-2222-3333-4444-555555555555", command: "bash" })]);
+
+    expect(el.querySelectorAll(".tree-leaf")).toHaveLength(2);
+    expect(rowOf(el)).not.toBe(before);
+  });
+
+  it("rebuilds when a session dies", () => {
+    const { store, push } = liveStore([session()]);
+    const { el } = renderSidebar(store, {});
+    const before = rowOf(el);
+
+    push([session({ status: "Dead" })]);
+
+    expect(rowOf(el)).not.toBe(before);
+    expect(rowOf(el).dataset.status).toBe("dead");
+  });
+
+  it("rebuilds when a session is renamed", () => {
+    const { store, push } = liveStore([session()]);
+    const { el } = renderSidebar(store, {});
+    const before = rowOf(el);
+
+    push([session({ metadata: { name: "harmony" } })]);
+
+    expect(rowOf(el)).not.toBe(before);
+    expect(rowOf(el).querySelector(".leaf-name")?.textContent).toBe("harmony");
+  });
+});

web/src/commandBar.test.ts

@@ -0,0 +1,309 @@
+// @vitest-environment happy-dom
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { SESSION_SELECT_EVENT } from "./catalog.js";
+import {
+  barGroups,
+  barRows,
+  closeCommandBar,
+  isCommandBarOpen,
+  openCommandBar,
+  orderSessionsForBar,
+  sessionBarCandidates,
+  sessionCandidate,
+} from "./commandBar.js";
+import { COMMAND_SPECS } from "./commands.js";
+import type { Session } from "./types.js";
+
+function session(id: string, over: Partial<Session> = {}): Session {
+  return {
+    id,
+    cwd: "/home/me/dev/api",
+    command: "bash",
+    env: {},
+    metadata: { name: id },
+    status: "Running",
+    created_at: "2026-01-01T00:00:00Z",
+    ...over,
+  };
+}
+
+afterEach(() => {
+  closeCommandBar();
+  document.body.replaceChildren();
+});
+
+function press(key: string, init: KeyboardEventInit = {}): void {
+  const input = document.querySelector(".cmdbar-input") as HTMLInputElement;
+  input.dispatchEvent(new KeyboardEvent("keydown", { key, bubbles: true, ...init }));
+}
+
+function type(value: string): void {
+  const input = document.querySelector(".cmdbar-input") as HTMLInputElement;
+  input.value = value;
+  input.dispatchEvent(new Event("input", { bubbles: true }));
+}
+
+function rowNames(): string[] {
+  return [...document.querySelectorAll(".cmdbar-row-name")].map((r) => r.textContent ?? "");
+}
+
+function activeName(): string | undefined {
+  return document.querySelector(".cmdbar-row.is-active .cmdbar-row-name")?.textContent ?? undefined;
+}
+
+describe("empty-query ordering", () => {
+  it("sorts most recently focused first", () => {
+    const older = session("older", { last_focused_at: "2026-01-01T10:00:00Z" });
+    const newer = session("newer", { last_focused_at: "2026-01-01T11:00:00Z" });
+    expect(orderSessionsForBar([older, newer]).map((s) => s.id)).toEqual(["newer", "older"]);
+  });
+
+  it("sorts a never-focused session after every focused one, newest created first", () => {
+    const focused = session("focused", {
+      last_focused_at: "2020-01-01T00:00:00Z",
+      created_at: "2020-01-01T00:00:00Z",
+    });
+    const oldFresh = session("old-fresh", { created_at: "2026-01-01T00:00:00Z" });
+    const newFresh = session("new-fresh", { created_at: "2026-06-01T00:00:00Z" });
+    expect(orderSessionsForBar([oldFresh, newFresh, focused]).map((s) => s.id)).toEqual([
+      "focused",
+      "new-fresh",
+      "old-fresh",
+    ]);
+  });
+
+  it("sorts dead sessions after live ones regardless of recency", () => {
+    const deadRecent = session("dead", {
+      status: "Dead",
+      last_focused_at: "2026-06-01T00:00:00Z",
+    });
+    const liveStale = session("live", { last_focused_at: "2020-01-01T00:00:00Z" });
+    const liveNever = session("never");
+    expect(orderSessionsForBar([deadRecent, liveNever, liveStale]).map((s) => s.id)).toEqual([
+      "live",
+      "never",
+      "dead",
+    ]);
+  });
+
+  it("treats a null last_focused_at as never focused", () => {
+    const nulled = session("nulled", { last_focused_at: null });
+    const stamped = session("stamped", { last_focused_at: "2020-01-01T00:00:00Z" });
+    expect(orderSessionsForBar([nulled, stamped]).map((s) => s.id)).toEqual(["stamped", "nulled"]);
+  });
+});
+
+describe("session candidates", () => {
+  it("carries the candidate table's fields, with the directory abbreviated", () => {
+    const s = session("api", {
+      metadata: { name: "api" },
+      command: "claude --resume",
+      current_cwd: "/home/me/dev/api",
+    });
+    expect(sessionCandidate(s, "/home/me")).toEqual({
+      kind: "session",
+      session: s,
+      fields: {
+        name: "api",
+        directory: "~/dev/api",
+        command: "claude --resume",
+        tool: "claude",
+      },
+    });
+  });
+
+  it("leaves the tool out when the program has no mark, and groups a worktree by its repo", () => {
+    const s = session("edit", {
+      metadata: {},
+      command: "hx src/",
+      worktree: { path: "/home/me/dev/api/wt/x", base_repo: "/home/me/dev/api" },
+    });
+    const candidate = sessionCandidate(s, "/home/me");
+    expect(candidate.fields.tool).toBeUndefined();
+    expect(candidate.fields.directory).toBe("~/dev/api");
+    // No `metadata.name`: the sidebar's fallback is the command line.
+    expect(candidate.fields.name).toBe("hx src/");
+  });
+
+  it("builds candidates in the empty-query order", () => {
+    const a = session("a", { last_focused_at: "2026-01-01T10:00:00Z" });
+    const b = session("b", { last_focused_at: "2026-01-01T11:00:00Z" });
+    expect(sessionBarCandidates([a, b]).map((c) => c.session.id)).toEqual(["b", "a"]);
+  });
+});
+
+describe("rows and grouping", () => {
+  it("an empty query keeps every session in input order", () => {
+    const candidates = sessionBarCandidates([session("a"), session("b")]);
+    expect(barRows("", candidates).map((r) => r.candidate.session.id)).toEqual(["a", "b"]);
+  });
+
+  it("groups by kind without reordering the ranking", () => {
+    const candidates = sessionBarCandidates([
+      session("worker", { metadata: { name: "worker" }, current_cwd: "/home/me/dev/api" }),
+      session("api", { metadata: { name: "api" }, current_cwd: "/home/me/dev/web" }),
+    ]);
+    const rows = barRows("api", candidates);
+    const groups = barGroups(rows);
+    expect(groups).toHaveLength(1);
+    expect(groups[0].title).toBe("Sessions");
+    expect(groups[0].results.map((r) => r.candidate.session.id)).toEqual(
+      rows.map((r) => r.candidate.session.id),
+    );
+    // F6: the name beats the directory, and the directory match highlights
+    // inside the directory.
+    expect(groups[0].results[0].candidate.session.id).toBe("api");
+    expect(groups[0].results[1].field).toBe("directory");
+  });
+});
+
+describe("the overlay", () => {
+  const sessions = [
+    session("api", {
+      metadata: { name: "api" },
+      current_cwd: "/home/me/dev/api",
+      last_focused_at: "2026-01-01T11:00:00Z",
+    }),
+    session("worker", {
+      metadata: { name: "worker" },
+      current_cwd: "/home/me/dev/worker",
+      last_focused_at: "2026-01-01T10:00:00Z",
+    }),
+    session("notes", { metadata: { name: "notes" }, current_cwd: "/home/me/notes" }),
+  ];
+
+  function open(over: Parameters<typeof openCommandBar>[0] | null = null) {
+    return openCommandBar(over ?? { sessions, homeDir: "/home/me", onOpenSession: () => {} });
+  }
+
+  it("is a registry command, so the help overlay lists it", () => {
+    const spec = COMMAND_SPECS.find((s) => s.id === "bar.open");
+    expect(spec?.keys).toEqual(["ctrl-k"]);
+    expect(spec?.scope).toBe("global");
+  });
+
+  it("lists sessions by recency under a kind header on an empty query", () => {
+    open();
+    expect([...document.querySelectorAll(".cmdbar-group-title")].map((h) => h.textContent)).toEqual([
+      "Sessions",
+    ]);
+    expect(rowNames()).toEqual(["api", "worker", "notes"]);
+    expect(activeName()).toBe("api");
+  });
+
+  it("opening twice leaves one overlay", () => {
+    open();
+    open();
+    expect(document.querySelectorAll(".cmdbar-overlay")).toHaveLength(1);
+    expect(isCommandBarOpen()).toBe(true);
+  });
+
+  it("ranks a typed query through the matcher and highlights the matched range", () => {
+    open();
+    type("wor");
+    expect(rowNames()).toEqual(["worker"]);
+    const marks = [...document.querySelectorAll(".cmdbar-row-name mark")].map((m) => m.textContent);
+    expect(marks).toEqual(["wor"]);
+  });
+
+  it("highlights inside the directory when that is the field that matched", () => {
+    open();
+    type("notes");
+    const row = document.querySelector(".cmdbar-row") as HTMLElement;
+    expect(row.dataset.sessionId).toBe("notes");
+    type("dev/wor");
+    expect(rowNames()).toEqual(["worker"]);
+    expect(
+      [...document.querySelectorAll(".cmdbar-row-meta mark")].map((m) => m.textContent).join(""),
+    ).toBe("dev/wor");
+  });
+
+  it("renders a no-results state rather than an empty list", () => {
+    open();
+    type("zzz");
+    expect(rowNames()).toEqual([]);
+    expect(document.querySelector(".cmdbar-empty")?.textContent).toBe("No matches");
+  });
+
+  it("moves the highlight with the arrows and ctrl-p/ctrl-n, without wrapping", () => {
+    open();
+    press("ArrowUp");
+    expect(activeName()).toBe("api");
+    press("ArrowDown");
+    expect(activeName()).toBe("worker");
+    press("n", { ctrlKey: true });
+    expect(activeName()).toBe("notes");
+    press("ArrowDown");
+    expect(activeName()).toBe("notes");
+    press("p", { ctrlKey: true });
+    expect(activeName()).toBe("worker");
+  });
+
+  it("puts the highlight back on the best row whenever the query changes", () => {
+    open();
+    press("ArrowDown");
+    expect(activeName()).toBe("worker");
+    type("o");
+    expect(activeName()).toBe(document.querySelector(".cmdbar-row-name")?.textContent);
+  });
+
+  it("opens the highlighted session through the shared open path on Enter", () => {
+    const seen: string[] = [];
+    const listener = (e: Event) => seen.push((e as CustomEvent<string>).detail);
+    document.addEventListener(SESSION_SELECT_EVENT, listener);
+    openCommandBar({ sessions, homeDir: "/home/me" });
+    press("ArrowDown");
+    press("Enter");
+    document.removeEventListener(SESSION_SELECT_EVENT, listener);
+    expect(seen).toEqual(["worker"]);
+    expect(isCommandBarOpen()).toBe(false);
+  });
+
+  it("Enter on an empty result list does nothing", () => {
+    const onOpenSession = vi.fn();
+    open({ sessions, homeDir: "/home/me", onOpenSession });
+    type("zzz");
+    press("Enter");
+    expect(onOpenSession).not.toHaveBeenCalled();
+    expect(isCommandBarOpen()).toBe(true);
+  });
+
+  it("closes on Escape and on a press outside the panel", () => {
+    open();
+    press("Escape");
+    expect(isCommandBarOpen()).toBe(false);
+
+    open();
+    (document.querySelector(".cmdbar-overlay") as HTMLElement).dispatchEvent(
+      new MouseEvent("mousedown", { bubbles: true }),
+    );
+    expect(isCommandBarOpen()).toBe(false);
+  });
+
+  it("stays open for a press inside the panel", () => {
+    open();
+    (document.querySelector(".cmdbar-panel") as HTMLElement).dispatchEvent(
+      new MouseEvent("mousedown", { bubbles: true }),
+    );
+    expect(isCommandBarOpen()).toBe(true);
+  });
+
+  it("returns the keyboard to whatever held it when it opened", () => {
+    const before = document.createElement("button");
+    document.body.appendChild(before);
+    before.focus();
+    open();
+    expect(document.activeElement).toBe(document.querySelector(".cmdbar-input"));
+    press("Escape");
+    expect(document.activeElement).toBe(before);
+  });
+
+  it("clicking a row opens that session", () => {
+    const onOpenSession = vi.fn();
+    open({ sessions, homeDir: "/home/me", onOpenSession });
+    (document.querySelectorAll(".cmdbar-row")[1] as HTMLElement).click();
+    expect(onOpenSession).toHaveBeenCalledWith("worker");
+    expect(isCommandBarOpen()).toBe(false);
+  });
+});

web/src/commandBar.ts

@@ -0,0 +1,381 @@
+// The `ctrl-k` command bar (docs/COMMAND-BAR.md): a query line over a result
+// list, opened from the sidebar, closed with Escape.
+//
+// Sessions are the only kind here (#149); the sigils, the action page and the
+// terminal-focus binding land in #150-#152.
+
+import { SESSION_SELECT_EVENT } from "./catalog.js";
+import {
+  matchAndRank,
+  type CandidateKind,
+  type MatchRange,
+  type MatchResult,
+  type SessionCandidate,
+} from "./matcher.js";
+import { splitCommand } from "./toolIcon.js";
+import { abbreviateCwd, sessionName, sessionTreePath, type Session } from "./types.js";
+
+/** A matcher candidate that remembers which session it came from, so a result
+ *  can be acted on without a second lookup. The extra property is invisible to
+ *  the matcher, which only ever reads `kind` and `fields`. */
+export type SessionBarCandidate = SessionCandidate & { session: Session };
+
+export type BarCandidate = SessionBarCandidate;
+export type BarResult = MatchResult<BarCandidate>;
+
+/** One kind's slice of the ranked list, in rank order. */
+export interface BarGroup {
+  kind: CandidateKind;
+  title: string;
+  results: BarResult[];
+}
+
+const KIND_TITLES: Record<CandidateKind, string> = {
+  session: "Sessions",
+  command: "Commands",
+  directory: "Directories",
+};
+
+// ---- candidates ----
+
+function focusedAt(s: Session): number | null {
+  const stamp = s.last_focused_at;
+  if (typeof stamp !== "string" || stamp === "") return null;
+  const ms = Date.parse(stamp);
+  return Number.isNaN(ms) ? null : ms;
+}
+
+function createdAt(s: Session): number {
+  const ms = Date.parse(s.created_at ?? "");
+  return Number.isNaN(ms) ? 0 : ms;
+}
+
+/** The empty-query order (docs/COMMAND-BAR.md, "Empty query"): most recently
+ *  focused first; a session that has never been focused sorts after every
+ *  session that has, most recently created first among those; and a dead
+ *  session sorts after every live one regardless of recency, because a session
+ *  you cannot attach to is not where you just were.
+ *
+ *  This is also the input order for a non-empty query, which is what the
+ *  matcher's last tie-break preserves. */
+export function orderSessionsForBar(sessions: readonly Session[]): Session[] {
+  return [...sessions].sort((a, b) => {
+    const deadA = a.status === "Dead" ? 1 : 0;
+    const deadB = b.status === "Dead" ? 1 : 0;
+    if (deadA !== deadB) return deadA - deadB;
+
+    const focusA = focusedAt(a);
+    const focusB = focusedAt(b);
+    if ((focusA === null) !== (focusB === null)) return focusA === null ? 1 : -1;
+    if (focusA !== null && focusB !== null && focusA !== focusB) return focusB - focusA;
+
+    return createdAt(b) - createdAt(a);
+  });
+}
+
+/** Build one session's candidate: the fields docs/COMMAND-BAR.md's candidate
+ *  table names, with the directory abbreviated the way the sidebar shows it. */
+export function sessionCandidate(s: Session, homeDir?: string): SessionBarCandidate {
+  const treePath = sessionTreePath(s);
+  const directory = treePath ? abbreviateCwd(treePath, homeDir) : undefined;
+  const tool = splitCommand(s.command).tool ?? undefined;
+  return {
+    kind: "session",
+    session: s,
+    fields: {
+      name: sessionName(s),
+      ...(directory ? { directory } : {}),
+      ...(s.command ? { command: s.command } : {}),
+      ...(tool ? { tool } : {}),
+    },
+  };
+}
+
+/** Every session as a candidate, in the empty-query order. */
+export function sessionBarCandidates(
+  sessions: readonly Session[],
+  homeDir?: string,
+): SessionBarCandidate[] {
+  return orderSessionsForBar(sessions).map((s) => sessionCandidate(s, homeDir));
+}
+
+// ---- grouping ----
+
+/** Bucket a ranked list by kind for rendering. Grouping is a rendering of the
+ *  ranking, never a reordering of it: a group holds its matches in rank order,
+ *  and groups appear in the order their best-scoring member does — so the first
+ *  row under the first header is the globally best result. */
+export function barGroups(results: readonly BarResult[]): BarGroup[] {
+  const groups: BarGroup[] = [];
+  for (const result of results) {
+    const kind = result.candidate.kind;
+    let group = groups.find((g) => g.kind === kind);
+    if (!group) {
+      group = { kind, title: KIND_TITLES[kind], results: [] };
+      groups.push(group);
+    }
+    group.results.push(result);
+  }
+  return groups;
+}
+
+/** The rows a query produces, flat and in rank order — what the highlight walks
+ *  and what Enter acts on. Headers are labels, not rows, so they are never in
+ *  this list. */
+export function barRows(query: string, candidates: readonly BarCandidate[]): BarResult[] {
+  return matchAndRank(query, candidates);
+}
+
+// ---- rendering ----
+
+/** Text with its matched ranges wrapped in `<mark>`. Ranges come from the
+ *  matcher as `[start, end)` character pairs over the field that won. */
+export function renderHighlighted(text: string, ranges: readonly MatchRange[]): DocumentFragment {
+  const frag = document.createDocumentFragment();
+  let cursor = 0;
+  for (const [start, end] of ranges) {
+    if (start > cursor) frag.append(text.slice(cursor, start));
+    const mark = document.createElement("mark");
+    mark.className = "cmdbar-hit";
+    mark.textContent = text.slice(start, end);
+    frag.append(mark);
+    cursor = end;
+  }
+  if (cursor < text.length) frag.append(text.slice(cursor));
+  return frag;
+}
+
+/** The secondary line under a row's name: the field the match was found in when
+ *  that was not the name, so a session found through its directory says so. */
+function metaText(result: BarResult): string | undefined {
+  const fields = result.candidate.fields;
+  switch (result.field) {
+    case "directory":
+      return fields.directory;
+    case "command":
+      return fields.command;
+    case "tool":
+      return fields.tool;
+    default:
+      return fields.directory;
+  }
+}
+
+function renderRow(result: BarResult, index: number): HTMLElement {
+  const row = document.createElement("div");
+  row.className = "cmdbar-row";
+  row.setAttribute("role", "option");
+  row.id = `cmdbar-row-${index}`;
+  row.dataset.index = String(index);
+  row.dataset.sessionId = result.candidate.session.id;
+  if (result.candidate.session.status === "Dead") row.classList.add("is-dead");
+
+  const name = document.createElement("span");
+  name.className = "cmdbar-row-name";
+  const nameText = result.candidate.fields.name;
+  name.append(
+    result.field === "name" ? renderHighlighted(nameText, result.ranges) : nameText,
+  );
+  row.appendChild(name);
+
+  const meta = metaText(result);
+  if (meta) {
+    const el = document.createElement("span");
+    el.className = "cmdbar-row-meta";
+    const highlighted = result.field !== undefined && result.field !== "name";
+    el.append(highlighted ? renderHighlighted(meta, result.ranges) : meta);
+    row.appendChild(el);
+  }
+  return row;
+}
+
+// ---- the overlay ----
+
+export interface CommandBarOptions {
+  /** Sessions to build candidates from, as the store has them right now. */
+  sessions: readonly Session[];
+  /** The daemon's home dir, for the directory field's `~/…` abbreviation. */
+  homeDir?: string;
+  /** Open the highlighted session. Defaults to the shared open path — the
+   *  sidebar's click event — which is what the contract requires; tests pass
+   *  their own. */
+  onOpenSession?: (sessionId: string) => void;
+}
+
+interface OpenBar {
+  el: HTMLElement;
+  dispose: () => void;
+}
+
+let current: OpenBar | null = null;
+
+export function isCommandBarOpen(): boolean {
+  return current !== null;
+}
+
+export function closeCommandBar(): void {
+  current?.dispose();
+}
+
+/** Mount the bar. Opening while one is up replaces it, so a stray second call
+ *  can never stack two overlays. */
+export function openCommandBar(opts: CommandBarOptions): HTMLElement {
+  closeCommandBar();
+
+  // Closing returns the keyboard to whatever held it when the bar opened: a
+  // round trip through the bar never silently moves focus.
+  const previouslyFocused = document.activeElement as HTMLElement | null;
+  const openSession =
+    opts.onOpenSession ??
+    ((id: string) => document.dispatchEvent(new CustomEvent(SESSION_SELECT_EVENT, { detail: id })));
+
+  const candidates: BarCandidate[] = sessionBarCandidates(opts.sessions, opts.homeDir);
+
+  const el = document.createElement("div");
+  el.className = "cmdbar-overlay";
+  el.setAttribute("role", "dialog");
+  el.setAttribute("aria-modal", "true");
+  el.setAttribute("aria-label", "Command bar");
+
+  const panel = document.createElement("div");
+  panel.className = "cmdbar-panel";
+
+  const input = document.createElement("input");
+  input.type = "text";
+  input.className = "cmdbar-input";
+  input.setAttribute("role", "combobox");
+  input.setAttribute("aria-expanded", "true");
+  input.setAttribute("aria-controls", "cmdbar-results");
+  input.setAttribute("aria-label", "Search sessions");
+  input.setAttribute("autocomplete", "off");
+  input.spellcheck = false;
+  input.placeholder = "Go to a session…";
+
+  const results = document.createElement("div");
+  results.className = "cmdbar-results";
+  results.id = "cmdbar-results";
+  results.setAttribute("role", "listbox");
+
+  panel.append(input, results);
+  el.appendChild(panel);
+  document.body.appendChild(el);
+
+  let rows: BarResult[] = [];
+  let highlighted = 0;
+
+  function paintHighlight(): void {
+    for (const row of results.querySelectorAll<HTMLElement>(".cmdbar-row")) {
+      const active = Number(row.dataset.index) === highlighted;
+      row.classList.toggle("is-active", active);
+      row.setAttribute("aria-selected", active ? "true" : "false");
+      if (active) {
+        row.scrollIntoView({ block: "nearest" });
+        input.setAttribute("aria-activedescendant", row.id);
+      }
+    }
+    if (rows.length === 0) input.removeAttribute("aria-activedescendant");
+  }
+
+  function render(): void {
+    rows = barRows(input.value, candidates);
+    // The highlight starts on the globally best row every time the list
+    // changes: an old index would point at a different result.
+    highlighted = 0;
+    results.replaceChildren();
+
+    if (rows.length === 0) {
+      const empty = document.createElement("div");
+      empty.className = "cmdbar-empty";
+      empty.textContent = "No matches";
+      results.appendChild(empty);
+      paintHighlight();
+      return;
+    }
+
+    let index = 0;
+    for (const group of barGroups(rows)) {
+      const header = document.createElement("div");
+      header.className = "cmdbar-group-title";
+      header.setAttribute("role", "presentation");
+      header.textContent = group.title;
+      results.appendChild(header);
+      for (const result of group.results) {
+        const at = index;
+        const row = renderRow(result, at);
+        row.addEventListener("click", () => activate(at));
+        results.appendChild(row);
+        index += 1;
+      }
+    }
+    paintHighlight();
+  }
+
+  /** The highlight does not wrap: it stops at the first and last row. */
+  function move(delta: number): void {
+    if (rows.length === 0) return;
+    highlighted = Math.min(rows.length - 1, Math.max(0, highlighted + delta));
+    paintHighlight();
+  }
+
+  function activate(index: number): void {
+    const result = rows[index];
+    if (!result) return;
+    const sessionId = result.candidate.session.id;
+    close();
+    openSession(sessionId);
+  }
+
+  function onKeydown(e: KeyboardEvent): void {
+    switch (e.key) {
+      case "Escape":
+        e.preventDefault();
+        close();
+        return;
+      case "Enter":
+        e.preventDefault();
+        activate(highlighted);
+        return;
+      case "ArrowDown":
+        e.preventDefault();
+        move(1);
+        return;
+      case "ArrowUp":
+        e.preventDefault();
+        move(-1);
+        return;
+      case "n":
+        if (e.ctrlKey) {
+          e.preventDefault();
+          move(1);
+        }
+        return;
+      case "p":
+        if (e.ctrlKey) {
+          e.preventDefault();
+          move(-1);
+        }
+        return;
+    }
+  }
+
+  function close(): void {
+    if (current?.el !== el) return;
+    current = null;
+    el.remove();
+    // Restoring focus is what makes the bar a view over the app rather than a
+    // place in it; a detached node cannot take it.
+    if (previouslyFocused?.isConnected) previouslyFocused.focus();
+  }
+
+  input.addEventListener("keydown", onKeydown);
+  input.addEventListener("input", render);
+  // A press on the scrim closes; one inside the panel is left alone.
+  el.addEventListener("mousedown", (ev) => {
+    if (!panel.contains(ev.target as Node)) close();
+  });
+
+  current = { el, dispose: close };
+  render();
+  input.focus();
+  return el;
+}

web/src/commands.test.ts

@@ -0,0 +1,236 @@
+// @vitest-environment happy-dom
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  COMMAND_SPECS,
+  CommandSet,
+  DEFAULT_LEADER,
+  canonicalizeKey,
+  defineCommands,
+  isTypingTarget,
+  keyCaps,
+  publishedCommands,
+} from "./commands.js";
+
+function key(k: string, init: KeyboardEventInit = {}): KeyboardEvent {
+  return new KeyboardEvent("keydown", { key: k, cancelable: true, ...init });
+}
+
+function el(html: string): HTMLElement {
+  const d = document.createElement("div");
+  d.innerHTML = html;
+  return d.firstElementChild as HTMLElement;
+}
+
+/** Dispatch on a target, so `isTypingTarget` sees something other than null. */
+function pressOn(set: CommandSet, target: HTMLElement, k: string, init?: KeyboardEventInit): boolean {
+  const e = key(k, init);
+  Object.defineProperty(e, "target", { value: target });
+  return set.handle(e);
+}
+
+describe("command specs", () => {
+  it("has a unique id and at least one chord per command", () => {
+    const ids = COMMAND_SPECS.map((s) => s.id);
+    expect(new Set(ids).size).toBe(ids.length);
+    for (const spec of COMMAND_SPECS) {
+      expect(spec.keys.length).toBeGreaterThan(0);
+      expect(spec.label.length).toBeGreaterThan(0);
+    }
+  });
+
+  it("binds each chord once within a scope", () => {
+    const seen = new Set<string>();
+    for (const spec of COMMAND_SPECS) {
+      for (const k of spec.keys) {
+        const slot = `${spec.scope}:${k}`;
+        expect(seen.has(slot)).toBe(false);
+        seen.add(slot);
+      }
+    }
+  });
+
+  it("rejects a handler for an id that isn't in the registry", () => {
+    expect(() => defineCommands({ "nope.missing": () => {} })).toThrow(/unknown command id/);
+  });
+
+  it("carries every spec field onto the defined command", () => {
+    const [cmd] = defineCommands({ "spawn.open": () => {} });
+    expect(cmd).toMatchObject({ id: "spawn.open", keys: ["n"], scope: "global" });
+  });
+});
+
+describe("canonicalizeKey", () => {
+  it("spells keys the way the TUI's InputKey::canonical does", () => {
+    expect(canonicalizeKey(key("n"))).toBe("n");
+    expect(canonicalizeKey(key("N", { shiftKey: true }))).toBe("N");
+    expect(canonicalizeKey(key("?", { shiftKey: true }))).toBe("?");
+    expect(canonicalizeKey(key("a", { ctrlKey: true }))).toBe("ctrl-a");
+    expect(canonicalizeKey(key("Escape"))).toBe("esc");
+    expect(canonicalizeKey(key("Enter"))).toBe("enter");
+    expect(canonicalizeKey(key("Tab"))).toBe("tab");
+    expect(canonicalizeKey(key("Tab", { shiftKey: true }))).toBe("backtab");
+    expect(canonicalizeKey(key("ArrowDown"))).toBe("down");
+  });
+
+  it("folds a modified letter to lower case with an explicit shift-", () => {
+    expect(canonicalizeKey(key("H", { ctrlKey: true, shiftKey: true }))).toBe("ctrl-shift-h");
+    expect(canonicalizeKey(key("h", { ctrlKey: true, shiftKey: true }))).toBe("ctrl-shift-h");
+  });
+
+  it("has no canonical form for a modifier pressed alone", () => {
+    expect(canonicalizeKey(key("Control", { ctrlKey: true }))).toBeNull();
+    expect(canonicalizeKey(key("Shift", { shiftKey: true }))).toBeNull();
+  });
+});
+
+describe("keyCaps", () => {
+  it("renders one cap per modifier and key", () => {
+    expect(keyCaps("ctrl-shift-h")).toEqual(["Ctrl", "Shift", "H"]);
+    expect(keyCaps("enter")).toEqual(["Enter"]);
+    expect(keyCaps("j")).toEqual(["j"]);
+    expect(keyCaps("N")).toEqual(["N"]);
+    expect(keyCaps("?")).toEqual(["?"]);
+    expect(keyCaps("ctrl-a ctrl-k")).toEqual(["Ctrl", "A", "then", "Ctrl", "K"]);
+  });
+});
+
+describe("CommandSet", () => {
+  it("runs the command bound to a chord, and swallows the browser default", () => {
+    const run = vi.fn();
+    const set = new CommandSet(defineCommands({ "spawn.open": run }));
+    const e = key("n");
+    expect(set.handle(e)).toBe(true);
+    expect(run).toHaveBeenCalledTimes(1);
+    expect(e.defaultPrevented).toBe(true);
+  });
+
+  it("leaves an unbound key alone", () => {
+    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }));
+    const e = key("q");
+    expect(set.handle(e)).toBe(false);
+    expect(e.defaultPrevented).toBe(false);
+  });
+
+  it("treats a modified key as a different binding", () => {
+    const run = vi.fn();
+    const set = new CommandSet(defineCommands({ "spawn.open": run }));
+    expect(set.handle(key("n", { ctrlKey: true }))).toBe(false);
+    expect(set.handle(key("n", { metaKey: true }))).toBe(false);
+    expect(run).not.toHaveBeenCalled();
+  });
+
+  it("runs every alias of a command", () => {
+    const run = vi.fn();
+    const set = new CommandSet(defineCommands({ "list.next": run }));
+    set.handle(key("j"));
+    set.handle(key("ArrowDown"));
+    expect(run).toHaveBeenCalledTimes(2);
+  });
+
+  it("keeps plain keys deaf inside a form field, and chorded ones live", () => {
+    const plain = vi.fn();
+    const chorded = vi.fn();
+    const set = new CommandSet(
+      defineCommands({ "spawn.open": plain, "focus.toggle": chorded }),
+    );
+    const input = el("<input>");
+    expect(pressOn(set, input, "n")).toBe(false);
+    expect(plain).not.toHaveBeenCalled();
+    expect(pressOn(set, input, "H", { ctrlKey: true, shiftKey: true })).toBe(true);
+    expect(chorded).toHaveBeenCalledTimes(1);
+  });
+
+  it("keeps pane commands live inside the terminal's textarea", () => {
+    const run = vi.fn();
+    const set = new CommandSet(defineCommands({ "pane.focusList": run }), {
+      preventDefault: false,
+    });
+    const textarea = el('<textarea class="xterm-helper-textarea"></textarea>');
+    const e = key("Escape");
+    Object.defineProperty(e, "target", { value: textarea });
+    expect(set.handle(e)).toBe(true);
+    expect(run).toHaveBeenCalledTimes(1);
+    // xterm is told to swallow by the return value, not by the browser default.
+    expect(e.defaultPrevented).toBe(false);
+  });
+});
+
+describe("the leader", () => {
+  it("defaults to the TUI's ctrl-a", () => {
+    expect(DEFAULT_LEADER).toBe("ctrl-a");
+  });
+
+  it("holds the leader as a partial chord instead of selecting the page", () => {
+    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }), {
+      leader: DEFAULT_LEADER,
+    });
+    const e = key("a", { ctrlKey: true });
+    expect(set.handle(e)).toBe(true);
+    expect(e.defaultPrevented).toBe(true);
+  });
+
+  it("swallows the key after the leader rather than running its plain binding", () => {
+    const run = vi.fn();
+    const set = new CommandSet(defineCommands({ "spawn.open": run }), {
+      leader: DEFAULT_LEADER,
+    });
+    set.handle(key("a", { ctrlKey: true }));
+    expect(set.handle(key("n"))).toBe(true);
+    expect(run).not.toHaveBeenCalled();
+    // The next key is an ordinary one again.
+    set.handle(key("n"));
+    expect(run).toHaveBeenCalledTimes(1);
+  });
+
+  it("forgets a held leader once the chord timeout passes", () => {
+    const run = vi.fn();
+    let now = 0;
+    const set = new CommandSet(defineCommands({ "spawn.open": run }), {
+      leader: DEFAULT_LEADER,
+      chordTimeoutMs: 1000,
+      now: () => now,
+    });
+    set.handle(key("a", { ctrlKey: true }));
+    now = 1500;
+    set.handle(key("n"));
+    expect(run).toHaveBeenCalledTimes(1);
+  });
+
+  it("leaves select-all alone in a real form field", () => {
+    const set = new CommandSet(defineCommands({ "spawn.open": vi.fn() }), {
+      leader: DEFAULT_LEADER,
+    });
+    const input = el("<input>");
+    const e = key("a", { ctrlKey: true });
+    Object.defineProperty(e, "target", { value: input });
+    expect(set.handle(e)).toBe(false);
+    expect(e.defaultPrevented).toBe(false);
+  });
+});
+
+describe("publishing", () => {
+  it("lists a constructed set's commands, replacing an id rather than doubling it", () => {
+    new CommandSet(defineCommands({ "list.kill": () => {} }));
+    new CommandSet(defineCommands({ "list.kill": () => {} }));
+    const ids = publishedCommands().map((c) => c.id);
+    expect(ids.filter((id) => id === "list.kill")).toEqual(["list.kill"]);
+  });
+
+  it("keeps published commands in registry order", () => {
+    const order = COMMAND_SPECS.map((s) => s.id);
+    const ids = publishedCommands().map((c) => c.id);
+    expect(ids).toEqual(order.filter((id) => ids.includes(id)));
+  });
+});
+
+describe("isTypingTarget", () => {
+  it("is true for form fields and editable nodes, false otherwise", () => {
+    expect(isTypingTarget(el("<input>"))).toBe(true);
+    expect(isTypingTarget(el("<textarea></textarea>"))).toBe(true);
+    expect(isTypingTarget(el("<select></select>"))).toBe(true);
+    expect(isTypingTarget(el('<div contenteditable="true"></div>'))).toBe(true);
+    expect(isTypingTarget(el("<button></button>"))).toBe(false);
+    expect(isTypingTarget(null)).toBe(false);
+  });
+});

web/src/commands.ts

@@ -0,0 +1,393 @@
+// The web client's command registry (#148). One entry per command — a stable
+// id, a plain-language label, the key chord it answers to, and a `run()` — so
+// there is exactly one list of what the client can do. The `?` overlay renders
+// from it (`help.ts`), and every keybinding is dispatched through it; a command
+// added here is bound and documented in the same edit.
+//
+// Keys are canonical strings, the same spelling the TUI's `InputKey::canonical`
+// produces (`ctrl-shift-h`, `enter`, `esc`, `n`, `N`) and chords are those
+// joined by a space (`ctrl-a ctrl-k`). Matching the TUI's spelling is what lets
+// docs/COMMAND-BAR.md describe one key model for both clients.
+
+/** Where a command's keys are listened for. `global` is the window, `list` the
+ *  sidebar's session tree, `pane` the attached terminal, `overlay` the help
+ *  dialog while it is up. */
+export type CommandScope = "global" | "list" | "pane" | "overlay";
+
+export interface CommandSpec {
+  /** Stable identifier. Never rendered; safe to bind config and tests to. */
+  id: string;
+  /** Plain-language label — what the `?` overlay and (later) the command bar
+   *  show. */
+  label: string;
+  /** Help-overlay section. Groups render in the order they first appear here. */
+  group: string;
+  /** Canonical chords that run it. The first is the one shown to the operator;
+   *  the rest are aliases (`j` and `down`). */
+  keys: string[];
+  scope: CommandScope;
+}
+
+export interface Command extends CommandSpec {
+  run: () => void;
+}
+
+/** Every command the web client has. The single list this issue exists to
+ *  create: labels, chords and grouping live here and nowhere else. */
+export const COMMAND_SPECS: readonly CommandSpec[] = [
+  {
+    id: "spawn.open",
+    label: "Open the spawn form",
+    group: "Sessions",
+    keys: ["n"],
+    scope: "global",
+  },
+  {
+    id: "spawn.fastForward",
+    label: "Spawn a session with every default resolved",
+    group: "Sessions",
+    keys: ["N"],
+    scope: "global",
+  },
+  {
+    id: "bar.open",
+    label: "Open the command bar",
+    group: "Sessions",
+    keys: ["ctrl-k"],
+    scope: "global",
+  },
+  {
+    id: "focus.toggle",
+    label: "Move the keyboard between the session list and the pane",
+    group: "Session list",
+    keys: ["ctrl-shift-h"],
+    scope: "global",
+  },
+  {
+    id: "list.next",
+    label: "Highlight the next session",
+    group: "Session list",
+    keys: ["j", "down"],
+    scope: "list",
+  },
+  {
+    id: "list.prev",
+    label: "Highlight the previous session",
+    group: "Session list",
+    keys: ["k", "up"],
+    scope: "list",
+  },
+  {
+    id: "list.activate",
+    label: "Open the highlighted session, or expand a folder",
+    group: "Session list",
+    keys: ["enter"],
+    scope: "list",
+  },
+  {
+    id: "list.toggleFolder",
+    label: "Collapse or expand the highlighted folder",
+    group: "Session list",
+    keys: ["c"],
+    scope: "list",
+  },
+  {
+    id: "list.rename",
+    label: "Rename the highlighted session",
+    group: "Session list",
+    keys: ["r"],
+    scope: "list",
+  },
+  {
+    id: "list.kill",
+    label: "Kill the highlighted session",
+    group: "Session list",
+    keys: ["x"],
+    scope: "list",
+  },
+  {
+    id: "list.focusPane",
+    label: "Send the keyboard to the pane",
+    group: "Session list",
+    keys: ["tab"],
+    scope: "list",
+  },
+  {
+    id: "pane.focusList",
+    label: "Hand the keyboard back to the session list, from the pane",
+    group: "Session list",
+    keys: ["esc"],
+    scope: "pane",
+  },
+  {
+    id: "help.toggle",
+    label: "Show or hide this help",
+    group: "Help",
+    keys: ["?"],
+    scope: "global",
+  },
+  {
+    id: "help.close",
+    label: "Close the help overlay or an open menu",
+    group: "Help",
+    keys: ["esc"],
+    scope: "overlay",
+  },
+  {
+    id: "debug.toggleHud",
+    label: "Toggle the debug HUD",
+    group: "Debug",
+    keys: ["ctrl-shift-d"],
+    scope: "global",
+  },
+];
+
+const SPEC_BY_ID = new Map(COMMAND_SPECS.map((s) => [s.id, s]));
+
+/** Attach handlers to specs, by id. Throws on an unknown id, so a typo is a
+ *  test failure rather than a key that silently does nothing. */
+export function defineCommands(handlers: Record<string, () => void>): Command[] {
+  return Object.entries(handlers).map(([id, run]) => {
+    const spec = SPEC_BY_ID.get(id);
+    if (!spec) throw new Error(`unknown command id: ${id}`);
+    return { ...spec, run };
+  });
+}
+
+// ---- what the help overlay renders ----
+
+const published = new Map<string, Command>();
+
+/** Record commands as bound. Re-registering an id replaces it, so a second
+ *  sidebar (tests, hot reload) doesn't duplicate rows in the overlay. */
+export function publishCommands(cmds: Command[]): void {
+  for (const c of cmds) published.set(c.id, c);
+}
+
+/** Every bound command, in `COMMAND_SPECS` order. */
+export function publishedCommands(): Command[] {
+  return COMMAND_SPECS.map((s) => published.get(s.id)).filter((c): c is Command => c !== undefined);
+}
+
+// ---- key canonicalisation ----
+
+const NAMED: Record<string, string> = {
+  Escape: "esc",
+  Enter: "enter",
+  Tab: "tab",
+  Backspace: "backspace",
+  ArrowUp: "up",
+  ArrowDown: "down",
+  ArrowLeft: "left",
+  ArrowRight: "right",
+  Home: "home",
+  End: "end",
+  PageUp: "pageup",
+  PageDown: "pagedown",
+  Delete: "delete",
+  " ": "space",
+};
+
+/** The canonical string for one keydown. Mirrors the TUI's
+ *  `InputKey::canonical`: modifier prefixes in ctrl/alt/shift order, then the
+ *  key. A shifted character already spells itself (`N`, `?`), so `shift-` is
+ *  only written when another modifier is present and the char was folded to
+ *  lower case. */
+export function canonicalizeKey(e: KeyboardEvent): string | null {
+  if (!e.key) return null;
+  // Modifier keys pressed alone are never a binding.
+  if (e.key === "Control" || e.key === "Alt" || e.key === "Shift" || e.key === "Meta") return null;
+  const named = NAMED[e.key];
+  if (named === "tab" && e.shiftKey) return "backtab";
+  let out = "";
+  if (e.ctrlKey) out += "ctrl-";
+  if (e.altKey) out += "alt-";
+  if (e.metaKey) out += "meta-";
+  if (named) {
+    if (e.shiftKey) out += "shift-";
+    return out + named;
+  }
+  if (e.key.length === 1) {
+    if (out === "") return e.key;
+    if (e.shiftKey) out += "shift-";
+    return out + e.key.toLowerCase();
+  }
+  if (e.shiftKey) out += "shift-";
+  return out + e.key.toLowerCase();
+}
+
+const MOD_PREFIX = /^(ctrl|alt|meta|shift)-/;
+
+/** True when a chord carries a modifier or more than one key. Plain single-key
+ *  chords are the ones that stay deaf inside form fields. */
+function isChorded(chord: string): boolean {
+  return chord.includes(" ") || MOD_PREFIX.test(chord);
+}
+
+/** True when the event target swallows plain keystrokes — a form field, or the
+ *  hidden textarea xterm types into. Every plain single-key binding is deaf in
+ *  the same places. */
+export function isTypingTarget(target: EventTarget | null): boolean {
+  const el = target as HTMLElement | null;
+  if (!el || typeof el.tagName !== "string") return false;
+  return (
+    el.tagName === "INPUT" ||
+    el.tagName === "TEXTAREA" ||
+    el.tagName === "SELECT" ||
+    el.isContentEditable
+  );
+}
+
+/** xterm's offscreen textarea. It is a typing target like any other, but it is
+ *  also where the leader has to work — a pane is exactly where the operator
+ *  needs the escape hatch (docs/COMMAND-BAR.md). */
+function isTerminalTextarea(target: EventTarget | null): boolean {
+  const el = target as HTMLElement | null;
+  return !!el && typeof el.className === "string" && el.classList?.contains("xterm-helper-textarea");
+}
+
+// ---- display ----
+
+const CAPS: Record<string, string> = {
+  ctrl: "Ctrl",
+  alt: "Alt",
+  meta: "Meta",
+  shift: "Shift",
+  esc: "Esc",
+  enter: "Enter",
+  tab: "Tab",
+  backtab: "Shift Tab",
+  backspace: "Backspace",
+  up: "Up",
+  down: "Down",
+  left: "Left",
+  right: "Right",
+  home: "Home",
+  end: "End",
+  pageup: "PgUp",
+  pagedown: "PgDn",
+  delete: "Del",
+  space: "Space",
+};
+
+/** Keycaps for a chord, left to right: `ctrl-shift-h` → Ctrl, Shift, H. A
+ *  multi-key chord separates its keys with a `then` cap. */
+export function keyCaps(chord: string): string[] {
+  const caps: string[] = [];
+  for (const [i, key] of chord.split(" ").entries()) {
+    if (i > 0) caps.push("then");
+    const parts = key.split("-");
+    // A bare `-` key splits into two empties; treat it as the key itself.
+    if (parts.every((p) => p === "")) {
+      caps.push("-");
+      continue;
+    }
+    const last = parts.pop() as string;
+    const mods = parts.filter((p) => p !== "");
+    for (const m of mods) caps.push(CAPS[m] ?? m);
+    caps.push(CAPS[last] ?? (mods.length > 0 && last.length === 1 ? last.toUpperCase() : last));
+  }
+  return caps;
+}
+
+// ---- dispatch ----
+
+/** Default leader, mirroring the TUI's `[tui].leader`. `ctrl-a` is select-all
+ *  in a browser, so a set that owns the leader `preventDefault`s it. */
+export const DEFAULT_LEADER = "ctrl-a";
+
+/** How long a partial chord waits for its next key — the TUI's
+ *  `chord_timeout_ms` default. */
+export const DEFAULT_CHORD_TIMEOUT_MS = 1000;
+
+export interface CommandSetOptions {
+  /** Canonical leader key. A set given one holds every leader press as a
+   *  pending chord, whether or not anything is bound behind it yet. */
+  leader?: string | null;
+  chordTimeoutMs?: number;
+  /** Call `preventDefault()` on a handled key. Off for the terminal's own key
+   *  handler, which swallows by returning `false` to xterm instead. */
+  preventDefault?: boolean;
+  /** Clock, for tests. */
+  now?: () => number;
+}
+
+/** A group of commands listening on one surface. Resolves a keydown to a
+ *  command the way the TUI's `ChordState` does: hold while the sequence is a
+ *  strict prefix of some binding, otherwise resolve and dispatch. */
+export class CommandSet {
+  private readonly byChord = new Map<string, Command>();
+  private readonly leader: string | null;
+  private readonly timeout: number;
+  private readonly preventDefault: boolean;
+  private readonly now: () => number;
+  private held: string[] = [];
+  private lastPress = 0;
+
+  constructor(
+    readonly commands: Command[],
+    opts: CommandSetOptions = {},
+  ) {
+    for (const c of commands) for (const k of c.keys) this.byChord.set(k, c);
+    this.leader = opts.leader ?? null;
+    this.timeout = opts.chordTimeoutMs ?? DEFAULT_CHORD_TIMEOUT_MS;
+    this.preventDefault = opts.preventDefault ?? true;
+    this.now = opts.now ?? (() => Date.now());
+    publishCommands(commands);
+  }
+
+  /** Whether any binding starts with `candidate` and continues. */
+  private isPrefix(candidate: string): boolean {
+    const marker = `${candidate} `;
+    for (const chord of this.byChord.keys()) if (chord.startsWith(marker)) return true;
+    return false;
+  }
+
+  /** Feed one keydown. Returns true when the key was consumed — dispatched, or
+   *  held as a partial chord. */
+  handle(e: KeyboardEvent): boolean {
+    const key = canonicalizeKey(e);
+    if (key === null) return false;
+    if (this.held.length > 0 && this.now() - this.lastPress > this.timeout) this.held = [];
+    const candidate = this.held.length > 0 ? `${this.held.join(" ")} ${key}` : key;
+    this.lastPress = this.now();
+
+    // The leader is a prefix by construction, so it stops being select-all
+    // before anything is bound behind it (#149 binds the first chord).
+    if (this.leader !== null && this.held.length === 0 && key === this.leader) {
+      if (isTypingTarget(e.target) && !isTerminalTextarea(e.target)) return false;
+      this.held = [key];
+      if (this.preventDefault) e.preventDefault();
+      return true;
+    }
+
+    if (this.isPrefix(candidate)) {
+      this.held.push(key);
+      if (this.preventDefault) e.preventDefault();
+      return true;
+    }
+
+    const wasChord = this.held.length > 0;
+    this.held = [];
+    const cmd = this.byChord.get(candidate);
+    if (!cmd) {
+      // A chord that resolved to nothing is still consumed: the leader took
+      // the key, so it must not also fall through to a plain binding.
+      return wasChord;
+    }
+    // Plain single-key bindings are deaf where typing happens; chorded ones are
+    // not, and neither are the pane's and the overlay's, which are only fed
+    // from the surface that owns them.
+    if (
+      !isChorded(candidate) &&
+      cmd.scope !== "pane" &&
+      cmd.scope !== "overlay" &&
+      isTypingTarget(e.target)
+    ) {
+      return false;
+    }
+    if (this.preventDefault) e.preventDefault();
+    cmd.run();
+    return true;
+  }
+}

web/src/debug.ts

@@ -2,6 +2,8 @@
 // survives reloads, flipped by a keybind (Ctrl+Shift+D), and force-enabled by
 // `?hud` in dev. A `maestro-hud-toggle` event lets the HUD re-render on change.
 
+import { CommandSet, defineCommands } from "./commands.js";
+
 const STORAGE_KEY = "maestro:hud";
 export const HUD_TOGGLE_EVENT = "maestro-hud-toggle";
 
@@ -31,12 +33,9 @@ export function toggleHud(): void {
   setHudEnabled(!isHudEnabled());
 }
 
+const hudKeys = new CommandSet(defineCommands({ "debug.toggleHud": () => toggleHud() }));
+
 /** Global keybind: Ctrl+Shift+D toggles the debug HUD. */
 export function installHudKeybind(): void {
-  window.addEventListener("keydown", (e) => {
-    if (e.ctrlKey && e.shiftKey && (e.key === "D" || e.key === "d")) {
-      e.preventDefault();
-      toggleHud();
-    }
-  });
+  window.addEventListener("keydown", (e) => hudKeys.handle(e));
 }

web/src/help.test.ts

@@ -1,14 +1,8 @@
 // @vitest-environment happy-dom
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 
-import {
-  SHORTCUTS,
-  closeHelp,
-  installHelpKeybind,
-  isHelpOpen,
-  isTypingTarget,
-  openHelp,
-} from "./help.js";
+import { keyCaps, publishedCommands } from "./commands.js";
+import { closeHelp, groupedCommands, installHelpKeybind, isHelpOpen, openHelp } from "./help.js";
 
 beforeEach(() => {
   installHelpKeybind();
@@ -30,14 +24,24 @@ function rows(): string[] {
 }
 
 describe("help overlay", () => {
-  it("renders every registered shortcut, grouped", () => {
+  it("renders exactly the commands the registry has bound, grouped", () => {
     openHelp();
-    const groups = [...document.querySelectorAll(".help-group-title")].map((h) => h.textContent);
-    expect(groups).toEqual(SHORTCUTS.map((g) => g.title));
-    expect(rows()).toEqual(SHORTCUTS.flatMap((g) => g.items.map((s) => s.keys.join(" "))));
-    expect(document.querySelectorAll(".help-desc")).toHaveLength(
-      SHORTCUTS.reduce((n, g) => n + g.items.length, 0),
+    const groups = groupedCommands();
+    expect([...document.querySelectorAll(".help-group-title")].map((h) => h.textContent)).toEqual(
+      groups.map((g) => g.title),
     );
+    expect(rows()).toEqual(
+      groups.flatMap((g) => g.items.map((c) => keyCaps(c.keys[0]).join(" "))),
+    );
+    expect([...document.querySelectorAll(".help-desc")].map((d) => d.textContent)).toEqual(
+      groups.flatMap((g) => g.items.map((c) => c.label)),
+    );
+  });
+
+  it("names each row by its command id, so a row can't drift from its command", () => {
+    openHelp();
+    expect([...document.querySelectorAll<HTMLElement>(".help-row")].map((r) => r.dataset.commandId))
+      .toEqual(publishedCommands().map((c) => c.id));
   });
 
   it("opens on ? and closes on a second ?", () => {
@@ -94,19 +98,3 @@ describe("help overlay", () => {
     expect(document.querySelectorAll(".help-overlay")).toHaveLength(1);
   });
 });
-
-describe("isTypingTarget", () => {
-  it("is true for form fields and editable nodes, false otherwise", () => {
-    const el = (html: string) => {
-      const d = document.createElement("div");
-      d.innerHTML = html;
-      return d.firstElementChild as HTMLElement;
-    };
-    expect(isTypingTarget(el("<input>"))).toBe(true);
-    expect(isTypingTarget(el("<textarea></textarea>"))).toBe(true);
-    expect(isTypingTarget(el("<select></select>"))).toBe(true);
-    expect(isTypingTarget(el('<div contenteditable="true"></div>'))).toBe(true);
-    expect(isTypingTarget(el("<button></button>"))).toBe(false);
-    expect(isTypingTarget(null)).toBe(false);
-  });
-});

web/src/help.ts

@@ -1,69 +1,15 @@
 /** Keyboard-shortcut overlay (`?`), the web counterpart of the TUI's help
- *  overlay. One registry drives both the rendering and what we claim is bound,
- *  so a binding added to `main.ts` without an entry here reads as missing. */
+ *  overlay. It renders the command registry (`commands.ts`) — the same list
+ *  that dispatches the keys — so a binding can never be documented as one
+ *  thing and do another. */
 
-export interface Shortcut {
-  /** Keycaps, rendered left to right as separate <kbd>. */
-  keys: string[];
-  description: string;
-}
-
-export interface ShortcutGroup {
-  title: string;
-  items: Shortcut[];
-}
-
-export const SHORTCUTS: ShortcutGroup[] = [
-  {
-    title: "Sessions",
-    items: [
-      { keys: ["n"], description: "Open the spawn form" },
-      { keys: ["N"], description: "Spawn a session with every default resolved" },
-    ],
-  },
-  {
-    title: "Session list",
-    items: [
-      {
-        keys: ["Ctrl", "Shift", "H"],
-        description: "Move the keyboard between the session list and the pane",
-      },
-      { keys: ["j"], description: "Highlight the next session" },
-      { keys: ["k"], description: "Highlight the previous session" },
-      { keys: ["Enter"], description: "Open the highlighted session, or expand a folder" },
-      { keys: ["c"], description: "Collapse or expand the highlighted folder" },
-      { keys: ["r"], description: "Rename the highlighted session" },
-      { keys: ["x"], description: "Kill the highlighted session" },
-      { keys: ["Tab"], description: "Send the keyboard to the pane" },
-      { keys: ["Esc"], description: "Hand the keyboard back to the session list, from the pane" },
-    ],
-  },
-  {
-    title: "Help",
-    items: [
-      { keys: ["?"], description: "Show or hide this help" },
-      { keys: ["Esc"], description: "Close the help overlay or an open menu" },
-    ],
-  },
-  {
-    title: "Debug",
-    items: [{ keys: ["Ctrl", "Shift", "D"], description: "Toggle the debug HUD" }],
-  },
-];
-
-/** True when the event target swallows plain keystrokes — a form field, or the
- *  hidden textarea xterm types into. Shared with `main.ts` so every global
- *  single-key binding is deaf in the same places. */
-export function isTypingTarget(target: EventTarget | null): boolean {
-  const el = target as HTMLElement | null;
-  if (!el || typeof el.tagName !== "string") return false;
-  return (
-    el.tagName === "INPUT" ||
-    el.tagName === "TEXTAREA" ||
-    el.tagName === "SELECT" ||
-    el.isContentEditable
-  );
-}
+import {
+  CommandSet,
+  defineCommands,
+  keyCaps,
+  publishedCommands,
+  type Command,
+} from "./commands.js";
 
 let open: { el: HTMLElement; dispose: () => void } | null = null;
 
@@ -108,7 +54,7 @@ export function openHelp(): HTMLElement {
   head.append(title, close);
   panel.appendChild(head);
 
-  for (const group of SHORTCUTS) {
+  for (const group of groupedCommands()) {
     const section = document.createElement("section");
     section.className = "help-group";
     const heading = document.createElement("h3");
@@ -116,19 +62,20 @@ export function openHelp(): HTMLElement {
     heading.textContent = group.title;
     const list = document.createElement("dl");
     list.className = "help-list";
-    for (const item of group.items) {
+    for (const cmd of group.items) {
       const row = document.createElement("div");
       row.className = "help-row";
+      row.dataset.commandId = cmd.id;
       const keys = document.createElement("dt");
       keys.className = "help-keys";
-      for (const key of item.keys) {
+      for (const key of keyCaps(cmd.keys[0])) {
         const cap = document.createElement("kbd");
         cap.textContent = key;
         keys.appendChild(cap);
       }
       const desc = document.createElement("dd");
       desc.className = "help-desc";
-      desc.textContent = item.description;
+      desc.textContent = cmd.label;
       row.append(keys, desc);
       list.appendChild(row);
     }
@@ -153,6 +100,26 @@ export function openHelp(): HTMLElement {
   return el;
 }
 
+/** The registry's commands, in registry order, bucketed into the help
+ *  overlay's sections. Groups appear in the order their first command does. */
+export function groupedCommands(): { title: string; items: Command[] }[] {
+  const groups: { title: string; items: Command[] }[] = [];
+  for (const cmd of publishedCommands()) {
+    let group = groups.find((g) => g.title === cmd.group);
+    if (!group) {
+      group = { title: cmd.group, items: [] };
+      groups.push(group);
+    }
+    group.items.push(cmd);
+  }
+  return groups;
+}
+
+// The overlay's own two commands. `help.close` is `overlay`-scoped: it is only
+// fed keys while the dialog is up.
+const helpKeys = new CommandSet(defineCommands({ "help.toggle": () => toggleHelp() }));
+const overlayKeys = new CommandSet(defineCommands({ "help.close": () => closeHelp() }));
+
 let installed = false;
 
 /** Global keybind: `?` toggles the overlay, Escape closes it. Idempotent, so a
@@ -161,16 +128,7 @@ export function installHelpKeybind(): void {
   if (installed) return;
   installed = true;
   window.addEventListener("keydown", (e) => {
-    if (e.key === "Escape" && open) {
-      e.preventDefault();
-      closeHelp();
-      return;
-    }
-    // Shift is how `?` is typed on most layouts; the others would be a
-    // different binding entirely.
-    if (e.key !== "?" || e.ctrlKey || e.altKey || e.metaKey) return;
-    if (isTypingTarget(e.target)) return;
-    e.preventDefault();
-    toggleHelp();
+    if (open && overlayKeys.handle(e)) return;
+    helpKeys.handle(e);
   });
 }

web/src/kit.ts

@@ -129,6 +129,7 @@ export function renderKit(): HTMLElement {
       "--muted",
       "--faint",
       "--accent",
+      "--preview",
       "--danger",
       "--warn",
     ];

web/src/main.ts

@@ -6,7 +6,9 @@ import { renderSidebar } from "./catalog.js";
 import { ConnectionPool } from "./connections.js";
 import { installDrawer, installDrawerSwipe, requestToggleDrawer } from "./drawer.js";
 import { installHudKeybind } from "./debug.js";
-import { installHelpKeybind, isHelpOpen, isTypingTarget } from "./help.js";
+import { installHelpKeybind, isHelpOpen } from "./help.js";
+import { CommandSet, DEFAULT_LEADER, defineCommands, isTypingTarget } from "./commands.js";
+import { isCommandBarOpen, openCommandBar } from "./commandBar.js";
 import { DaemonLink } from "./daemonLink.js";
 import { CatalogStore } from "./events.js";
 import { installRestartOverlay } from "./restartOverlay.js";
@@ -29,6 +31,7 @@ import { mountHud, type Hud } from "./hud.js";
 import { emptyLayout, type Layout, openSessions } from "./layout.js";
 import { createMultiView, type MultiView } from "./multiview.js";
 import { loadLayout, saveLayout } from "./persistence.js";
+import { createPreviewSchedule } from "./previewSchedule.js";
 import {
   FOCUS_PANE_EVENT,
   FOCUS_SIDEBAR_EVENT,
@@ -78,6 +81,15 @@ async function bootApp(): Promise<void> {
 
 const store = new CatalogStore();
 
+// The daemon's home dir, for the command bar's `~/…` directory abbreviation.
+// Absolute paths are a fine fallback until it lands.
+let homeDir: string | undefined;
+void getDaemonInfo()
+  .then((info) => (homeDir = info.home_dir))
+  .catch(() => {
+    /* absolute paths are a fine fallback */
+  });
+
 // The daemon's identity and liveness: names the release in the sidebar's status
 // dot, and blocks the UI behind the restart overlay while the daemon is away
 // (docs/RESTART.md). The events socket is the trigger — it dies first.
@@ -105,20 +117,14 @@ shellEl.dataset.route = "catalog";
 // point `mv` is assigned.
 let mv: MultiView;
 
-// Preview timing (docs/PREVIEW.md): a keyboard step shows almost at once; a
-// mouse sweep waits long enough that rows crossed on the way somewhere else
-// never flash up. The same delay applies to clearing, so the gap between two
-// rows doesn't blink the previous view back.
-const PREVIEW_DELAY = { key: 60, hover: 150 } as const;
-let previewTimer: number | undefined;
-function schedulePreview(sessionId: string | null, source: "key" | "hover"): void {
-  clearTimeout(previewTimer);
-  previewTimer = window.setTimeout(() => {
-    ensureMultiView();
-    mv?.previewSession(sessionId);
-    updateShellRoute();
-  }, PREVIEW_DELAY[source]);
-}
+// Preview timing (docs/PREVIEW.md): the first move shows at once, and a burst
+// — j held down, or the pointer sweeping the whole list — is coalesced so it
+// costs a couple of pane mounts instead of one per row walked.
+const schedulePreview = createPreviewSchedule((sessionId) => {
+  ensureMultiView();
+  mv?.previewSession(sessionId);
+  updateShellRoute();
+});
 
 const sidebar = renderSidebar(store, {
   onLeafDrag: (id, e) => mv?.beginSessionDrag(id, e),
@@ -366,38 +372,75 @@ async function requestFastForward(): Promise<void> {
   });
 }
 
-// Keyboard pair (#67): `n` opens the spawn modal, `N` fast-forwards a spawn.
-// Ignored while typing anywhere (form fields, the terminal's hidden
-// textarea, search) so an attached session's keys are never hijacked.
-document.addEventListener("keydown", (e) => {
-  if (e.ctrlKey || e.altKey || e.metaKey) return;
-  if (isTypingTarget(e.target)) return;
-  // The help overlay owns the keyboard while it is up.
-  if (isHelpOpen()) return;
-  if (e.key === "n") {
-    e.preventDefault();
-    requestOpenSpawn();
-  } else if (e.key === "N") {
-    e.preventDefault();
-    void requestFastForward();
-  }
-});
+// The global half of the command registry (#148). Two sets, because they
+// differ in one thing: the help overlay owns the keyboard while it is up, so
+// the plain keys go deaf behind it while the focus chord does not — an
+// attached terminal must never be able to trap the focus keys.
+//
+// `n` opens the spawn modal, `N` fast-forwards a spawn (#67). Both are plain
+// keys, so `isTypingTarget` keeps them out of form fields and the terminal's
+// hidden textarea.
+const spawnKeys = new CommandSet(
+  defineCommands({
+    "spawn.open": () => requestOpenSpawn(),
+    "spawn.fastForward": () => void requestFastForward(),
+  }),
+);
 
 // Ctrl+Shift+H moves the keyboard between the session list and the pane, the
 // web counterpart of the TUI's `ctrl-w h`. It has to be a chord: an attached
 // terminal owns every plain keystroke, so nothing unmodified could ever get
 // the focus back out of it.
-window.addEventListener("keydown", (e) => {
-  if (!e.ctrlKey || !e.shiftKey || e.altKey || e.metaKey) return;
-  if (e.key !== "H" && e.key !== "h") return;
-  e.preventDefault();
-  if (sidebar.hasListFocus()) {
-    pool.focusTerminal();
-  } else {
-    drawer.open(); // no-op on desktop; on mobile the list is off-canvas
-    sidebar.focusList();
-  }
-});
+//
+// This set also owns the leader (`ctrl-a`, the TUI's default): it holds the
+// key as a partial chord and takes select-all off it, so the escape hatch
+// docs/COMMAND-BAR.md describes has somewhere to land (#149).
+const focusKeys = new CommandSet(
+  defineCommands({
+    "focus.toggle": () => {
+      if (sidebar.hasListFocus()) {
+        pool.focusTerminal();
+      } else {
+        drawer.open(); // no-op on desktop; on mobile the list is off-canvas
+        sidebar.focusList();
+      }
+    },
+  }),
+  { leader: DEFAULT_LEADER },
+);
+
+// Ctrl+K opens the command bar (docs/COMMAND-BAR.md). It is a registry command
+// like any other, so the `?` overlay lists it without a second list.
+const barKeys = new CommandSet(
+  defineCommands({
+    "bar.open": () => {
+      // Opening while a session is previewed discards the preview first, like
+      // any other real change (docs/PREVIEW.md): the bar is not previewed into.
+      schedulePreview.cancel();
+      mv?.previewSession(null);
+      openCommandBar({ sessions: [...store.snapshot().sessions.values()], homeDir });
+    },
+  }),
+);
+
+// Capture phase: an attached xterm swallows every keystroke it is given, so the
+// bar's binding has to be seen ahead of the terminal (docs/COMMAND-BAR.md).
+window.addEventListener(
+  "keydown",
+  (e) => {
+    // The bar owns the keyboard while it is up; its own input handles the keys.
+    if (isCommandBarOpen()) return;
+    if (focusKeys.handle(e)) return;
+    // The help overlay owns the keyboard while it is up.
+    if (isHelpOpen()) return;
+    // Opening the bar over a focused terminal is #152; until then the pane's
+    // hidden textarea keeps its Ctrl+K, like any other typing target.
+    if (!isTypingTarget(e.target) && barKeys.handle(e)) return;
+    spawnKeys.handle(e);
+  },
+  true,
+);
+
 
 // Tab in the session list hands the keyboard to the pane; Escape in the pane
 // hands it back — the pair the TUI gets from `tab` and `esc`.
@@ -418,7 +461,7 @@ document.addEventListener(FOCUS_SIDEBAR_EVENT, () => {
  *  on `hashchange` alone — a split or drag can move focus without the hash
  *  changing, leaving a click back onto that session's row silently ignored. */
 function focusSession(sessionId: string): void {
-  clearTimeout(previewTimer);
+  schedulePreview.cancel();
   showMultiView();
   mv.openSession(sessionId);
   updateShellRoute();

web/src/matcher.test.ts

@@ -0,0 +1,201 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  matchAndRank,
+  type CommandCandidate,
+  type DirectoryCandidate,
+  type MatchCandidate,
+  type MatchResult,
+  type SessionCandidate,
+} from "./matcher.js";
+
+function session(
+  name: string,
+  directory?: string,
+  command?: string,
+  tool?: string,
+): SessionCandidate {
+  return { kind: "session", fields: { name, directory, command, tool } };
+}
+
+function command(label: string): CommandCandidate {
+  return { kind: "command", fields: { label } };
+}
+
+function directory(path: string): DirectoryCandidate {
+  return { kind: "directory", fields: { path } };
+}
+
+function label(result: MatchResult): string {
+  switch (result.candidate.kind) {
+    case "session":
+      return `session:${result.candidate.fields.name}`;
+    case "command":
+      return `command:${result.candidate.fields.label}`;
+    case "directory":
+      return `directory:${result.candidate.fields.path}`;
+  }
+}
+
+function positions(result: MatchResult): number[] {
+  return result.ranges.flatMap(([start, end]) =>
+    Array.from({ length: end - start }, (_, offset) => start + offset),
+  );
+}
+
+function expectResults(
+  query: string,
+  candidates: MatchCandidate[],
+  expected: Array<[label: string, score: number, field?: string, positions?: number[]]>,
+): void {
+  const results = matchAndRank(query, candidates);
+
+  expect(results.map((result) => [label(result), result.score])).toEqual(
+    expected.map(([candidateLabel, score]) => [candidateLabel, score]),
+  );
+  expect(results.map((result) => result.field)).toEqual(
+    expected.map(([, , field]) => field),
+  );
+  expect(results.map(positions)).toEqual(expected.map(([, , , matched]) => matched ?? []));
+}
+
+describe("matchAndRank fixtures", () => {
+  it("F1: an empty query keeps input order", () => {
+    expectResults(
+      "",
+      [
+        session("kill", "~/dev/api", "bash"),
+        session("killer-app", "~/dev/killer-app", "claude --resume", "claude"),
+        command("Kill selected session"),
+      ],
+      [
+        ["session:kill", 0],
+        ["session:killer-app", 0],
+        ["command:Kill selected session", 0],
+      ],
+    );
+  });
+
+  it("F2: an exact session name beats a prefix and kind breaks a tie", () => {
+    expectResults(
+      "kill",
+      [
+        session("kill", "~/dev/api", "bash"),
+        session("killer-app", "~/dev/killer-app", "claude --resume", "claude"),
+        command("Kill selected session"),
+      ],
+      [
+        ["session:kill", 178, "name", [0, 1, 2, 3]],
+        ["session:killer-app", 146, "name", [0, 1, 2, 3]],
+        ["command:Kill selected session", 146, "label", [0, 1, 2, 3]],
+      ],
+    );
+  });
+
+  it("F3: path segment boundaries beat mid-segment matches", () => {
+    expectResults(
+      "foo",
+      [directory("~/dev/foobar"), directory("~/src/myfoo"), directory("~/foo")],
+      [
+        ["directory:~/foo", 78, "path", [2, 3, 4]],
+        ["directory:~/dev/foobar", 74, "path", [6, 7, 8]],
+        ["directory:~/src/myfoo", 56, "path", [8, 9, 10]],
+      ],
+    );
+  });
+
+  it("F4: a query matching nothing returns no candidates", () => {
+    expectResults("zzz", [session("kill", "~/dev/api", "bash"), command("Kill selected session")], []);
+  });
+
+  it("F5: the highest-scoring embedding can differ from the greedy embedding", () => {
+    expectResults(
+      "mtu",
+      [session("maestro-tui"), session("maestro-daemon"), session("mtui-scratch")],
+      [
+        ["session:mtui-scratch", 122, "name", [0, 1, 2]],
+        ["session:maestro-tui", 91, "name", [0, 8, 9]],
+      ],
+    );
+  });
+
+  it("F6: a name beats a weighted directory match", () => {
+    expectResults(
+      "api",
+      [session("api", "~/dev/web", "bash"), session("worker", "~/dev/api", "bash")],
+      [
+        ["session:api", 154, "name", [0, 1, 2]],
+        ["session:worker", 50, "directory", [6, 7, 8]],
+      ],
+    );
+  });
+
+  it("F7: matching is case-insensitive and field length breaks a tie", () => {
+    expectResults(
+      "api",
+      [session("API-Gateway"), session("apiary")],
+      [
+        ["session:apiary", 122, "name", [0, 1, 2]],
+        ["session:API-Gateway", 122, "name", [0, 1, 2]],
+      ],
+    );
+  });
+
+  it("F8: the exact tool field beats the command field", () => {
+    expectResults(
+      "claude",
+      [session("nameless", "~/dev/x", "claude --resume", "claude"), session("clay", "~/dev/y", "bash")],
+      [["session:nameless", 186, "tool", [0, 1, 2, 3, 4, 5]]],
+    );
+  });
+
+  it("F9: a separator earns a word-boundary bonus", () => {
+    expectResults(
+      "ws",
+      [session("websearch"), session("web-search")],
+      [
+        ["session:web-search", 71, "name", [0, 4]],
+        ["session:websearch", 56, "name", [0, 3]],
+      ],
+    );
+  });
+
+  it("F10: command labels rank by boundary and initial gap", () => {
+    expectResults(
+      "se",
+      [command("Kill selected session"), command("Create a session"), command("Show help")],
+      [
+        ["command:Show help", 53, "label", [0, 6]],
+        ["command:Kill selected session", 51, "label", [5, 6]],
+        ["command:Create a session", 47, "label", [9, 10]],
+      ],
+    );
+  });
+
+  it("F11: directory matches separate on their initial gap", () => {
+    expectResults(
+      "dev",
+      [
+        session("api", "~/dev/api", "bash"),
+        session("notes", "~/documents/dev-notes", "nvim"),
+        session("scratch", "~/srv/devops", "bash"),
+      ],
+      [
+        ["session:api", 54, "directory", [2, 3, 4]],
+        ["session:scratch", 50, "directory", [6, 7, 8]],
+        ["session:notes", 44, "directory", [12, 13, 14]],
+      ],
+    );
+  });
+
+  it("F12: an exact field beats a prefix", () => {
+    expectResults(
+      "quit",
+      [command("Quit Maestro"), command("Quit")],
+      [
+        ["command:Quit", 178, "label", [0, 1, 2, 3]],
+        ["command:Quit Maestro", 146, "label", [0, 1, 2, 3]],
+      ],
+    );
+  });
+});

web/src/matcher.ts

@@ -0,0 +1,224 @@
+export type CandidateKind = "session" | "command" | "directory";
+
+export interface SessionCandidate {
+  kind: "session";
+  fields: {
+    name: string;
+    directory?: string;
+    command?: string;
+    tool?: string;
+  };
+}
+
+export interface CommandCandidate {
+  kind: "command";
+  fields: { label: string };
+}
+
+export interface DirectoryCandidate {
+  kind: "directory";
+  fields: { path: string };
+}
+
+export type MatchCandidate = SessionCandidate | CommandCandidate | DirectoryCandidate;
+export type MatchFieldName = "name" | "directory" | "command" | "tool" | "label" | "path";
+export type MatchRange = readonly [start: number, end: number];
+
+export interface MatchResult<C extends MatchCandidate = MatchCandidate> {
+  candidate: C;
+  score: number;
+  field: MatchFieldName | undefined;
+  ranges: MatchRange[];
+}
+
+interface Field {
+  name: MatchFieldName;
+  text: string;
+  weight: number;
+}
+
+interface Embedding {
+  score: number;
+  positions: number[];
+}
+
+interface RankedResult<C extends MatchCandidate> extends MatchResult<C> {
+  matchedText: string;
+  inputIndex: number;
+}
+
+const KIND_ORDER: Record<CandidateKind, number> = {
+  session: 0,
+  command: 1,
+  directory: 2,
+};
+
+function fields(candidate: MatchCandidate): Field[] {
+  switch (candidate.kind) {
+    case "session": {
+      const values: Array<[MatchFieldName, string | undefined, number]> = [
+        ["name", candidate.fields.name, 0],
+        ["directory", candidate.fields.directory, -24],
+        ["command", candidate.fields.command, -32],
+        ["tool", candidate.fields.tool, -40],
+      ];
+      return values.flatMap(([name, text, weight]) =>
+        text === undefined ? [] : [{ name, text, weight }],
+      );
+    }
+    case "command":
+      return [{ name: "label", text: candidate.fields.label, weight: 0 }];
+    case "directory":
+      return [{ name: "path", text: candidate.fields.path, weight: 0 }];
+  }
+}
+
+function normalizeQuery(query: string): string {
+  return query.toLowerCase().replace(/\s/g, "");
+}
+
+function boundaryBonus(text: string, position: number): number {
+  if (position === 0) return 18;
+
+  const previous = text[position - 1];
+  if ("/\\-_ .:".includes(previous)) return 16;
+
+  const current = text[position];
+  const isUppercase = current !== current.toLowerCase() && current === current.toUpperCase();
+  const previousIsLowercase =
+    previous !== previous.toUpperCase() && previous === previous.toLowerCase();
+  if (isUppercase && previousIsLowercase) return 12;
+
+  const isDigit = current >= "0" && current <= "9";
+  const previousIsDigit = previous >= "0" && previous <= "9";
+  if (isDigit && !previousIsDigit) return 12;
+
+  return 0;
+}
+
+function contribution(text: string, position: number, previousPosition: number): number {
+  const gap = position - previousPosition - 1;
+  return 16 + boundaryBonus(text, position) + (gap === 0 ? 8 : -Math.min(gap, 12));
+}
+
+function isBetterEmbedding(candidate: Embedding, incumbent: Embedding | undefined): boolean {
+  if (!incumbent || candidate.score !== incumbent.score) {
+    return !incumbent || candidate.score > incumbent.score;
+  }
+  for (let index = 0; index < candidate.positions.length; index++) {
+    if (candidate.positions[index] !== incumbent.positions[index]) {
+      return candidate.positions[index] < incumbent.positions[index];
+    }
+  }
+  return false;
+}
+
+function bestEmbedding(query: string, text: string): Embedding | undefined {
+  const lowerText = text.toLowerCase();
+  let previousStates = new Map<number, Embedding>();
+
+  for (let queryIndex = 0; queryIndex < query.length; queryIndex++) {
+    const states = new Map<number, Embedding>();
+    for (let position = 0; position < lowerText.length; position++) {
+      if (lowerText[position] !== query[queryIndex]) continue;
+
+      if (queryIndex === 0) {
+        states.set(position, {
+          score: contribution(text, position, -1),
+          positions: [position],
+        });
+        continue;
+      }
+
+      for (const [previousPosition, previous] of previousStates) {
+        if (previousPosition >= position) continue;
+        const candidate = {
+          score: previous.score + contribution(text, position, previousPosition),
+          positions: [...previous.positions, position],
+        };
+        if (isBetterEmbedding(candidate, states.get(position))) states.set(position, candidate);
+      }
+    }
+    if (states.size === 0) return undefined;
+    previousStates = states;
+  }
+
+  let best: Embedding | undefined;
+  for (const embedding of previousStates.values()) {
+    if (isBetterEmbedding(embedding, best)) best = embedding;
+  }
+  return best;
+}
+
+function toRanges(positions: number[]): MatchRange[] {
+  const ranges: MatchRange[] = [];
+  for (const position of positions) {
+    const previous = ranges[ranges.length - 1];
+    if (previous && previous[1] === position) {
+      ranges[ranges.length - 1] = [previous[0], position + 1];
+    } else {
+      ranges.push([position, position + 1]);
+    }
+  }
+  return ranges;
+}
+
+function compareByCodePoint(left: string, right: string): number {
+  const leftPoints = Array.from(left, (character) => character.codePointAt(0)!);
+  const rightPoints = Array.from(right, (character) => character.codePointAt(0)!);
+  const length = Math.min(leftPoints.length, rightPoints.length);
+  for (let index = 0; index < length; index++) {
+    if (leftPoints[index] !== rightPoints[index]) return leftPoints[index] - rightPoints[index];
+  }
+  return leftPoints.length - rightPoints.length;
+}
+
+export function matchAndRank<C extends MatchCandidate>(
+  query: string,
+  candidates: readonly C[],
+): MatchResult<C>[] {
+  const normalizedQuery = normalizeQuery(query);
+  if (normalizedQuery === "") {
+    return candidates.map((candidate) => ({ candidate, score: 0, field: undefined, ranges: [] }));
+  }
+
+  const results: RankedResult<C>[] = [];
+  candidates.forEach((candidate, inputIndex) => {
+    let best:
+      | { field: Field; score: number; positions: number[] }
+      | undefined;
+
+    for (const field of fields(candidate)) {
+      const embedding = bestEmbedding(normalizedQuery, field.text);
+      if (!embedding) continue;
+
+      const compactText = field.text.toLowerCase().replace(/\s/g, "");
+      const adjustment =
+        compactText === normalizedQuery ? 64 : compactText.startsWith(normalizedQuery) ? 32 : 0;
+      const score = embedding.score + adjustment + field.weight;
+      if (!best || score > best.score) best = { field, score, positions: embedding.positions };
+    }
+
+    if (best) {
+      results.push({
+        candidate,
+        score: best.score,
+        field: best.field.name,
+        ranges: toRanges(best.positions),
+        matchedText: best.field.text,
+        inputIndex,
+      });
+    }
+  });
+
+  results.sort(
+    (left, right) =>
+      right.score - left.score ||
+      KIND_ORDER[left.candidate.kind] - KIND_ORDER[right.candidate.kind] ||
+      left.matchedText.length - right.matchedText.length ||
+      compareByCodePoint(left.matchedText, right.matchedText) ||
+      left.inputIndex - right.inputIndex,
+  );
+
+  return results.map(({ candidate, score, field, ranges }) => ({ candidate, score, field, ranges }));
+}

web/src/multiview.test.ts

@@ -36,6 +36,7 @@ function fakeSidebar(): SidebarHandle {
     el: document.createElement("aside"),
     setActive() {},
     setHighlights() {},
+    setPreview() {},
     focusList() {},
     hasListFocus() {
       return false;

web/src/multiview.ts

@@ -221,6 +221,12 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
     const tab = activeTab(layout);
     for (const pane of canvas.querySelectorAll<HTMLElement>(".mv-pane")) {
       pane.classList.toggle("is-focused", pane.dataset.leafId === tab.focusedLeafId);
+      // The previewed pane's titlebar wears the preview colour instead of the
+      // accent tint a focused pane gets (docs/PREVIEW.md).
+      pane.classList.toggle(
+        "is-preview",
+        preview !== null && pane.dataset.sessionId === preview.sessionId,
+      );
     }
     // A preview is not a focused pane: reporting it would clear the session's
     // `AwaitingInput` glow just because the operator scrolled past it.
@@ -229,6 +235,9 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
       open: realOpenSessions(),
       focused: focusedLeafSession(),
     });
+    // The row the preview came from wears the same colour, so the sidebar and
+    // the pane read as one thing rather than two unrelated highlights.
+    sidebar.setPreview(preview?.sessionId ?? null);
   }
 
   function focusLeaf(leafId: string): void {
@@ -549,6 +558,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
       if (!preview) pool.setFocus(null);
       canvas.appendChild(renderWelcome());
       sidebar.setHighlights({ open: realOpenSessions(), focused: null });
+      sidebar.setPreview(preview?.sessionId ?? null);
       persist();
       return;
     }
@@ -588,6 +598,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
 
     const pane = buildPane(focused);
     pane.el.classList.add("is-focused"); // the only pane — never dimmed
+    if (preview && focused.sessionId === preview.sessionId) pane.el.classList.add("is-preview");
     wrap.appendChild(pane.el);
     canvas.appendChild(wrap);
 
@@ -598,6 +609,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
     );
     if (!preview) pool.setFocus(focused.sessionId ?? null);
     sidebar.setHighlights({ open: realOpenSessions(), focused: focused.sessionId ?? null });
+    sidebar.setPreview(preview?.sessionId ?? null);
   }
 
   function closeSession(sessionId: string): void {

web/src/preview.test.ts

@@ -45,11 +45,17 @@ function fakePool(): Spy {
   return { pool, visible: () => visible, focusCalls, mountedWithFocus };
 }
 
+/** Last value the controller pushed to `SidebarHandle.setPreview`. */
+const previewRow: { id: string | null } = { id: null };
+
 function fakeSidebar(): SidebarHandle {
   return {
     el: document.createElement("aside"),
     setActive() {},
     setHighlights() {},
+    setPreview(id: string | null) {
+      previewRow.id = id;
+    },
     focusList() {},
     hasListFocus() {
       return false;
@@ -88,6 +94,7 @@ describe("sidebar preview", () => {
   beforeEach(() => {
     stubFetch();
     document.body.replaceChildren();
+    previewRow.id = null;
   });
 
   afterEach(() => {
@@ -110,6 +117,23 @@ describe("sidebar preview", () => {
     expect(serializeLayout(layout)).toEqual(before);
   });
 
+  it("marks the previewed pane and its sidebar row, and unmarks them after", () => {
+    const layout = twoTabs();
+    const spy = fakePool();
+    const mv = makeMv(layout, spy.pool);
+
+    mv.previewSession("s1");
+    expect(previewRow.id).toBe("s1");
+    expect(mv.el.querySelectorAll(".mv-pane.is-preview")).toHaveLength(1);
+    expect(
+      (mv.el.querySelector(".mv-pane.is-preview") as HTMLElement).dataset.sessionId,
+    ).toBe("s1");
+
+    mv.previewSession(null);
+    expect(previewRow.id).toBeNull();
+    expect(mv.el.querySelectorAll(".mv-pane.is-preview")).toHaveLength(0);
+  });
+
   it("shows a session no pane holds in a throwaway tab that leaves no trace", () => {
     const layout = twoTabs();
     const before = serializeLayout(layout);

web/src/previewSchedule.test.ts

@@ -0,0 +1,92 @@
+import { describe, expect, it } from "vitest";
+
+import { createPreviewSchedule, PREVIEW_MIN_GAP_MS } from "./previewSchedule.js";
+
+/** Hand-driven clock + timer queue, so the schedule is asserted without waiting. */
+function harness() {
+  let now = 1_000;
+  const timers = new Map<number, { at: number; fn: () => void }>();
+  let nextHandle = 1;
+  const emitted: (string | null)[] = [];
+
+  const schedule = createPreviewSchedule((id) => emitted.push(id), {
+    now: () => now,
+    setTimer: (fn, ms) => {
+      const h = nextHandle++;
+      timers.set(h, { at: now + ms, fn });
+      return h;
+    },
+    clearTimer: (h) => {
+      timers.delete(h);
+    },
+  });
+
+  /** Advance the clock, firing any timer that comes due. */
+  const advance = (ms: number) => {
+    now += ms;
+    for (const [h, t] of [...timers]) {
+      if (t.at <= now) {
+        timers.delete(h);
+        t.fn();
+      }
+    }
+  };
+
+  return { schedule, emitted, advance };
+}
+
+describe("preview schedule", () => {
+  it("shows the first preview immediately", () => {
+    const { schedule, emitted } = harness();
+    schedule("s1");
+    expect(emitted).toEqual(["s1"]);
+  });
+
+  it("coalesces a burst into one trailing preview", () => {
+    const { schedule, emitted, advance } = harness();
+    // A pointer sweep across the list, or j held down: every row in between
+    // is walked well inside one gap.
+    schedule("s1");
+    schedule("s2");
+    schedule("s3");
+    expect(emitted).toEqual(["s1"]);
+    advance(PREVIEW_MIN_GAP_MS);
+    expect(emitted).toEqual(["s1", "s3"]);
+  });
+
+  it("shows the next preview immediately once the gap has passed", () => {
+    const { schedule, emitted, advance } = harness();
+    schedule("s1");
+    advance(PREVIEW_MIN_GAP_MS);
+    schedule("s2");
+    expect(emitted).toEqual(["s1", "s2"]);
+  });
+
+  it("drops a superseded trailing preview rather than replaying it", () => {
+    const { schedule, emitted, advance } = harness();
+    schedule("s1");
+    schedule("s2");
+    schedule("s1"); // back where we started inside the same gap
+    advance(PREVIEW_MIN_GAP_MS);
+    // s1 is already on screen, so the trailing edge has nothing to do.
+    expect(emitted).toEqual(["s1"]);
+  });
+
+  it("clears through the same gap, so leaving and re-entering does not blink", () => {
+    const { schedule, emitted, advance } = harness();
+    schedule("s1");
+    schedule(null); // pointer crosses the gap between two rows
+    schedule("s2");
+    advance(PREVIEW_MIN_GAP_MS);
+    expect(emitted).toEqual(["s1", "s2"]);
+  });
+
+  it("cancel drops a pending trailing preview", () => {
+    const { schedule, emitted, advance } = harness();
+    schedule("s1");
+    schedule("s2");
+    schedule.cancel();
+    advance(PREVIEW_MIN_GAP_MS);
+    expect(emitted).toEqual(["s1"]);
+  });
+});

web/src/previewSchedule.ts

@@ -0,0 +1,87 @@
+/**
+ * When the content pane follows the sidebar highlight (docs/PREVIEW.md).
+ *
+ * The highlight itself is never scheduled — that is a class on a row and lands
+ * on the same frame as the input. This governs only the pane swap behind it,
+ * which mounts a terminal and, for a session the connection pool isn't already
+ * holding, opens an attach socket the daemon answers with a `tmux capture-pane`.
+ *
+ * A plain debounce would put that cost in front of every preview, including the
+ * one preview the operator actually meant. Instead the first move shows at once
+ * and the rest of a burst is coalesced: walking a list with `j` held down, or
+ * sweeping the pointer from the top of the sidebar to the bottom, costs one
+ * preview at the start and one at the row you stopped on, not one per row.
+ */
+
+/** Shortest gap between two pane swaps. Long enough that a fast walk mounts a
+ *  couple of terminals rather than one per row; short enough that a deliberate
+ *  second move never waits on it. */
+export const PREVIEW_MIN_GAP_MS = 120;
+
+export interface PreviewScheduleDeps {
+  now?: () => number;
+  setTimer?: (fn: () => void, ms: number) => number;
+  clearTimer?: (handle: number) => void;
+  /** Override the gap; tests and callers otherwise take {@link PREVIEW_MIN_GAP_MS}. */
+  minGapMs?: number;
+}
+
+export interface PreviewSchedule {
+  (sessionId: string | null): void;
+  /** Drop a pending trailing preview without showing it. */
+  cancel(): void;
+}
+
+/**
+ * Wrap `show` so it fires on the leading edge and at most once per gap.
+ *
+ * `show` is called with the session to preview, or `null` to put back whatever
+ * the operator actually opened.
+ */
+export function createPreviewSchedule(
+  show: (sessionId: string | null) => void,
+  deps: PreviewScheduleDeps = {},
+): PreviewSchedule {
+  const now = deps.now ?? (() => Date.now());
+  const setTimer = deps.setTimer ?? ((fn, ms) => window.setTimeout(fn, ms));
+  const clearTimer = deps.clearTimer ?? ((h) => window.clearTimeout(h));
+  const minGap = deps.minGapMs ?? PREVIEW_MIN_GAP_MS;
+
+  let lastShownAt = Number.NEGATIVE_INFINITY;
+  let shown: string | null | undefined;
+  let pendingTimer: number | undefined;
+  let pendingId: string | null = null;
+
+  const emit = (id: string | null) => {
+    // Nothing to do when the burst ended on the view already up: re-showing it
+    // would tear down and re-mount the pane for no visible change.
+    if (shown === id) return;
+    shown = id;
+    lastShownAt = now();
+    show(id);
+  };
+
+  const cancelPending = () => {
+    if (pendingTimer === undefined) return;
+    clearTimer(pendingTimer);
+    pendingTimer = undefined;
+  };
+
+  const schedule = ((sessionId: string | null) => {
+    pendingId = sessionId;
+    const waited = now() - lastShownAt;
+    if (waited >= minGap) {
+      cancelPending();
+      emit(sessionId);
+      return;
+    }
+    if (pendingTimer !== undefined) return; // already waiting; `pendingId` wins
+    pendingTimer = setTimer(() => {
+      pendingTimer = undefined;
+      emit(pendingId);
+    }, minGap - waited);
+  }) as PreviewSchedule;
+
+  schedule.cancel = cancelPending;
+  return schedule;
+}

web/src/sidebarNav.test.ts

@@ -169,33 +169,30 @@ describe("sidebar keyboard navigation", () => {
 
 describe("sidebar preview requests (docs/PREVIEW.md)", () => {
   it("asks for a preview on every keyboard step, and for none once the list blurs", () => {
-    const seen: [string | null, string][] = [];
-    const { el } = twoFolders({ onPreview: (id, source) => seen.push([id, source]) });
+    const seen: (string | null)[] = [];
+    const { el } = twoFolders({ onPreview: (id) => seen.push(id) });
 
     press(tree(el), "j");
     press(tree(el), "j");
-    expect(seen).toEqual([
-      [A, "key"],
-      [B, "key"],
-    ]);
+    expect(seen).toEqual([A, B]);
 
     tree(el).dispatchEvent(new FocusEvent("blur"));
-    expect(seen.at(-1)).toEqual([null, "key"]);
+    expect(seen.at(-1)).toBe(null);
   });
 
   it("asks for a preview of the hovered card, and clears it on the way out", () => {
-    const seen: [string | null, string][] = [];
-    const { el } = twoFolders({ onPreview: (id, source) => seen.push([id, source]) });
+    const seen: (string | null)[] = [];
+    const { el } = twoFolders({ onPreview: (id) => seen.push(id) });
     const card = el.querySelectorAll<HTMLElement>(".tree-leaf")[0];
 
     card.dispatchEvent(new PointerEvent("pointerover", { bubbles: true, pointerType: "mouse" }));
-    expect(seen).toEqual([[A, "hover"]]);
+    expect(seen).toEqual([A]);
     // Moving within the same card is not a new preview.
     card.dispatchEvent(new PointerEvent("pointerover", { bubbles: true, pointerType: "mouse" }));
     expect(seen).toHaveLength(1);
 
     tree(el).dispatchEvent(new PointerEvent("pointerleave", { pointerType: "mouse" }));
-    expect(seen.at(-1)).toEqual([null, "hover"]);
+    expect(seen.at(-1)).toBe(null);
   });
 
   it("ignores touch, where a tap already opens the session", () => {

web/src/styles.css

@@ -87,6 +87,28 @@
   --accent-tint: oklch(0.92 0.005 256 / 0.1);
   --accent-ring: oklch(0.92 0.005 256 / 0.5);
 
+  /* preview (docs/PREVIEW.md): a provisional view needs a colour that is not
+     the accent, because the accent is what says "this is the one you picked".
+     Defined once, off a single hue variable, so a palette whose accent already
+     sits on that hue can move it (see periwinkle/orchid below); `light-dark()`
+     keeps the light pair here instead of in all eighteen theme blocks. */
+  --preview-h: 305;
+  --preview: light-dark(
+    oklch(0.55 0.16 var(--preview-h)),
+    oklch(0.78 0.14 var(--preview-h))
+  );
+  --preview-ink: light-dark(
+    oklch(0.99 0.005 var(--preview-h)),
+    oklch(0.19 0.045 var(--preview-h))
+  );
+  /* Opaque, not a wash: the previewed row reads as a fill, and a fill has to
+     land on the same colour whatever tier the row was already painted. */
+  --preview-tint: color-mix(in oklab, var(--preview) 30%, var(--surface-2));
+  --preview-ring: light-dark(
+    oklch(0.55 0.16 var(--preview-h) / 0.5),
+    oklch(0.78 0.14 var(--preview-h) / 0.6)
+  );
+
   --live: oklch(0.84 0.17 152);
   --live-glow: oklch(0.84 0.17 152 / 0.55);
 
@@ -256,6 +278,9 @@
   --accent-ink: oklch(0.18 0.04 278);
   --accent-tint: oklch(0.75 0.125 275 / 0.14);
   --accent-ring: oklch(0.75 0.125 275 / 0.55);
+  /* This accent is already violet, so preview moves to cyan to stay legible
+     as "not the accent". Set once here: the light blocks below don't touch it. */
+  --preview-h: 195;
   --term-bg: oklch(0.155 0.018 278);
 }
 :root[data-palette="periwinkle"][data-theme="light"],
@@ -437,6 +462,8 @@
   --accent-ink: oklch(0.22 0.05 310);
   --accent-tint: oklch(0.78 0.13 310 / 0.14);
   --accent-ring: oklch(0.78 0.13 310 / 0.55);
+  /* Same collision as periwinkle: an orchid accent needs a non-purple preview. */
+  --preview-h: 195;
   --term-bg: oklch(0.155 0.014 305);
 }
 :root[data-palette="orchid"][data-theme="light"],
@@ -1064,7 +1091,6 @@ textarea {
   cursor: pointer;
   font-family: var(--font-mono);
   font-size: var(--fs-12);
-  transition: color var(--dur-fast) var(--ease-out);
 }
 
 .tree-folder-header:hover {
@@ -1076,9 +1102,9 @@ textarea {
   text-align: center;
   color: var(--faint);
   font-size: var(--fs-11);
-  transition:
-    transform var(--dur) var(--ease-out),
-    color var(--dur-fast) var(--ease-out);
+  /* The rotation is the collapse animation and stays; the hover colour is
+     immediate, like the row's own hover. */
+  transition: transform var(--dur) var(--ease-out);
 }
 
 .tree-folder-header[aria-expanded="false"] .chevron {
@@ -1115,9 +1141,11 @@ textarea {
   border-radius: var(--r-1);
   color: var(--ink);
   position: relative;
-  transition:
-    background var(--dur-fast) var(--ease-out),
-    box-shadow var(--dur-fast) var(--ease-out);
+  /* No transition on `background`: it is what hover, the keyboard cursor and
+     the preview all paint, and easing it puts a visible delay between the input
+     landing on a row and the row admitting it. `.is-active`'s ring still eases
+     — being open in a pane is a state, not a response to the pointer. */
+  transition: box-shadow var(--dur-fast) var(--ease-out);
 }
 
 /* "Alive" reads as a faint wash on the row itself — no per-row status icon. */
@@ -1125,12 +1153,14 @@ textarea {
   background: color-mix(in oklab, var(--accent) 6%, transparent);
 }
 
+/* Hovering a row is what previews it (docs/PREVIEW.md), so hover reads in the
+   preview hue — never the accent, which belongs to the row actually open. */
 .tree-leaf:hover {
-  background: var(--surface-2);
+  background: color-mix(in oklab, var(--preview) 12%, var(--surface-2));
 }
 
 .tree-leaf[data-status="running"]:hover {
-  background: color-mix(in oklab, var(--accent) 13%, var(--surface-2));
+  background: color-mix(in oklab, var(--preview) 18%, var(--surface-2));
 }
 
 .tree-leaf:focus-visible {
@@ -1138,10 +1168,18 @@ textarea {
   background: color-mix(in oklab, var(--accent) 16%, var(--surface-2));
 }
 
-/* Where the keyboard walk (j/k) is standing. Distinct from `.is-active`: this
-   is a cursor, not a statement about what is mounted, so it reads as a ring
-   rather than a fill and the two can sit on the same row. */
-.tree-leaf.is-highlighted,
+/* Where the keyboard walk (j/k) is standing. On a session row the cursor is
+   also what previews it, so it reads exactly like a hover — the preview hue,
+   deepening to the full fill once the preview lands. A folder row previews
+   nothing, so it keeps the plain cursor ring. */
+.tree-leaf.is-highlighted {
+  background: color-mix(in oklab, var(--preview) 12%, var(--surface-2));
+}
+
+.tree-leaf.is-highlighted[data-status="running"] {
+  background: color-mix(in oklab, var(--preview) 18%, var(--surface-2));
+}
+
 .tree-folder-header.is-highlighted {
   box-shadow: inset 0 0 0 2px var(--accent-ring);
 }
@@ -1161,6 +1199,16 @@ textarea {
   color: var(--ink);
 }
 
+/* The row the content pane is previewing right now — after `.is-active` so a
+   preview of an already-open session still reads as provisional. */
+.tree-leaf.is-previewing,
+.tree-leaf.is-previewing[data-status="running"],
+.tree-leaf.is-previewing.is-active,
+.tree-leaf.is-previewing.is-highlighted {
+  background: var(--preview-tint);
+  box-shadow: none;
+}
+
 /* Exited sessions recede: dimmed name + an "exited" badge carry status, so it's
    never the running tint's absence alone doing the work. */
 .tree-leaf[data-status="dead"] {
@@ -1377,6 +1425,128 @@ input.leaf-rename:focus {
   color: var(--muted);
 }
 
+/* ---------- command bar (Ctrl+K) — docs/COMMAND-BAR.md ---------- */
+/* Same family of surface as the spawn modal and the help overlay: the overlay
+   tokens below are theirs, not a third set. */
+.cmdbar-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: var(--z-modal);
+  display: grid;
+  grid-template-rows: 12vh auto 1fr;
+  justify-items: center;
+  padding: var(--sp-4);
+  background: oklch(0 0 0 / 0.5);
+  backdrop-filter: blur(4px);
+}
+
+.cmdbar-panel {
+  grid-row: 2;
+  display: flex;
+  flex-direction: column;
+  width: min(560px, 100%);
+  max-height: min(60vh, 520px);
+  overflow: hidden;
+  background: var(--surface);
+  border: 1px solid var(--border-strong);
+  border-radius: var(--r-3);
+  box-shadow: var(--shadow-2);
+}
+
+.cmdbar-input {
+  appearance: none;
+  background: none;
+  border: 0;
+  border-bottom: 1px solid var(--border);
+  border-radius: 0;
+  color: var(--ink);
+  font-family: var(--font-mono);
+  font-size: var(--fs-15);
+  padding: var(--sp-3) var(--sp-4);
+}
+
+.cmdbar-input:focus-visible {
+  outline: none;
+}
+
+.cmdbar-results {
+  overflow-y: auto;
+  padding: var(--sp-2) 0;
+}
+
+.cmdbar-group-title {
+  padding: var(--sp-2) var(--sp-4) var(--sp-1);
+  font-size: var(--fs-11);
+  font-weight: 600;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  color: var(--faint);
+}
+
+.cmdbar-row {
+  display: flex;
+  align-items: baseline;
+  gap: var(--sp-3);
+  padding: var(--sp-1) var(--sp-4);
+  cursor: pointer;
+}
+
+.cmdbar-row.is-active {
+  background: var(--surface-3);
+}
+
+.cmdbar-row-name {
+  font-size: var(--fs-13);
+  color: var(--ink);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+/* A dead session still lists — it just is not where you just were. */
+.cmdbar-row.is-dead .cmdbar-row-name {
+  color: var(--muted);
+}
+
+.cmdbar-row-meta {
+  flex: 1 1 auto;
+  min-width: 0;
+  font-size: var(--fs-11);
+  color: var(--faint);
+  text-align: right;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.cmdbar-hit {
+  background: none;
+  color: var(--accent);
+  font-weight: 600;
+}
+
+.cmdbar-empty {
+  padding: var(--sp-3) var(--sp-4);
+  font-size: var(--fs-13);
+  color: var(--muted);
+}
+
+/* Phone: the bottom-sheet treatment the spawn modal already uses. */
+@media (max-width: 600px) {
+  .cmdbar-overlay {
+    grid-template-rows: 1fr auto;
+    padding: 0;
+  }
+
+  .cmdbar-panel {
+    grid-row: 2;
+    width: 100%;
+    max-height: 70vh;
+    border-radius: var(--r-3) var(--r-3) 0 0;
+    border-bottom: 0;
+  }
+}
+
 /* Line 2 — dot + duration in the state's colour, then muted fragments. The
    state word itself is never spelled out here; the colour carries it. */
 .card-line2 {
@@ -2884,10 +3054,14 @@ input.leaf-rename:focus {
 }
 
 /* Preview (docs/PREVIEW.md): the content pane is showing a session the
-   operator only highlighted, so it reads as provisional — a dashed tab and a
-   dashed inset ring on the canvas — and reverts when the highlight moves. */
+   operator only highlighted, so it reads as provisional — the preview hue on
+   the pane's titlebar, a dashed tab, a dashed inset ring on the canvas — and
+   reverts when the highlight moves. The hue is deliberately not the accent:
+   the accent means "this is what you picked", which a preview is not. */
 .mv-tab.is-preview {
   border-style: dashed;
+  border-color: var(--preview-ring);
+  color: var(--preview);
   font-style: italic;
 }
 .mv.mv-previewing .mv-canvas::before {
@@ -2900,8 +3074,8 @@ input.leaf-rename:focus {
   border-radius: var(--r-1);
   font: 500 var(--fs-11) / 1.5 var(--font-mono);
   letter-spacing: 0.04em;
-  color: var(--accent-ink);
-  background: var(--accent);
+  color: var(--preview-ink);
+  background: var(--preview);
   opacity: 0.85;
   pointer-events: none;
 }
@@ -2910,7 +3084,7 @@ input.leaf-rename:focus {
   position: absolute;
   inset: 0;
   pointer-events: none;
-  border: 1px dashed var(--accent-ring);
+  border: 1px dashed var(--preview-ring);
   border-radius: var(--r-1);
   z-index: var(--z-sticky);
 }
@@ -3028,6 +3202,15 @@ input.leaf-rename:focus {
 .mv-pane:not(.is-focused) .attach-header {
   opacity: 0.7;
 }
+/* The previewed pane's titlebar carries the preview hue, so the chip is not the
+   only thing saying the pane is provisional — and so it is never mistaken for
+   the accent tint of the pane the operator actually focused. It keeps full
+   strength even though a preview never takes focus. */
+.mv-pane.is-preview .attach-header,
+.mv-pane.is-preview.is-focused .attach-header {
+  background: color-mix(in oklab, var(--preview) 34%, var(--surface));
+  opacity: 1;
+}
 /* A pane with no session yet: a quiet hint rather than blank terminal black. */
 .mv-pane-empty {
   flex: 1;

web/src/types.ts

@@ -50,6 +50,12 @@ export interface Session {
    * create one. `base_repo` is the repository's main checkout, which is what
    * the session tree groups by (#99). */
   worktree?: SessionWorktree | null;
+  /** Wall-clock of when this session last became the pane a client was showing
+   * (#145) — stamped by both `POST /api/sessions/:id/focus` and opening
+   * `/api/attach/:id`. Absent until the session has been focused once, which is
+   * 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;
 }
 
 /** A session's daemon-created worktree (`SessionWorktree` on the wire). */