fix(maestro): focus the kill button in kill dialogs

Enter now confirms the kill the operator just asked for; Escape and the scrim still cancel.

crates/maestro-daemon/src/attach.rs

@@ -26,11 +26,17 @@ pub(crate) async fn serve(
 ) -> Result<(), axum::Error> {
     let (mut sink, mut stream) = socket.split();
 
+    // This client's claim on the shared window size. Registered up front and
+    // released on every exit below, so a socket that dies mid-session stops
+    // constraining the size for the clients still attached.
+    let viewport = manager.attach_viewport();
+
     // NAP-229: send buffered scrollback up-front so the client sees the last
     // screenful immediately instead of a blank terminal. The replay lock the
     // bridge held during snapshot+subscribe guarantees no byte appears both
     // here and on the live receiver, and none is dropped at the seam.
     if !replay.is_empty() && sink.send(Message::Binary(replay)).await.is_err() {
+        manager.release_viewport(id, viewport).await;
         return Ok(());
     }
 
@@ -70,7 +76,7 @@ pub(crate) async fn serve(
                     if let Ok(ctrl) = serde_json::from_str::<ClientControl>(&text) {
                         match ctrl {
                             ClientControl::Resize { cols, rows } => {
-                                let _ = manager.resize(id, cols, rows).await;
+                                let _ = manager.set_viewport(id, viewport, cols, rows).await;
                             }
                             ClientControl::Ping => {
                                 let pong = serde_json::to_string(&ClientControl::Pong)
@@ -88,6 +94,8 @@ pub(crate) async fn serve(
         }
     }
 
+    manager.release_viewport(id, viewport).await;
+
     if session_ended {
         let _ = sink.send(Message::Close(None)).await;
     }

crates/maestro-daemon/src/lib.rs

@@ -30,6 +30,7 @@ pub mod spawn_history;
 #[cfg(feature = "web")]
 pub mod static_bundle;
 pub mod tmux;
+pub mod viewport;
 pub mod worktree;
 pub mod worktree_probe;
 

crates/maestro-daemon/src/session.rs

@@ -7,6 +7,7 @@
 
 use std::collections::{HashMap, HashSet};
 use std::path::PathBuf;
+use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -23,6 +24,7 @@ use crate::pty::{pipe_pane_command, PtyBridge};
 use crate::sidecar::{SidecarError, SidecarStore};
 use crate::spawn_history::{RecentDir, SpawnHistory, SpawnHistoryRecord};
 use crate::tmux::TmuxError;
+use crate::viewport::{ViewportId, Viewports};
 use crate::worktree::{WorktreeError, WorktreeManager};
 
 /// Capacity of the session-events broadcast channel. A subscriber that falls
@@ -166,6 +168,14 @@ struct Inner {
     report_ttl: Duration,
     sessions: Mutex<HashMap<Uuid, SessionRecord>>,
     events: broadcast::Sender<CatalogEvent>,
+    /// Sizes reported by the clients attached to each session, and what tmux
+    /// was last told. See [`crate::viewport`] for why the window is not simply
+    /// set to whatever arrived most recently.
+    viewports: Mutex<Viewports>,
+    /// Hands out [`ViewportId`]s. Monotonic for the daemon's lifetime, so a
+    /// client that reconnects never collides with the registration its
+    /// previous socket has not finished releasing.
+    next_viewport: AtomicU64,
 }
 
 impl SessionManager {
@@ -206,6 +216,8 @@ impl SessionManager {
                 report_ttl: crate::activity::REPORT_TTL,
                 sessions: Mutex::new(HashMap::new()),
                 events,
+                viewports: Mutex::new(Viewports::new()),
+                next_viewport: AtomicU64::new(0),
             }),
         }
     }
@@ -770,6 +782,52 @@ impl SessionManager {
             .map_err(SessionError::Tmux)
     }
 
+    /// Register a client that is about to start reporting its display size,
+    /// and hand back the handle it reports under.
+    ///
+    /// Cheap and infallible: the session it will report against is not
+    /// consulted until the first [`Self::set_viewport`].
+    pub fn attach_viewport(&self) -> ViewportId {
+        self.inner.next_viewport.fetch_add(1, Ordering::Relaxed)
+    }
+
+    /// A client reported the size it can display.
+    ///
+    /// The shared tmux window is resized only when the size arbitrated across
+    /// every attached client actually changes — see [`crate::viewport`]. Two
+    /// clients of different sizes used to resize the window past each other on
+    /// every report, which leaves a full-screen agent repainting into rows it
+    /// never clears and looking, to the operator, like a pane that has stopped
+    /// accepting input.
+    pub async fn set_viewport(
+        &self,
+        id: Uuid,
+        viewport: ViewportId,
+        cols: u16,
+        rows: u16,
+    ) -> Result<(), SessionError> {
+        let target = self
+            .inner
+            .viewports
+            .lock()
+            .await
+            .set(id, viewport, cols, rows);
+        match target {
+            Some((cols, rows)) => self.resize(id, cols, rows).await,
+            None => Ok(()),
+        }
+    }
+
+    /// Drop a detached client's claim on the window size, resizing to what the
+    /// clients still attached can display. Errors are the caller's to ignore:
+    /// a socket closing because its session died has nothing left to resize.
+    pub async fn release_viewport(&self, id: Uuid, viewport: ViewportId) {
+        let target = self.inner.viewports.lock().await.release(id, viewport);
+        if let Some((cols, rows)) = target {
+            let _ = self.resize(id, cols, rows).await;
+        }
+    }
+
     /// Rename a session (#125): set `metadata.name`, or clear it when the
     /// requested name is blank so the session falls back to its command.
     ///

crates/maestro-daemon/src/viewport.rs

@@ -0,0 +1,186 @@
+//! What size the shared tmux window should be, given every client watching it.
+//!
+//! A tmux window has one size, but a session can have several clients attached
+//! at once — two browser panes, a browser and the TUI. Each reports the size
+//! *it* can display, and applying whichever arrived last makes the window
+//! flip-flop. Every flip forces a full-screen application (Claude Code, vim) to
+//! repaint at a new height, and the rows it drew at the old height are never
+//! cleared: the operator ends up looking at a stale input box, types into a
+//! box that is not where the screen says it is, and concludes the pane is
+//! stuck.
+//!
+//! So the window is sized to the smallest attached client on each axis — the
+//! same rule tmux uses for its own multiple clients, and the only size every
+//! client can render without truncation. The size last handed to tmux is
+//! remembered, so a report that changes nothing costs no `tmux` fork at all.
+
+use std::collections::HashMap;
+
+use uuid::Uuid;
+
+/// One attached client within a session. Allocated by
+/// [`crate::session::SessionManager`] and opaque to everything else.
+pub type ViewportId = u64;
+
+/// Per-session client sizes, and what tmux was last told.
+#[derive(Debug, Default)]
+pub struct Viewports {
+    clients: HashMap<Uuid, HashMap<ViewportId, (u16, u16)>>,
+    applied: HashMap<Uuid, (u16, u16)>,
+}
+
+impl Viewports {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Record what `viewport` can display. Returns the size tmux must be set
+    /// to, or `None` when the window already has it.
+    pub fn set(
+        &mut self,
+        session: Uuid,
+        viewport: ViewportId,
+        cols: u16,
+        rows: u16,
+    ) -> Option<(u16, u16)> {
+        self.clients
+            .entry(session)
+            .or_default()
+            .insert(viewport, (cols, rows));
+        self.settle(session)
+    }
+
+    /// Drop a client that has detached. Returns the size tmux must be set to
+    /// now that it no longer constrains the window.
+    ///
+    /// The last client leaving settles nothing: the window keeps the size it
+    /// has rather than snapping to some remembered default no one is watching.
+    pub fn release(&mut self, session: Uuid, viewport: ViewportId) -> Option<(u16, u16)> {
+        let clients = self.clients.get_mut(&session)?;
+        clients.remove(&viewport);
+        if clients.is_empty() {
+            self.clients.remove(&session);
+            self.applied.remove(&session);
+            return None;
+        }
+        self.settle(session)
+    }
+
+    /// The smallest size every attached client can render, but only when it
+    /// differs from what tmux was last told.
+    ///
+    /// A zero on either axis is a client that cannot display anything yet — a
+    /// pane still laying out, a hidden tab — and must not drag the shared
+    /// window down with it, so it is held but left out of the arbitration.
+    fn settle(&mut self, session: Uuid) -> Option<(u16, u16)> {
+        let clients = self.clients.get(&session)?;
+        let mut cols = u16::MAX;
+        let mut rows = u16::MAX;
+        for &(c, r) in clients.values() {
+            if c == 0 || r == 0 {
+                continue;
+            }
+            cols = cols.min(c);
+            rows = rows.min(r);
+        }
+        if cols == u16::MAX || rows == u16::MAX {
+            return None;
+        }
+        let target = (cols, rows);
+        if self.applied.get(&session) == Some(&target) {
+            return None;
+        }
+        self.applied.insert(session, target);
+        Some(target)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn the_first_report_settles_the_window() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        assert_eq!(v.set(s, 1, 80, 24), Some((80, 24)));
+    }
+
+    #[test]
+    fn a_report_that_changes_nothing_costs_no_resize() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        v.set(s, 1, 80, 24);
+        assert_eq!(v.set(s, 1, 80, 24), None);
+        assert_eq!(v.set(s, 1, 80, 24), None);
+    }
+
+    /// The bug this module exists for: two clients of different sizes used to
+    /// resize the window past each other on every report.
+    #[test]
+    fn two_clients_settle_on_the_smaller_instead_of_fighting() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        assert_eq!(v.set(s, 1, 53, 46), Some((53, 46)));
+        assert_eq!(v.set(s, 2, 53, 20), Some((53, 20)));
+        // Whatever order they re-report in, the answer stays the smaller one.
+        assert_eq!(v.set(s, 1, 53, 46), None);
+        assert_eq!(v.set(s, 2, 53, 20), None);
+        assert_eq!(v.set(s, 1, 53, 46), None);
+    }
+
+    #[test]
+    fn each_axis_is_arbitrated_on_its_own() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        v.set(s, 1, 200, 20);
+        assert_eq!(v.set(s, 2, 53, 46), Some((53, 20)));
+    }
+
+    #[test]
+    fn a_zero_sized_client_does_not_shrink_the_window() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        assert_eq!(v.set(s, 1, 80, 24), Some((80, 24)));
+        assert_eq!(v.set(s, 2, 0, 0), None);
+        assert_eq!(v.set(s, 2, 0, 30), None);
+    }
+
+    #[test]
+    fn releasing_the_small_client_gives_the_window_back() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        v.set(s, 1, 80, 46);
+        v.set(s, 2, 80, 20);
+        assert_eq!(v.release(s, 2), Some((80, 46)));
+    }
+
+    #[test]
+    fn releasing_the_last_client_settles_nothing() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        v.set(s, 1, 80, 24);
+        assert_eq!(v.release(s, 1), None);
+        // ...and the session is forgotten, so a fresh attach settles again.
+        assert_eq!(v.set(s, 2, 80, 24), Some((80, 24)));
+    }
+
+    #[test]
+    fn releasing_an_unknown_viewport_is_harmless() {
+        let mut v = Viewports::new();
+        let s = Uuid::new_v4();
+        assert_eq!(v.release(s, 7), None);
+        v.set(s, 1, 80, 24);
+        assert_eq!(v.release(s, 7), None);
+    }
+
+    #[test]
+    fn sessions_do_not_arbitrate_against_each_other() {
+        let mut v = Viewports::new();
+        let a = Uuid::new_v4();
+        let b = Uuid::new_v4();
+        assert_eq!(v.set(a, 1, 80, 24), Some((80, 24)));
+        assert_eq!(v.set(b, 2, 53, 20), Some((53, 20)));
+        assert_eq!(v.set(a, 1, 80, 24), None);
+    }
+}

crates/maestro-daemon/tests/session_decisions.rs

@@ -555,3 +555,63 @@ async fn spawn_overrides_client_supplied_maestro_variables() {
         Some(&"http://127.0.0.1:7070".to_string())
     );
 }
+
+/// Two clients attached to one session used to resize the shared window past
+/// each other on every report they made. Every flip repaints a full-screen
+/// agent at a new height and orphans the rows it drew at the old one, which
+/// reads to the operator as a pane that has stopped taking input.
+#[tokio::test]
+async fn clients_of_different_sizes_do_not_resize_the_window_past_each_other() {
+    let fx = Fx::new();
+    let s = fx.manager.create(fx.request("bash")).await.expect("create");
+    let web = fx.manager.attach_viewport();
+    let tui = fx.manager.attach_viewport();
+
+    fx.manager.set_viewport(s.id, web, 53, 46).await.unwrap();
+    fx.manager.set_viewport(s.id, tui, 53, 20).await.unwrap();
+    // Both keep reporting, as a browser's ResizeObserver and the TUI's own
+    // redraw loop do. Neither report changes the arbitrated size.
+    for _ in 0..5 {
+        fx.manager.set_viewport(s.id, web, 53, 46).await.unwrap();
+        fx.manager.set_viewport(s.id, tui, 53, 20).await.unwrap();
+    }
+
+    let resizes: Vec<_> = fx
+        .fake
+        .calls()
+        .into_iter()
+        .filter_map(|c| match c {
+            Call::ResizeWindow { cols, rows, .. } => Some((cols, rows)),
+            _ => None,
+        })
+        .collect();
+    assert_eq!(
+        resizes,
+        vec![(53, 46), (53, 20)],
+        "the window was resized more than the arbitrated size actually changed"
+    );
+}
+
+/// The smaller client leaving hands the window back to the one still attached.
+#[tokio::test]
+async fn releasing_a_client_resizes_to_what_is_left() {
+    let fx = Fx::new();
+    let s = fx.manager.create(fx.request("bash")).await.expect("create");
+    let web = fx.manager.attach_viewport();
+    let tui = fx.manager.attach_viewport();
+    fx.manager.set_viewport(s.id, web, 80, 46).await.unwrap();
+    fx.manager.set_viewport(s.id, tui, 80, 20).await.unwrap();
+
+    fx.manager.release_viewport(s.id, tui).await;
+
+    let resizes: Vec<_> = fx
+        .fake
+        .calls()
+        .into_iter()
+        .filter_map(|c| match c {
+            Call::ResizeWindow { cols, rows, .. } => Some((cols, rows)),
+            _ => None,
+        })
+        .collect();
+    assert_eq!(resizes, vec![(80, 46), (80, 20), (80, 46)]);
+}

docs/COMMAND-BAR.md

@@ -158,12 +158,12 @@ searchable — the query line keeps working, now over those actions.
   ambiguous.
 - Escape, or backspace at an empty query, returns to the result list **with the
   previous query intact**. Drilling in and backing out is free.
-- Each action raises the flow it already has: kill goes through the existing
-  confirm-and-blockers dialog (`docs/WORKTREES.md`), rename through the
-  existing prompt pre-filled with the session's own name
-  (`docs/SIDEBAR.md`), spawn similar through the spawn form seeded from the
-  session's directory and command. The bar picks the action; it never
-  reimplements one.
+- Each action raises the flow it already has: kill through the confirmation
+  both clients ask for (`docs/SIDEBAR.md`) and the blockers dialog behind it
+  (`docs/WORKTREES.md`), rename through the existing prompt pre-filled with the
+  session's own name (`docs/SIDEBAR.md`), spawn similar through the spawn form
+  seeded from the session's directory and command. The bar picks the action; it
+  never reimplements one.
 
 No actions beyond those three, and no action across more than one session.
 

docs/PREVIEW.md

@@ -47,6 +47,7 @@ Web client (`--preview` and friends in `web/src/styles.css`):
 | 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 state the row already had — but the row of the session already showing in the pane keeps its accent fill, since previewing it changes nothing on screen. |
+| The sidebar row of the session the operator picked | Keeps its accent fill for the whole preview. A preview never moves the accent; only opening another session does. |
 | 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 — see the tier ladder in

docs/SIDEBAR.md

@@ -316,7 +316,7 @@ Everything else is the same key on both clients:
 | `Tab`   | hand the keyboard to the pane               |
 | `c`     | collapse or expand the highlighted folder   |
 | `r`     | rename the highlighted session              |
-| `x`     | kill the highlighted session                |
+| `x`     | kill the highlighted session (confirms)     |
 | `n`     | open the spawn form                         |
 | `N`     | spawn with every default resolved           |
 | `?`     | show the shortcut overlay                   |
@@ -324,3 +324,18 @@ Everything else is the same key on both clients:
 The TUI binds these through its keymap, so a user can rebind any of them; the
 web client's are fixed. A binding added to one client belongs in this table and
 in both help overlays.
+
+## Killing a session
+
+**Every kill confirms first, in both clients** (#160). A kill is destructive
+and unattended agents live in these sessions, so neither client sends
+`DELETE /api/sessions/:id` off a single press. The TUI raises
+`OverlayKind::KillConfirm` (`[y]`/`[n]`); the web raises the same dialog its
+`✕` button and the command bar's action page both use. Cancel holds the focus
+in the web's dialog, so nothing kills on a stray Enter.
+
+The confirmation names what the card last saw in the way, when anything was —
+the daemon will refuse an unforced kill over such a worktree, and saying so
+before the attempt is cheaper than a refusal. What comes back from that refusal
+is a second, separate prompt offering `force=true`; `docs/WORKTREES.md` owns
+what a forced kill leaves behind.

web/src/barActions.test.ts

@@ -65,7 +65,7 @@ async function flush(): Promise<void> {
 }
 
 describe("kill from the action page", () => {
-  it("goes through the daemon, without a first confirmation", async () => {
+  it("goes through the same confirmation the sidebar raises (#160)", async () => {
     const calls: string[] = [];
     window.fetch = ((url: string, init?: RequestInit) => {
       calls.push(`${init?.method ?? "GET"} ${url}`);
@@ -75,6 +75,12 @@ describe("kill from the action page", () => {
     mount(s);
     raise(KILL_SESSION_EVENT, s);
     await flush();
+    expect(document.querySelector(".kill-dialog")?.getAttribute("aria-label")).toBe(
+      "Kill amber-falcon",
+    );
+    expect(calls.filter((c) => c.startsWith("DELETE"))).toHaveLength(0);
+    document.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
+    await flush();
     expect(calls).toContain(`DELETE /api/sessions/${s.id}`);
     expect(document.querySelector(".kill-dialog")).toBeNull();
   });
@@ -101,6 +107,8 @@ describe("kill from the action page", () => {
     mount(s);
     raise(KILL_SESSION_EVENT, s);
     await flush();
+    document.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
+    await flush();
     const dialog = document.querySelector(".kill-dialog");
     expect(dialog?.getAttribute("aria-label")).toBe("Kill amber-falcon");
     expect(dialog?.textContent).toContain("1 untracked file");

web/src/catalog.test.ts

@@ -98,7 +98,7 @@ describe("blocked-work indicator (#83)", () => {
     expect(rowFor(el, unprobed.id)?.querySelector(".leaf-blocked")).toBeNull();
   });
 
-  it("kills straight away, without a first confirmation", async () => {
+  it("confirms before an unguarded kill (#160)", async () => {
     const calls: string[] = [];
     window.fetch = ((url: string, init?: RequestInit) => {
       calls.push(`${init?.method ?? "GET"} ${url}`);
@@ -108,10 +108,45 @@ describe("blocked-work indicator (#83)", () => {
     const el = renderSidebar(storeWith([plain])).el;
     rowFor(el, plain.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
     await flush();
+    const dialog = document.querySelector(".kill-dialog");
+    expect(dialog?.getAttribute("aria-label")).toBe("Kill claude");
+    expect(calls.filter((c) => c.startsWith("DELETE"))).toHaveLength(0);
+    dialog?.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
+    await flush();
     expect(calls).toContain(`DELETE /api/sessions/${plain.id}`);
     expect(document.querySelector(".kill-dialog")).toBeNull();
   });
 
+  it("kills nothing when the confirmation is cancelled (#160)", async () => {
+    const calls: string[] = [];
+    window.fetch = ((url: string, init?: RequestInit) => {
+      calls.push(`${init?.method ?? "GET"} ${url}`);
+      return Promise.resolve(new Response(null, { status: 204 }));
+    }) as typeof fetch;
+    const plain = session({ id: "aaaaaaaa-0000-0000-0000-000000000007" });
+    const el = renderSidebar(storeWith([plain])).el;
+    rowFor(el, plain.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
+    await flush();
+    document.querySelector<HTMLButtonElement>(".kill-dialog-cancel")?.click();
+    await flush();
+    expect(document.querySelector(".kill-dialog")).toBeNull();
+    expect(calls.filter((c) => c.startsWith("DELETE"))).toHaveLength(0);
+  });
+
+  it("names the blockers in the confirmation, before the daemon refuses (#160)", async () => {
+    window.fetch = (() => Promise.reject(new Error("never called"))) as typeof fetch;
+    const blocked = session({
+      id: "aaaaaaaa-0000-0000-0000-000000000008",
+      blocked_work: { untracked_files: 1 },
+    });
+    const el = renderSidebar(storeWith([blocked])).el;
+    rowFor(el, blocked.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
+    await flush();
+    const dialog = document.querySelector(".kill-dialog");
+    expect(dialog?.textContent).toContain("1 untracked file");
+    expect(dialog?.textContent).toContain("refused unless it is forced");
+  });
+
   it("offers the override when the daemon refuses a guarded kill", async () => {
     const calls: string[] = [];
     window.fetch = ((url: string, init?: RequestInit) => {
@@ -138,6 +173,8 @@ describe("blocked-work indicator (#83)", () => {
     const el = renderSidebar(storeWith([blocked])).el;
     rowFor(el, blocked.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
     await flush();
+    document.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
+    await flush();
     const dialog = document.querySelector(".kill-dialog");
     expect(dialog?.textContent).toContain("1 untracked file");
     dialog?.querySelector<HTMLButtonElement>(".kill-dialog-force")?.click();
@@ -166,6 +203,8 @@ describe("blocked-work indicator (#83)", () => {
     const el = renderSidebar(storeWith([blocked])).el;
     rowFor(el, blocked.id)?.querySelector<HTMLButtonElement>(".leaf-kill")?.click();
     await flush();
+    document.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
+    await flush();
     document.querySelector<HTMLButtonElement>(".kill-dialog-cancel")?.click();
     expect(document.querySelector(".kill-dialog")).toBeNull();
     expect(calls.filter((c) => c.includes("force=true"))).toHaveLength(0);

web/src/catalog.ts

@@ -1,6 +1,6 @@
 import { escapeHtml } from "./html.js";
 import { ApiRequestError, getDaemonInfo, killSession, renameSession } from "./api.js";
-import { openForceKillDialog } from "./killDialog.js";
+import { openForceKillDialog, openKillConfirmDialog } from "./killDialog.js";
 import { openContextMenu } from "./contextMenu.js";
 import { toggleHelp } from "./help.js";
 import { CommandSet, defineCommands } from "./commands.js";
@@ -230,7 +230,7 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
   killBtn.addEventListener("click", (ev) => {
     ev.preventDefault();
     ev.stopPropagation();
-    void requestKill(cur, sessionName(cur));
+    requestKill(cur, sessionName(cur));
   });
   row.addEventListener("click", () => {
     document.dispatchEvent(new CustomEvent(SESSION_SELECT_EVENT, { detail: cur.id }));
@@ -248,7 +248,7 @@ function renderNode(node: TreeNode, depth: number): HTMLElement {
       {
         label: "Kill session",
         danger: true,
-        onSelect: () => void requestKill(cur, sessionName(cur)),
+        onSelect: () => requestKill(cur, sessionName(cur)),
       },
     ]);
   });
@@ -293,26 +293,33 @@ function treeSignature(node: TreeNode): string {
 }
 
 /**
- * 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
- * that refusal is worth a prompt, and it needs one `confirm()` cannot give —
- * a forced kill. Anything else surfaces as an alert.
+ * Kill behind a confirmation (#160): a kill is destructive and unattended
+ * agents live in these sessions, so the web asks first, the way the TUI always
+ * has. The daemon decides the rest — it refuses a kill over a worktree holding
+ * unsaved work, and that refusal needs a prompt the confirmation cannot give,
+ * a forced kill. Anything else surfaces in the dialog that asked.
  */
-async function requestKill(s: Session, name: string): Promise<void> {
-  try {
-    await killSession(s.id);
-  } catch (e) {
-    if (e instanceof ApiRequestError && e.code === "kill_guarded") {
-      openForceKillDialog({
-        name,
-        blockers: e.unsavedWork ?? sessionBlockers(s),
-        reason: e.detail,
-        onForce: () => killSession(s.id, true),
-      });
-      return;
-    }
-    alert(`Failed to kill: ${(e as Error).message}`);
-  }
+function requestKill(s: Session, name: string): void {
+  openKillConfirmDialog({
+    name,
+    blockers: sessionBlockers(s),
+    onKill: async () => {
+      try {
+        await killSession(s.id);
+      } catch (e) {
+        if (e instanceof ApiRequestError && e.code === "kill_guarded") {
+          openForceKillDialog({
+            name,
+            blockers: e.unsavedWork ?? sessionBlockers(s),
+            reason: e.detail,
+            onForce: () => killSession(s.id, true),
+          });
+          return;
+        }
+        throw e;
+      }
+    },
+  });
 }
 
 /**
@@ -719,7 +726,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
       },
       "list.kill": () => {
         const hit = highlightedSession();
-        if (hit) void requestKill(hit.session, sessionName(hit.session));
+        if (hit) requestKill(hit.session, sessionName(hit.session));
       },
       "list.focusPane": () => document.dispatchEvent(new CustomEvent(FOCUS_PANE_EVENT)),
     }),
@@ -782,7 +789,7 @@ export function renderSidebar(store: CatalogStore, opts: SidebarOptions = {}): S
   // than by row.
   const killHandler = (ev: Event) => {
     const s = (ev as CustomEvent<Session>).detail;
-    void requestKill(s, sessionName(s));
+    requestKill(s, sessionName(s));
   };
   const renameHandler = (ev: Event) => {
     const s = (ev as CustomEvent<Session>).detail;

web/src/fastForward.test.ts

@@ -34,12 +34,14 @@ describe("resolveFastForward (#67)", () => {
     const res = resolveFastForward(projects, presets, "amber-falcon");
     expect(res.project?.path).toBe("/repos/fresh");
     expect(res.command).toBe("aider");
-    expect(res.name).toBe("amber-falcon");
+    expect(res.handle).toBe("amber-falcon");
 
     const req = buildFastForwardRequest(res)!;
     expect(req.cwd).toBe("/repos/fresh");
     expect(req.command).toBe("aider");
-    expect(req.metadata).toEqual({ name: "amber-falcon" });
+    // No name (#131): the daemon names the session after its first prompt,
+    // and a name here would collide with the branch handle.
+    expect(req.metadata).toBeUndefined();
     expect(req.worktree).toEqual({
       base_repo: "/repos/fresh",
       branch: "amber-falcon",
@@ -88,9 +90,9 @@ describe("resolveFastForward (#67)", () => {
     expect(buildFastForwardRequest(res)).toBeNull();
   });
 
-  it("downgrades to a draft when the generated name is missing", () => {
+  it("downgrades to a draft when the generated handle is missing", () => {
     const res = resolveFastForward([project({ last_command: "claude" })], presets);
-    expect(res.name).toBeUndefined();
+    expect(res.handle).toBeUndefined();
     expect(buildFastForwardRequest(res)).toBeNull();
   });
 
@@ -108,6 +110,17 @@ describe("resolveFastForward (#67)", () => {
     });
   });
 
+  it("seeds the handle as the branch and leaves the name field empty (#131)", () => {
+    const res = resolveFastForward(
+      [project({ path: "/repos/p", base_repo: "/repos/p", last_command: "aider" })],
+      presets,
+      "amber-falcon",
+    );
+    const seed = fastForwardSeed(res);
+    expect(seed.name).toBe("");
+    expect(seed.worktreeBranch).toBe("amber-falcon");
+  });
+
   it("leaves the worktree default alone when not even a project resolved", () => {
     // Not `false`: the form defaults the toggle on and a false would stick,
     // so the fallback draft would disagree with a normally-opened draft and

web/src/fastForward.ts

@@ -10,19 +10,21 @@ import { sortProjects } from "./projectList.js";
 export interface FastForwardResolution {
   project?: Project;
   command?: string;
-  name?: string;
+  /** A generated handle for the worktree branch (#131). Not a session name:
+   *  the fast path names no session. */
+  handle?: string;
 }
 
 /** The defaults: the currently focused session's project when it's still a
  *  known project, else the most recent one (fresh-first, same ordering the
  *  picker shows) — so `N` lands where the operator currently is, matching
  *  what plain `n` seeds from `spawnSimilarProjectSeed`. Its last command
- *  falls back to the first non-custom preset, and the name is freshly
- *  generated when the daemon supplied one. */
+ *  falls back to the first non-custom preset, and the branch handle is
+ *  freshly generated when the daemon supplied one. */
 export function resolveFastForward(
   projects: Project[],
   presets: SpawnPreset[],
-  name?: string,
+  handle?: string,
   focusedCwd?: string,
 ): FastForwardResolution {
   const project =
@@ -30,41 +32,45 @@ export function resolveFastForward(
   const lastCommand = project?.last_command?.trim();
   const command =
     lastCommand || presets.find((p) => p.command !== "")?.command || undefined;
-  return { project, command, name: name || undefined };
+  return { project, command, handle: handle || undefined };
 }
 
 /** The immediate spawn request — worktree on, new branch named after the
- *  generated session name — or `null` when any default is missing. */
+ *  generated handle — or `null` when any default is missing.
+ *
+ *  The request carries no name (#131): the daemon assigns a provisional one
+ *  and replaces it once the session sees its first prompt. A name here would
+ *  also collide with the branch handle's own session. */
 export function buildFastForwardRequest(
   res: FastForwardResolution,
 ): CreateSessionRequest | null {
-  const { project, command, name } = res;
-  if (!project || !command?.trim() || !name) return null;
+  const { project, command, handle } = res;
+  if (!project || !command?.trim() || !handle) return null;
   return {
     cwd: project.path,
     command,
-    metadata: { name },
     worktree: {
       base_repo: project.base_repo ?? project.path,
-      branch: name,
+      branch: handle,
       create_branch: true,
     },
   };
 }
 
 /** Seed for the fallback spawn form: whatever did resolve goes into the
- *  form; the rest stays with its own defaults. */
+ *  form; the rest stays with its own defaults. The name field stays empty
+ *  (#131) — the handle seeds the branch, not the session name. */
 export function fastForwardSeed(res: FastForwardResolution) {
   return {
     cwd: res.project?.path ?? "",
     command: res.command ?? "",
-    name: res.name ?? "",
+    name: "",
     // Left undefined rather than false when nothing resolved: the form
     // defaults the toggle on, and `false` would stick, so the fallback form
     // would disagree with both a normally-opened form and the TUI's fast path
     // (#67 review).
     worktreeEnabled: res.project ? true : undefined,
     worktreeBranch:
-      res.project && res.name ? res.name : undefined,
+      res.project && res.handle ? res.handle : undefined,
   };
 }

web/src/killDialog.test.ts

@@ -0,0 +1,33 @@
+// @vitest-environment happy-dom
+import { beforeEach, describe, expect, it } from "vitest";
+import {
+  closeForceKillDialog,
+  openForceKillDialog,
+  openKillConfirmDialog,
+} from "./killDialog.js";
+
+describe("kill dialogs", () => {
+  beforeEach(() => {
+    closeForceKillDialog();
+    document.body.innerHTML = "";
+  });
+
+  it("focuses the kill button, so Enter confirms", () => {
+    const el = openKillConfirmDialog({
+      name: "alpha",
+      blockers: null,
+      onKill: () => Promise.resolve(),
+    });
+    expect(document.activeElement).toBe(el.querySelector(".kill-dialog-kill"));
+  });
+
+  it("focuses the force button too", () => {
+    const el = openForceKillDialog({
+      name: "alpha",
+      blockers: null,
+      reason: "worktree is dirty.",
+      onForce: () => Promise.resolve(),
+    });
+    expect(document.activeElement).toBe(el.querySelector(".kill-dialog-force"));
+  });
+});

web/src/killDialog.ts

@@ -1,14 +1,44 @@
 /**
- * Forced-kill prompt (#81).
+ * The two kill prompts (#81, #160).
  *
- * The daemon refuses to kill a session whose worktree still holds uncommitted
- * or unpushed work. `confirm()` can only ask the same question twice, so the
- * refusal gets its own dialog: it names what is in the way and offers the
- * override the daemon's `force=true` already implements. A kill the daemon
- * accepts never reaches here — there is nothing to warn about.
+ * A kill is destructive and unattended agents live in these sessions, so both
+ * clients ask before one goes through — the TUI's `KillConfirm`, and
+ * `openKillConfirmDialog` here (#160). Where the session's worktree still
+ * holds uncommitted or unpushed work, the confirmation says so up front, the
+ * same way the TUI's does.
+ *
+ * The daemon decides the rest: it refuses a kill over such a worktree, and
+ * that refusal needs an answer the confirmation cannot give — a forced kill.
+ * `openForceKillDialog` is that second prompt. A kill the daemon accepts never
+ * reaches it.
  */
 import { formatInTheWay, type InTheWay } from "./types.js";
 
+/** What both prompts need: a target to name and a button that acts on it. */
+interface KillDialogSpec {
+  /** Session name, as the sidebar shows it. */
+  name: string;
+  /** Sentence under the title. */
+  body: string;
+  /** Label on the acting button. */
+  confirmLabel: string;
+  /** Extra class on the acting button, so tests and styles can find it. */
+  confirmClass: string;
+  /** Run it. A rejection is rendered in the dialog, which stays open so the
+   *  press can be retried. */
+  onConfirm: () => Promise<void>;
+}
+
+export interface KillConfirmPrompt {
+  name: string;
+  /** What the card last saw in the way, when anything was. Shown before the
+   *  attempt, so "this will be refused" is not a surprise. */
+  blockers: InTheWay | null;
+  /** Run the plain kill. Opening a further dialog from here is allowed: the
+   *  confirmation only closes itself if it is still the one on screen. */
+  onKill: () => Promise<void>;
+}
+
 export interface ForceKillPrompt {
   /** Session name, as the sidebar shows it. */
   name: string;
@@ -30,9 +60,9 @@ export function closeForceKillDialog(): void {
   open = null;
 }
 
-/** Mount the prompt. Opening while one is up replaces it, so a second refusal
- *  can never stack two dialogs. */
-export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
+/** Mount one of the prompts. Opening while one is up replaces it, so the
+ *  confirmation and a refusal that follows it can never stack. */
+function mount(p: KillDialogSpec): HTMLElement {
   closeForceKillDialog();
 
   const el = document.createElement("div");
@@ -50,9 +80,7 @@ export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
 
   const body = document.createElement("p");
   body.className = "kill-dialog-body";
-  body.textContent = p.blockers
-    ? `Its worktree still has ${formatInTheWay(p.blockers)}. Forcing the kill removes the session and leaves the worktree on disk.`
-    : `${p.reason} Forcing the kill removes the session and leaves the worktree on disk.`;
+  body.textContent = p.body;
 
   const error = document.createElement("p");
   error.className = "kill-dialog-error";
@@ -65,22 +93,27 @@ export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
   cancel.className = "btn btn-ghost kill-dialog-cancel";
   cancel.textContent = "Cancel";
   cancel.addEventListener("click", closeForceKillDialog);
-  const force = document.createElement("button");
-  force.type = "button";
-  force.className = "btn btn-danger kill-dialog-force";
-  force.textContent = "Force kill";
-  force.addEventListener("click", () => {
-    force.disabled = true;
+  const confirm = document.createElement("button");
+  confirm.type = "button";
+  confirm.className = `btn btn-danger ${p.confirmClass}`;
+  confirm.textContent = p.confirmLabel;
+  confirm.addEventListener("click", () => {
+    confirm.disabled = true;
     void p
-      .onForce()
-      .then(closeForceKillDialog)
+      .onConfirm()
+      .then(() => {
+        // A handler that opened the refusal prompt has already replaced this
+        // dialog; closing here would take that one down with it.
+        if (open?.el === el) closeForceKillDialog();
+      })
       .catch((e: unknown) => {
-        force.disabled = false;
+        if (open?.el !== el) return;
+        confirm.disabled = false;
         error.hidden = false;
         error.textContent = `Failed to kill: ${(e as Error).message}`;
       });
   });
-  actions.append(cancel, force);
+  actions.append(cancel, confirm);
 
   panel.append(title, body, error, actions);
 
@@ -99,6 +132,34 @@ export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
   };
   window.addEventListener("keydown", onKeydown, true);
   open = { el, onKeydown };
-  cancel.focus();
+  // The acting button takes the focus in both prompts: the operator already
+  // asked for the kill, so Enter confirms it. Escape and the scrim cancel.
+  confirm.focus();
   return el;
 }
+
+/** Ask before a kill the daemon has not seen yet (#160). */
+export function openKillConfirmDialog(p: KillConfirmPrompt): HTMLElement {
+  return mount({
+    name: p.name,
+    body: p.blockers
+      ? `Its worktree still has ${formatInTheWay(p.blockers)}. The kill will be refused unless it is forced.`
+      : "The session and everything running in it go away. Its worktree stays on disk.",
+    confirmLabel: "Kill",
+    confirmClass: "kill-dialog-kill",
+    onConfirm: p.onKill,
+  });
+}
+
+/** Offer the override after the daemon refuses a guarded kill (#81). */
+export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
+  return mount({
+    name: p.name,
+    body: p.blockers
+      ? `Its worktree still has ${formatInTheWay(p.blockers)}. Forcing the kill removes the session and leaves the worktree on disk.`
+      : `${p.reason} Forcing the kill removes the session and leaves the worktree on disk.`,
+    confirmLabel: "Force kill",
+    confirmClass: "kill-dialog-force",
+    onConfirm: p.onForce,
+  });
+}

web/src/main.ts

@@ -356,14 +356,14 @@ async function spawnPresets(): Promise<SpawnPreset[]> {
 }
 
 async function requestFastForward(): Promise<void> {
-  const [discovered, name] = await Promise.all([
+  const [discovered, handle] = await Promise.all([
     fetchProjects().catch(() => [] as Project[]),
     fetchNames(1)
       .then((batch) => batch.names[0])
       .catch(() => undefined),
   ]);
   const presets = await spawnPresets();
-  const resolved = resolveFastForward(discovered, presets, name, focusedProjectCwd());
+  const resolved = resolveFastForward(discovered, presets, handle, focusedProjectCwd());
   const req = buildFastForwardRequest(resolved);
   if (req) {
     try {
@@ -390,7 +390,7 @@ async function requestFastForward(): Promise<void> {
 // one outside any repo spawns without a worktree, since there is no repo to cut
 // a branch from. Anything still unresolved opens the pre-filled form.
 async function requestSpawnInDirectory(path: string): Promise<void> {
-  const [discovered, name] = await Promise.all([
+  const [discovered, handle] = await Promise.all([
     fetchProjects().catch(() => [] as Project[]),
     fetchNames(1)
       .then((batch) => batch.names[0])
@@ -399,7 +399,7 @@ async function requestSpawnInDirectory(path: string): Promise<void> {
   const presets = await spawnPresets();
   const known = discovered.find((p) => p.path === path);
   const project: Project = known ?? { path, name: path.split("/").filter(Boolean).pop() ?? path };
-  const resolved = resolveFastForward([project], presets, name, path);
+  const resolved = resolveFastForward([project], presets, handle, path);
   const req = buildFastForwardRequest(resolved);
   if (req) {
     const inRepo =

web/src/multiview.ts

@@ -215,6 +215,20 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
     return fl?.sessionId ?? null;
   }
 
+  /** The session the operator actually picked — what `focusedLeafSession()`
+   *  would return with the preview undone. A preview moves the active tab and
+   *  its focus, but it is a view: the accent stays on the row the operator
+   *  chose until they choose another (docs/PREVIEW.md). */
+  function realFocusedSession(): string | null {
+    const p = preview;
+    if (!p) return focusedLeafSession();
+    const tab = layout.tabs.find((t) => t.id === p.prevActiveTabId) ?? activeTab(layout);
+    const leafId =
+      p.prevFocus && p.prevFocus.tabId === tab.id ? p.prevFocus.leafId : tab.focusedLeafId;
+    const fl = leafId ? findLeaf(tab.root, leafId) : null;
+    return fl?.sessionId ?? null;
+  }
+
   /** Update focus styling + pool focus + sidebar highlights without rebuilding
    *  the DOM (cheap path for click-to-focus). */
   function syncFocus(): void {
@@ -233,7 +247,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
     if (!preview) pool.setFocus(focusedLeafSession());
     sidebar.setHighlights({
       open: realOpenSessions(),
-      focused: focusedLeafSession(),
+      focused: realFocusedSession(),
     });
     // 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.
@@ -608,7 +622,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
       { focus: !preview && !quietRender },
     );
     if (!preview) pool.setFocus(focused.sessionId ?? null);
-    sidebar.setHighlights({ open: realOpenSessions(), focused: focused.sessionId ?? null });
+    sidebar.setHighlights({ open: realOpenSessions(), focused: realFocusedSession() });
     sidebar.setPreview(preview?.sessionId ?? null);
   }
 
@@ -817,7 +831,7 @@ export function createMultiView(opts: MultiViewOptions): MultiView {
     openSessions: realOpenSessions,
     beginSessionDrag,
     render,
-    focusedSessionId: focusedLeafSession,
+    focusedSessionId: realFocusedSession,
     previewSession,
     previewedSessionId: () => preview?.sessionId ?? null,
   };

web/src/preview.test.ts

@@ -47,12 +47,20 @@ function fakePool(): Spy {
 
 /** Last value the controller pushed to `SidebarHandle.setPreview`. */
 const previewRow: { id: string | null } = { id: null };
+/** Last highlights the controller pushed to `SidebarHandle.setHighlights`. */
+const rowHighlights: { open: Set<string>; focused: string | null } = {
+  open: new Set(),
+  focused: null,
+};
 
 function fakeSidebar(): SidebarHandle {
   return {
     el: document.createElement("aside"),
     setActive() {},
-    setHighlights() {},
+    setHighlights(h) {
+      rowHighlights.open = h.open;
+      rowHighlights.focused = h.focused;
+    },
     setPreview(id: string | null) {
       previewRow.id = id;
     },
@@ -95,6 +103,8 @@ describe("sidebar preview", () => {
     stubFetch();
     document.body.replaceChildren();
     previewRow.id = null;
+    rowHighlights.open = new Set();
+    rowHighlights.focused = null;
   });
 
   afterEach(() => {
@@ -134,6 +144,28 @@ describe("sidebar preview", () => {
     expect(mv.el.querySelectorAll(".mv-pane.is-preview")).toHaveLength(0);
   });
 
+  it("leaves the accent on the session the pane actually holds", () => {
+    const layout = twoTabs();
+    const spy = fakePool();
+    const mv = makeMv(layout, spy.pool);
+    expect(rowHighlights.focused).toBe("s2");
+
+    // Walking past other rows never moves the accent off what the operator
+    // picked: only a real open does (docs/PREVIEW.md).
+    mv.previewSession("s1");
+    expect(rowHighlights.focused).toBe("s2");
+    expect(mv.focusedSessionId()).toBe("s2");
+
+    mv.previewSession("s9");
+    expect(rowHighlights.focused).toBe("s2");
+
+    mv.previewSession(null);
+    expect(rowHighlights.focused).toBe("s2");
+
+    mv.openSession("s1");
+    expect(rowHighlights.focused).toBe("s1");
+  });
+
   it("shows a session no pane holds in a throwaway tab that leaves no trace", () => {
     const layout = twoTabs();
     const before = serializeLayout(layout);

web/src/sidebarNav.test.ts

@@ -143,7 +143,7 @@ describe("sidebar keyboard navigation", () => {
     field!.dispatchEvent(new KeyboardEvent("keydown", { key: "Escape", bubbles: true }));
   });
 
-  it("x kills the highlighted session", async () => {
+  it("x kills the highlighted session, once confirmed (#160)", async () => {
     const { el } = twoFolders();
     const killed: string[] = [];
     window.fetch = ((input: RequestInfo | URL, init?: RequestInit) => {
@@ -153,6 +153,8 @@ describe("sidebar keyboard navigation", () => {
 
     press(tree(el), "j");
     press(tree(el), "x");
+    expect(killed.some((r) => r.startsWith("DELETE"))).toBe(false);
+    document.querySelector<HTMLButtonElement>(".kill-dialog-kill")?.click();
     await Promise.resolve();
     expect(killed.some((r) => r.startsWith("DELETE") && r.includes(A))).toBe(true);
   });