feat: live document title — chat tab shows session name + activity (writing…/tool name/working…), overview shows busy/active counts; 268 tests, gates ≥95%

web/src/ChatView.test.tsx

@@ -1692,3 +1692,29 @@ describe("ChatView ⋯ menu and timestamps", () => {
 		expect(container.querySelectorAll(".ts")).toHaveLength(1);
 	});
 });
+
+describe("document title", () => {
+	it("chat view claims title with session label and activity", async () => {
+		mockFetchJson((url) => {
+			if (url.startsWith("http://srv/api/sessions/s1/events")) return historyEvents();
+			if (url.endsWith("/stats")) return { turns: 0, inputTokens: 0, outputTokens: 0, totalCost: 0, sessionsCount: 0, onlineCount: 0 };
+			return [];
+		});
+		renderChat(makeStore());
+		await waitFor(() => expect(document.title).toContain("worker"));
+		expect(document.title).toContain("lvmh");
+	});
+
+	it("busy + running tool shows the tool name in the title", async () => {
+		mockFetchJson((url) => {
+			if (url.startsWith("http://srv/api/sessions/s1/events")) {
+				seq = 0;
+				return [...historyEvents(), ev("agent_start"), ev("tool_execution_start", { toolCallId: "tc9", toolName: "bash" })];
+			}
+			if (url.endsWith("/stats")) return { turns: 0, inputTokens: 0, outputTokens: 0, totalCost: 0, sessionsCount: 0, onlineCount: 0 };
+			return [];
+		});
+		renderChat(makeStore());
+		await waitFor(() => expect(document.title).toContain("bash"));
+	});
+});

web/src/ChatView.tsx

@@ -8,6 +8,7 @@ import type {
 	SetModelBody,
 } from "./protocol";
 import { EventType, Route } from "./protocol";
+import { useTitle } from "./title";
 import { ApiError, errMessage, fetchJson } from "./api";
 import {
 	deriveChat,
@@ -210,6 +211,22 @@ export default function ChatView({ store, pushToast }: Props) {
 	// session must never look busy (B2)
 	const busy: boolean = chat.busy && session?.online !== false;
 
+	// Live tab title: session name + what the agent is doing right now.
+	const label: string = session?.name ?? session?.repo ?? sessionId;
+	const streaming: boolean = chat.messages.some((m) => m.streaming);
+	const toolNow: string | undefined = [...chat.tools.values()]
+		.filter((t) => t.running)
+		.map((t) => t.name)[0];
+	const titleClaim: string | null =
+		!busy
+			? label
+			: streaming
+				? `${label} · writing…`
+				: toolNow !== undefined
+					? `${label} · ${toolNow}`
+					: `${label} · working…`;
+	useTitle(titleClaim);
+
 	const minSeq: number = useMemo(
 		() => (events.length === 0 ? 0 : Math.min(...events.map((e) => e.seq))),
 		[events],

web/src/SessionsView.test.tsx

@@ -512,3 +512,15 @@ describe("busy indicator on cards", () => {
 		expect(pips).toHaveLength(1);
 	});
 });
+
+describe("sessions title", () => {
+	it("overview shows active/working count in the tab title", () => {
+		renderView({
+			sessions: [
+				session({ id: "a", name: "x", busy: true }),
+				session({ id: "b", name: "y" }),
+			],
+		});
+		expect(document.title).toContain("1 working");
+	});
+});

web/src/SessionsView.tsx

@@ -3,6 +3,7 @@ import { useNavigate } from "react-router-dom";
 import type { SessionListItem, StatsTotals } from "./protocol";
 import { Route } from "./protocol";
 import { fetchJson } from "./api";
+import { useTitle } from "./title";
 import { classNames, formatTokens, relativeTime } from "./store";
 
 interface Props {
@@ -143,6 +144,12 @@ export default function SessionsView({
 	const active = sessions.filter((s) => s.online).sort(byActivity);
 	const archived = sessions.filter((s) => !s.online).sort(byActivity);
 
+	// Tab title on the overview: activity summary (busy sessions first).
+	const busyCount: number = active.filter((s) => s.busy).length;
+	const titleClaim: string | null =
+		active.length === 0 ? null : busyCount > 0 ? `${busyCount} working` : `${active.length} active`;
+	useTitle(titleClaim);
+
 	const remove = async (e: MouseEvent, s: SessionListItem): Promise<void> => {
 		e.preventDefault();
 		e.stopPropagation();

web/src/title.ts

@@ -0,0 +1,38 @@
+import { useEffect } from "react";
+
+// Live document-title state: the deepest mounted view pushes its strip;
+// when it unmounts the title falls back to the previous claimant.
+let base = "lvmh";
+let current: string | null = null;
+const listeners = new Set<() => void>();
+
+function emit(): void {
+	document.title = current === null ? base : `${current} — ${base}`;
+	for (const l of listeners) l();
+}
+
+/** Set the app-wide base name (kept when no view claims a title). */
+export function setBaseTitle(name: string): void {
+	base = name;
+	emit();
+}
+
+/** Claim the document title while the calling view is mounted. */
+export function useTitle(claim: string | null): void {
+	useEffect(() => {
+		current = claim;
+		emit();
+		return () => {
+			if (current === claim) {
+				current = null;
+				emit();
+			}
+		};
+	}, [claim]);
+}
+
+/** Force-refresh consumers (used after setBaseTitle). */
+export function subscribeTitle(fn: () => void): () => void {
+	listeners.add(fn);
+	return () => listeners.delete(fn);
+}