feat(tabs): drag-reorder + double-click rename + per-tab chat draft

- TabBar: HTML5 drag-and-drop to reorder user tabs (subagent tabs untouched);
  double-click a tab title to rename (Enter/blur confirm, Escape cancel).
- Store: add reorderTabs/renameTab/setDraft; per-tab in-memory `draft` and
  `manualTitle` fields. Manual rename suppresses first-message auto-title.
- ChatInput: bind to the active tab's draft so switching tabs saves/restores
  unsent text instead of clobbering it.
- Backend: updateTabPositions() + PATCH /tabs/reorder persist tab order to the
  existing `position` column; tabs without a stored position fall to the end
  then get explicit positions on first reorder.
- Tests: store reorder/rename/auto-title-guard/draft coverage; core
  updateTabPositions coverage (FakeDatabase extended with transaction support).

8 files changed, 431 insertions, 11 deletions

diff --git a/packages/api/src/routes/tabs.ts b/packages/api/src/routes/tabs.ts
index f52ee99..28a89f1 100644
--- a/packages/api/src/routes/tabs.ts
+++ b/packages/api/src/routes/tabs.ts
@@ -11,6 +11,7 @@ import {
 	listOpenTabs,
 	setSetting,
 	updateTabModel,
+	updateTabPositions,
 	updateTabStatus,
 	updateTabTitle,
 } from "@dispatch/core";
@@ -63,6 +64,18 @@ tabsRoutes.put("/settings/title-model", async (c) => {
 	return c.json({ success: true });
 });
 
+// Reorder open tabs. Body `{ ids }` is the new left-to-right order of tab ids;
+// each tab's `position` is rewritten to its index. Must be declared before the
+// `/:id` routes so "reorder" isn't captured as an id param.
+tabsRoutes.patch("/reorder", async (c) => {
+	const body = await c.req.json<{ ids?: string[] }>();
+	if (!Array.isArray(body.ids) || body.ids.some((id) => typeof id !== "string")) {
+		return c.json({ error: "ids must be an array of strings" }, 400);
+	}
+	updateTabPositions(body.ids);
+	return c.json({ success: true });
+});
+
 tabsRoutes.get("/:id", (c) => {
 	const id = c.req.param("id");
 	const tab = getTab(id);
diff --git a/packages/core/src/db/tabs.ts b/packages/core/src/db/tabs.ts
index 8b290d2..f719a01 100644
--- a/packages/core/src/db/tabs.ts
+++ b/packages/core/src/db/tabs.ts
@@ -115,6 +115,20 @@ export function updateTabStatus(id: string, status: string): void {
 	});
 }
 
+export function updateTabPositions(idsInOrder: string[]): void {
+	const db = getDatabase();
+	const now = Date.now();
+	const update = db.query("UPDATE tabs SET position = $position, updated_at = $now WHERE id = $id");
+	// One transaction so a reorder is atomic: either every tab lands at its new
+	// slot or none does, never a half-applied ordering.
+	const applyAll = db.transaction(() => {
+		idsInOrder.forEach((id, index) => {
+			update.run({ $id: id, $position: index, $now: now });
+		});
+	});
+	applyAll();
+}
+
 export function archiveTab(id: string): void {
 	const db = getDatabase();
 	db.query("UPDATE tabs SET is_open = 0, updated_at = $now WHERE id = $id").run({
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 7818024..f67ad53 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -56,6 +56,7 @@ export {
 	shortestUniquePrefix,
 	type TabRow,
 	updateTabModel,
+	updateTabPositions,
 	updateTabStatus,
 	updateTabTitle,
 } from "./db/tabs.js";
diff --git a/packages/core/tests/db/tabs.test.ts b/packages/core/tests/db/tabs.test.ts
index 67533dc..2cd226b 100644
--- a/packages/core/tests/db/tabs.test.ts
+++ b/packages/core/tests/db/tabs.test.ts
@@ -50,6 +50,15 @@ class FakeDatabase {
 		};
 	}
 
+	/**
+	 * Match Bun's `db.transaction(fn)` shape: returns a callable that runs
+	 * `fn` synchronously. The fake is in-memory and single-threaded, so we
+	 * don't emulate rollback — callers just need the wrapper to be invocable.
+	 */
+	transaction(fn: () => void): () => void {
+		return () => fn();
+	}
+
 	private execSelect(sql: string, params?: Record<string, unknown>): unknown[] {
 		const norm = sql.replace(/\s+/g, " ").trim();
 
@@ -89,6 +98,11 @@ class FakeDatabase {
 			return this.rows.filter((r) => r.is_open === 1).map((r) => ({ id: r.id }));
 		}
 
+		// listOpenTabs: every open tab ordered by position.
+		if (norm === "SELECT * FROM tabs WHERE is_open = 1 ORDER BY position ASC") {
+			return this.rows.filter((r) => r.is_open === 1).sort((a, b) => a.position - b.position);
+		}
+
 		throw new Error(`FakeDatabase: unsupported SELECT: ${norm}`);
 	}
 
@@ -129,6 +143,16 @@ class FakeDatabase {
 			return;
 		}
 
+		// updateTabPositions: rewrite a single tab's position (run per id inside a txn)
+		if (norm === "UPDATE tabs SET position = $position, updated_at = $now WHERE id = $id") {
+			const row = this.rows.find((r) => r.id === params?.$id);
+			if (row) {
+				row.position = (params?.$position as number) ?? row.position;
+				row.updated_at = (params?.$now as number) ?? Date.now();
+			}
+			return;
+		}
+
 		throw new Error(`FakeDatabase: unsupported mutation: ${norm}`);
 	}
 }
@@ -150,8 +174,16 @@ vi.mock("../../src/db/index.js", () => ({
 // Dynamic import AFTER `vi.mock` registers (vitest hoists `vi.mock` to
 // the very top of the file, so by the time this line runs the mock is
 // active for `./index.js` resolution inside `tabs.ts`).
-const { archiveTab, createTab, getDescendantIds, getTab, resolveTabPrefix, shortestUniquePrefix } =
-	await import("../../src/db/tabs.js");
+const {
+	archiveTab,
+	createTab,
+	getDescendantIds,
+	getTab,
+	listOpenTabs,
+	resolveTabPrefix,
+	shortestUniquePrefix,
+	updateTabPositions,
+} = await import("../../src/db/tabs.js");
 
 beforeAll(() => {
 	fakeDb = new FakeDatabase();
@@ -351,3 +383,36 @@ describe("shortestUniquePrefix", () => {
 		expect(shortestUniquePrefix("abcd1111-0000-4000-8000-000000000000")).toBe("abcd");
 	});
 });
+
+// ---------------------------------------------------------------------------
+// updateTabPositions — drag-and-drop reorder persistence
+// ---------------------------------------------------------------------------
+describe("updateTabPositions", () => {
+	it("rewrites each tab's position to its index in the given order", () => {
+		createTab("a", "A"); // position 0
+		createTab("b", "B"); // position 1
+		createTab("c", "C"); // position 2
+
+		updateTabPositions(["c", "a", "b"]);
+
+		// listOpenTabs orders by position → reflects the new order.
+		expect(listOpenTabs().map((t) => t.id)).toEqual(["c", "a", "b"]);
+		expect(getTab("c")?.position).toBe(0);
+		expect(getTab("a")?.position).toBe(1);
+		expect(getTab("b")?.position).toBe(2);
+	});
+
+	it("is a no-op for an empty list", () => {
+		createTab("a", "A");
+		createTab("b", "B");
+		updateTabPositions([]);
+		expect(listOpenTabs().map((t) => t.id)).toEqual(["a", "b"]);
+	});
+
+	it("ignores ids that don't exist without throwing", () => {
+		createTab("a", "A");
+		expect(() => updateTabPositions(["ghost", "a"])).not.toThrow();
+		// "a" took index 1 in the requested order.
+		expect(getTab("a")?.position).toBe(1);
+	});
+});
diff --git a/packages/frontend/src/lib/components/ChatInput.svelte b/packages/frontend/src/lib/components/ChatInput.svelte
index 0c99078..71eb496 100644
--- a/packages/frontend/src/lib/components/ChatInput.svelte
+++ b/packages/frontend/src/lib/components/ChatInput.svelte
@@ -4,12 +4,17 @@ import { tabStore } from "../tabs.svelte.js";
 const MAX_LINES = 7;
 
 let inputEl: HTMLTextAreaElement | undefined;
-let inputValue = $state("");
 
 const agentStatus = $derived(tabStore.activeTab?.agentStatus ?? "idle");
 const tabId = $derived(tabStore.activeTab?.id ?? "");
+// The current input text lives on the active tab (in-memory draft), so
+// switching tabs saves the current draft and restores the target tab's text
+// automatically — drafts are never lost or clobbered by tab switching.
+const inputValue = $derived(tabStore.activeTab?.draft ?? "");
 
 $effect(() => {
+	// Re-focus when switching tabs.
+	void tabId;
 	inputEl?.focus();
 });
 
@@ -29,13 +34,19 @@ function resize() {
 	el.style.overflowY = el.scrollHeight > maxHeight ? "auto" : "hidden";
 }
 
-// Re-run resize whenever the value changes (covers programmatic clears too).
+// Re-run resize whenever the value changes (covers tab switches and
+// programmatic clears too).
 $effect(() => {
 	// Touch inputValue so this effect tracks it.
 	void inputValue;
 	resize();
 });
 
+function handleInput(e: Event) {
+	if (!tabId) return;
+	tabStore.setDraft(tabId, (e.currentTarget as HTMLTextAreaElement).value);
+}
+
 function handleKeydown(e: KeyboardEvent) {
 	if (e.key === "Enter" && !e.shiftKey) {
 		e.preventDefault();
@@ -46,7 +57,7 @@ function handleKeydown(e: KeyboardEvent) {
 function submit() {
 	const text = inputValue.trim();
 	if (!text) return;
-	inputValue = "";
+	if (tabId) tabStore.setDraft(tabId, "");
 	tabStore.sendMessage(text);
 }
 </script>
@@ -75,12 +86,12 @@ function submit() {
 	{/if}
 	<textarea
 		bind:this={inputEl}
-		bind:value={inputValue}
+		value={inputValue}
 		rows="1"
 		placeholder="Type a message..."
 		class="textarea textarea-ghost flex-1 resize-none leading-normal !min-h-0 h-auto"
 		onkeydown={handleKeydown}
-		oninput={resize}
+		oninput={handleInput}
 	></textarea>
 	<button
 		type="button"
diff --git a/packages/frontend/src/lib/components/TabBar.svelte b/packages/frontend/src/lib/components/TabBar.svelte
index 3cbd849..4fbe3b1 100644
--- a/packages/frontend/src/lib/components/TabBar.svelte
+++ b/packages/frontend/src/lib/components/TabBar.svelte
@@ -1,4 +1,5 @@
 <script lang="ts">
+import { tick } from "svelte";
 import { tabStore } from "../tabs.svelte.js";
 
 function statusColor(status: string): string {
@@ -20,6 +21,59 @@ const activeUserTabId = $derived(
 		? activeTab.parentTabId
 		: tabStore.activeTabId,
 );
+
+// ── Drag-and-drop reorder (user tabs only) ──
+// Mirrors the native HTML5 DnD pattern used in AgentBuilder.svelte.
+let dragIndex = $state<number | null>(null);
+let dragOverIndex = $state<number | null>(null);
+
+function dropReorder(targetIndex: number): void {
+	if (dragIndex !== null && dragIndex !== targetIndex) {
+		const ids = userTabs.map((t) => t.id);
+		const moved = ids.splice(dragIndex, 1)[0];
+		if (moved) {
+			ids.splice(targetIndex, 0, moved);
+			tabStore.reorderTabs(ids);
+		}
+	}
+	dragIndex = null;
+	dragOverIndex = null;
+}
+
+// ── Double-click rename (user tabs only) ──
+let editingTabId = $state<string | null>(null);
+let editValue = $state("");
+let editInputEl = $state<HTMLInputElement | undefined>(undefined);
+
+async function startRename(tab: { id: string; title: string }): Promise<void> {
+	editingTabId = tab.id;
+	editValue = tab.title;
+	await tick();
+	editInputEl?.focus();
+	editInputEl?.select();
+}
+
+function commitRename(): void {
+	if (editingTabId === null) return;
+	const id = editingTabId;
+	editingTabId = null;
+	const next = editValue.trim();
+	if (next) tabStore.renameTab(id, next);
+}
+
+function cancelRename(): void {
+	editingTabId = null;
+}
+
+function handleRenameKeydown(e: KeyboardEvent): void {
+	if (e.key === "Enter") {
+		e.preventDefault();
+		commitRename();
+	} else if (e.key === "Escape") {
+		e.preventDefault();
+		cancelRename();
+	}
+}
 </script>
 
 <!-- Top row: user tabs -->
@@ -45,19 +99,48 @@ const activeUserTabId = $derived(
 			+
 		</button>
 
-		{#each userTabs as tab (tab.id)}
+		{#each userTabs as tab, i (tab.id)}
 			<!-- svelte-ignore a11y_no_static_element_interactions -->
 			<div
 				role="tab"
-				class="tab !flex items-stretch gap-1.5 {tab.id === activeUserTabId ? 'tab-active' : ''}"
+				class="tab !flex items-stretch gap-1.5 {tab.id === activeUserTabId ? 'tab-active' : ''} {dragOverIndex === i ? 'bg-primary/10' : ''} {dragIndex === i ? 'opacity-50' : ''}"
+				draggable={editingTabId === tab.id ? "false" : "true"}
 				onclick={() => tabStore.switchTab(tab.id)}
 				onkeydown={(e) => { if (e.key === 'Enter' || e.key === ' ') tabStore.switchTab(tab.id); }}
+				ondragstart={(e) => {
+					dragIndex = i;
+					if (e.dataTransfer) e.dataTransfer.effectAllowed = "move";
+				}}
+				ondragover={(e) => {
+					e.preventDefault();
+					if (e.dataTransfer) e.dataTransfer.dropEffect = "move";
+					dragOverIndex = i;
+				}}
+				ondragleave={() => { if (dragOverIndex === i) dragOverIndex = null; }}
+				ondrop={(e) => { e.preventDefault(); dropReorder(i); }}
+				ondragend={() => { dragIndex = null; dragOverIndex = null; }}
 				tabindex="0"
 			>
 				<span class="flex items-center gap-1.5">
 					<span class="w-1.5 h-1.5 rounded-full shrink-0 {statusColor(tab.agentStatus)}"></span>
 					<span class="font-mono text-[10px] px-1 py-0.5 rounded bg-base-300 text-base-content/60 shrink-0" title="Tab ID — agents address this tab by this handle">{tabStore.shortHandleFor(tab.id)}</span>
-					<span class="max-w-32 truncate text-xs">{tab.title}</span>
+					{#if editingTabId === tab.id}
+						<input
+							bind:this={editInputEl}
+							bind:value={editValue}
+							class="max-w-32 text-xs bg-base-100 rounded px-1 outline-none ring-1 ring-primary/40"
+							onclick={(e) => e.stopPropagation()}
+							ondblclick={(e) => e.stopPropagation()}
+							onkeydown={handleRenameKeydown}
+							onblur={commitRename}
+						/>
+					{:else}
+						<span
+							class="max-w-32 truncate text-xs"
+							ondblclick={(e) => { e.stopPropagation(); startRename(tab); }}
+							title="Double-click to rename"
+						>{tab.title}</span>
+					{/if}
 				</span>
 				<button
 					type="button"
diff --git a/packages/frontend/src/lib/tabs.svelte.ts b/packages/frontend/src/lib/tabs.svelte.ts
index ec718bd..1c94593 100644
--- a/packages/frontend/src/lib/tabs.svelte.ts
+++ b/packages/frontend/src/lib/tabs.svelte.ts
@@ -177,6 +177,19 @@ export interface Tab {
 	/** Total chunk count for this tab on the backend (drives "more to load?"). */
 	totalChunks: number;
 	/**
+	 * Unsent chat-input text for THIS tab (in-memory only — never persisted).
+	 * Saved/restored on tab switch so a draft is never lost or clobbered by
+	 * switching tabs. Cleared on send.
+	 */
+	draft: string;
+	/**
+	 * True once the user has manually renamed this tab (double-click rename).
+	 * Suppresses the first-message auto-title so a chosen name is never
+	 * clobbered. In-memory only — a renamed tab is no longer "New Tab" on
+	 * reload, so the auto-title guard already won't fire for it.
+	 */
+	manualTitle: boolean;
+	/**
 	 * Cumulative prompt-cache token telemetry for this tab since the page
 	 * loaded (in-memory only — resets on reload). Undefined until the first
 	 * `usage` event arrives. Drives the "Cache Rate" sidebar view.
@@ -298,6 +311,8 @@ export function createTabStore() {
 			workingDirectory: null,
 			queuedMessages: [],
 			chunkLimit: appSettings.chunkLimit,
+			draft: "",
+			manualTitle: false,
 			oldestLoadedSeq: null,
 			totalChunks: 0,
 		};
@@ -373,6 +388,8 @@ export function createTabStore() {
 				workingDirectory: null,
 				queuedMessages: [],
 				chunkLimit: appSettings.chunkLimit,
+				draft: "",
+				manualTitle: false,
 				oldestLoadedSeq: win.oldestSeq,
 				totalChunks: win.total,
 			};
@@ -426,6 +443,61 @@ export function createTabStore() {
 	}
 
 	/**
+	 * Rename a tab. Records `manualTitle` so the first-message auto-title never
+	 * clobbers the user's chosen name, and persists the new title to the DB
+	 * (fire-and-forget — the optimistic local update is the source of truth for
+	 * the open session).
+	 */
+	function renameTab(id: string, title: string): void {
+		const trimmed = title.trim();
+		if (!trimmed) return;
+		updateTab(id, { title: trimmed, manualTitle: true });
+		fetch(`${config.apiBase}/tabs/${id}`, {
+			method: "PATCH",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ title: trimmed }),
+		}).catch(() => {});
+	}
+
+	/**
+	 * Reorder the top-row USER tabs to match `orderedUserTabIds`. Subagent tabs
+	 * (those with a `parentTabId`) keep their relative order untouched — they
+	 * live in a separate row and aren't draggable. The new left-to-right user
+	 * order is persisted via `PATCH /tabs/reorder`, which rewrites each open
+	 * tab's `position` (fire-and-forget, matching the title-persist style).
+	 */
+	function reorderTabs(orderedUserTabIds: string[]): void {
+		const byId = new Map(tabs.map((t) => [t.id, t]));
+		const ordered = orderedUserTabIds
+			.map((id) => byId.get(id))
+			.filter((t): t is Tab => t !== undefined && t.parentTabId === null);
+		// Bail if the requested order doesn't cover exactly the current user tabs
+		// (stale drag against a since-changed tab set) — never drop tabs.
+		const currentUserCount = tabs.filter((t) => t.parentTabId === null).length;
+		if (ordered.length !== currentUserCount) return;
+		const subagentTabs = tabs.filter((t) => t.parentTabId !== null);
+		tabs = [...ordered, ...subagentTabs];
+		// Persist the full open-tab order (user tabs first, then subagents) so the
+		// backend `position` column matches what the user sees on reload.
+		const persistOrder = [...ordered, ...subagentTabs].map((t) => t.id);
+		fetch(`${config.apiBase}/tabs/reorder`, {
+			method: "PATCH",
+			headers: { "Content-Type": "application/json" },
+			body: JSON.stringify({ ids: persistOrder }),
+		}).catch(() => {});
+	}
+
+	/**
+	 * Persist the unsent chat-input text for a tab (in-memory only). Saved on
+	 * every keystroke so switching tabs preserves the draft and restoring the
+	 * target tab shows its own text. No-op if the tab is gone.
+	 */
+	function setDraft(id: string, text: string): void {
+		if (!getTabById(id)) return;
+		updateTab(id, { draft: text });
+	}
+
+	/**
 	 * Record whether a tab's chat view is scrolled up (viewing older history).
 	 * Used to suppress automatic eviction while the user is reading old
 	 * messages — we don't want to delete what they're currently looking at.
@@ -854,6 +926,8 @@ export function createTabStore() {
 				workingDirectory: null,
 				queuedMessages: [],
 				chunkLimit: appSettings.chunkLimit,
+				draft: "",
+				manualTitle: false,
 				oldestLoadedSeq: win.oldestSeq,
 				totalChunks: win.total,
 				cacheStats: row.usageStats ?? undefined,
@@ -1203,6 +1277,8 @@ export function createTabStore() {
 						workingDirectory: newTabEvent.workingDirectory ?? null,
 						queuedMessages: [],
 						chunkLimit: appSettings.chunkLimit,
+						draft: "",
+						manualTitle: false,
 						oldestLoadedSeq: null,
 						totalChunks: 0,
 					};
@@ -1589,7 +1665,7 @@ export function createTabStore() {
 		updateTab(tab.id, { live: [...tab.live, userMsg] });
 		// Generate a title from the first user message of an empty tab.
 		const isFirstMessage = tab.chunks.length === 0 && tab.live.length === 0;
-		if (isFirstMessage || tab.title === "New Tab") {
+		if (!tab.manualTitle && (isFirstMessage || tab.title === "New Tab")) {
 			const titleText = text.length > 50 ? `${text.slice(0, 47)}...` : text;
 			updateTab(tab.id, { title: titleText });
 			fetch(`${config.apiBase}/tabs/${tab.id}`, {
@@ -2033,6 +2109,9 @@ export function createTabStore() {
 		createNewTab,
 		switchTab,
 		closeTab,
+		renameTab,
+		reorderTabs,
+		setDraft,
 		sendMessage,
 		cancelQueuedMessage,
 		stopGeneration,
diff --git a/packages/frontend/tests/chat-store.test.ts b/packages/frontend/tests/chat-store.test.ts
index c0763cd..a0d4ead 100644
--- a/packages/frontend/tests/chat-store.test.ts
+++ b/packages/frontend/tests/chat-store.test.ts
@@ -1972,3 +1972,157 @@ describe("tabStore — chunk-native eviction / pagination / reconcile", () => {
 		expect(tab?.live.some((m) => m.turnId === "turn-a")).toBe(false);
 	});
 });
+
+describe("tabStore — tab reorder", () => {
+	it("reorders user tabs and persists the new order", async () => {
+		const calls: Array<{ url: string; body: string }> = [];
+		vi.stubGlobal(
+			"fetch",
+			vi.fn((url: string, opts?: { body?: string }) => {
+				calls.push({ url, body: opts?.body ?? "" });
+				return Promise.resolve({ ok: true, json: () => Promise.resolve({ success: true }) });
+			}),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		const b = await store.createNewTab();
+		const c = await store.createNewTab();
+		expect(store.tabs.map((t) => t.id)).toEqual([a.id, b.id, c.id]);
+
+		// Move the last tab to the front.
+		store.reorderTabs([c.id, a.id, b.id]);
+		expect(store.tabs.map((t) => t.id)).toEqual([c.id, a.id, b.id]);
+
+		const reorderCall = calls.find((call) => call.url.endsWith("/tabs/reorder"));
+		expect(reorderCall).toBeTruthy();
+		expect(JSON.parse(reorderCall?.body ?? "{}")).toEqual({ ids: [c.id, a.id, b.id] });
+	});
+
+	it("ignores a stale order that doesn't cover all user tabs", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({}) })),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		const b = await store.createNewTab();
+		store.reorderTabs([a.id]); // missing b → no-op
+		expect(store.tabs.map((t) => t.id)).toEqual([a.id, b.id]);
+	});
+
+	it("keeps subagent tabs after the user tabs when reordering", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({}) })),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		const b = await store.createNewTab();
+		// A subagent tab arrives via WS (parentTabId set).
+		store.handleEvent({
+			type: "tab-created",
+			id: "sub",
+			title: "Sub",
+			keyId: null,
+			modelId: null,
+			parentTabId: a.id,
+		});
+		store.reorderTabs([b.id, a.id]);
+		const ids = store.tabs.map((t) => t.id);
+		expect(ids).toEqual([b.id, a.id, "sub"]);
+	});
+});
+
+describe("tabStore — rename + auto-title guard", () => {
+	it("renameTab sets the title and persists it", async () => {
+		const calls: Array<{ url: string; method?: string; body: string }> = [];
+		vi.stubGlobal(
+			"fetch",
+			vi.fn((url: string, opts?: { method?: string; body?: string }) => {
+				calls.push({ url, method: opts?.method, body: opts?.body ?? "" });
+				return Promise.resolve({ ok: true, json: () => Promise.resolve({}) });
+			}),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		store.renameTab(a.id, "  My Tab  ");
+		expect(store.tabs[0]?.title).toBe("My Tab");
+		expect(store.tabs[0]?.manualTitle).toBe(true);
+		const patch = calls.find(
+			(call) => call.url.endsWith(`/tabs/${a.id}`) && call.method === "PATCH",
+		);
+		expect(JSON.parse(patch?.body ?? "{}")).toEqual({ title: "My Tab" });
+	});
+
+	it("renameTab ignores an empty/whitespace name", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({}) })),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		store.renameTab(a.id, "   ");
+		expect(store.tabs[0]?.title).toBe("New Tab");
+		expect(store.tabs[0]?.manualTitle).toBe(false);
+	});
+
+	it("sendMessage does NOT auto-title a manually renamed tab", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({ status: "ok" }) })),
+		);
+		const store = createTabStore();
+		await store.createNewTab();
+		store.renameTab(store.tabs[0]?.id ?? "", "Keep Me");
+		await store.sendMessage("hello there this is the first message");
+		expect(store.tabs[0]?.title).toBe("Keep Me");
+	});
+
+	it("sendMessage still auto-titles a tab that was never renamed", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({ status: "ok" }) })),
+		);
+		const store = createTabStore();
+		await store.createNewTab();
+		await store.sendMessage("first message becomes the title");
+		expect(store.tabs[0]?.title).toBe("first message becomes the title");
+		expect(store.tabs[0]?.manualTitle).toBe(false);
+	});
+});
+
+describe("tabStore — per-tab chat input draft", () => {
+	it("stores drafts per tab and restores them on switch", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({}) })),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		const b = await store.createNewTab();
+
+		store.switchTab(a.id);
+		store.setDraft(a.id, "draft for A");
+		store.switchTab(b.id);
+		store.setDraft(b.id, "draft for B");
+
+		// Active tab is B → its draft is exposed.
+		expect(store.activeTab?.draft).toBe("draft for B");
+		// Switching back to A restores A's draft without clobbering B's.
+		store.switchTab(a.id);
+		expect(store.activeTab?.draft).toBe("draft for A");
+		expect(store.tabs.find((t) => t.id === b.id)?.draft).toBe("draft for B");
+	});
+
+	it("new tabs start with an empty draft and setDraft no-ops for unknown tabs", async () => {
+		vi.stubGlobal(
+			"fetch",
+			vi.fn(() => Promise.resolve({ ok: true, json: () => Promise.resolve({}) })),
+		);
+		const store = createTabStore();
+		const a = await store.createNewTab();
+		expect(a.draft).toBe("");
+		store.setDraft("nope", "ignored"); // unknown tab → no throw, no effect
+		expect(store.tabs.every((t) => t.draft === "")).toBe(true);
+	});
+});