diff --git a/packages/web/src/components/chat-room/chat-room-header.tsx b/packages/web/src/components/chat-room/chat-room-header.tsx
index 5e78c22b..5b7504bf 100644
--- a/packages/web/src/components/chat-room/chat-room-header.tsx
+++ b/packages/web/src/components/chat-room/chat-room-header.tsx
@@ -2,15 +2,19 @@
 
 import {
 	Activity,
+	Check,
 	FileText,
 	Loader2,
 	MessageCircle,
 	PanelLeft,
+	Pencil,
 	RotateCcw,
+	X,
 } from "lucide-react";
-import type { ReactElement } from "react";
+import { type FormEvent, type ReactElement, useState } from "react";
 
 import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
 import { Typography } from "@/components/ui/typography";
 import { cn } from "@/lib/utils";
 import { buildChatRoomHeaderTabs } from "./chat-room-header-tabs";
@@ -23,17 +27,43 @@ export function ChatRoomHeader({
 	isRerunDisabled,
 	isRerunning,
 	isRerunVisible,
+	isRenamingTitle,
 	title,
 	onOpenAction,
 	onOpenMessages,
 	onOpenSidebar,
 	onOpenTaskDetails,
+	onRenameTitle,
 	onRerunWorkflow,
 }: ChatRoomHeaderProps): ReactElement {
+	const [draftTitle, setDraftTitle] = useState(title);
+	const [isEditingTitle, setIsEditingTitle] = useState(false);
 	const tabs = buildChatRoomHeaderTabs({
 		activeTab,
 		hasTaskDetails: Boolean(activeTaskId),
 	});
+	const trimmedDraftTitle = draftTitle.trim();
+
+	function startEditingTitle(): void {
+		setDraftTitle(title);
+		setIsEditingTitle(true);
+	}
+
+	function cancelEditingTitle(): void {
+		setDraftTitle(title);
+		setIsEditingTitle(false);
+	}
+
+	async function saveTitle(event: FormEvent<HTMLFormElement>): Promise<void> {
+		event.preventDefault();
+		if (!trimmedDraftTitle || isRenamingTitle) {
+			return;
+		}
+		const didSave = await onRenameTitle(trimmedDraftTitle);
+		if (didSave !== false) {
+			setIsEditingTitle(false);
+		}
+	}
 
 	function selectTab(key: ChatRoomHeaderTabKey): void {
 		if (key === "taskDetails") {
@@ -61,9 +91,64 @@ export function ChatRoomHeader({
 					>
 						<PanelLeft size={17} />
 					</Button>
-					<div className="min-w-0">
-						<Typography className="truncate text-zinc-300">{title}</Typography>
-					</div>
+					{isEditingTitle ? (
+						<form
+							className="flex min-w-0 flex-1 items-center gap-2"
+							onSubmit={(event) => void saveTitle(event)}
+						>
+							<Input
+								aria-label="Session title"
+								className="h-8 min-w-0"
+								disabled={isRenamingTitle}
+								onChange={(event) => setDraftTitle(event.currentTarget.value)}
+								value={draftTitle}
+							/>
+							<Button
+								aria-label="Save session title"
+								disabled={!trimmedDraftTitle || isRenamingTitle}
+								size="icon"
+								type="submit"
+								variant="ghost"
+							>
+								{isRenamingTitle ? (
+									<Loader2
+										aria-hidden="true"
+										className="animate-spin"
+										size={15}
+									/>
+								) : (
+									<Check aria-hidden="true" size={15} />
+								)}
+							</Button>
+							<Button
+								aria-label="Cancel session title edit"
+								disabled={isRenamingTitle}
+								onClick={cancelEditingTitle}
+								size="icon"
+								type="button"
+								variant="ghost"
+							>
+								<X aria-hidden="true" size={15} />
+							</Button>
+						</form>
+					) : (
+						<>
+							<div className="min-w-0">
+								<Typography className="truncate text-zinc-300">
+									{title}
+								</Typography>
+							</div>
+							<Button
+								aria-label="Edit session title"
+								onClick={startEditingTitle}
+								size="icon"
+								type="button"
+								variant="ghost"
+							>
+								<Pencil aria-hidden="true" size={14} />
+							</Button>
+						</>
+					)}
 				</div>
 				<div className="flex shrink-0 items-center gap-2">
 					{isRerunVisible ? (
diff --git a/packages/web/src/components/chat-room/chat-room-panel-view.tsx b/packages/web/src/components/chat-room/chat-room-panel-view.tsx
index de0c3b02..20aff7e9 100644
--- a/packages/web/src/components/chat-room/chat-room-panel-view.tsx
+++ b/packages/web/src/components/chat-room/chat-room-panel-view.tsx
@@ -27,6 +27,7 @@ export function ChatRoomPanelView({
 	isRerunDisabled,
 	isRerunning,
 	isRerunVisible,
+	isRenamingTitle,
 	isSending,
 	isPlanning,
 	isThinking,
@@ -44,6 +45,7 @@ export function ChatRoomPanelView({
 	onOpenMessages,
 	onOpenSidebar,
 	onOpenTaskDetails,
+	onRenameTitle,
 	onRerunWorkflow,
 	onSelectCommand,
 	onSelectOption,
@@ -93,11 +95,13 @@ export function ChatRoomPanelView({
 						isRerunDisabled={isRerunDisabled}
 						isRerunning={isRerunning}
 						isRerunVisible={isRerunVisible}
+						isRenamingTitle={isRenamingTitle}
 						title={selectedSession.title}
 						onOpenAction={onOpenAction}
 						onOpenMessages={onOpenMessages}
 						onOpenSidebar={onOpenSidebar}
 						onOpenTaskDetails={onOpenTaskDetails}
+						onRenameTitle={onRenameTitle}
 						onRerunWorkflow={onRerunWorkflow}
 					/>
 					{layout.contentMode === "taskDetails" ? (
diff --git a/packages/web/src/components/chat-room/chat-room-panel.tsx b/packages/web/src/components/chat-room/chat-room-panel.tsx
index a0f83d78..f7029733 100644
--- a/packages/web/src/components/chat-room/chat-room-panel.tsx
+++ b/packages/web/src/components/chat-room/chat-room-panel.tsx
@@ -17,18 +17,16 @@ import { useRealtimeStore } from "@/lib/realtime";
 
 import { useChatClarificationState } from "./chat-clarification-state";
 import { createChatClarificationSubmitters } from "./chat-clarification-submitters";
-import {
-	createStreamLine,
-	streamLineFromCommandEvent,
-} from "./chat-command-stream-lines";
 import { parseChatCommand } from "./chat-command-utils";
 import { executeChatRoomInput } from "./chat-room-execute-input";
 import { useChatRoomMission } from "./chat-room-mission";
 import { useChatRoomDraftState } from "./chat-room-panel-draft-state";
 import { ChatRoomPanelView } from "./chat-room-panel-view";
+import { rerunChatSessionWorkflow } from "./chat-room-rerun-workflow";
 import { selectChatSession } from "./chat-room-selection";
 import { resolveChatRoomStreamState } from "./chat-room-stream-state";
 import { resolveChatSessionRerunState } from "./chat-session-rerun-state";
+import { createChatSessionTitleRenameHandler } from "./chat-session-title-rename";
 import { useWorkingSectionState } from "./chat-working-section-state";
 import type * as CRT from "./types/chat-room.types";
 import { useChatRoomContentModeState } from "./use-chat-room-content-mode-state";
@@ -115,6 +113,11 @@ export function ChatRoomPanel({
 		selectedSession,
 		sendMessage: (input) => sendMessage.mutateAsync(input),
 	});
+	const renameSessionTitle = createChatSessionTitleRenameHandler({
+		renameSession: (input) => updateSession.mutateAsync(input),
+		selectedSession,
+		showError: (message) => toast.error(message),
+	});
 
 	async function startNewSession(): Promise<void> {
 		if (!workspaceId) {
@@ -173,39 +176,18 @@ export function ChatRoomPanel({
 			toast.error("Workflow cannot be rerun yet.");
 			return;
 		}
-		let finalStatus: "succeeded" | "failed" | "rejected" | null = null;
-		let finalError: string | undefined;
-		setIsRerunning(true);
-		setSubmittedRerunKey(rerunSubmissionKey);
-		setCommandLines([createStreamLine("system", "Queued workflow rerun.")]);
-		try {
-			await apiClient.streamCliCommand(rerunState.command, (event) => {
-				if (event.type === "complete") {
-					finalStatus = event.result.status;
-					finalError = event.result.error;
-				}
-				const line = streamLineFromCommandEvent(event);
-				if (line) setCommandLines((current) => [...current, line]);
-			});
-			await Promise.allSettled([
-				sessionsQuery.refetch(),
-				messagesQuery.refetch(),
-				refetchActiveTask(),
-			]);
-			if (finalStatus && finalStatus !== "succeeded") {
-				toast.error(finalError ?? "Workflow rerun failed.");
-			}
-		} catch (error) {
-			const message =
-				error instanceof Error ? error.message : "Workflow rerun failed.";
-			setCommandLines((current) => [
-				...current,
-				createStreamLine("stderr", message),
-			]);
-			toast.error(message);
-		} finally {
-			setIsRerunning(false);
-		}
+		await rerunChatSessionWorkflow({
+			command: rerunState.command,
+			refetchActiveTask,
+			refetchMessages: messagesQuery.refetch,
+			refetchSessions: sessionsQuery.refetch,
+			setCommandLines,
+			setIsRerunning,
+			setSubmittedRerunKey,
+			streamCliCommand: apiClient.streamCliCommand,
+			submissionKey: rerunSubmissionKey,
+			showError: (message) => toast.error(message),
+		});
 	}
 
 	return (
@@ -218,6 +200,7 @@ export function ChatRoomPanel({
 			isRerunDisabled={rerunState.isDisabled}
 			isRerunning={isRerunning}
 			isRerunVisible={rerunState.isVisible}
+			isRenamingTitle={updateSession.isPending}
 			isSending={sendMessage.isPending}
 			isPlanning={isPlanning}
 			isThinking={isThinking}
@@ -237,6 +220,7 @@ export function ChatRoomPanel({
 			onOpenMessages={contentMode.openMessages}
 			onOpenSidebar={onOpenSidebar}
 			onOpenTaskDetails={contentMode.openTaskDetails}
+			onRenameTitle={renameSessionTitle}
 			onRerunWorkflow={() => void handleRerunWorkflow()}
 			onSelectCommand={setDraft}
 			onSelectOption={(index, value) =>
diff --git a/packages/web/src/components/chat-room/chat-room-rerun-workflow.ts b/packages/web/src/components/chat-room/chat-room-rerun-workflow.ts
new file mode 100644
index 00000000..675fbc8e
--- /dev/null
+++ b/packages/web/src/components/chat-room/chat-room-rerun-workflow.ts
@@ -0,0 +1,68 @@
+import type { CliCommandStreamEvent, CliCommandStreamRequest } from "@/lib/api";
+import type { Dispatch, SetStateAction } from "react";
+import {
+	createStreamLine,
+	streamLineFromCommandEvent,
+} from "./chat-command-stream-lines";
+import type { ChatStreamLine } from "./types/chat-room.types";
+
+export async function rerunChatSessionWorkflow({
+	command,
+	refetchActiveTask,
+	refetchMessages,
+	refetchSessions,
+	setCommandLines,
+	setIsRerunning,
+	setSubmittedRerunKey,
+	streamCliCommand,
+	submissionKey,
+	showError,
+}: {
+	command: CliCommandStreamRequest;
+	refetchActiveTask: () => Promise<unknown>;
+	refetchMessages: () => Promise<unknown>;
+	refetchSessions: () => Promise<unknown>;
+	setCommandLines: Dispatch<SetStateAction<ChatStreamLine[]>>;
+	setIsRerunning: (value: boolean) => void;
+	setSubmittedRerunKey: (value: string) => void;
+	streamCliCommand: (
+		command: CliCommandStreamRequest,
+		onEvent: (event: CliCommandStreamEvent) => void,
+	) => Promise<unknown>;
+	submissionKey: string;
+	showError: (message: string) => void;
+}): Promise<void> {
+	let finalStatus: "succeeded" | "failed" | "rejected" | null = null;
+	let finalError: string | undefined;
+	setIsRerunning(true);
+	setSubmittedRerunKey(submissionKey);
+	setCommandLines([createStreamLine("system", "Queued workflow rerun.")]);
+	try {
+		await streamCliCommand(command, (event) => {
+			if (event.type === "complete") {
+				finalStatus = event.result.status;
+				finalError = event.result.error;
+			}
+			const line = streamLineFromCommandEvent(event);
+			if (line) setCommandLines((current) => [...current, line]);
+		});
+		await Promise.allSettled([
+			refetchSessions(),
+			refetchMessages(),
+			refetchActiveTask(),
+		]);
+		if (finalStatus && finalStatus !== "succeeded") {
+			showError(finalError ?? "Workflow rerun failed.");
+		}
+	} catch (error) {
+		const message =
+			error instanceof Error ? error.message : "Workflow rerun failed.";
+		setCommandLines((current) => [
+			...current,
+			createStreamLine("stderr", message),
+		]);
+		showError(message);
+	} finally {
+		setIsRerunning(false);
+	}
+}
diff --git a/packages/web/src/components/chat-room/chat-session-title-rename.ts b/packages/web/src/components/chat-room/chat-session-title-rename.ts
new file mode 100644
index 00000000..c38f6331
--- /dev/null
+++ b/packages/web/src/components/chat-room/chat-session-title-rename.ts
@@ -0,0 +1,34 @@
+import type { ChatSessionRecord, ChatSessionUpdateRequest } from "@/lib/api";
+
+export function createChatSessionTitleRenameHandler({
+	renameSession,
+	selectedSession,
+	showError,
+}: {
+	renameSession: (input: {
+		sessionId: string;
+		session: ChatSessionUpdateRequest;
+	}) => Promise<unknown>;
+	selectedSession: ChatSessionRecord | null;
+	showError: (message: string) => void;
+}): (title: string) => Promise<boolean> {
+	return async (title) => {
+		const nextTitle = title.trim();
+		if (!selectedSession || !nextTitle) {
+			return false;
+		}
+		if (nextTitle === selectedSession.title.trim()) {
+			return true;
+		}
+		try {
+			await renameSession({
+				sessionId: selectedSession.id,
+				session: { title: nextTitle },
+			});
+			return true;
+		} catch (error) {
+			showError(error instanceof Error ? error.message : "Rename failed");
+			return false;
+		}
+	};
+}
diff --git a/packages/web/src/components/chat-room/types/chat-room.types.ts b/packages/web/src/components/chat-room/types/chat-room.types.ts
index 25f0ee04..dfbf6ce8 100644
--- a/packages/web/src/components/chat-room/types/chat-room.types.ts
+++ b/packages/web/src/components/chat-room/types/chat-room.types.ts
@@ -23,11 +23,13 @@ export interface ChatRoomHeaderProps {
 	isRerunDisabled: boolean;
 	isRerunning: boolean;
 	isRerunVisible: boolean;
+	isRenamingTitle: boolean;
 	title: string;
 	onOpenAction: () => void;
 	onOpenMessages: () => void;
 	onOpenSidebar: () => void;
 	onOpenTaskDetails: () => void;
+	onRenameTitle: (title: string) => Promise<boolean> | boolean;
 	onRerunWorkflow: () => void;
 }
 
@@ -86,6 +88,7 @@ export interface ChatRoomPanelViewProps {
 	isRerunDisabled: boolean;
 	isRerunning: boolean;
 	isRerunVisible: boolean;
+	isRenamingTitle: boolean;
 	isSending: boolean;
 	isPlanning: boolean;
 	isThinking: boolean;
@@ -103,6 +106,7 @@ export interface ChatRoomPanelViewProps {
 	onOpenMessages: () => void;
 	onOpenSidebar: () => void;
 	onOpenTaskDetails: () => void;
+	onRenameTitle: (title: string) => Promise<boolean> | boolean;
 	onRerunWorkflow: () => void;
 	onSelectCommand: (value: string) => void;
 	onSelectOption: (index: number, value: string) => Promise<void> | void;
diff --git a/packages/web/tests/chat-client.test.ts b/packages/web/tests/chat-client.test.ts
index d18c61d4..07134bbf 100644
--- a/packages/web/tests/chat-client.test.ts
+++ b/packages/web/tests/chat-client.test.ts
@@ -76,6 +76,34 @@ describe("chat API client", () => {
 		expect(session.archived).toBe(true);
 	});
 
+	it("sends title updates for chat sessions", async () => {
+		const fetchFn = (async (input: URL | RequestInfo, init?: RequestInit) => {
+			expect(String(input)).toBe("/api/chat/sessions/session-1");
+			expect(init?.method).toBe("PATCH");
+			expect(JSON.parse(String(init?.body))).toEqual({ title: "Renamed" });
+			return okJsonResponse({
+				id: "session-1",
+				workspaceId: "owner-1",
+				projectId: "default",
+				taskId: "task-1",
+				title: "Renamed",
+				pendingRequest: null,
+				pendingQuestions: [],
+				archived: false,
+				createdAt: "2026-05-20T00:00:00.000Z",
+				updatedAt: "2026-05-20T00:01:00.000Z",
+				lastSeenAt: "2026-05-20T00:00:00.000Z",
+			});
+		}) as typeof fetch;
+		const client = createApiClient({ fetchFn });
+
+		const session = await client.updateChatSession("session-1", {
+			title: "Renamed",
+		});
+
+		expect(session.title).toBe("Renamed");
+	});
+
 	it("parses chat send responses with the linked issue", async () => {
 		const fetchFn = (async (input: URL | RequestInfo, init?: RequestInit) => {
 			expect(String(input)).toBe("/api/chat/sessions/session-1/send");
diff --git a/packages/web/tests/chat-session-cache.test.ts b/packages/web/tests/chat-session-cache.test.ts
index 6d97c498..d568e3c4 100644
--- a/packages/web/tests/chat-session-cache.test.ts
+++ b/packages/web/tests/chat-session-cache.test.ts
@@ -40,6 +40,19 @@ describe("chat session cache", () => {
 		expect(preserved).toEqual([seenAtT2]);
 		expect(isChatSessionUnread(preserved[0] ?? delayedUnreadAtT2)).toBe(false);
 	});
+
+	it("replaces cached sessions with newer renamed titles", () => {
+		const current = chatSession({
+			title: "Untitled",
+			updatedAt: "2026-05-16T00:01:00.000Z",
+		});
+		const renamed = chatSession({
+			title: "Renamed",
+			updatedAt: "2026-05-16T00:02:00.000Z",
+		});
+
+		expect(mergeChatSessions([current], [renamed])).toEqual([renamed]);
+	});
 });
 
 function chatSession(
diff --git a/packages/web/tests/chat-session-title-rename.test.ts b/packages/web/tests/chat-session-title-rename.test.ts
new file mode 100644
index 00000000..c449b458
--- /dev/null
+++ b/packages/web/tests/chat-session-title-rename.test.ts
@@ -0,0 +1,76 @@
+import { describe, expect, it } from "bun:test";
+import { createChatSessionTitleRenameHandler } from "../src/components/chat-room/chat-session-title-rename";
+import type { ChatSessionRecord } from "../src/lib/api";
+
+describe("chat session title rename", () => {
+	it("trims changed titles before updating the session", async () => {
+		const updates: unknown[] = [];
+		const renameTitle = createChatSessionTitleRenameHandler({
+			renameSession: async (input) => {
+				updates.push(input);
+			},
+			selectedSession: chatSession({ title: "Untitled" }),
+			showError: () => {},
+		});
+
+		await expect(renameTitle(" Renamed ")).resolves.toBe(true);
+
+		expect(updates).toEqual([
+			{
+				sessionId: "session-1",
+				session: { title: "Renamed" },
+			},
+		]);
+	});
+
+	it("skips empty and unchanged titles", async () => {
+		const updates: unknown[] = [];
+		const renameTitle = createChatSessionTitleRenameHandler({
+			renameSession: async (input) => {
+				updates.push(input);
+			},
+			selectedSession: chatSession({ title: "Untitled" }),
+			showError: () => {},
+		});
+
+		await expect(renameTitle("   ")).resolves.toBe(false);
+		await expect(renameTitle(" Untitled ")).resolves.toBe(true);
+
+		expect(updates).toEqual([]);
+	});
+
+	it("keeps edit mode open when the update fails", async () => {
+		const errors: string[] = [];
+		const renameTitle = createChatSessionTitleRenameHandler({
+			renameSession: async () => {
+				throw new Error("Network failed");
+			},
+			selectedSession: chatSession({ title: "Untitled" }),
+			showError: (message) => errors.push(message),
+		});
+
+		await expect(renameTitle("Renamed")).resolves.toBe(false);
+
+		expect(errors).toEqual(["Network failed"]);
+	});
+});
+
+function chatSession(
+	overrides: Partial<ChatSessionRecord> = {},
+): ChatSessionRecord {
+	return {
+		id: "session-1",
+		workspaceId: "owner-1",
+		projectId: "default",
+		taskId: "task-1",
+		title: "Untitled",
+		pendingRequest: null,
+		pendingQuestions: [],
+		archived: false,
+		workflowState: null,
+		createdAt: "2026-05-16T00:00:00.000Z",
+		updatedAt: "2026-05-16T00:00:00.000Z",
+		lastSeenAt: "2026-05-16T00:00:00.000Z",
+		...overrides,
+	};
+}