diff --git a/.mcp.json b/.mcp.json
index a36a88a..22f1f26 100644
--- a/.mcp.json
+++ b/.mcp.json
@@ -2,7 +2,7 @@
   "mcpServers": {
     "story-kit": {
       "type": "http",
-      "url": "http://localhost:3001/mcp"
+      "url": "http://localhost:3010/mcp"
     }
   }
 }
diff --git a/frontend/src/components/Chat.test.tsx b/frontend/src/components/Chat.test.tsx
index 29bbf5f..39208c0 100644
--- a/frontend/src/components/Chat.test.tsx
+++ b/frontend/src/components/Chat.test.tsx
@@ -1275,3 +1275,114 @@ describe("Remove bubble styling from streaming messages (Story 163)", () => {
 		expect(styleAttr).not.toContain("background: transparent");
 	});
 });
+
+describe("Bug 264: Claude Code session ID persisted across browser refresh", () => {
+	const PROJECT_PATH = "/tmp/project";
+	const SESSION_KEY = `storykit-claude-session-id:${PROJECT_PATH}`;
+	const STORAGE_KEY = `storykit-chat-history:${PROJECT_PATH}`;
+
+	beforeEach(() => {
+		capturedWsHandlers = null;
+		lastSendChatArgs = null;
+		localStorage.clear();
+		setupMocks();
+	});
+
+	afterEach(() => {
+		localStorage.clear();
+	});
+
+	it("AC1: session_id is persisted to localStorage when onSessionId fires", async () => {
+		render(<Chat projectPath={PROJECT_PATH} onCloseProject={vi.fn()} />);
+
+		await waitFor(() => expect(capturedWsHandlers).not.toBeNull());
+
+		act(() => {
+			capturedWsHandlers?.onSessionId("test-session-abc");
+		});
+
+		await waitFor(() => {
+			expect(localStorage.getItem(SESSION_KEY)).toBe("test-session-abc");
+		});
+	});
+
+	it("AC2: after remount, next sendChat includes session_id from localStorage", async () => {
+		// Step 1: Render, receive a session ID, then unmount (simulate refresh)
+		localStorage.setItem(SESSION_KEY, "persisted-session-xyz");
+		localStorage.setItem(
+			STORAGE_KEY,
+			JSON.stringify([
+				{ role: "user", content: "Prior message" },
+				{ role: "assistant", content: "Prior reply" },
+			]),
+		);
+
+		const { unmount } = render(
+			<Chat projectPath={PROJECT_PATH} onCloseProject={vi.fn()} />,
+		);
+		await waitFor(() => expect(capturedWsHandlers).not.toBeNull());
+		unmount();
+
+		// Step 2: Remount (simulates page reload)
+		capturedWsHandlers = null;
+		lastSendChatArgs = null;
+		render(<Chat projectPath={PROJECT_PATH} onCloseProject={vi.fn()} />);
+		await waitFor(() => expect(capturedWsHandlers).not.toBeNull());
+
+		// Prior messages should be visible
+		expect(await screen.findByText("Prior message")).toBeInTheDocument();
+
+		// Step 3: Send a new message — config should include session_id
+		const input = screen.getByPlaceholderText("Send a message...");
+		await act(async () => {
+			fireEvent.change(input, { target: { value: "Continue" } });
+		});
+		await act(async () => {
+			fireEvent.keyDown(input, { key: "Enter", shiftKey: false });
+		});
+
+		expect(lastSendChatArgs).not.toBeNull();
+		expect(
+			(lastSendChatArgs?.config as Record<string, unknown>).session_id,
+		).toBe("persisted-session-xyz");
+	});
+
+	it("AC3: clearing the session also clears the persisted session_id", async () => {
+		localStorage.setItem(SESSION_KEY, "session-to-clear");
+
+		const confirmSpy = vi.spyOn(window, "confirm").mockReturnValue(true);
+
+		render(<Chat projectPath={PROJECT_PATH} onCloseProject={vi.fn()} />);
+
+		await waitFor(() => expect(capturedWsHandlers).not.toBeNull());
+
+		const newSessionBtn = screen.getByText(/New Session/);
+		await act(async () => {
+			fireEvent.click(newSessionBtn);
+		});
+
+		expect(localStorage.getItem(SESSION_KEY)).toBeNull();
+
+		confirmSpy.mockRestore();
+	});
+
+	it("AC1: storage key is scoped to project path", async () => {
+		const otherPath = "/other/project";
+		const otherKey = `storykit-claude-session-id:${otherPath}`;
+		localStorage.setItem(otherKey, "other-session");
+
+		render(<Chat projectPath={PROJECT_PATH} onCloseProject={vi.fn()} />);
+		await waitFor(() => expect(capturedWsHandlers).not.toBeNull());
+
+		act(() => {
+			capturedWsHandlers?.onSessionId("my-session");
+		});
+
+		await waitFor(() => {
+			expect(localStorage.getItem(SESSION_KEY)).toBe("my-session");
+		});
+
+		// Other project's session should be untouched
+		expect(localStorage.getItem(otherKey)).toBe("other-session");
+	});
+});
diff --git a/frontend/src/components/Chat.tsx b/frontend/src/components/Chat.tsx
index 8b9e605..b656594 100644
--- a/frontend/src/components/Chat.tsx
+++ b/frontend/src/components/Chat.tsx
@@ -171,7 +171,16 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
 		merge: [],
 		done: [],
 	});
-	const [claudeSessionId, setClaudeSessionId] = useState<string | null>(null);
+	const [claudeSessionId, setClaudeSessionId] = useState<string | null>(() => {
+		try {
+			return (
+				localStorage.getItem(`storykit-claude-session-id:${projectPath}`) ??
+				null
+			);
+		} catch {
+			return null;
+		}
+	});
 	const [activityStatus, setActivityStatus] = useState<string | null>(null);
 	const [permissionQueue, setPermissionQueue] = useState<
 		{
@@ -247,6 +256,21 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
 		};
 	}, [messages, streamingContent, model]);
 
+	useEffect(() => {
+		try {
+			if (claudeSessionId !== null) {
+				localStorage.setItem(
+					`storykit-claude-session-id:${projectPath}`,
+					claudeSessionId,
+				);
+			} else {
+				localStorage.removeItem(`storykit-claude-session-id:${projectPath}`);
+			}
+		} catch {
+			// Ignore — quota or security errors.
+		}
+	}, [claudeSessionId, projectPath]);
+
 	useEffect(() => {
 		api
 			.getOllamaModels()
@@ -664,6 +688,11 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
 			setLoading(false);
 			setActivityStatus(null);
 			setClaudeSessionId(null);
+			try {
+				localStorage.removeItem(`storykit-claude-session-id:${projectPath}`);
+			} catch {
+				// Ignore — quota or security errors.
+			}
 		}
 	};