diff --git a/extension/dist/background.js b/extension/dist/background.js
index 7a34be1..6849431 100644
--- a/extension/dist/background.js
+++ b/extension/dist/background.js
@@ -160,30 +160,35 @@ function scheduleReconnect() {
     connect();
   }, delay);
 }
-let automationWindowId = null;
-let windowIdleTimer = null;
+const automationSessions = /* @__PURE__ */ new Map();
 const WINDOW_IDLE_TIMEOUT = 3e4;
-function resetWindowIdleTimer() {
-  if (windowIdleTimer) clearTimeout(windowIdleTimer);
-  windowIdleTimer = setTimeout(async () => {
-    if (automationWindowId !== null) {
-      try {
-        await chrome.windows.remove(automationWindowId);
-        console.log(`[opencli] Automation window ${automationWindowId} closed (idle timeout)`);
-      } catch {
-      }
-      automationWindowId = null;
+function getWorkspaceKey(workspace) {
+  return workspace?.trim() || "default";
+}
+function resetWindowIdleTimer(workspace) {
+  const session = automationSessions.get(workspace);
+  if (!session) return;
+  if (session.idleTimer) clearTimeout(session.idleTimer);
+  session.idleDeadlineAt = Date.now() + WINDOW_IDLE_TIMEOUT;
+  session.idleTimer = setTimeout(async () => {
+    const current = automationSessions.get(workspace);
+    if (!current) return;
+    try {
+      await chrome.windows.remove(current.windowId);
+      console.log(`[opencli] Automation window ${current.windowId} (${workspace}) closed (idle timeout)`);
+    } catch {
     }
-    windowIdleTimer = null;
+    automationSessions.delete(workspace);
   }, WINDOW_IDLE_TIMEOUT);
 }
-async function getAutomationWindow() {
-  if (automationWindowId !== null) {
+async function getAutomationWindow(workspace) {
+  const existing = automationSessions.get(workspace);
+  if (existing) {
     try {
-      await chrome.windows.get(automationWindowId);
-      return automationWindowId;
+      await chrome.windows.get(existing.windowId);
+      return existing.windowId;
     } catch {
-      automationWindowId = null;
+      automationSessions.delete(workspace);
     }
   }
   const win = await chrome.windows.create({
@@ -193,17 +198,22 @@ async function getAutomationWindow() {
     height: 900,
     type: "normal"
   });
-  automationWindowId = win.id;
-  console.log(`[opencli] Created automation window ${automationWindowId}`);
-  return automationWindowId;
+  const session = {
+    windowId: win.id,
+    idleTimer: null,
+    idleDeadlineAt: Date.now() + WINDOW_IDLE_TIMEOUT
+  };
+  automationSessions.set(workspace, session);
+  console.log(`[opencli] Created automation window ${session.windowId} (${workspace})`);
+  resetWindowIdleTimer(workspace);
+  return session.windowId;
 }
 chrome.windows.onRemoved.addListener((windowId) => {
-  if (windowId === automationWindowId) {
-    console.log("[opencli] Automation window closed");
-    automationWindowId = null;
-    if (windowIdleTimer) {
-      clearTimeout(windowIdleTimer);
-      windowIdleTimer = null;
+  for (const [workspace, session] of automationSessions.entries()) {
+    if (session.windowId === windowId) {
+      console.log(`[opencli] Automation window closed (${workspace})`);
+      if (session.idleTimer) clearTimeout(session.idleTimer);
+      automationSessions.delete(workspace);
     }
   }
 });
@@ -226,21 +236,24 @@ chrome.alarms.onAlarm.addListener((alarm) => {
   if (alarm.name === "keepalive") connect();
 });
 async function handleCommand(cmd) {
-  resetWindowIdleTimer();
+  const workspace = getWorkspaceKey(cmd.workspace);
+  resetWindowIdleTimer(workspace);
   try {
     switch (cmd.action) {
       case "exec":
-        return await handleExec(cmd);
+        return await handleExec(cmd, workspace);
       case "navigate":
-        return await handleNavigate(cmd);
+        return await handleNavigate(cmd, workspace);
       case "tabs":
-        return await handleTabs(cmd);
+        return await handleTabs(cmd, workspace);
       case "cookies":
         return await handleCookies(cmd);
       case "screenshot":
-        return await handleScreenshot(cmd);
+        return await handleScreenshot(cmd, workspace);
       case "close-window":
-        return await handleCloseWindow(cmd);
+        return await handleCloseWindow(cmd, workspace);
+      case "sessions":
+        return await handleSessions(cmd);
       default:
         return { id: cmd.id, ok: false, error: `Unknown action: ${cmd.action}` };
     }
@@ -256,9 +269,9 @@ function isWebUrl(url) {
   if (!url) return false;
   return !url.startsWith("chrome://") && !url.startsWith("chrome-extension://");
 }
-async function resolveTabId(tabId) {
+async function resolveTabId(tabId, workspace) {
   if (tabId !== void 0) return tabId;
-  const windowId = await getAutomationWindow();
+  const windowId = await getAutomationWindow(workspace);
   const tabs = await chrome.tabs.query({ windowId });
   const webTab = tabs.find((t) => t.id && isWebUrl(t.url));
   if (webTab?.id) return webTab.id;
@@ -267,22 +280,23 @@ async function resolveTabId(tabId) {
   if (!newTab.id) throw new Error("Failed to create tab in automation window");
   return newTab.id;
 }
-async function listAutomationTabs() {
-  if (automationWindowId === null) return [];
+async function listAutomationTabs(workspace) {
+  const session = automationSessions.get(workspace);
+  if (!session) return [];
   try {
-    return await chrome.tabs.query({ windowId: automationWindowId });
+    return await chrome.tabs.query({ windowId: session.windowId });
   } catch {
-    automationWindowId = null;
+    automationSessions.delete(workspace);
     return [];
   }
 }
-async function listAutomationWebTabs() {
-  const tabs = await listAutomationTabs();
+async function listAutomationWebTabs(workspace) {
+  const tabs = await listAutomationTabs(workspace);
   return tabs.filter((tab) => isWebUrl(tab.url));
 }
-async function handleExec(cmd) {
+async function handleExec(cmd, workspace) {
   if (!cmd.code) return { id: cmd.id, ok: false, error: "Missing code" };
-  const tabId = await resolveTabId(cmd.tabId);
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   try {
     const data = await evaluateAsync(tabId, cmd.code);
     return { id: cmd.id, ok: true, data };
@@ -290,9 +304,9 @@ async function handleExec(cmd) {
     return { id: cmd.id, ok: false, error: err instanceof Error ? err.message : String(err) };
   }
 }
-async function handleNavigate(cmd) {
+async function handleNavigate(cmd, workspace) {
   if (!cmd.url) return { id: cmd.id, ok: false, error: "Missing url" };
-  const tabId = await resolveTabId(cmd.tabId);
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   await chrome.tabs.update(tabId, { url: cmd.url });
   await new Promise((resolve) => {
     chrome.tabs.get(tabId).then((tab2) => {
@@ -316,10 +330,10 @@ async function handleNavigate(cmd) {
   const tab = await chrome.tabs.get(tabId);
   return { id: cmd.id, ok: true, data: { title: tab.title, url: tab.url, tabId } };
 }
-async function handleTabs(cmd) {
+async function handleTabs(cmd, workspace) {
   switch (cmd.op) {
     case "list": {
-      const tabs = await listAutomationWebTabs();
+      const tabs = await listAutomationWebTabs(workspace);
       const data = tabs.map((t, i) => ({
         index: i,
         tabId: t.id,
@@ -330,20 +344,20 @@ async function handleTabs(cmd) {
       return { id: cmd.id, ok: true, data };
     }
     case "new": {
-      const windowId = await getAutomationWindow();
+      const windowId = await getAutomationWindow(workspace);
       const tab = await chrome.tabs.create({ windowId, url: cmd.url ?? "about:blank", active: true });
       return { id: cmd.id, ok: true, data: { tabId: tab.id, url: tab.url } };
     }
     case "close": {
       if (cmd.index !== void 0) {
-        const tabs = await listAutomationWebTabs();
+        const tabs = await listAutomationWebTabs(workspace);
         const target = tabs[cmd.index];
         if (!target?.id) return { id: cmd.id, ok: false, error: `Tab index ${cmd.index} not found` };
         await chrome.tabs.remove(target.id);
         detach(target.id);
         return { id: cmd.id, ok: true, data: { closed: target.id } };
       }
-      const tabId = await resolveTabId(cmd.tabId);
+      const tabId = await resolveTabId(cmd.tabId, workspace);
       await chrome.tabs.remove(tabId);
       detach(tabId);
       return { id: cmd.id, ok: true, data: { closed: tabId } };
@@ -355,7 +369,7 @@ async function handleTabs(cmd) {
         await chrome.tabs.update(cmd.tabId, { active: true });
         return { id: cmd.id, ok: true, data: { selected: cmd.tabId } };
       }
-      const tabs = await listAutomationWebTabs();
+      const tabs = await listAutomationWebTabs(workspace);
       const target = tabs[cmd.index];
       if (!target?.id) return { id: cmd.id, ok: false, error: `Tab index ${cmd.index} not found` };
       await chrome.tabs.update(target.id, { active: true });
@@ -381,8 +395,8 @@ async function handleCookies(cmd) {
   }));
   return { id: cmd.id, ok: true, data };
 }
-async function handleScreenshot(cmd) {
-  const tabId = await resolveTabId(cmd.tabId);
+async function handleScreenshot(cmd, workspace) {
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   try {
     const data = await screenshot(tabId, {
       format: cmd.format,
@@ -394,13 +408,25 @@ async function handleScreenshot(cmd) {
     return { id: cmd.id, ok: false, error: err instanceof Error ? err.message : String(err) };
   }
 }
-async function handleCloseWindow(cmd) {
-  if (automationWindowId !== null) {
+async function handleCloseWindow(cmd, workspace) {
+  const session = automationSessions.get(workspace);
+  if (session) {
     try {
-      await chrome.windows.remove(automationWindowId);
+      await chrome.windows.remove(session.windowId);
     } catch {
     }
-    automationWindowId = null;
+    if (session.idleTimer) clearTimeout(session.idleTimer);
+    automationSessions.delete(workspace);
   }
   return { id: cmd.id, ok: true, data: { closed: true } };
 }
+async function handleSessions(cmd) {
+  const now = Date.now();
+  const data = await Promise.all([...automationSessions.entries()].map(async ([workspace, session]) => ({
+    workspace,
+    windowId: session.windowId,
+    tabCount: (await chrome.tabs.query({ windowId: session.windowId })).filter((tab) => isWebUrl(tab.url)).length,
+    idleMsRemaining: Math.max(0, session.idleDeadlineAt - now)
+  })));
+  return { id: cmd.id, ok: true, data };
+}
diff --git a/extension/src/background.test.ts b/extension/src/background.test.ts
index 483e80f..0f1f39e 100644
--- a/extension/src/background.test.ts
+++ b/extension/src/background.test.ts
@@ -104,9 +104,9 @@ describe('background tab isolation', () => {
     vi.stubGlobal('chrome', chrome);
 
     const mod = await import('./background');
-    mod.__test__.setAutomationWindowId(1);
+    mod.__test__.setAutomationWindowId('site:twitter', 1);
 
-    const result = await mod.__test__.handleTabs({ id: '1', action: 'tabs', op: 'list' });
+    const result = await mod.__test__.handleTabs({ id: '1', action: 'tabs', op: 'list', workspace: 'site:twitter' }, 'site:twitter');
 
     expect(result.ok).toBe(true);
     expect(result.data).toEqual([
@@ -125,11 +125,27 @@ describe('background tab isolation', () => {
     vi.stubGlobal('chrome', chrome);
 
     const mod = await import('./background');
-    mod.__test__.setAutomationWindowId(1);
+    mod.__test__.setAutomationWindowId('site:twitter', 1);
 
-    const result = await mod.__test__.handleTabs({ id: '2', action: 'tabs', op: 'new', url: 'https://new.example' });
+    const result = await mod.__test__.handleTabs({ id: '2', action: 'tabs', op: 'new', url: 'https://new.example', workspace: 'site:twitter' }, 'site:twitter');
 
     expect(result.ok).toBe(true);
     expect(create).toHaveBeenCalledWith({ windowId: 1, url: 'https://new.example', active: true });
   });
+
+  it('reports sessions per workspace', async () => {
+    const { chrome } = createChromeMock();
+    vi.stubGlobal('chrome', chrome);
+
+    const mod = await import('./background');
+    mod.__test__.setAutomationWindowId('site:twitter', 1);
+    mod.__test__.setAutomationWindowId('site:zhihu', 2);
+
+    const result = await mod.__test__.handleSessions({ id: '3', action: 'sessions' });
+    expect(result.ok).toBe(true);
+    expect(result.data).toEqual(expect.arrayContaining([
+      expect.objectContaining({ workspace: 'site:twitter', windowId: 1 }),
+      expect.objectContaining({ workspace: 'site:zhihu', windowId: 2 }),
+    ]));
+  });
 });
diff --git a/extension/src/background.ts b/extension/src/background.ts
index c8b2e69..878c6bd 100644
--- a/extension/src/background.ts
+++ b/extension/src/background.ts
@@ -90,36 +90,48 @@ function scheduleReconnect(): void {
 // user's active browsing session is never touched.
 // The window auto-closes after 30s of idle (no commands).
 
-let automationWindowId: number | null = null;
-let windowIdleTimer: ReturnType<typeof setTimeout> | null = null;
+type AutomationSession = {
+  windowId: number;
+  idleTimer: ReturnType<typeof setTimeout> | null;
+  idleDeadlineAt: number;
+};
+
+const automationSessions = new Map<string, AutomationSession>();
 const WINDOW_IDLE_TIMEOUT = 30000; // 30s
 
-function resetWindowIdleTimer(): void {
-  if (windowIdleTimer) clearTimeout(windowIdleTimer);
-  windowIdleTimer = setTimeout(async () => {
-    if (automationWindowId !== null) {
-      try {
-        await chrome.windows.remove(automationWindowId);
-        console.log(`[opencli] Automation window ${automationWindowId} closed (idle timeout)`);
-      } catch {
-        // Already gone
-      }
-      automationWindowId = null;
+function getWorkspaceKey(workspace?: string): string {
+  return workspace?.trim() || 'default';
+}
+
+function resetWindowIdleTimer(workspace: string): void {
+  const session = automationSessions.get(workspace);
+  if (!session) return;
+  if (session.idleTimer) clearTimeout(session.idleTimer);
+  session.idleDeadlineAt = Date.now() + WINDOW_IDLE_TIMEOUT;
+  session.idleTimer = setTimeout(async () => {
+    const current = automationSessions.get(workspace);
+    if (!current) return;
+    try {
+      await chrome.windows.remove(current.windowId);
+      console.log(`[opencli] Automation window ${current.windowId} (${workspace}) closed (idle timeout)`);
+    } catch {
+      // Already gone
     }
-    windowIdleTimer = null;
+    automationSessions.delete(workspace);
   }, WINDOW_IDLE_TIMEOUT);
 }
 
 /** Get or create the dedicated automation window. */
-async function getAutomationWindow(): Promise<number> {
+async function getAutomationWindow(workspace: string): Promise<number> {
   // Check if our window is still alive
-  if (automationWindowId !== null) {
+  const existing = automationSessions.get(workspace);
+  if (existing) {
     try {
-      await chrome.windows.get(automationWindowId);
-      return automationWindowId;
+      await chrome.windows.get(existing.windowId);
+      return existing.windowId;
     } catch {
       // Window was closed by user
-      automationWindowId = null;
+      automationSessions.delete(workspace);
     }
   }
 
@@ -131,17 +143,25 @@ async function getAutomationWindow(): Promise<number> {
     height: 900,
     type: 'normal',
   });
-  automationWindowId = win.id!;
-  console.log(`[opencli] Created automation window ${automationWindowId}`);
-  return automationWindowId;
+  const session: AutomationSession = {
+    windowId: win.id!,
+    idleTimer: null,
+    idleDeadlineAt: Date.now() + WINDOW_IDLE_TIMEOUT,
+  };
+  automationSessions.set(workspace, session);
+  console.log(`[opencli] Created automation window ${session.windowId} (${workspace})`);
+  resetWindowIdleTimer(workspace);
+  return session.windowId;
 }
 
 // Clean up when the automation window is closed
 chrome.windows.onRemoved.addListener((windowId) => {
-  if (windowId === automationWindowId) {
-    console.log('[opencli] Automation window closed');
-    automationWindowId = null;
-    if (windowIdleTimer) { clearTimeout(windowIdleTimer); windowIdleTimer = null; }
+  for (const [workspace, session] of automationSessions.entries()) {
+    if (session.windowId === windowId) {
+      console.log(`[opencli] Automation window closed (${workspace})`);
+      if (session.idleTimer) clearTimeout(session.idleTimer);
+      automationSessions.delete(workspace);
+    }
   }
 });
 
@@ -173,22 +193,25 @@ chrome.alarms.onAlarm.addListener((alarm) => {
 // ─── Command dispatcher ─────────────────────────────────────────────
 
 async function handleCommand(cmd: Command): Promise<Result> {
+  const workspace = getWorkspaceKey(cmd.workspace);
   // Reset idle timer on every command (window stays alive while active)
-  resetWindowIdleTimer();
+  resetWindowIdleTimer(workspace);
   try {
     switch (cmd.action) {
       case 'exec':
-        return await handleExec(cmd);
+        return await handleExec(cmd, workspace);
       case 'navigate':
-        return await handleNavigate(cmd);
+        return await handleNavigate(cmd, workspace);
       case 'tabs':
-        return await handleTabs(cmd);
+        return await handleTabs(cmd, workspace);
       case 'cookies':
         return await handleCookies(cmd);
       case 'screenshot':
-        return await handleScreenshot(cmd);
+        return await handleScreenshot(cmd, workspace);
       case 'close-window':
-        return await handleCloseWindow(cmd);
+        return await handleCloseWindow(cmd, workspace);
+      case 'sessions':
+        return await handleSessions(cmd);
       default:
         return { id: cmd.id, ok: false, error: `Unknown action: ${cmd.action}` };
     }
@@ -214,11 +237,11 @@ function isWebUrl(url?: string): boolean {
  * If explicit tabId is given, use that directly.
  * Otherwise, find or create a tab in the dedicated automation window.
  */
-async function resolveTabId(tabId?: number): Promise<number> {
+async function resolveTabId(tabId: number | undefined, workspace: string): Promise<number> {
   if (tabId !== undefined) return tabId;
 
   // Get (or create) the automation window
-  const windowId = await getAutomationWindow();
+  const windowId = await getAutomationWindow(workspace);
 
   // Find the active tab in our automation window
   const tabs = await chrome.tabs.query({ windowId });
@@ -234,24 +257,25 @@ async function resolveTabId(tabId?: number): Promise<number> {
   return newTab.id;
 }
 
-async function listAutomationTabs(): Promise<chrome.tabs.Tab[]> {
-  if (automationWindowId === null) return [];
+async function listAutomationTabs(workspace: string): Promise<chrome.tabs.Tab[]> {
+  const session = automationSessions.get(workspace);
+  if (!session) return [];
   try {
-    return await chrome.tabs.query({ windowId: automationWindowId });
+    return await chrome.tabs.query({ windowId: session.windowId });
   } catch {
-    automationWindowId = null;
+    automationSessions.delete(workspace);
     return [];
   }
 }
 
-async function listAutomationWebTabs(): Promise<chrome.tabs.Tab[]> {
-  const tabs = await listAutomationTabs();
+async function listAutomationWebTabs(workspace: string): Promise<chrome.tabs.Tab[]> {
+  const tabs = await listAutomationTabs(workspace);
   return tabs.filter((tab) => isWebUrl(tab.url));
 }
 
-async function handleExec(cmd: Command): Promise<Result> {
+async function handleExec(cmd: Command, workspace: string): Promise<Result> {
   if (!cmd.code) return { id: cmd.id, ok: false, error: 'Missing code' };
-  const tabId = await resolveTabId(cmd.tabId);
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   try {
     const data = await executor.evaluateAsync(tabId, cmd.code);
     return { id: cmd.id, ok: true, data };
@@ -260,9 +284,9 @@ async function handleExec(cmd: Command): Promise<Result> {
   }
 }
 
-async function handleNavigate(cmd: Command): Promise<Result> {
+async function handleNavigate(cmd: Command, workspace: string): Promise<Result> {
   if (!cmd.url) return { id: cmd.id, ok: false, error: 'Missing url' };
-  const tabId = await resolveTabId(cmd.tabId);
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   await chrome.tabs.update(tabId, { url: cmd.url });
 
   // Wait for page to finish loading, checking current status first to avoid race
@@ -290,10 +314,10 @@ async function handleNavigate(cmd: Command): Promise<Result> {
   return { id: cmd.id, ok: true, data: { title: tab.title, url: tab.url, tabId } };
 }
 
-async function handleTabs(cmd: Command): Promise<Result> {
+async function handleTabs(cmd: Command, workspace: string): Promise<Result> {
   switch (cmd.op) {
     case 'list': {
-      const tabs = await listAutomationWebTabs();
+      const tabs = await listAutomationWebTabs(workspace);
       const data = tabs
         .map((t, i) => ({
           index: i,
@@ -305,20 +329,20 @@ async function handleTabs(cmd: Command): Promise<Result> {
       return { id: cmd.id, ok: true, data };
     }
     case 'new': {
-      const windowId = await getAutomationWindow();
+      const windowId = await getAutomationWindow(workspace);
       const tab = await chrome.tabs.create({ windowId, url: cmd.url ?? 'about:blank', active: true });
       return { id: cmd.id, ok: true, data: { tabId: tab.id, url: tab.url } };
     }
     case 'close': {
       if (cmd.index !== undefined) {
-        const tabs = await listAutomationWebTabs();
+        const tabs = await listAutomationWebTabs(workspace);
         const target = tabs[cmd.index];
         if (!target?.id) return { id: cmd.id, ok: false, error: `Tab index ${cmd.index} not found` };
         await chrome.tabs.remove(target.id);
         executor.detach(target.id);
         return { id: cmd.id, ok: true, data: { closed: target.id } };
       }
-      const tabId = await resolveTabId(cmd.tabId);
+      const tabId = await resolveTabId(cmd.tabId, workspace);
       await chrome.tabs.remove(tabId);
       executor.detach(tabId);
       return { id: cmd.id, ok: true, data: { closed: tabId } };
@@ -330,7 +354,7 @@ async function handleTabs(cmd: Command): Promise<Result> {
         await chrome.tabs.update(cmd.tabId, { active: true });
         return { id: cmd.id, ok: true, data: { selected: cmd.tabId } };
       }
-      const tabs = await listAutomationWebTabs();
+      const tabs = await listAutomationWebTabs(workspace);
       const target = tabs[cmd.index!];
       if (!target?.id) return { id: cmd.id, ok: false, error: `Tab index ${cmd.index} not found` };
       await chrome.tabs.update(target.id, { active: true });
@@ -358,8 +382,8 @@ async function handleCookies(cmd: Command): Promise<Result> {
   return { id: cmd.id, ok: true, data };
 }
 
-async function handleScreenshot(cmd: Command): Promise<Result> {
-  const tabId = await resolveTabId(cmd.tabId);
+async function handleScreenshot(cmd: Command, workspace: string): Promise<Result> {
+  const tabId = await resolveTabId(cmd.tabId, workspace);
   try {
     const data = await executor.screenshot(tabId, {
       format: cmd.format,
@@ -372,22 +396,46 @@ async function handleScreenshot(cmd: Command): Promise<Result> {
   }
 }
 
-async function handleCloseWindow(cmd: Command): Promise<Result> {
-  if (automationWindowId !== null) {
+async function handleCloseWindow(cmd: Command, workspace: string): Promise<Result> {
+  const session = automationSessions.get(workspace);
+  if (session) {
     try {
-      await chrome.windows.remove(automationWindowId);
+      await chrome.windows.remove(session.windowId);
     } catch {
       // Window may already be closed
     }
-    automationWindowId = null;
+    if (session.idleTimer) clearTimeout(session.idleTimer);
+    automationSessions.delete(workspace);
   }
   return { id: cmd.id, ok: true, data: { closed: true } };
 }
 
+async function handleSessions(cmd: Command): Promise<Result> {
+  const now = Date.now();
+  const data = await Promise.all([...automationSessions.entries()].map(async ([workspace, session]) => ({
+    workspace,
+    windowId: session.windowId,
+    tabCount: (await chrome.tabs.query({ windowId: session.windowId })).filter((tab) => isWebUrl(tab.url)).length,
+    idleMsRemaining: Math.max(0, session.idleDeadlineAt - now),
+  })));
+  return { id: cmd.id, ok: true, data };
+}
+
 export const __test__ = {
   handleTabs,
-  getAutomationWindowId: () => automationWindowId,
-  setAutomationWindowId: (windowId: number | null) => {
-    automationWindowId = windowId;
+  handleSessions,
+  getAutomationWindowId: (workspace: string = 'default') => automationSessions.get(workspace)?.windowId ?? null,
+  setAutomationWindowId: (workspace: string, windowId: number | null) => {
+    if (windowId === null) {
+      const session = automationSessions.get(workspace);
+      if (session?.idleTimer) clearTimeout(session.idleTimer);
+      automationSessions.delete(workspace);
+      return;
+    }
+    automationSessions.set(workspace, {
+      windowId,
+      idleTimer: null,
+      idleDeadlineAt: Date.now() + WINDOW_IDLE_TIMEOUT,
+    });
   },
 };
diff --git a/extension/src/protocol.ts b/extension/src/protocol.ts
index 8e9f19c..0d05386 100644
--- a/extension/src/protocol.ts
+++ b/extension/src/protocol.ts
@@ -5,7 +5,7 @@
  * Everything else is just JS code sent via 'exec'.
  */
 
-export type Action = 'exec' | 'navigate' | 'tabs' | 'cookies' | 'screenshot' | 'close-window';
+export type Action = 'exec' | 'navigate' | 'tabs' | 'cookies' | 'screenshot' | 'close-window' | 'sessions';
 
 export interface Command {
   /** Unique request ID */
@@ -16,6 +16,8 @@ export interface Command {
   tabId?: number;
   /** JS code to evaluate in page context (exec action) */
   code?: string;
+  /** Logical workspace for automation session reuse */
+  workspace?: string;
   /** URL to navigate to (navigate action) */
   url?: string;
   /** Sub-operation for tabs: list, new, close, select */
diff --git a/src/browser/cdp.ts b/src/browser/cdp.ts
index 83d6eb3..4682329 100644
--- a/src/browser/cdp.ts
+++ b/src/browser/cdp.ts
@@ -18,7 +18,7 @@ export class CDPBridge {
   private _idCounter = 0;
   private _pending = new Map<number, { resolve: (val: any) => void; reject: (err: Error) => void }>();
 
-  async connect(opts?: { timeout?: number }): Promise<IPage> {
+  async connect(opts?: { timeout?: number; workspace?: string }): Promise<IPage> {
     const endpoint = process.env.OPENCLI_CDP_ENDPOINT;
     if (!endpoint) throw new Error('OPENCLI_CDP_ENDPOINT is not set');
 
diff --git a/src/browser/daemon-client.ts b/src/browser/daemon-client.ts
index 6239cb7..77d5ba8 100644
--- a/src/browser/daemon-client.ts
+++ b/src/browser/daemon-client.ts
@@ -15,9 +15,10 @@ function generateId(): string {
 
 export interface DaemonCommand {
   id: string;
-  action: 'exec' | 'navigate' | 'tabs' | 'cookies' | 'screenshot' | 'close-window';
+  action: 'exec' | 'navigate' | 'tabs' | 'cookies' | 'screenshot' | 'close-window' | 'sessions';
   tabId?: number;
   code?: string;
+  workspace?: string;
   url?: string;
   op?: string;
   index?: number;
@@ -111,3 +112,8 @@ export async function sendCommand(
   // Unreachable — the loop always returns or throws
   throw new Error('sendCommand: max retries exhausted');
 }
+
+export async function listSessions(): Promise<any[]> {
+  const result = await sendCommand('sessions');
+  return Array.isArray(result) ? result : [];
+}
diff --git a/src/browser/mcp.ts b/src/browser/mcp.ts
index a42a744..655810a 100644
--- a/src/browser/mcp.ts
+++ b/src/browser/mcp.ts
@@ -26,7 +26,7 @@ export class BrowserBridge {
     return this._state;
   }
 
-  async connect(opts: { timeout?: number } = {}): Promise<IPage> {
+  async connect(opts: { timeout?: number; workspace?: string } = {}): Promise<IPage> {
     if (this._state === 'connected' && this._page) return this._page;
     if (this._state === 'connecting') throw new Error('Already connecting');
     if (this._state === 'closing') throw new Error('Session is closing');
@@ -36,7 +36,7 @@ export class BrowserBridge {
 
     try {
       await this._ensureDaemon(opts.timeout);
-      this._page = new Page();
+      this._page = new Page(opts.workspace);
       this._state = 'connected';
       return this._page;
     } catch (err) {
diff --git a/src/browser/page.ts b/src/browser/page.ts
index a1623d0..7096be3 100644
--- a/src/browser/page.ts
+++ b/src/browser/page.ts
@@ -19,6 +19,8 @@ import { wrapForEval } from './utils.js';
  * Page — implements IPage by talking to the daemon via HTTP.
  */
 export class Page implements IPage {
+  constructor(private readonly workspace: string = 'default') {}
+
   /** Active tab ID, set after navigate and used in all subsequent commands */
   private _tabId: number | undefined;
 
@@ -27,9 +29,14 @@ export class Page implements IPage {
     return this._tabId !== undefined ? { tabId: this._tabId } : {};
   }
 
+  private _workspaceOpt(): { workspace: string } {
+    return { workspace: this.workspace };
+  }
+
   async goto(url: string): Promise<void> {
     const result = await sendCommand('navigate', {
       url,
+      ...this._workspaceOpt(),
       ...this._tabOpt(),
     }) as { tabId?: number };
     // Remember the tabId for subsequent exec calls
@@ -41,7 +48,7 @@ export class Page implements IPage {
   /** Close the automation window in the extension */
   async closeWindow(): Promise<void> {
     try {
-      await sendCommand('close-window', {});
+      await sendCommand('close-window', { ...this._workspaceOpt() });
     } catch {
       // Window may already be closed or daemon may be down
     }
@@ -49,11 +56,11 @@ export class Page implements IPage {
 
   async evaluate(js: string): Promise<any> {
     const code = wrapForEval(js);
-    return sendCommand('exec', { code, ...this._tabOpt() });
+    return sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   async getCookies(opts: { domain?: string; url?: string } = {}): Promise<any[]> {
-    const result = await sendCommand('cookies', opts);
+    const result = await sendCommand('cookies', { ...this._workspaceOpt(), ...opts });
     return Array.isArray(result) ? result : [];
   }
 
@@ -86,7 +93,7 @@ export class Page implements IPage {
         return buildTree(document.body, 0);
       })()
     `;
-    const raw = await sendCommand('exec', { code, ...this._tabOpt() });
+    const raw = await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
     if (opts.raw) return raw;
     if (typeof raw === 'string') return formatSnapshot(raw, opts);
     return raw;
@@ -105,7 +112,7 @@ export class Page implements IPage {
         return 'clicked';
       })()
     `;
-    await sendCommand('exec', { code, ...this._tabOpt() });
+    await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   async typeText(ref: string, text: string): Promise<void> {
@@ -124,7 +131,7 @@ export class Page implements IPage {
         return 'typed';
       })()
     `;
-    await sendCommand('exec', { code, ...this._tabOpt() });
+    await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   async pressKey(key: string): Promise<void> {
@@ -136,7 +143,7 @@ export class Page implements IPage {
         return 'pressed';
       })()
     `;
-    await sendCommand('exec', { code, ...this._tabOpt() });
+    await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   async wait(options: number | { text?: string; time?: number; timeout?: number }): Promise<void> {
@@ -161,24 +168,24 @@ export class Page implements IPage {
           check();
         })
       `;
-      await sendCommand('exec', { code, ...this._tabOpt() });
+      await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
     }
   }
 
   async tabs(): Promise<any> {
-    return sendCommand('tabs', { op: 'list' });
+    return sendCommand('tabs', { op: 'list', ...this._workspaceOpt() });
   }
 
   async closeTab(index?: number): Promise<void> {
-    await sendCommand('tabs', { op: 'close', ...(index !== undefined ? { index } : {}) });
+    await sendCommand('tabs', { op: 'close', ...this._workspaceOpt(), ...(index !== undefined ? { index } : {}) });
   }
 
   async newTab(): Promise<void> {
-    await sendCommand('tabs', { op: 'new' });
+    await sendCommand('tabs', { op: 'new', ...this._workspaceOpt() });
   }
 
   async selectTab(index: number): Promise<void> {
-    await sendCommand('tabs', { op: 'select', index });
+    await sendCommand('tabs', { op: 'select', index, ...this._workspaceOpt() });
   }
 
   async networkRequests(includeStatic: boolean = false): Promise<any> {
@@ -195,7 +202,7 @@ export class Page implements IPage {
           }));
       })()
     `;
-    return sendCommand('exec', { code, ...this._tabOpt() });
+    return sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   /**
@@ -221,6 +228,7 @@ export class Page implements IPage {
     path?: string;
   } = {}): Promise<string> {
     const base64 = await sendCommand('screenshot', {
+      ...this._workspaceOpt(),
       format: options.format,
       quality: options.quality,
       fullPage: options.fullPage,
@@ -243,6 +251,7 @@ export class Page implements IPage {
     const dy = direction === 'up' ? -amount : direction === 'down' ? amount : 0;
     await sendCommand('exec', {
       code: `window.scrollBy(${dx}, ${dy})`,
+      ...this._workspaceOpt(),
       ...this._tabOpt(),
     });
   }
@@ -270,7 +279,7 @@ export class Page implements IPage {
         }
       })()
     `;
-    await sendCommand('exec', { code, ...this._tabOpt() });
+    await sendCommand('exec', { code, ...this._workspaceOpt(), ...this._tabOpt() });
   }
 
   async installInterceptor(pattern: string): Promise<void> {
diff --git a/src/cli.ts b/src/cli.ts
index 92ee5fd..f2b8758 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -64,13 +64,13 @@ export function runCli(BUILTIN_CLIS: string, USER_CLIS: string): void {
     });
 
   program.command('explore').alias('probe').description('Explore a website: discover APIs, stores, and recommend strategies').argument('<url>').option('--site <name>').option('--goal <text>').option('--wait <s>', '', '3').option('--auto', 'Enable interactive fuzzing (simulate clicks to trigger lazy APIs)').option('--click <labels>', 'Comma-separated labels to click before fuzzing (e.g. "字幕,CC,评论")')
-    .action(async (url, opts) => { const { exploreUrl, renderExploreSummary } = await import('./explore.js'); const clickLabels = opts.click ? opts.click.split(',').map((s: string) => s.trim()) : undefined; const BrowserFactory = process.env.OPENCLI_CDP_ENDPOINT ? CDPBridge : BrowserBridge; console.log(renderExploreSummary(await exploreUrl(url, { BrowserFactory: BrowserFactory as any, site: opts.site, goal: opts.goal, waitSeconds: parseFloat(opts.wait), auto: opts.auto, clickLabels }))); });
+    .action(async (url, opts) => { const { exploreUrl, renderExploreSummary } = await import('./explore.js'); const clickLabels = opts.click ? opts.click.split(',').map((s: string) => s.trim()) : undefined; const BrowserFactory = process.env.OPENCLI_CDP_ENDPOINT ? CDPBridge : BrowserBridge; const workspace = `explore:${opts.site ?? (() => { try { return new URL(url).host; } catch { return 'default'; } })()}`; console.log(renderExploreSummary(await exploreUrl(url, { BrowserFactory: BrowserFactory as any, site: opts.site, goal: opts.goal, waitSeconds: parseFloat(opts.wait), auto: opts.auto, clickLabels, workspace }))); });
 
   program.command('synthesize').description('Synthesize CLIs from explore').argument('<target>').option('--top <n>', '', '3')
     .action(async (target, opts) => { const { synthesizeFromExplore, renderSynthesizeSummary } = await import('./synthesize.js'); console.log(renderSynthesizeSummary(synthesizeFromExplore(target, { top: parseInt(opts.top) }))); });
 
   program.command('generate').description('One-shot: explore → synthesize → register').argument('<url>').option('--goal <text>').option('--site <name>')
-    .action(async (url, opts) => { const { generateCliFromUrl, renderGenerateSummary } = await import('./generate.js'); const BrowserFactory = process.env.OPENCLI_CDP_ENDPOINT ? CDPBridge : BrowserBridge; const r = await generateCliFromUrl({ url, BrowserFactory: BrowserFactory as any, builtinClis: BUILTIN_CLIS, userClis: USER_CLIS, goal: opts.goal, site: opts.site }); console.log(renderGenerateSummary(r)); process.exitCode = r.ok ? 0 : 1; });
+    .action(async (url, opts) => { const { generateCliFromUrl, renderGenerateSummary } = await import('./generate.js'); const BrowserFactory = process.env.OPENCLI_CDP_ENDPOINT ? CDPBridge : BrowserBridge; const workspace = `generate:${opts.site ?? (() => { try { return new URL(url).host; } catch { return 'default'; } })()}`; const r = await generateCliFromUrl({ url, BrowserFactory: BrowserFactory as any, builtinClis: BUILTIN_CLIS, userClis: USER_CLIS, goal: opts.goal, site: opts.site, workspace }); console.log(renderGenerateSummary(r)); process.exitCode = r.ok ? 0 : 1; });
 
   program.command('cascade').description('Strategy cascade: find simplest working strategy').argument('<url>').option('--site <name>')
     .action(async (url, opts) => {
@@ -80,16 +80,17 @@ export function runCli(BUILTIN_CLIS: string, USER_CLIS: string): void {
         // Navigate to the site first for cookie context
         try { const siteUrl = new URL(url); await page.goto(`${siteUrl.protocol}//${siteUrl.host}`); await page.wait(2); } catch {}
         return cascadeProbe(page, url);
-      });
+      }, { workspace: `cascade:${opts.site ?? (() => { try { return new URL(url).host; } catch { return 'default'; } })()}` });
       console.log(renderCascadeResult(result));
     });
 
   program.command('doctor')
     .description('Diagnose opencli browser bridge connectivity')
     .option('--live', 'Test browser connectivity (requires Chrome running)', false)
+    .option('--sessions', 'Show active automation sessions', false)
     .action(async (opts) => {
       const { runBrowserDoctor, renderBrowserDoctorReport } = await import('./doctor.js');
-      const report = await runBrowserDoctor({ live: opts.live, cliVersion: PKG_VERSION });
+      const report = await runBrowserDoctor({ live: opts.live, sessions: opts.sessions, cliVersion: PKG_VERSION });
       console.log(renderBrowserDoctorReport(report));
     });
 
@@ -161,7 +162,7 @@ export function runCli(BUILTIN_CLIS: string, USER_CLIS: string): void {
           const BrowserFactory = process.env.OPENCLI_CDP_ENDPOINT ? CDPBridge : BrowserBridge;
           result = await browserSession(BrowserFactory as any, async (page) => {
             return runWithTimeout(executeCommand(cmd, page, kwargs, actionOpts.verbose), { timeout: cmd.timeoutSeconds ?? DEFAULT_BROWSER_COMMAND_TIMEOUT, label: fullName(cmd) });
-          });
+          }, { workspace: `site:${cmd.site}` });
         } else { result = await executeCommand(cmd, null, kwargs, actionOpts.verbose); }
         if (actionOpts.verbose && (!result || (Array.isArray(result) && result.length === 0))) {
           console.error(chalk.yellow(`[Verbose] Warning: Command returned an empty result. If the website structural API changed or requires authentication, check the network or update the adapter.`));
diff --git a/src/doctor.ts b/src/doctor.ts
index b01073e..733bbd5 100644
--- a/src/doctor.ts
+++ b/src/doctor.ts
@@ -8,12 +8,13 @@
 import chalk from 'chalk';
 import { checkDaemonStatus } from './browser/discover.js';
 import { BrowserBridge } from './browser/index.js';
-import { browserSession } from './runtime.js';
+import { listSessions } from './browser/daemon-client.js';
 
 export type DoctorOptions = {
   fix?: boolean;
   yes?: boolean;
   live?: boolean;
+  sessions?: boolean;
   cliVersion?: string;
 };
 
@@ -28,6 +29,7 @@ export type DoctorReport = {
   daemonRunning: boolean;
   extensionConnected: boolean;
   connectivity?: ConnectivityResult;
+  sessions?: Array<{ workspace: string; windowId: number; tabCount: number; idleMsRemaining: number }>;
   issues: string[];
 };
 
@@ -55,6 +57,9 @@ export async function runBrowserDoctor(opts: DoctorOptions = {}): Promise<Doctor
   if (opts.live) {
     connectivity = await checkConnectivity();
   }
+  const sessions = opts.sessions && status.running && status.extensionConnected
+    ? await listSessions() as Array<{ workspace: string; windowId: number; tabCount: number; idleMsRemaining: number }>
+    : undefined;
 
   const issues: string[] = [];
   if (!status.running) {
@@ -78,6 +83,7 @@ export async function runBrowserDoctor(opts: DoctorOptions = {}): Promise<Doctor
     daemonRunning: status.running,
     extensionConnected: status.extensionConnected,
     connectivity,
+    sessions,
     issues,
   };
 }
@@ -104,6 +110,17 @@ export function renderBrowserDoctorReport(report: DoctorReport): string {
     lines.push(`${chalk.dim('[SKIP]')} Connectivity: not tested (use --live)`);
   }
 
+  if (report.sessions) {
+    lines.push('', chalk.bold('Sessions:'));
+    if (report.sessions.length === 0) {
+      lines.push(chalk.dim('  • no active automation sessions'));
+    } else {
+      for (const session of report.sessions) {
+        lines.push(chalk.dim(`  • ${session.workspace} → window ${session.windowId}, tabs=${session.tabCount}, idle=${Math.ceil(session.idleMsRemaining / 1000)}s`));
+      }
+    }
+  }
+
   if (report.issues.length) {
     lines.push('', chalk.yellow('Issues:'));
     for (const issue of report.issues) {
@@ -115,4 +132,3 @@ export function renderBrowserDoctorReport(report: DoctorReport): string {
 
   return lines.join('\n');
 }
-
diff --git a/src/explore.ts b/src/explore.ts
index d86bc06..9b24e03 100644
--- a/src/explore.ts
+++ b/src/explore.ts
@@ -231,7 +231,7 @@ export async function exploreUrl(
     BrowserFactory: new () => any;
     site?: string; goal?: string; authenticated?: boolean;
     outDir?: string; waitSeconds?: number; query?: string;
-    clickLabels?: string[]; auto?: boolean;
+    clickLabels?: string[]; auto?: boolean; workspace?: string;
   },
 ): Promise<Record<string, any>> {
   const waitSeconds = opts.waitSeconds ?? 3.0;
@@ -438,7 +438,7 @@ export async function exploreUrl(
 
       return { ...result, out_dir: targetDir };
     })(), { timeout: exploreTimeout, label: `Explore ${url}` });
-  });
+  }, { workspace: opts.workspace });
 }
 
 export function renderExploreSummary(result: Record<string, any>): string {
diff --git a/src/generate.ts b/src/generate.ts
index cc669f4..103cfba 100644
--- a/src/generate.ts
+++ b/src/generate.ts
@@ -65,6 +65,7 @@ export async function generateCliFromUrl(opts: any): Promise<any> {
     site: opts.site,
     goal: normalizeGoal(opts.goal) ?? opts.goal,
     waitSeconds: opts.waitSeconds ?? 3,
+    workspace: opts.workspace,
   });
 
   // Step 2: Synthesize candidates
diff --git a/src/runtime.ts b/src/runtime.ts
index 642c988..5cf3eef 100644
--- a/src/runtime.ts
+++ b/src/runtime.ts
@@ -30,17 +30,18 @@ export function withTimeoutMs<T>(promise: Promise<T>, timeoutMs: number, message
 
 /** Interface for browser factory (BrowserBridge or test mocks) */
 export interface IBrowserFactory {
-  connect(opts?: { timeout?: number }): Promise<IPage>;
+  connect(opts?: { timeout?: number; workspace?: string }): Promise<IPage>;
   close(): Promise<void>;
 }
 
 export async function browserSession<T>(
   BrowserFactory: new () => IBrowserFactory,
   fn: (page: IPage) => Promise<T>,
+  opts: { workspace?: string } = {},
 ): Promise<T> {
   const mcp = new BrowserFactory();
   try {
-    const page = await mcp.connect({ timeout: DEFAULT_BROWSER_CONNECT_TIMEOUT });
+    const page = await mcp.connect({ timeout: DEFAULT_BROWSER_CONNECT_TIMEOUT, workspace: opts.workspace });
     return await fn(page);
   } finally {
     await mcp.close().catch(() => {});