diff --git a/backend/app/agent/factory/browser.py b/backend/app/agent/factory/browser.py
index 8d257bfe..b2cf35d1 100644
--- a/backend/app/agent/factory/browser.py
+++ b/backend/app/agent/factory/browser.py
@@ -49,7 +49,7 @@ def _is_cdp_port_alive(port: int, timeout: float = 1.0) -> bool:
     try:
         with socket.create_connection(("localhost", port), timeout=timeout):
             return True
-    except (ConnectionRefusedError, OSError, socket.timeout):
+    except (TimeoutError, ConnectionRefusedError, OSError):
         return False
 
 
@@ -234,7 +234,11 @@ def browser_agent(options: Chat):
         browser_log_to_file=True,
         stealth=True,
         session_id=toolkit_session_id,
-        **({"default_start_url": "about:blank"} if not use_pool_browser else {}),
+        **(
+            {"default_start_url": "about:blank"}
+            if not use_pool_browser
+            else {}
+        ),
         cdp_url=f"http://localhost:{selected_port}",
         cdp_keep_current_page=use_pool_browser,
         enabled_tools=[
diff --git a/backend/app/controller/tool_controller.py b/backend/app/controller/tool_controller.py
index 83d01d57..11678bd8 100644
--- a/backend/app/controller/tool_controller.py
+++ b/backend/app/controller/tool_controller.py
@@ -78,15 +78,11 @@ def _find_chromium_executable() -> str | None:
     system = pf.system()
 
     if system == "Darwin":
-        cache_dir = os.path.join(
-            home, "Library", "Caches", "ms-playwright"
-        )
+        cache_dir = os.path.join(home, "Library", "Caches", "ms-playwright")
     elif system == "Linux":
         cache_dir = os.path.join(home, ".cache", "ms-playwright")
     elif system == "Windows":
-        cache_dir = os.path.join(
-            home, "AppData", "Local", "ms-playwright"
-        )
+        cache_dir = os.path.join(home, "AppData", "Local", "ms-playwright")
     else:
         return None
 
@@ -138,9 +134,7 @@ def _find_chromium_executable() -> str | None:
                 ),
             ]
         elif system == "Linux":
-            candidates = [
-                os.path.join(base, "chrome-linux", "chrome")
-            ]
+            candidates = [os.path.join(base, "chrome-linux", "chrome")]
         else:  # Windows
             candidates = [
                 os.path.join(base, "chrome-win64", "chrome.exe"),
@@ -160,8 +154,7 @@ def _find_system_chrome() -> str | None:
 
     if system == "Darwin":
         chrome_path = (
-            "/Applications/Google Chrome.app"
-            "/Contents/MacOS/Google Chrome"
+            "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
         )
         if os.path.exists(chrome_path):
             return chrome_path
@@ -1007,9 +1000,7 @@ async def launch_cdp_browser():
                 ),
             )
 
-        logger.info(
-            f"[BROWSER LAUNCH] Found available port: {port}"
-        )
+        logger.info(f"[BROWSER LAUNCH] Found available port: {port}")
 
         # 2. Find Chromium executable
         chrome_executable = _find_chromium_executable()
@@ -1022,9 +1013,7 @@ async def launch_cdp_browser():
                 ),
             )
 
-        logger.info(
-            f"[BROWSER LAUNCH] Using Chromium: {chrome_executable}"
-        )
+        logger.info(f"[BROWSER LAUNCH] Using Chromium: {chrome_executable}")
 
         # 3. Create user data directory
         user_data_dir = os.path.join(
@@ -1044,10 +1033,7 @@ async def launch_cdp_browser():
             "about:blank",
         ]
 
-        logger.info(
-            "[BROWSER LAUNCH] Spawning Chromium"
-            f" on port {port}"
-        )
+        logger.info(f"[BROWSER LAUNCH] Spawning Chromium on port {port}")
 
         process = subprocess.Popen(
             args,
@@ -1056,10 +1042,7 @@ async def launch_cdp_browser():
         )
 
         _launched_browser_processes[port] = process
-        logger.info(
-            "[BROWSER LAUNCH] Chromium spawned,"
-            f" PID: {process.pid}"
-        )
+        logger.info(f"[BROWSER LAUNCH] Chromium spawned, PID: {process.pid}")
 
         # 5. Poll for browser readiness (max 5 seconds)
         max_wait = 5.0
@@ -1104,18 +1087,13 @@ async def launch_cdp_browser():
             "success": True,
             "port": port,
             "data": browser_info,
-            "message": (
-                "Browser launched successfully"
-                f" on port {port}"
-            ),
+            "message": (f"Browser launched successfully on port {port}"),
         }
 
     except HTTPException:
         raise
     except Exception as e:
-        logger.error(
-            f"[BROWSER LAUNCH] Failed: {e}", exc_info=True
-        )
+        logger.error(f"[BROWSER LAUNCH] Failed: {e}", exc_info=True)
         raise HTTPException(
             status_code=500,
             detail=f"Failed to launch browser: {e!s}",
@@ -1171,10 +1149,7 @@ async def launch_chrome_with_profile(
         if not os.path.isdir(profile_path):
             raise HTTPException(
                 status_code=404,
-                detail=(
-                    f"Profile '{request.profile_directory}'"
-                    " not found"
-                ),
+                detail=(f"Profile '{request.profile_directory}' not found"),
             )
 
         # 4. Find available port
@@ -1203,9 +1178,7 @@ async def launch_chrome_with_profile(
         os.makedirs(wrapper_dir, exist_ok=True)
 
         # Symlink requested profile into wrapper
-        link_dst = os.path.join(
-            wrapper_dir, request.profile_directory
-        )
+        link_dst = os.path.join(wrapper_dir, request.profile_directory)
         real_profile = os.path.join(
             chrome_user_data_dir, request.profile_directory
         )
@@ -1216,12 +1189,8 @@ async def launch_chrome_with_profile(
         os.symlink(real_profile, link_dst)
 
         # Copy Local State (small JSON, needed by Chrome)
-        local_state_src = os.path.join(
-            chrome_user_data_dir, "Local State"
-        )
-        local_state_dst = os.path.join(
-            wrapper_dir, "Local State"
-        )
+        local_state_src = os.path.join(chrome_user_data_dir, "Local State")
+        local_state_dst = os.path.join(wrapper_dir, "Local State")
         if os.path.isfile(local_state_src):
             shutil.copy2(local_state_src, local_state_dst)
 
@@ -1241,10 +1210,7 @@ async def launch_chrome_with_profile(
         )
 
         _launched_browser_processes[port] = process
-        logger.info(
-            "[CHROME LAUNCH] Chrome spawned,"
-            f" PID: {process.pid}"
-        )
+        logger.info(f"[CHROME LAUNCH] Chrome spawned, PID: {process.pid}")
 
         # 6. Poll for browser readiness (max 8 seconds,
         #    real Chrome may be slower than Chromium)
@@ -1273,16 +1239,12 @@ async def launch_chrome_with_profile(
             elapsed = time.time() - start_time
             raise HTTPException(
                 status_code=409,
-                detail=(
-                    "Chrome failed to start CDP"
-                    f" (waited {elapsed:.1f}s)"
-                ),
+                detail=(f"Chrome failed to start CDP (waited {elapsed:.1f}s)"),
             )
 
         elapsed = time.time() - start_time
         logger.info(
-            "[CHROME LAUNCH] Chrome ready on"
-            f" port {port} after {elapsed:.1f}s"
+            f"[CHROME LAUNCH] Chrome ready on port {port} after {elapsed:.1f}s"
         )
 
         return {
@@ -1300,9 +1262,7 @@ async def launch_chrome_with_profile(
     except HTTPException:
         raise
     except Exception as e:
-        logger.error(
-            f"[CHROME LAUNCH] Failed: {e}", exc_info=True
-        )
+        logger.error(f"[CHROME LAUNCH] Failed: {e}", exc_info=True)
         raise HTTPException(
             status_code=500,
             detail=f"Failed to launch Chrome: {e!s}",
diff --git a/src/components/Layout/index.tsx b/src/components/Layout/index.tsx
index ed4e319f..b5a00920 100644
--- a/src/components/Layout/index.tsx
+++ b/src/components/Layout/index.tsx
@@ -58,14 +58,14 @@ const Layout = () => {
       if (['running', 'pause'].includes(currentStatus)) {
         setNoticeOpen(true);
       } else {
-        window.electronAPI.closeWindow(true);
+        window.electronAPI?.closeWindow(true);
       }
     };
 
-    window.ipcRenderer.on('before-close', handleBeforeClose);
+    window.ipcRenderer?.on('before-close', handleBeforeClose);
 
     return () => {
-      window.ipcRenderer.removeAllListeners('before-close');
+      window.ipcRenderer?.removeAllListeners('before-close');
     };
   }, [chatStore.tasks, chatStore.activeTaskId]);
 
diff --git a/src/components/TopBar/index.tsx b/src/components/TopBar/index.tsx
index 6c956ab7..317eab71 100644
--- a/src/components/TopBar/index.tsx
+++ b/src/components/TopBar/index.tsx
@@ -66,8 +66,8 @@ function HeaderWin() {
     isInstalling || installationState === 'waiting-backend';
 
   useEffect(() => {
-    const p = window.electronAPI.getPlatform();
-    setPlatform(p);
+    const p = window.electronAPI?.getPlatform();
+    if (p) setPlatform(p);
   }, []);
   const logoSrc = appearance === 'dark' ? folderIconWhite : folderIconBlack;
 
diff --git a/src/components/WindowControls/index.tsx b/src/components/WindowControls/index.tsx
index f5725998..55bd6bbf 100644
--- a/src/components/WindowControls/index.tsx
+++ b/src/components/WindowControls/index.tsx
@@ -21,8 +21,8 @@ export default function WindowControls() {
   const [platform, setPlatform] = useState<string>('');
 
   useEffect(() => {
-    const p = window.electronAPI.getPlatform();
-    setPlatform(p);
+    const p = window.electronAPI?.getPlatform();
+    if (p) setPlatform(p);
 
     // Hide custom controls on macOS (uses native traffic lights)
     // and on Windows (now uses native frame with native controls)
diff --git a/src/components/WorkSpaceMenu/index.tsx b/src/components/WorkSpaceMenu/index.tsx
index 83a75a56..40c5462a 100644
--- a/src/components/WorkSpaceMenu/index.tsx
+++ b/src/components/WorkSpaceMenu/index.tsx
@@ -96,7 +96,7 @@ export function WorkSpaceMenu() {
 
   useEffect(() => {
     if (!chatStore) return;
-    const cleanup = window.electronAPI.onWebviewNavigated(
+    const cleanup = window.electronAPI?.onWebviewNavigated(
       (id: string, url: string) => {
         if (!chatStore.activeTaskId) return;
         let webViewUrls = [
diff --git a/src/components/update/index.tsx b/src/components/update/index.tsx
index 60d17987..835660b0 100644
--- a/src/components/update/index.tsx
+++ b/src/components/update/index.tsx
@@ -24,7 +24,7 @@ const Update = () => {
   const { t } = useTranslation();
 
   const checkUpdate = () => {
-    window.ipcRenderer.invoke('check-update');
+    window.ipcRenderer?.invoke('check-update');
   };
 
   const onUpdateCanAvailable = useCallback(
diff --git a/src/hooks/useInstallationSetup.ts b/src/hooks/useInstallationSetup.ts
index 10caf706..cb9cd3cc 100644
--- a/src/hooks/useInstallationSetup.ts
+++ b/src/hooks/useInstallationSetup.ts
@@ -55,7 +55,7 @@ export const useInstallationSetup = () => {
     // Immediately check backend status once
     const checkBackendStatus = async () => {
       try {
-        const backendPort = await window.electronAPI.getBackendPort();
+        const backendPort = await window.electronAPI?.getBackendPort();
         if (backendPort && backendPort > 0) {
           console.log(
             '[useInstallationSetup] Backend immediately detected on port:',
@@ -101,7 +101,7 @@ export const useInstallationSetup = () => {
       // This is a fallback in case the backend-ready event is missed
       const pollInterval = setInterval(async () => {
         try {
-          const backendPort = await window.electronAPI.getBackendPort();
+          const backendPort = await window.electronAPI?.getBackendPort();
           if (backendPort && backendPort > 0) {
             console.log(
               '[useInstallationSetup] Backend poll detected ready on port:',
@@ -178,7 +178,7 @@ export const useInstallationSetup = () => {
 
     const checkToolInstalled = async () => {
       try {
-        const result = await window.ipcRenderer.invoke('check-tool-installed');
+        const result = await window.ipcRenderer?.invoke('check-tool-installed');
 
         if (result.success) {
           if (result.isInstalled) {
@@ -217,7 +217,7 @@ export const useInstallationSetup = () => {
     const checkBackendStatus = async (_toolResult?: any) => {
       try {
         const installationStatus =
-          await window.electronAPI.getInstallationStatus();
+          await window.electronAPI?.getInstallationStatus();
 
         if (installationStatus.success && installationStatus.isInstalling) {
           startInstallation();
@@ -325,16 +325,16 @@ export const useInstallationSetup = () => {
       }
     };
 
-    window.electronAPI.onInstallDependenciesStart(handleInstallStart);
-    window.electronAPI.onInstallDependenciesLog(handleInstallLog);
-    window.electronAPI.onInstallDependenciesComplete(handleInstallComplete);
-    window.electronAPI.onBackendReady(handleBackendReady);
+    window.electronAPI?.onInstallDependenciesStart(handleInstallStart);
+    window.electronAPI?.onInstallDependenciesLog(handleInstallLog);
+    window.electronAPI?.onInstallDependenciesComplete(handleInstallComplete);
+    window.electronAPI?.onBackendReady(handleBackendReady);
 
     return () => {
-      window.electronAPI.removeAllListeners('install-dependencies-start');
-      window.electronAPI.removeAllListeners('install-dependencies-log');
-      window.electronAPI.removeAllListeners('install-dependencies-complete');
-      window.electronAPI.removeAllListeners('backend-ready');
+      window.electronAPI?.removeAllListeners('install-dependencies-start');
+      window.electronAPI?.removeAllListeners('install-dependencies-log');
+      window.electronAPI?.removeAllListeners('install-dependencies-complete');
+      window.electronAPI?.removeAllListeners('backend-ready');
     };
   }, [
     startInstallation,
diff --git a/src/pages/Dashboard/Browser.tsx b/src/pages/Dashboard/Browser.tsx
index 522bcb65..288d40ea 100644
--- a/src/pages/Dashboard/Browser.tsx
+++ b/src/pages/Dashboard/Browser.tsx
@@ -20,6 +20,7 @@ import {
   Chrome,
   Cookie,
   Globe,
+  Link2,
   Loader2,
   Plus,
   RefreshCw,
@@ -81,6 +82,12 @@ export default function Browser() {
     null
   );
 
+  // Connect Existing Browser dialog
+  const [showConnectDialog, setShowConnectDialog] = useState(false);
+  const [connectPort, setConnectPort] = useState('');
+  const [connectChecking, setConnectChecking] = useState(false);
+  const [connectError, setConnectError] = useState('');
+
   // Extract main domain (e.g., "aa.bb.cc" -> "bb.cc", "www.google.com" -> "google.com")
   const getMainDomain = (domain: string): string => {
     // Remove leading dot if present
@@ -281,6 +288,59 @@ export default function Browser() {
       });
     }
   };
+  const handleConnectExistingBrowser = () => {
+    setConnectPort('');
+    setConnectError('');
+    setShowConnectDialog(true);
+  };
+
+  const handleCheckAndConnect = async () => {
+    const portNum = parseInt(connectPort, 10);
+    if (isNaN(portNum) || portNum < 1 || portNum > 65535) {
+      setConnectError(t('layout.invalid-port'));
+      return;
+    }
+
+    // Check if port is already in the pool
+    if (cdpBrowsers.some((b) => b.port === portNum)) {
+      setConnectError(t('layout.port-already-in-use'));
+      return;
+    }
+
+    setConnectChecking(true);
+    setConnectError('');
+
+    try {
+      // Probe the port to check if a CDP browser is listening
+      const controller = new AbortController();
+      const timeoutId = setTimeout(() => controller.abort(), 3000);
+      const response = await fetch(`http://localhost:${portNum}/json/version`, {
+        signal: controller.signal,
+      });
+      clearTimeout(timeoutId);
+
+      if (!response.ok) {
+        setConnectError(t('layout.no-browser-on-port', { port: portNum }));
+        return;
+      }
+
+      // Port is alive — add to CDP pool
+      if (window.electronAPI?.addCdpBrowser) {
+        await window.electronAPI.addCdpBrowser(
+          portNum,
+          true,
+          `External Browser (${portNum})`
+        );
+      }
+
+      toast.success(t('layout.connected-browser', { port: portNum }));
+      setShowConnectDialog(false);
+    } catch {
+      setConnectError(t('layout.no-browser-on-port', { port: portNum }));
+    } finally {
+      setConnectChecking(false);
+    }
+  };
 
   const handleBrowserLogin = async () => {
     setLoginLoading(true);
@@ -499,6 +559,59 @@ export default function Browser() {
           </div>
         </div>
       )}
+      {/* Connect Existing Browser Dialog */}
+      {showConnectDialog && (
+        <div className="bg-black/50 fixed inset-0 z-50 flex items-center justify-center">
+          <div className="w-full max-w-md rounded-xl bg-surface-primary p-6 shadow-lg">
+            <div className="text-body-base mb-2 font-bold text-text-heading">
+              {t('layout.connect-existing-browser')}
+            </div>
+            <p className="mb-4 text-label-xs text-text-label">
+              {t('layout.connect-existing-browser-description')}
+            </p>
+            <input
+              type="text"
+              value={connectPort}
+              onChange={(e) => {
+                setConnectPort(e.target.value);
+                setConnectError('');
+              }}
+              placeholder={t('layout.enter-port-number')}
+              className="w-full rounded-lg border border-border-disabled bg-surface-secondary px-4 py-2 text-body-sm text-text-body outline-none focus:border-border-focus"
+              onKeyDown={(e) => {
+                if (e.key === 'Enter') handleCheckAndConnect();
+              }}
+            />
+            {connectError && (
+              <p className="mt-2 text-label-xs text-text-cuation">
+                {connectError}
+              </p>
+            )}
+            <div className="mt-4 flex justify-end gap-2">
+              <Button
+                variant="ghost"
+                size="sm"
+                onClick={() => setShowConnectDialog(false)}
+              >
+                {t('layout.cancel')}
+              </Button>
+              <Button
+                variant="primary"
+                size="sm"
+                onClick={handleCheckAndConnect}
+                disabled={connectChecking}
+              >
+                {connectChecking ? (
+                  <Loader2 className="h-4 w-4 animate-spin" />
+                ) : (
+                  <Link2 className="h-4 w-4" />
+                )}
+                {t('layout.check-and-connect')}
+              </Button>
+            </div>
+          </div>
+        </div>
+      )}
 
       <div className="flex h-auto w-full px-6">
         {/* Left Sidebar */}
@@ -562,6 +675,14 @@ export default function Browser() {
                     ? t('layout.launching-chrome')
                     : t('layout.open-my-chrome')}
                 </Button>
+                <Button
+                  variant="outline"
+                  size="sm"
+                  onClick={handleConnectExistingBrowser}
+                >
+                  <Link2 className="h-4 w-4 text-button-tertiery-text-default" />
+                  {t('layout.connect-existing-browser')}
+                </Button>
               </div>
 
               {/* CDP Browser Pool */}
diff --git a/src/pages/Home.tsx b/src/pages/Home.tsx
index 7f070829..0d562de0 100644
--- a/src/pages/Home.tsx
+++ b/src/pages/Home.tsx
@@ -170,7 +170,7 @@ export default function Home() {
     const webviewContainer = document.getElementById('webview-container');
     if (webviewContainer) {
       const rect = webviewContainer.getBoundingClientRect();
-      window.electronAPI.setSize({
+      window.electronAPI?.setSize({
         x: rect.left,
         y: rect.top,
         width: rect.width,