diff --git a/extension/dist/background.js b/extension/dist/background.js
index e3605fb..dfe3542 100644
--- a/extension/dist/background.js
+++ b/extension/dist/background.js
@@ -169,6 +169,21 @@ function scheduleReconnect() {
 	}, delay);
 }
 var automationWindowId = null;
+var windowIdleTimer = null;
+var 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;
+		}
+		windowIdleTimer = null;
+	}, WINDOW_IDLE_TIMEOUT);
+}
 /** Get or create the dedicated automation window. */
 async function getAutomationWindow() {
 	if (automationWindowId !== null) try {
@@ -191,6 +206,10 @@ chrome.windows.onRemoved.addListener((windowId) => {
 	if (windowId === automationWindowId) {
 		console.log("[opencli] Automation window closed");
 		automationWindowId = null;
+		if (windowIdleTimer) {
+			clearTimeout(windowIdleTimer);
+			windowIdleTimer = null;
+		}
 	}
 });
 var initialized = false;
@@ -212,6 +231,7 @@ chrome.alarms.onAlarm.addListener((alarm) => {
 	if (alarm.name === "keepalive") connect();
 });
 async function handleCommand(cmd) {
+	resetWindowIdleTimer();
 	try {
 		switch (cmd.action) {
 			case "exec": return await handleExec(cmd);
diff --git a/extension/src/background.ts b/extension/src/background.ts
index ba64fe1..629d7a0 100644
--- a/extension/src/background.ts
+++ b/extension/src/background.ts
@@ -88,8 +88,27 @@ function scheduleReconnect(): void {
 // ─── Automation window isolation ─────────────────────────────────────
 // All opencli operations happen in a dedicated Chrome window so the
 // 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;
+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;
+    }
+    windowIdleTimer = null;
+  }, WINDOW_IDLE_TIMEOUT);
+}
 
 /** Get or create the dedicated automation window. */
 async function getAutomationWindow(): Promise<number> {
@@ -122,6 +141,7 @@ chrome.windows.onRemoved.addListener((windowId) => {
   if (windowId === automationWindowId) {
     console.log('[opencli] Automation window closed');
     automationWindowId = null;
+    if (windowIdleTimer) { clearTimeout(windowIdleTimer); windowIdleTimer = null; }
   }
 });
 
@@ -153,6 +173,8 @@ chrome.alarms.onAlarm.addListener((alarm) => {
 // ─── Command dispatcher ─────────────────────────────────────────────
 
 async function handleCommand(cmd: Command): Promise<Result> {
+  // Reset idle timer on every command (window stays alive while active)
+  resetWindowIdleTimer();
   try {
     switch (cmd.action) {
       case 'exec':
diff --git a/src/runtime.ts b/src/runtime.ts
index 9677e12..642c988 100644
--- a/src/runtime.ts
+++ b/src/runtime.ts
@@ -1,5 +1,4 @@
 import type { IPage } from './types.js';
-import type { Page } from './browser/page.js';
 
 export const DEFAULT_BROWSER_CONNECT_TIMEOUT = parseInt(process.env.OPENCLI_BROWSER_CONNECT_TIMEOUT ?? '30', 10);
 export const DEFAULT_BROWSER_COMMAND_TIMEOUT = parseInt(process.env.OPENCLI_BROWSER_COMMAND_TIMEOUT ?? '60', 10);
@@ -42,12 +41,7 @@ export async function browserSession<T>(
   const mcp = new BrowserFactory();
   try {
     const page = await mcp.connect({ timeout: DEFAULT_BROWSER_CONNECT_TIMEOUT });
-    const result = await fn(page);
-    // Close the automation window after command completes
-    if (typeof (page as Page).closeWindow === 'function') {
-      await (page as Page).closeWindow();
-    }
-    return result;
+    return await fn(page);
   } finally {
     await mcp.close().catch(() => {});
   }