diff --git a/browse/src/server.ts b/browse/src/server.ts
index fe288e9e..8d5a49e0 100644
--- a/browse/src/server.ts
+++ b/browse/src/server.ts
@@ -18,6 +18,7 @@ import { handleReadCommand } from './read-commands';
 import { handleWriteCommand } from './write-commands';
 import { handleMetaCommand } from './meta-commands';
 import { handleCookiePickerRoute } from './cookie-picker-routes';
+import { sanitizeExtensionUrl } from './sidebar-utils';
 import { COMMAND_DESCRIPTIONS } from './commands';
 import { handleSnapshot, SNAPSHOT_FLAGS } from './snapshot';
 import { resolveConfig, ensureStateDir, readVersionHash } from './config';
@@ -123,7 +124,7 @@ let sidebarSession: SidebarSession | null = null;
 let agentProcess: ChildProcess | null = null;
 let agentStatus: 'idle' | 'processing' | 'hung' = 'idle';
 let agentStartTime: number | null = null;
-let messageQueue: Array<{message: string, ts: string}> = [];
+let messageQueue: Array<{message: string, ts: string, extensionUrl?: string | null}> = [];
 let currentMessage: string | null = null;
 let chatBuffer: ChatEntry[] = [];
 let chatNextId = 0;
@@ -371,18 +372,27 @@ function processAgentEvent(event: any): void {
   }
 }
 
-function spawnClaude(userMessage: string): void {
+function spawnClaude(userMessage: string, extensionUrl?: string | null): void {
   agentStatus = 'processing';
   agentStartTime = Date.now();
   currentMessage = userMessage;
 
-  const pageUrl = browserManager.getCurrentUrl() || 'about:blank';
+  // Prefer the URL from the Chrome extension (what the user actually sees)
+  // over Playwright's page.url() which can be stale in headed mode.
+  const sanitizedExtUrl = sanitizeExtensionUrl(extensionUrl);
+  const playwrightUrl = browserManager.getCurrentUrl() || 'about:blank';
+  const pageUrl = sanitizedExtUrl || playwrightUrl;
   const B = BROWSE_BIN;
   const systemPrompt = [
     'You are a browser assistant running in a Chrome sidebar.',
-    `Current page: ${pageUrl}`,
+    `The user is currently viewing: ${pageUrl}`,
     `Browse binary: ${B}`,
     '',
+    'IMPORTANT: You are controlling a SHARED browser. The user may have navigated',
+    'manually. Always run `' + B + ' url` first to check the actual current URL.',
+    'If it differs from above, the user navigated — work with the ACTUAL page.',
+    'Do NOT navigate away from the user\'s current page unless they ask you to.',
+    '',
     'Commands (run via bash):',
     `  ${B} goto <url>    ${B} click <@ref>    ${B} fill <@ref> <text>`,
     `  ${B} snapshot -i   ${B} text            ${B} screenshot`,
@@ -404,8 +414,8 @@ function spawnClaude(userMessage: string): void {
   // fails with ENOENT on everything, including /bin/bash). Instead,
   // write the command to a queue file that the sidebar-agent process
   // (running as non-compiled bun) picks up and spawns claude.
-  const gstackDir = path.join(process.env.HOME || '/tmp', '.gstack');
-  const agentQueue = path.join(gstackDir, 'sidebar-agent-queue.jsonl');
+  const agentQueue = process.env.SIDEBAR_QUEUE_PATH || path.join(process.env.HOME || '/tmp', '.gstack', 'sidebar-agent-queue.jsonl');
+  const gstackDir = path.dirname(agentQueue);
   const entry = JSON.stringify({
     ts: new Date().toISOString(),
     message: userMessage,
@@ -414,6 +424,7 @@ function spawnClaude(userMessage: string): void {
     stateFile: config.stateFile,
     cwd: (sidebarSession as any)?.worktreePath || process.cwd(),
     sessionId: sidebarSession?.claudeSessionId || null,
+    pageUrl: pageUrl,
   });
   try {
     fs.mkdirSync(gstackDir, { recursive: true });
@@ -781,12 +792,16 @@ async function start() {
   const port = await findPort();
 
   // Launch browser (headless or headed with extension)
-  const headed = process.env.BROWSE_HEADED === '1';
-  if (headed) {
-    await browserManager.launchHeaded();
-    console.log(`[browse] Launched headed Chromium with extension`);
-  } else {
-    await browserManager.launch();
+  // BROWSE_HEADLESS_SKIP=1 skips browser launch entirely (for HTTP-only testing)
+  const skipBrowser = process.env.BROWSE_HEADLESS_SKIP === '1';
+  if (!skipBrowser) {
+    const headed = process.env.BROWSE_HEADED === '1';
+    if (headed) {
+      await browserManager.launchHeaded();
+      console.log(`[browse] Launched headed Chromium with extension`);
+    } else {
+      await browserManager.launch();
+    }
   }
 
   const startTime = Date.now();
@@ -935,17 +950,21 @@ async function start() {
         if (!msg) {
           return new Response(JSON.stringify({ error: 'Empty message' }), { status: 400, headers: { 'Content-Type': 'application/json' } });
         }
+        // The Chrome extension sends the active tab's URL — prefer it over
+        // Playwright's page.url() which can be stale in headed mode when
+        // the user navigates manually.
+        const extensionUrl = body.activeTabUrl || null;
         const ts = new Date().toISOString();
         addChatEntry({ ts, role: 'user', message: msg });
         if (sidebarSession) { sidebarSession.lastActiveAt = ts; saveSession(); }
 
         if (agentStatus === 'idle') {
-          spawnClaude(msg);
+          spawnClaude(msg, extensionUrl);
           return new Response(JSON.stringify({ ok: true, processing: true }), {
             status: 200, headers: { 'Content-Type': 'application/json' },
           });
         } else if (messageQueue.length < MAX_QUEUE) {
-          messageQueue.push({ message: msg, ts });
+          messageQueue.push({ message: msg, ts, extensionUrl });
           return new Response(JSON.stringify({ ok: true, queued: true, position: messageQueue.length }), {
             status: 200, headers: { 'Content-Type': 'application/json' },
           });
@@ -979,7 +998,7 @@ async function start() {
         // Process next in queue
         if (messageQueue.length > 0) {
           const next = messageQueue.shift()!;
-          spawnClaude(next.message);
+          spawnClaude(next.message, next.extensionUrl);
         }
         return new Response(JSON.stringify({ ok: true }), { status: 200, headers: { 'Content-Type': 'application/json' } });
       }
@@ -1065,7 +1084,7 @@ async function start() {
           // Process next queued message
           if (messageQueue.length > 0) {
             const next = messageQueue.shift()!;
-            spawnClaude(next.message);
+            spawnClaude(next.message, next.extensionUrl);
           } else {
             agentStatus = 'idle';
           }
diff --git a/extension/background.js b/extension/background.js
index ee4fa517..a4e72d3f 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -194,17 +194,23 @@ chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
       sendResponse({ error: 'Not connected' });
       return true;
     }
-    fetch(`${base}/sidebar-command`, {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/json',
-        'Authorization': `Bearer ${authToken}`,
-      },
-      body: JSON.stringify({ message: msg.message }),
-    })
-      .then(r => r.json())
-      .then(data => sendResponse(data))
-      .catch(err => sendResponse({ error: err.message }));
+    // Capture the active tab's URL so the sidebar agent knows what page
+    // the user is actually looking at (Playwright's page.url() can be stale
+    // if the user navigated manually in headed mode).
+    chrome.tabs.query({ active: true, currentWindow: true }, (tabs) => {
+      const activeTabUrl = tabs?.[0]?.url || null;
+      fetch(`${base}/sidebar-command`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'Authorization': `Bearer ${authToken}`,
+        },
+        body: JSON.stringify({ message: msg.message, activeTabUrl }),
+      })
+        .then(r => r.json())
+        .then(data => sendResponse(data))
+        .catch(err => sendResponse({ error: err.message }));
+    });
     return true;
   }
 });