fix(navigate): ensure content script is ready before returning

Navigate, reload, goBack, goForward, and tabNew now ping the content
script after page load to confirm it can receive commands. Previously,
commands sent immediately after navigate could time out because the
content script hadn't been injected yet — especially on cross-origin
navigations in script mode.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: six-ddc

apps/extension/src/entrypoints/content.ts

@@ -21,6 +21,12 @@ export default defineContentScript({
         _sender: Browser.runtime.MessageSender,
         sendResponse: (response: unknown) => void,
       ) => {
+        // Ping handler — background script uses this to verify content script is ready
+        if (message.type === 'browser-cli-ping') {
+          sendResponse({ ready: true });
+          return false;
+        }
+
         if (message.type !== 'browser-cli-command') return false;
 
         // Validate the command against the schema

apps/extension/src/lib/command-router.ts

@@ -150,8 +150,9 @@ async function routeCommand(
       const { url } = command.params;
       assertSafeUrl(url);
       await browser.tabs.update(targetTabId, { url });
-      // Wait for navigation to complete
+      // Wait for navigation to complete and content script to be ready
       await waitForTabLoad(targetTabId);
+      await waitForContentScriptReady(targetTabId);
       const tab = await browser.tabs.get(targetTabId);
       return { url: tab.url, title: tab.title };
     }
@@ -162,6 +163,7 @@ async function routeCommand(
         func: () => history.back(),
       });
       await waitForUrlChange(targetTabId, beforeBack.url || '');
+      await waitForContentScriptReady(targetTabId);
       const tab = await browser.tabs.get(targetTabId);
       return { url: tab.url };
     }
@@ -172,12 +174,14 @@ async function routeCommand(
         func: () => history.forward(),
       });
       await waitForUrlChange(targetTabId, beforeFwd.url || '');
+      await waitForContentScriptReady(targetTabId);
       const tab = await browser.tabs.get(targetTabId);
       return { url: tab.url };
     }
     case 'reload': {
       await browser.tabs.reload(targetTabId);
       await waitForTabLoad(targetTabId);
+      await waitForContentScriptReady(targetTabId);
       const tab = await browser.tabs.get(targetTabId);
       return { url: tab.url, title: tab.title };
     }
@@ -198,6 +202,10 @@ async function routeCommand(
       if (container) {
         if (!import.meta.env.FIREFOX) {
           const tab = await browser.tabs.create({ url: url || 'about:blank' });
+          if (url && tab.id) {
+            await waitForTabLoad(tab.id);
+            await waitForContentScriptReady(tab.id);
+          }
           const result: Record<string, unknown> = {
             tabId: tab.id,
             url: tab.url || url || 'about:blank',
@@ -225,6 +233,10 @@ async function routeCommand(
         url: url || 'about:blank',
         ...((cookieStoreId != null ? { cookieStoreId } : {}) as Record<string, unknown>),
       } as Browser.tabs.CreateProperties);
+      if (url && tab.id) {
+        await waitForTabLoad(tab.id);
+        await waitForContentScriptReady(tab.id);
+      }
       const result: Record<string, unknown> = {
         tabId: tab.id,
         url: tab.url || url || 'about:blank',
@@ -1097,6 +1109,38 @@ function waitForUrlChange(tabId: number, previousUrl: string, timeoutMs = 15_000
   });
 }
 
+/**
+ * Ping the content script to verify it's ready to receive commands.
+ * Used after navigation to ensure the new page's content script is injected.
+ * Resolves (never rejects) — special pages (chrome://, about:, PDF) may never
+ * have a content script, so we don't want to block the command flow.
+ */
+function waitForContentScriptReady(tabId: number, timeoutMs = 5_000): Promise<void> {
+  const POLL_INTERVAL = 200;
+  return new Promise((resolve) => {
+    const deadline = Date.now() + timeoutMs;
+    const attempt = () => {
+      if (Date.now() > deadline) {
+        resolve();
+        return;
+      }
+      browser.tabs
+        .sendMessage(tabId, { type: 'browser-cli-ping' }, { frameId: 0 })
+        .then((response: unknown) => {
+          if (response && (response as { ready?: boolean }).ready) {
+            resolve();
+          } else {
+            setTimeout(attempt, POLL_INTERVAL);
+          }
+        })
+        .catch(() => {
+          setTimeout(attempt, POLL_INTERVAL);
+        });
+    };
+    attempt();
+  });
+}
+
 function waitForTabLoad(tabId: number, timeoutMs = 15_000): Promise<void> {
   return new Promise((resolve) => {
     const timer = setTimeout(() => {