Linux: Chrome plugin auto-selects Brave but does not update its native-host manifest

What version of the Codex app are you using?

Codex Desktop Chrome plugin bundle 26.721.41059; ChatGPT Chrome Extension 1.2.27221.15725_0.

What platform is your computer?

EndeavourOS Linux x86_64, KDE Plasma/Wayland, Brave Browser (default browser).

What issue are you seeing?

The Chrome plugin diagnostics auto-select Brave and report that the ChatGPT extension is installed and enabled, but the Linux native-host installer only updates Google Chrome's manifest. A stale Brave manifest can therefore remain in place and point to a missing host binary. The extension side panel then loops on “Install the app to use ChatGPT in Chrome”, even after reinstalling both the extension and plugin.

The official documentation says non-Chrome Chromium browsers are unsupported, so the main bug here is the inconsistent detection/recovery path: Brave is selected as if it were supported, while the installer cannot repair it and the manifest checker reports a misleading success.

Evidence

• check-extension-installed.js --json selects Brave's user-data directory and reports the extension installed/enabled in profile Default.
• Brave manifest exists at ~/.config/BraveSoftware/Brave-Browser/NativeMessagingHosts/com.openai.codexextension.json, but its path points to a missing legacy binary: ~/.codex/plugins/cache/openai-bundled/chrome/native-host.
• Google Chrome's manifest points to the current executable: ~/.codex/plugins/cache/openai-bundled/chrome/latest/extension-host/linux/x64/extension-host.
• Inspection of the current Linux installer shows that it writes only ~/.config/google-chrome/NativeMessagingHosts.
• The native-host manifest check reports correct: true because it finds the valid Google Chrome manifest first, despite Brave being the browser selected by the extension diagnostic.
• The browser client exposes only the in-app browser; requesting the extension backend returns Browser is not available: extension.

Steps to reproduce

1. Use Brave as the default Chromium browser on Linux with the ChatGPT extension installed.
2. Have an existing/stale Brave native-messaging manifest (for example from an older setup).
3. Reinstall the current Chrome plugin from Codex Desktop.
4. Run the bundled extension diagnostic: Brave is selected and the extension is reported as installed/enabled.
5. Run the bundled native-host diagnostic: it reports the Google Chrome manifest as correct.
6. Open the extension side panel in Brave or request the extension browser backend.

Expected behavior

One of the following should happen consistently:

1. If Brave remains unsupported, diagnostics should not auto-select it, and the UI should explicitly report that the browser is unsupported instead of asking the user to reinstall the app; or
2. Brave should be supported end-to-end and its native-host manifest should be installed/updated.

In either case, the manifest check should validate the manifest corresponding to the browser/profile selected by the extension diagnostic and verify that the target exists and is executable.

Additional context

An in-app /feedback report with current-session logs was also submitted under ID 019f9f12-8b20-7a00-bd1b-aa12f9c20506. Browser tabs and browser logs were not included.