Check a website before release with Codex and Chrome

A setup guide can look finished in the editor while visitors still miss the right command or a required step. Codex can use MCP Browser Extension to check the rendered website in your own Chrome, follow its links and read the instructions a visitor receives.

This run checked a local preview of the MCP Browser Extension website. It covered three questions: does the Codex install tab show the right command, does Quickstart explain email verification, and does the Codex guide include desktop, editor and Windows instructions?

A prompt to try

Open my website preview in your own Chrome tab.
Check that the Codex install tab shows a Codex command.
Follow Quickstart and check that it explains email verification.
Open the Codex guide and check for desktop app, IDE and Windows instructions.
For each check, report the page and the text you found.
Leave publishing and account settings to me.

Replace “my website preview” with the address of your running local site or staging environment. For this recording it was http://127.0.0.1:3492. Your development server may use a different port.

What Codex did

Codex first called chrome_status to confirm the extension connection. It opened its own tab with tab_new, inspected the page with snapshot, switched the install tabs with click, and read the active command with get_text.

The visible Codex tab returned:

codex mcp add mcp-browser-extension -- \
  npx -y mcp-browser-extension@latest \
  --allow-domain example.com --enable-mutations --persist-token

Next it opened Quickstart and read the page. The verification step explicitly named chrome_status, the email prompt, the sign-in link and Verify this device. The page also explained the local browser form and what to do while verification is pending.

Finally, Codex opened the updated guide in the local preview. It read the headings for the desktop app, CLI, IDE extension, manual configuration and Windows. It also checked that the Windows example used cmd /c npx.

The recording follows those browser checks. Scrolling moved between the relevant sections; the final captions summarize the observed results. The page text and commands came from the local preview, and no form was submitted.

The results

These results describe the pages inspected on 20 October 2026. The run checked the written Windows instructions on a Mac; it did not execute the command on Windows or create a fresh Codex installation. Normal build checks and browser tests remain part of the release process.

The demonstration uses a public-style local preview that requires no website login. The extension can also work with an existing signed-in session on a site you allow, but this recording makes no claim about testing a private dashboard.

Run a similar check on your site

1. Follow the Codex setup guide and complete verification and pairing.
2. Start your website preview on the computer Chrome can reach.
3. Allow its exact hostname. For a local preview, that may be localhost or 127.0.0.1. If Chrome requests site access, review and allow it from the extension.
4. Give Codex a short list of visible behaviors to check: an install command, a navigation link, a required instruction or a form validation message.
5. Ask for the observed text and source page alongside each result. Review the findings before publishing.

For client configuration, use the Quickstart. For checking JavaScript errors and failed requests, use the separate console and network walkthrough, which requires observers to be enabled.

FAQ

Can Codex inspect a local website in my Chrome?

Yes, when its MCP server can reach the Chrome extension and the preview hostname is allowed. The preview must be running and reachable from that Chrome browser.

Does this require signing in to the website again?

This demonstration uses a local page without a website login. On a site where Chrome already has a session, the extension uses that browser context. MCP Browser Extension's own email-verification step is separate.

Did the demo test the desktop app and Windows installation?

It checked that the website displayed those instructions. It did not install Codex or run a Windows machine. The configuration guidance is linked to official OpenAI documentation in the setup guide.