In-app Browser fails after desktop update: missing sandboxPolicy #29270

What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.616.41845, released 20 Jun 2026

What subscription do you have?

Plus

What platform is your computer?

Windows 11 - Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

After updating Codex Desktop to version 26.616.41845, Codex can no longer connect to the in-app browser.

Browser control fails before interacting with the page. The error indicates that the browser-control request is missing a required sandboxPolicy field.

Browser control worked normally on 20 Jun 2026 and first failed on 21 Jun 2026 after the desktop update.

What steps can reproduce the bug?

1. Open Codex Desktop.
2. Start a fresh session without attaching a project or personal workspace.
3. Open the in-app browser.
4. Navigate to https://example.com.
5. Ask Codex to use @browser to inspect the page.
6. Observe that browser control fails before accessing the page.

What is the expected behavior?

Codex should connect to the in-app browser and inspect the public page, including its title, heading, and links.

Additional information

Browser control fails before interacting with the page.

Observed error:

Mcp error: -32602: js: codex/sandbox-state-meta: missing field sandboxPolicy

• Operating system: Windows

• Application: Codex Desktop

• Version: 26.616.41845

• Release date: 20 Jun 2026

• Bundled Browser plugin installed and enabled

• In-app browser open with a public, unauthenticated page

• Fresh session with no project or personal workspace attached

• Confirmed the in-app browser was open

• Confirmed the Browser plugin was installed and enabled

• Retried browser control several times

• Tried a fresh Codex session

• Fully restarted Codex Desktop

• Rebooted Windows

• Used a public unauthenticated page

• Removed project and workspace context from the reproduction

The issue persists after all of these steps.

This appears to be a failure in the Codex Desktop/browser-control integration before page access, rather than a website permission problem.

The missing required metadata field suggests a request-schema or compatibility regression between Codex Desktop and the bundled Browser control runtime.

Version 26.616.41845 may have introduced a mismatch where the runtime expects codex/sandbox-state-meta.sandboxPolicy, but Codex Desktop does not include it in the request.

• Last known working: 20 Jun 2026
• First observed failure: 21 Jun 2026
• Browser control worked normally the previous day
• Failure began after updating to Codex Desktop 26.616.41845
• Failure persists after restarting Codex Desktop and rebooting Windows