Windows: Edge tab discovery fails with "Unable to load browser request-header policy"

Summary

In Codex Desktop on Windows, a read-only request to connect to Microsoft Edge and list its existing tabs fails before browser discovery completes. Two consecutive calls returned the same error:

Unable to load browser request-header policy. Retry the browser command.

This report was prepared and submitted by Codex at the user's request, based on tool outputs observed in this conversation on 2026-09-09.

Environment

• Codex Desktop on Windows.
• Requested browser: Microsoft Edge.
• Tool: mcp__cua_repl.js, using cua.getState().
• Exact Codex Desktop and Edge versions: not verified. A read-only Get-AppxPackage -Name OpenAI.Codex query returned no rows in the execution context, so no app version is inferred from it.

Steps to reproduce

1. In Codex Desktop, request: “Please connect to my Edge and only list the tabs, read-only.”
2. Invoke the browser inventory entry point:

   await cua.getState();
   

3. Observe the error below.
4. Retry the same command, as suggested by the error. In this session, the retry failed identically.

Actual behavior

Both calls returned:

{
  "apps": [],
  "browsers": [],
  "errors": [
    "Browsers: Error: Unable to load browser request-header policy. Retry the browser command."
  ]
}

The calls took approximately 21.7 seconds and 20.0 seconds respectively. The error stack originated in the CUA runtime's temporary kernel.js and worker-runtime.js files. User-specific filesystem paths are omitted.

No tab titles or URLs were obtained. The empty arrays are accompanied by an inventory failure and should not be interpreted as proof that no browsers or tabs were open. No tabs were opened, closed, navigated, or modified by these calls.

Expected behavior

The authorized read-only discovery request should enumerate available browsers and existing Edge tabs. If a prerequisite policy cannot be loaded, the error should identify an actionable cause rather than repeatedly suggesting a retry that returns the same result.

Scope and related reports

• Reproduced twice consecutively within one session. Persistence across app restarts, other machines, or other browsers has not been tested.
• The underlying cause is unknown; this report does not attribute it to Edge settings, authentication, a proxy, or a particular release.
• #31007 reports a different Edge/Windows policy-enforcement error concerning URL detection.
• #43437 reports Windows browser routing/authentication failures with different error messages and environment details.

These are related symptoms only, not confirmed duplicates or evidence of a shared root cause.

Start by reproducing the failure through mcp__cua_repl.js with the cua.getState() entry point and compare the two reported calls. Trace the browser inventory error from the temporary kernel.js and worker-runtime.js files; done means Edge discovery returns its existing tabs or reports an actionable prerequisite cause instead of the repeated retry message.