Browser Use IAB backend fails to connect on Windows #20846

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

26.429.30905

What subscription do you have?

ChatGPT Pro

What platform is your computer?

Windows x64

What issue are you seeing?

Title:
Codex Desktop Browser Use IAB bridge fails on Windows: pipes discovered but all handshakes time out

Environment:

• Codex Desktop: OpenAI.Codex_26.429.3425.0_x64
• OS: Windows
• Browser Use plugin: openai-bundled/browser-use/0.1.0-alpha1
• Local app URL: http://localhost:20002/question-data

Issue:
The Codex in-app browser is open and can display the local page, but the agent cannot connect to the Browser Use IAB backend.

Error:
Failed to connect to browser-use backend "iab".
No Codex IAB backends were discovered.

Diagnostics observed across retries:

• listedPipes increased from 2 to 4
• candidates increased from 4 to 6
• browsers=0
• iabBrowsers=0
• failures included:
  • discovered/timeout
  • legacy-iab/timeout
  • legacy-chrome/timeout
• pipeListingError=none

Local checks:

• Codex processes exist
• msedgewebview2 processes exist
• browser-use plugin file exists:
  C:\Users\12289.codex\plugins\cache\openai-bundled\browser-use\0.1.0-alpha1\scripts\browser-client.mjs
• Windows named pipes include codex-browser-use-* entries
• The local page itself is reachable over HTTP

Steps to reproduce:

1. Start Codex Desktop on Windows.
2. Open the in-app browser.
3. Navigate to http://localhost:20002/question-data.
4. Ask the agent to inspect or screenshot the in-app browser page through Browser Use.
5. The Browser Use setup with backend "iab" fails with timeout diagnostics.

Expected:
Browser Use should connect to the selected in-app browser tab and allow DOM/screenshot interactions.

Actual:
Browser Use discovers candidate named pipes, but all handshakes time out. No IAB browser backend is recognized.

Workarounds tried:

• Restarted Codex Desktop.
• Reopened/refreshed the in-app browser.
• Reset Node REPL kernel.
• Re-ran Browser Use setup multiple times.
• Verified the local page is accessible outside Browser Use.

Impact:
The agent cannot inspect, screenshot, or interact with the Codex in-app browser even though the page is visible to the user.

What steps can reproduce the bug?

Steps to reproduce:

1. Start Codex Desktop on Windows.
2. Open a workspace.
3. Open the Codex in-app browser.
4. Navigate the in-app browser to a local page, for example:
   http://localhost:20002/question-data
5. Ask the agent to inspect, screenshot, or interact with the in-app browser page.
6. The agent attempts to initialize Browser Use with backend "iab".
7. Browser Use fails to connect.

Minimal setup code used by the agent:

const { setupAtlasRuntime } = await import(
  "C:/Users/12289/.codex/plugins/cache/openai-bundled/browser-use/0.1.0-alpha1/scripts/browser-client.mjs"
);

const backend = "iab";
await setupAtlasRuntime({ globals: globalThis, backend });

await agent.browser.nameSession("question data");
globalThis.tab = await agent.browser.tabs.selected();

console.log({
  url: await tab.url(),
  title: await tab.title(),
  tabs: await agent.browser.tabs.list(),
});


### What is the expected behavior?

_No response_

### Additional information

_No response_