Windows: Browser Use external navigation fails with "failed to start codex app-server" when child process HOME is missing

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

26.429.3425.0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.22631.0 x64

What issue are you seeing?

On Windows, Browser Use / the in-app browser can fail to navigate to external websites because the helper process for codex app-server appears to start without a valid home-directory environment.

Observed behavior:

• Local URLs can reach the browser layer normally
• Example: http://127.0.0.1:65535
• Result: normal browser error such as net::ERR_CONNECTION_REFUSED
• External URLs fail earlier, before normal navigation
• Example: https://example.com
• Result:

failed to start codex app-server: 系统找不到指定的路径。 (os error 3)

I also observed that the Node REPL environment inside Codex reports homeDir: null at the time this happens.

This suggests the Windows app is launching the Browser Use / app-server helper without a complete user-home environment, even though the main app itself is running normally.

What steps can reproduce the bug?

1. Launch the Codex App on Windows.
2. Open a session that uses Browser Use / the in-app browser.
3. In the Node REPL, initialize the iab backend and get a tab.
4. Try to navigate to a local URL and then an external URL.

Repro snippet:

if (!globalThis.agent) {
  const { setupAtlasRuntime } = await import(
    'file:///C:/Users/<redacted>/.codex/plugins/cache/openai-bundled/browser-use/0.1.0-alpha1/scripts/browser-client.mjs'
  );
  await setupAtlasRuntime({ globals: globalThis, backend: 'iab' });
}

globalThis.tab = await agent.browser.tabs.selected() || await agent.browser.tabs.new();

await tab.goto('http://127.0.0.1:65535'); // reaches browser layer, usually ERR_CONNECTION_REFUSED
await tab.goto('https://example.com');    // fails earlier with app-server startup error


### What is the expected behavior?

_No response_

### Additional information

Possibly related to:
- #18248
- #16268
- #14364