Regression: VS Code “Sharing with Agent” remains undiscoverable after #24871 was marked fixed

Reproduce the issue using the listed Windows, VS Code, and Codex extension versions, then trace browser discovery after enabling Sharing with Agent. Compare the behavior with #24871 and the later reports in #25353, focusing on where the VS Code route should be registered. Done means the shared route appears in agent.browsers.list() and can be retrieved, or the UI reports an actionable failure instead.

Summary

The VS Code Sharing with Agent UI visibly indicates that a local web page is shared, but the current Codex session still receives no browser route. Browser discovery returns an empty list and the iab browser is unavailable.

This is reproducible on a current VS Code and a newer Codex extension after related issue #24871 was closed as completed with the maintainer comment “this is now fixed” on June 12, 2026.

This appears to be either:

• an incomplete fix that did not cover the VS Code Sharing with Agent route,
• an environment-specific remaining failure on Windows, or
• a regression in a newer extension build.

Environment

• OS: Windows x64, Microsoft Windows NT 10.0.19045.0
• VS Code: 1.130.0 (x64)
• Codex extension: openai.chatgpt@26.721.41059
• Browser plugin bundle observed in the session: openai-bundled/browser/26.623.141536
• Tested page: a local page on 127.0.0.1
• Date reproduced: July 25, 2026

Steps to reproduce

1. Open a local web page in the VS Code web page/editor surface.
2. Enable Sharing with Agent.
3. Confirm that VS Code visibly shows the active Sharing with Agent indicator.
4. Start a new Codex chat and ask the agent to inspect the shared page.
5. Initialize the bundled Browser runtime and request the VS Code/in-app browser route.

Actual behavior

The VS Code UI says the page is shared, but no browser backend is registered for the Codex session:

agent.browsers.get("iab") -> Browser is not available: iab
agent.browsers.list()      -> []

The result remained the same after:

• disabling and re-enabling Sharing with Agent,
• starting a new Codex chat,
• selecting the latest VS Code target,
• reconnecting the web page several times.

The web page itself remains visible and functional in VS Code. The failure occurs at browser route discovery/registration, before the agent can inspect the page.

Expected behavior

When VS Code displays the active Sharing with Agent indicator, the current Codex session should receive a session-owned browser route. agent.browsers.list() should return that route, and agent.browsers.get("iab") (or the appropriate VS Code sharing backend) should succeed.

If the surface cannot be shared, the VS Code UI should not display an active sharing state, and it should provide a clear actionable error.

Why this is a new regression report

• #24871 was closed as completed on June 12, 2026 after a maintainer stated the issue was fixed.
• Reports of the same browser-registration failure continued after that date.
• #25353 remains open and contains multiple later reproductions across VS Code on Windows and macOS.
• The failure described here reproduces on the newer extension 26.721.41059, specifically with the visible Sharing with Agent workflow.

Related issues:

• #24871 — closed as fixed/completed
• #25353 — still open; no session-owned browser route is registered
• #25647 — similar empty browser list in CLI, but a different host surface