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Codex Issues / #21618

Browser Use unavailable: node_repl / JavaScript execution tool not exposed despite Browser plugin installed

Open 💬 2 comments Opened May 8, 2026 by michaelplzno
💡 Likely answer: A maintainer (github-actions[bot], contributor) responded on this thread — see the highlighted reply below.

Environment:

  • OS: Windows 11
  • IDE: VS Code
  • Codex surface: VS Code extension / Codex app [choose whichever applies]
  • Codex version: [paste from About Codex or codex --version]
  • Browser Use plugin: installed and available
  • Workspace type: [native Windows / WSL / remote / other]

Issue:
Browser Use appears installed and the required client script exists, but Codex cannot drive the in-app browser because the required Node REPL / JavaScript execution tool is not exposed in the session.

Observed state:

  • Browser Use plugin: installed and available
  • Required client script: present at browser-client.mjs
  • Required runtime tool: node_repl / JavaScript execution is not currently exposed in this session, even after tool discovery
  • Searches for node_repl, js, JavaScript execution, and browser runtime tools find no callable tool

Expected:
When Browser Use is enabled and browser-client.mjs exists, Codex should expose the required node_repl/js or mcp__node_repl__js tool, or show a clear diagnostic explaining why it failed to load.

Actual:
The Browser plugin is installed, but Codex cannot bootstrap the in-app browser because the Node REPL tool is missing from the session.

Troubleshooting already tried:

  • Restarted Codex multiple times
  • Restarted VS Code
  • Confirmed Browser Use plugin is installed
  • Confirmed browser-client.mjs exists
  • Started new sessions/threads
  • Tool discovery still does not expose node_repl/js

Impact:
Codex can inspect files and run shell commands, but cannot test local web pages through the in-app browser. Browser-based verification has to fall back to Playwright or manual testing.

View original on GitHub ↗

2 Comments

github-actions[bot] contributor · 3 months ago

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

  • #21575
  • #21301
  • #20417
  • #20579
  • #21451

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Yemvis · 3 months ago

Additional reproduction from Codex Desktop on Windows (2026-05-15):

Environment:

  • OS: Windows NT 10.0.26200.0
  • Codex CLI: codex-cli 0.130.0
  • Surface: Codex Desktop app on Windows
  • Thread id: 019e2de6-25d5-7203-8a77-005cca8ab4ce
  • User was viewing a production Vercel page in Microsoft Edge and explicitly asked the agent to use [@chrome](plugin://chrome@openai-bundled) / @chrome to review it.

Observed behavior:

  • Browser/Chrome capability was requested explicitly by the user.
  • Tool discovery did not expose any callable browser, Chrome, Edge, node_repl js, or mcp__node_repl__js execution tool.
  • The exposed follow-up tools were unrelated connectors such as Figma, Vercel docs, Canva, GitHub, OpenAI Platform, and Notion.
  • The local Browser skill docs are present at C:\Users\Walter\.codex\plugins\cache\openai-bundled\browser-use\0.1.0-alpha2\skills\browser\SKILL.md and state that Browser Use should be bootstrapped through the Node REPL js tool, typically mcp__node_repl__js.
  • Because that execution tool was unavailable, the agent had to tell the user it could not directly control Edge/Chrome and could only review from the screenshot.

Expected behavior:

  • If the Browser/Chrome plugin is available or explicitly referenced in the prompt, Codex should expose the callable browser execution path in the same turn/session, or provide a first-class diagnostic saying why the browser backend is unavailable.
  • Tool discovery should not surface only unrelated tools when the user explicitly requests @chrome / browser control.

Impact:

  • Breaks browser-based QA/review workflows in Codex Desktop, especially for non-technical users who expect the agent to drive the visible browser rather than falling back to screenshots or manual instructions.
  • This has now appeared in more than one local session on this machine: browser skill docs were installed, but executable browser tooling was not exposed.