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Codex Issues / #4844

codex mcp-server doesn't work on the M4 Mac Mini

Resolved 💬 6 comments Opened Oct 6, 2025 by blackpatton17 Closed Oct 9, 2025
💡 Likely answer: A maintainer (github-actions[bot], contributor) responded on this thread — see the highlighted reply below.

What version of Codex is running?

codex-cli 0.45.0

Which model were you using?

gpt-5-codex

What platform is your computer?

Darwin 25.0.0 arm64 arm

What steps can reproduce the bug?

  1. Install codex via brew install codex
  2. Run npx @modelcontextprotocol/inspector codex mcp-server
  3. Attempt to connect the server via inspector.
  4. Connection failed.

<img width="2342" height="1332" alt="Image" src="https://github.com/user-attachments/assets/bcddaa67-21ff-4f91-a097-fc20733b41a6" />

What is the expected behavior?

A successful connection.

What do you see instead?

Connection Error - Check if your MCP server is running and proxy token is correct

Additional information

_No response_

View original on GitHub ↗

6 Comments

github-actions[bot] contributor · 10 months ago

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

  • #4651
  • #3712
  • #4223

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CptPirx · 10 months ago

I have similar connection issues since some update last week. Codex as MCP server can no longer be connected to from Claude Code.

CC version: v2.0.9
Codex version: v0.45.0

Edit:
Fixed structure and added version infromation.

itsmevictor · 10 months ago

Same issue as @CptPirx.

It used to work just fine after I ran claude mcp add codex --scope user -- codex -m gpt-5 mcp but doesn't anymore.

The logs don't say much:

  {
    "debug": "Starting connection with timeout of 30000ms",
    "timestamp": "2025-09-07T16:33:27.115Z",
    "sessionId": "ee5c640d-26d6-4cb2-b9ef-531cfc266647",
    "cwd": "/Users/victor/Downloads"
  },
  {
    "debug": "Connection timeout triggered after 30007ms (limit: 30000ms)",
    "timestamp": "2025-09-07T16:33:57.118Z",
    "sessionId": "ee5c640d-26d6-4cb2-b9ef-531cfc266647",
    "cwd": "/Users/victor/Downloads"
  },

FYI, I'm using:

Claude Code 2.0.9
codex-cli 0.45.0
blackpatton17 · 10 months ago

The temperature resolution I found is to downgrade codex back to 0.42.0 and use legacy approach codex mcp serve with MCP server inspector.

itsmevictor · 10 months ago

Update and partial solution: I guess reading the docs and particularly the diffs from the previous release would have helped. Per those docs (under advanced.md), the command to run codex as an MCP server has changed to codex mcp-server.

Thus, for Claude Code:

  • claude mcp add codex --scope user -- codex -m gpt-5 mcp becomes
  • claude mcp add codex --scope user -- codex mcp-server,

and after testing, it does work. This should solve your problem @CptPirx. I'm not too sure about @blackpatton17's since the npx call seems to be correct based on the changes from the new 0.45 release.

blackpatton17 · 10 months ago

My problem isn’t fully resolved. 0.45.0’s mcp-server still doesn’t work. Please reopen the issue.