Unable to use ACE MCP.
Open 💬 2 comments Opened Feb 27, 2026 by haoqinghai
💡 Likely answer: A maintainer (etraut-openai, contributor)
responded on this thread — see the highlighted reply below.
What version of the Codex App are you using (From “About Codex” dialog)?
26.226.940 (720)
What subscription do you have?
team
What platform is your computer?
Darwin 24.6.0 arm64 arm
What issue are you seeing?
"When I try to use ace mcp in the Codex app, I get the error: 'Error calling tool codebase-retrieval: This directory cannot be dynamically indexed for security reasons.' However, it works perfectly fine in Cursor APP."
<img width="862" height="111" alt="Image" src="https://github.com/user-attachments/assets/b2a80166-7246-4f90-bf8a-8a5f5bc80805" />
What steps can reproduce the bug?
"Configure Auggie ACE MCP to allow the agent to search the codebase."
What is the expected behavior?
_No response_
Additional information
_No response_
2 Comments
There's a possibility this is a codex issue, but it's more likely that it's a bug in the MCP.
Since you have a repro, you might want to investigate and see if you can diagnose the problem. We're unlikely to get to this bug any time soon.
@etraut-openai Calling the MCP via the Codex CLI works perfectly, but it fails to function correctly within the Codex App.