MCP not working with OpenAI Codex

Metadata

Source

tuist/tuist #8256

Updated

Jun 11, 2026

Domains

MCP

Details

What happened?

Hello, I’ve been trying to get tuist mcp start working with with OpenAI Codex but it isn’t returning any available tools. Directing Codex to use the tuist mcp server with a prompt like use the tuist mcp server to show me the available targets for this codebase results in Codex just calling the tuist command line.

I’ve configured the ~/.codex/config.toml as follows:

[mcp_servers.tuist]
command = "tuist"
args = ["mcp", "start"]

But Codex is unable to find any tools:

I would expect a list like this if things were working correctly:

Thank you!

How do we reproduce it?

Install OpenAI Codex
Add the tuist mcp server to ~/.codex/config.toml` as described here.
Run codex and then /mcp to see a list of MCP servers. Note how the tools section is empty for the tuist mcp

Error log

No errors shown when I run tuist mcp start in the console on its own. And no errors shown in codex either.

macOS version

26.0

Tuist version

4.67.2

Xcode version

Version 26.0 (17A324)

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Comments

D

dosubot[bot] Sep 21, 2025

Hi @Leeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee! I’m Dosu and I’m helping the tuist team.

The reason OpenAI Codex isn’t showing any tools for the Tuist MCP server is that the current implementation of tuist mcp start does not register or expose any tools to MCP clients. This is confirmed by the codebase, where the MCP server is started with an empty tools capability—only resources and prompts are available, not tools. No additional configuration or troubleshooting will resolve this until tool registration is implemented in Tuist MCP. You can keep an eye on future Tuist releases or discussions for updates on MCP tool support if/when it is added.
Reference: Tuist MCPCommandService.swift implementation

To reply, just mention @dosu.

Docs are dead. Just use Dosu.

R

romanr Jan 12, 2026

Same for Kiro. is it only working with Claude?

I

ivanglushko Jan 13, 2026

Opencode doesn’t pickup tuist’s MCP as well