What version of the Codex App are you using (From “About Codex” dialog)?
26.426.12240
What subscription do you have?
Third-party provider (aihubmix)
What platform is your computer?
Darwin 25.0.0 arm64 arm
What issue are you seeing?
In Codex desktop, MCP tools are unusable. As soon as an MCP tool is invoked, the tool call ends immediately instead of running normally. This makes MCP-based workflows impossible to use. Non-MCP behavior appears normal, but every MCP invocation fails in the same way.
What steps can reproduce the bug?
Open Codex desktop.
Start a normal conversation in a workspace.
Ask the agent to use any MCP tool.
The moment the MCP tool is invoked, the tool call ends immediately.
This happens consistently across repeated attempts.
What is the expected behavior?
No response
Additional information
No response
What version of the Codex App are you using (From “About Codex” dialog)?
26.426.12240
What subscription do you have?
Third-party provider (aihubmix)
What platform is your computer?
Darwin 25.0.0 arm64 arm
What issue are you seeing?
In Codex desktop, MCP tools are unusable. As soon as an MCP tool is invoked, the tool call ends immediately instead of running normally. This makes MCP-based workflows impossible to use. Non-MCP behavior appears normal, but every MCP invocation fails in the same way.
What steps can reproduce the bug?
Open Codex desktop.
Start a normal conversation in a workspace.
Ask the agent to use any MCP tool.
The moment the MCP tool is invoked, the tool call ends immediately.
This happens consistently across repeated attempts.
What is the expected behavior?
No response
Additional information
No response