Codex

InstallCopy Anchor Link

Add the Rehearsal marketplace, then add the plugin from it:

codex plugin marketplace add MitudruDutta/rehearsal
codex plugin add rehearsal@rehearsal

The plugin adds the Rehearsal skill and the Rehearsal MCP server. Codex starts the MCP server itself, with uvx. Install uv if you do not have it.

Sign inCopy Anchor Link

Run this in a terminal, once:

uvx --from rehearsal-kit rehearsal login

Add --url <address> for a server other than the default. Your browser opens the console. Check that the code matches your terminal, then choose Approve. The sign-in is saved for your user only, and the MCP server reads it.

On a machine with no browser, use rehearsal login --with-key. Or set REHEARSAL_URL and REHEARSAL_API_KEY in the environment that Codex runs in: they take precedence over a saved sign-in.

Check that it worksCopy Anchor Link

Start Codex and ask:

Show my Rehearsal workspace status.

Codex calls the workspace_status tool and reports your plan and what exists in the workspace. If the tool answers that Rehearsal is not signed in, run the sign-in command above and ask again.

What to askCopy Anchor Link

Evaluate my support agent on the published world for Gitea. Use the dev jobs and two repeats.
The instructions are in agent/instructions.txt.

Codex tells you the number of episodes and the cost, and waits for your yes, before it starts the run.

Why did the failed episodes fail? Group the causes.

Improve the agent from those failures, then compare both versions on holdout.

More prompts are in AI assistants.

End its accessCopy Anchor Link

Revoke the key on the console's API keys page. Codex loses access at once. Then remove the saved sign-in from the machine:

uvx --from rehearsal-kit rehearsal logout

To remove the plugin itself, use Codex's own plugin commands.