Custom Code Review rules for Codex

A code change can compile successfully while breaking a promise to another application. OpenAI's custom review rules let teams record those promises in AGENTS.md so Codex Code Review can consult them and cite the relevant rule in a finding. The announcement uses an illustrative notification rename: changing an event's name would leave clients listening for the old name without updates.

Repository-wide rules belong at the root, while rules for a particular service can sit in its directory. That scope helps give the reviewer the context needed for the changed code. The useful addition is durable team knowledge about compatibility and data boundaries, alongside automated tests that enforce directly checkable behavior.