PlaybookDiff

What is PlaybookDiff?

Claude Code and Codex can use the same repo and still receive different effective instructions. PlaybookDiff is an open-source, deterministic checker that compiles the instructions, skills, and MCP config each agent receives, then shows where they diverge and why. Run it from npm, use it in CI with the GitHub Action, or inspect the source. Read-only, no model calls, and it never executes your repo.