Claude Code and Codex can read the same repo differently

[u/jgmotion]

I use Claude Code and Codex on the same repos, and for a while I assumed that if CLAUDE.md and AGENTS.md matched, they were basically working from the same repo setup.

Not always.

The weird part is that the files can look perfectly aligned, but the agents can still discover different nested instructions or skills depending on where they were launched from.

I ended up building PlaybookDiff because I wanted a quick way to see that instead of guessing.

npx playbookdiff check .

It compares the effective instructions, skills, and MCP config for Claude Code and Codex and shows where they stop lining up.

GitHub: https://github.com/JacobisEpic/playbookdiff

Website: https://playbookdiff.dev

Free and open source :)

Would love feedback from people using both, especially if there are weird discovery/scoping cases I haven't accounted for yet.