ci: reject Claude and Codex co-authors in PR commits

[TomCC7]

Contribution path

Small CI fix; no tracking issue.

Problem

Commit 11f4958 reached main with a Claude co-author trailer. The existing check was case-sensitive and CI did not supply the commit range it needed to inspect.

Solution

Add a No AI co-authors job to the existing ci-complete gate, which main's active ruleset already requires. Check every incoming commit for pull requests and merge groups using full Git history and the event's base/head SHAs.

Reject co-author lines containing Claude, Codex, or an anthropic.com/openai.com email, regardless of capitalization. Report offending commit SHAs and ask contributors to amend them. Ordinary human co-authors and mentions of AI tools in commit prose pass; existing base-branch history is excluded.

Reuse the existing commit-check script and run its regression tests in lint CI. No new dependencies or repository settings changes.

How to Test

uv run pytest -c /dev/null --rootdir . --noconftest bin/hooks/test_filter_commit_message.py

18 tests passed, covering mixed-case trailers, both tools, human co-authors, older commits, merge parents, base-history exclusion, and invalid ranges. Also verified that the exact reported commit fails. Ruff, targeted mypy, workflow YAML validation, and commit hooks passed.

AI assistance

Codex (GPT-6) implemented and locally validated this change.

Checklist

• I have read and approved the CLA.

[greptile-apps]

Confidence Score: 4/5

Not safe to merge until legitimate human co-author trailers containing the name Claude are accepted.

Findings

1.  Human Claudes Are Rejected ▶

Summary

• This change adds commit-message scanning for AI co-author trailers. A reproduced false positive rejects legitimate human co-authors named Claude, so it should not merge until the detection is narrowed.

_{Reviews (1) · Last reviewed commit: "ci: reject AI co-authors in incoming com..."}

[greptile-apps]

Human Claudes Are Rejected

The name-only \bClaude\b alternative treats any co-author with Claude as a first or last name as an AI co-author, regardless of the email address. A normal trailer such as Co-authored-by: Claude Smith <claude@example.com> makes the required commit check fail and blocks otherwise valid changes from merging. This must be corrected before merging.

Artifacts

Evidence from the check

• Creates a temporary Git repository, commits the stated trailer, independently checks the regex, and invokes the hook over the commit range; it reproduces the false rejection.

Command output from the check

• Captured output from running the reproduction script in `/home/user/repo`, showing an independent regex match and `--check` exit status 1 with its exact diagnostic; it confirms the false rejection.

_{Ran code and verified through T-Rex}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

@@            Coverage Diff             @@
##             main    #4061      +/-   ##
==========================================
- Coverage   78.21%   78.21%   -0.01%     
==========================================
  Files        1428     1428              
  Lines      135077   135077              
  Branches    11708    11708              
==========================================
- Hits       105653   105647       -6     
- Misses      26104    26110       +6     
  Partials     3320     3320              

Components	Coverage Δ
Tests	94.72% <ø> (ø)

Flag	Coverage Δ
OS-ubuntu-24.04-arm	74.53% <ø> (-0.01%)	⬇️
OS-ubuntu-latest	75.10% <ø> (-0.01%)	⬇️
Py-3.10	75.09% <ø> (ø)
Py-3.11	75.10% <ø> (-0.01%)	⬇️
Py-3.12	?
Py-3.13	?
Py-3.14	75.10% <ø> (-0.01%)	⬇️
Py-3.14t	75.09% <ø> (-0.01%)	⬇️
SelfHosted-Linux	35.58% <ø> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.