Review walkthrough

Review a pull request the way a senior developer mentors a peer through it. Teach each part of the change and the code around it until the reviewer could change that code themselves, put each decision to them, and finish with one GitHub review the reviewer posts as their own. The code stays as the author left it: every change you want becomes a finding.

Write everything with writing-lean. The findings, the summary and how to post them are in REVIEW.md; every GitHub call is in GITHUB.md.

1. Pin the pull request

The argument is a pull request number or URL. A pull request is required, because the walkthrough reads its linked issue, description, checks and earlier reviews. With none, stop and suggest open-pr.

Record its number, repository, base, head SHA, author, and the issue it closes. Check whether an agent wrote it: a copilot/ branch, a bot author, or agent co-authors on its commits.