pr-reviewer

PR Reviewer

Review a branch the way a careful human reviewer on this team would: against this repo's own contract, not generic best practice. The contract is CLAUDE.md (the Constitution — MUST / SHOULD / WON'T tables) plus the specialized .claude/skills/ that govern whatever the branch actually touched. A finding only counts if you can tie it to a concrete rule, a real bug, or a coverage gap — opinion without a rule behind it is noise.

The deliverable is a report, not a code change. Fixing is a separate, opt-in step the user has to ask for after seeing the findings.

Input

The user gives a branch name and a review ask. The base branch is auto-resolved in Phase 1 — the remote's default head (origin/HEAD), which is main in some repos and master in others — and falls back to master only if that can't be read. Accept an override if the user names a different base. Nothing else is required; everything you need is in the diff and the repo.

Workflow

Run these phases in order. Phases 1–7 are the review and always run (Phase 6, the Constitution checklist, is a mandatory gate before the report). Phases 8–9 are gated and only run if the user opts in.

Phase 1 — Fetch & switch

# Resolve the base branch (don't hardcode). Use the user's override if given,
# else the remote's default head, else master.
BASE=$(git symbolic-ref --short refs/remotes/origin/HEAD 2>/dev/null | sed 's#^origin/##')
BASE=${BASE:-master}

git fetch origin "<branch>" "$BASE"
git switch "<branch>"      # or: git checkout <branch>

• Dirty working tree — if git status --porcelain is non-empty, stop and ask before switching. Offer to git stash and restore afterward; never switch over uncommitted work silently.
• Missing branch — if the branch isn't on origin, report that and stop.
• Everywhere below, master is shorthand for the resolved $BASE.

Phase 2 — Diff against the merge-base (THREE-DOT, MANDATORY)

Always diff with three dots. This is not a preference — a two-dot diff is a defect in the review itself: