PR Reviewer

Receipts, not polish. A review that says "looks good" is not a review. A review that says "line 47 will panic on a nil pointer and here is the fix" is a review.

This skill runs a structured code review and produces a verdict: approve, approve with comments, or request changes. Every finding is actionable. No findings without evidence.

When to use

• Before merging any PR
• When reviewing agent-generated code before committing
• When a significant refactor or new feature is complete
• As part of the release-readiness checklist

Procedure

1. Scope the review — fetch the diff. Identify:

   • Files changed and their purpose
   • The stated intent of the PR (what problem does it solve?)
   • Any linked spec, issue, or ADR

2. Correctness pass — look for bugs, not style:

   • Null / nil / undefined access on values that could be absent
   • Off-by-one errors in loops or index operations
   • Error returns that are silently ignored
   • Race conditions if the code is concurrent
   • Missing input validation at trust boundaries (user input, external API responses)
   • Logic that diverges from the stated intent of the PR

3. Reuse pass — look for duplication:

   • Does this code reimplement something that already exists in the codebase?
   • Is there a stdlib or already-installed dependency that does this?
   • Can the new code be expressed using an existing abstraction?

4. Simplification pass — look for unnecessary complexity:

   • Can this be fewer lines without losing clarity?
   • Is there an abstraction that has only one implementation? (remove it)
   • Is there a dependency added for something a few lines of code would do?
   • Is there "scaffolding for later" that should not exist yet?

5. Security and data boundary pass — look for:

   • Secrets or credentials in code or logs
   • User-controlled input reaching a shell, SQL query, or file path without validation
   • Data crossing a tenant or trust boundary without an explicit check
   • Missing authentication or authorisation checks on new endpoints

6. Classify findings:

   • BLOCKING: must be fixed before merge (correctness bugs, security issues)
   • SUGGESTED: improvement worth making but not a blocker (simplification, reuse)
   • NOTE: observation for awareness, no action required

7. Produce the verdict:

   • Approve: no BLOCKING findings
   • Approve with comments: no BLOCKING findings, SUGGESTED improvements noted
   • Request changes: one or more BLOCKING findings

Outputs

• Finding list: location | severity | description | suggested fix
• Verdict: Approve / Approve with comments / Request changes

Independent second reviewer (on demand)

The writer never approves its own work. Before merging, get a verdict from a different model or a fresh reviewer subagent: scripts/review-gate.sh --pr N (Gemini 3.8 flash high via the agy or gemini CLI; posts the verdict on the PR) or --staged for what the next commit will contain. It is on demand, not a hook default, because teams work on different machines; a clone can opt in with git config review.gate async|block. A changed candidate gets a fresh review; VERDICT: NONE (lane unavailable) is never an approval.

Guardrails

• Every BLOCKING finding must have a suggested fix. "This is wrong" is not actionable.
• Style is not a BLOCKING finding. Style enforcement belongs in the linter, not the review.
• Reuse requires evidence. "This might already exist" is not a finding. Find it or drop the comment.
• The review is not a rewrite. Surface the issues; let the author fix them.

---

See also: REFERENCE.md for a quick lookup of common patterns and their preferred alternatives.