pr-review-expert

# PR Review Expert

**Tier:** POWERFUL
**Category:** Engineering
**Domain:** Code Review / Quality Assurance

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## Overview

Structured, systematic code review for GitHub PRs and GitLab MRs. Goes beyond style nits — this skill
performs blast radius analysis, security scanning, breaking change detection, and test coverage delta
calculation. Produces a reviewer-ready report with a 30+ item checklist and prioritized findings.

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## Core Capabilities

- **Blast radius analysis** — trace which files, services, and downstream consumers could break
- **Security scan** — SQL injection, XSS, auth bypass, secret exposure, dependency vulns
- **Test coverage delta** — new code vs new tests ratio
- **Breaking change detection** — API contracts, DB schema migrations, config keys
- **Ticket linking** — verify Jira/Linear ticket exists and matches scope
- **Performance impact** — N+1 queries, bundle size regression, memory allocations

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## When to Use

- Before merging any PR/MR that touches shared libraries, APIs, or DB schema
- When a PR is large (>200 lines changed) and needs structured review
- Onboarding new contributors whose PRs need thorough feedback
- Security-sensitive code paths (auth, payments, PII handling)
- After an incident — review similar PRs proactively

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## Fetching the Diff

### GitHub (gh CLI)
```bash
# View diff in terminal
gh pr diff <PR_NUMBER>

# Get PR metadata (title, body, labels, linked issues)
gh pr view <PR_NUMBER> --json title,body,labels,assignees,milestone

# List files changed
gh pr diff <PR_NUMBER> --name-only

# Check CI status
gh pr checks <PR_NUMBER>

# Download diff to file for analysis
gh pr diff <PR_NUMBER> > /tmp/pr-<PR_NUMBER>.diff
```

### GitLab (glab CLI)
```bash
# View MR diff
glab mr diff <MR_IID>

# MR details as JSON
glab mr view <MR_IID> --output json

# List changed files
glab mr diff <MR_IID> --name-only

# Download diff
glab mr diff <MR_IID> > /tmp/mr-<MR_IID>.diff
```

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## Workflow

### Step 1 — Fetch Contex...