PR Review Expert

Structured, systematic code review for GitHub PRs and GitLab MRs. Goes beyond style nits to perform blast-radius analysis, security vulnerability scanning, breaking-change detection, test-coverage delta calculation, and performance impact assessment. Produces reviewer-ready reports with prioritized findings categorized as must-fix, should-fix, and suggestions.

Keywords: PR review, code review, pull request, merge request, blast radius, security scan, breaking changes, test coverage, review checklist, code quality

Core Capabilities

• Blast radius analysis — trace which files, services, and downstream consumers a diff could break; quantify severity CRITICAL/HIGH/MEDIUM/LOW.
• Security scanning — detect SQL injection, XSS vectors, hardcoded secrets, auth bypass, insecure crypto, path traversal, and prototype pollution in the diff.
• Breaking-change detection — flag API removals/renames, response-schema and required-field changes, DB column removals, env-var changes, and TS interface edits.
• Test coverage analysis — new-code vs new-test ratio, missing tests for new public functions, deleted tests without deleted code, coverage delta.
• Performance assessment — N+1 query patterns, bundle-size regressions, unbounded queries, missing indexes.
• Reviewer-ready output — prioritized must-fix / should-fix / suggestion report, a 35-item checklist, and consistent comment labels.

When to Use

• Before merging any PR that touches shared libraries, APIs, or database schemas.
• When a PR is large (>200 lines changed) and needs structured review.
• For PRs in security-sensitive code paths (auth, payments, PII handling).
• After an incident, to proactively review similar code changes.
• For onboarding new contributors whose PRs need thorough feedback.

Tools

| Tool | Purpose | Command | |------|---------|---------| | blast_radius_calculator.py | Calculate PR blast radius from import chains / dependency trees of changed files | git diff --name-only main...HEAD \| python scripts/blast_radius_calculator.py --root src | | diff_analyzer.py | Analyze a diff for risk indicators (large files, sensitive paths, config/breaking/security patterns) | gh pr diff $PR \| python scripts/diff_analyzer.py --json | | review_checklist_generator.py | Generate a tailored review checklist from changed file types/patterns | git diff --name-only main...HEAD \| python scripts/review_checklist_generator.py |

References

Load the reference that matches the task — keep this file lean and pull detail on demand:

• references/review-workflow-commands.md — the 6-step review workflow with the exact gh/grep command catalog for context gathering, blast radius, security scan, breaking-change detection, coverage delta, and performance impact (plus the blast-radius severity table and coverage rules). Read when actually performing a review.
• references/writeup-format-and-checklist.md — the review report template with worked examples, the complete 35-item review checklist, and the comment-label taxonomy. Read when writing up findings.
• references/best-practices-and-troubleshooting.md — common reviewer pitfalls, best-practice habits, the troubleshooting table, and the success-criteria bar. Read before and after a review for quality control.

Scope & Limitations

This skill covers:

• Structured review of GitHub PRs and GitLab MRs using a 35+ item checklist
• Blast radius analysis for monorepo and multi-service architectures
• Static security scanning of diffs for common vulnerability patterns (SQLi, XSS, secrets, auth bypass)
• Breaking change detection for APIs, database schemas, TypeScript interfaces, and environment variables

This skill does NOT cover:

• Automated code fixes or refactoring — use engineering/saas-scaffolder or engineering/migration-architect for code generation
• Runtime security analysis, SAST/DAST tool orchestration, or CVE database lookups — use engineering/dependency-auditor for dependency-level vulnerability scanning
• CI/CD pipeline configuration or build failure triage — use engineering/ci-cd-pipeline-builder for pipeline design
• Performance benchmarking or load testing — use engineering/performance-profiler for profiling and optimization guidance

Integration Points

| Skill | Integration | Data Flow | |-------|-------------|-----------| | engineering/dependency-auditor | Run dependency audit before reviewing PRs that add or upgrade packages | Audit report feeds into the Security section of the review report | | engineering/ci-cd-pipeline-builder | Embed review checklist gates into CI pipelines as automated PR checks | Checklist items become pass/fail signals in the pipeline | | engineering/performance-profiler | Escalate N+1 and unbounded query findings for detailed profiling | Flagged code paths from review become profiling targets | | engineering/migration-architect | Validate database migration safety for PRs that include schema changes | Migration risk assessment supplements the Breaking Changes section | | engineering/release-manager | Feed breaking change detection results into release notes and changelogs | Detected breaking changes auto-populate release documentation | | engineering/api-design-reviewer | Cross-reference API endpoint changes with API design standards | API review findings merge into the Blast Radius and Breaking Changes sections |