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

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