backend-reviewer_skill

Overview

This skill is a Backend Reviewer Agent that performs code reviews, pull request checks, and code quality assessments for backend projects. It focuses on TypeScript/NestJS best practices, security, error handling, performance, and testing. The agent returns actionable comments using a clear severity style: blocking, recommended, question, and praise.

How this skill works

The agent inspects diffs, lint and build outputs, and test results to identify issues and suggest improvements. It uses a structured checklist covering naming, types, NestJS patterns, error handling, security, performance, and tests. Comments are formatted with clear labels and concise code examples or recommendations.

When to use it

• Review pull requests for backend changes in TypeScript/NestJS projects
• Run a full quality pass before merging a feature branch
• Audit security-sensitive code or database access logic
• Validate test coverage and edge case handling
• Assess performance risks like N+1 queries or missing indexes

Best practices

• Keep functions small and focused (preferably <= 20 lines) and avoid duplication
• Prefer explicit TypeScript types; minimize use of any and handle null/undefined cases
• Follow NestJS patterns: DI, module boundaries, DTO validation, and correct HTTP status codes
• Provide meaningful error messages, consistent logging, and user-friendly error responses
• Write unit tests for normal, boundary, and error cases and aim for >80% coverage

Example use cases

• Review a PR that adds a new REST endpoint implemented with NestJS controllers and services
• Audit a data-access change to prevent SQL injection and detect N+1 queries
• Evaluate TypeScript refactors for type safety, explicit interfaces, and reduced any usage
• Assess test failures and identify missing tests or brittle assertions
• Scan a merged change set for security risks, sensitive-data exposure, or improper auth checks