GitHub Copilot

You are GitHub Copilot acting as a senior backend engineer. Task: generate a single-file Express.js CRUD endpoint (GET, POST, PUT, DELETE) for a resource named "items". Constraints: use TypeScript, ES modules (import/export), async/await, simple in-memory store (no DB), input validation for POST/PUT (id as UUID string, name non-empty). Output format: return a comment with the filename (src/routes/items.ts) then the complete TypeScript code block only. Example route: POST /items accepts { name: string } and returns created item with id.

You are GitHub Copilot acting as a frontend test engineer. Task: generate Jest + React Testing Library unit tests for a functional React component named "UserCard". Constraints: use TypeScript test (.test.tsx), mock props and simulate user events, cover rendering, accessibility role assertions, and one error state. Output format: provide a filename comment (tests/UserCard.test.tsx) then the complete test file code only. Example prop: { id: 'u1', name: 'Alice', onSelect: () => void } and simulate clicking a select button to assert onSelect called.

You are GitHub Copilot acting as a DevOps engineer. Task: create a GitHub Actions workflow for a Node.js monorepo using Yarn workspaces. Constraints: YAML format, run on push to main and PRs, matrix Node versions [14,16,18], install with cache, run lint, build, and test for changed packages only, and upload cache/artifacts. Output format: provide workflow filename comment (.github/workflows/ci.yml) then the full YAML workflow. Include a short section (3 lines) after the YAML explaining how changed-package detection works and one environment variable to override parallelism.

You are GitHub Copilot acting as a refactoring engineer. Task: convert a callback-based function named "fetchUserAndPosts" into async/await across its module. Constraints: present a file-by-file plan, include exact code diffs (unified format) for up to three files, preserve behavior and error handling, add TypeScript types where missing. Output format: list changed filenames, then for each file show a unified diff snippet (--- old +++ new lines) with full updated function implementations. Example: original uses callbacks like fetchUser(id, cb) and fetchPosts(userId, cb).

You are GitHub Copilot acting as a senior application security engineer. Task: analyze a provided PR diff (paste below) and produce a security review with prioritized findings, concrete remediation code snippets, and CI policy updates. Constraints: identify OWASP-relevant issues, insecure dependency changes, sensitive data leaks, and missing auth checks; assign severity (Critical/High/Medium/Low); for each critical/high issue give a one-paragraph exploit scenario and a patch code snippet; propose a GitHub Actions policy that blocks merges until automated checks pass. Output format: JSON with fields: findings[], patches[], ci_policy (YAML string), and summary (3-sentence). Paste PR diff into the prompt when using.

You are GitHub Copilot acting as a senior QA engineer. Task: produce property-based tests using fast-check for a pure function named "mergeUserProfiles(a,b)" that merges two user profile objects. Constraints: include generator definitions for profiles (optional fields, nested address, email format), shrinkers or minimal counterexample guidance, three property tests (commutativity where applicable, idempotence with identical profiles, and stability with null fields), and a failing example demonstrating a discovered bug. Output format: provide filenames and full code blocks for generators (tests/generators.ts) and tests (tests/mergeUserProfiles.prop.test.ts), plus one paragraph explaining how to run them and interpret counterexamples.

Choose GitHub Copilot when your team lives in GitHub and wants AI inside commits, PRs, reviews, CLI, and IDE workflows. Consider Cursor for AI-native editor workflows, Amazon Q for AWS-heavy teams, or Tabnine/Codeium when procurement or privacy requirements differ.