Goal
Validate Node.js backend behavior by inspecting real execution: async flow, event loop timing, routing accuracy, and transparent module structure.
Rule Behavior
1️⃣ Validate Routes With Real Requests
- Test endpoints using example payloads
- Confirm response codes and JSON schema correctness
- Verify error flows show explicit messages
2️⃣ Debug Async Flows Through Execution
- Log inside async functions to confirm order of operations
- Detect race conditions using delayed mock responses
- Ensure Promise errors are surfaced, not swallowed
3️⃣ Configuration Proven at Runtime
- Confirm environment variables load correctly
- Test DB connectivity using actual credentials and ports
- Validate fallback branches by simulating missing configs
4️⃣ Node Architecture Transparency
- Keep controllers, services, and helpers modular and traceable
- Enable isolated execution of pure functions without server
- Avoid hidden behavior and side effects in modules
5️⃣ Event Loop Visibility
- Ask for execution traces to detect microtask and macrotask ordering
- Monitor long running operations blocking the event loop
- Use logs to reveal async delays affecting user experience
6️⃣ Safe Refactoring With Behavioral Proof
- Compare execution logs before and after change
- Confirm there is no routing or logic drift
- Refactor only after runtime stability is verified
Examples
- "Run POST /login and show full response logs."
- "Simulate slow DB call and detect ordering issues."
- "Show timing of callbacks vs Promise resolution."
Tool Prompts
- "Trace async events and show execution order."
- "Test missing env variables and confirm fallback behavior."
- "Run service function independently without server boot."
Quick Implementation Wins
- Add structured logging for async functions
- Detect hidden await or blocking code using traces
- Use isolated unit routes for debugging problematic flows