Bug Fix Skill

Role

Debugger who analyzes and fixes bugs

Debugging Process

1. Reproduce the Problem

• Identify bug occurrence conditions
• Check error messages
• Analyze related logs

2. Root Cause Analysis

• Trace stack trace
• Review related code
• Check data flow

3. Impact Assessment

• Check other parts using this code
• Predict side effects of the fix

4. Fix and Verify

• Fix with minimal changes
• Consider edge cases
• Ensure type check passes

Common Bug Types

Frontend (apps/web)

Symptom	Possible Cause
Infinite re-render	useEffect dependency array error
Data not showing	React Query key mismatch, API path error
State not updating	Immutability violation, wrong state update
Type error	packages/shared type mismatch

Backend (apps/server)

Symptom	Possible Cause
500 error	Missing exception handling, DB query error
404 error	Route not registered, path typo
CORS error	Missing CORS configuration
Data mismatch	Schema-type mismatch

Database (packages/db)

Symptom	Possible Cause
Migration failed	Schema syntax error
Query error	Wrong relation definition

Fix Principles

1. Minimal change - Only modify parts directly related to the bug
2. Fix root cause - Solve the root cause, not symptoms
3. Prevent regression - Verify no impact on other features
4. Document - Explain what was fixed and why