| name | systematic-debugging |
| description | [Debug] Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes - four-phase framework (root cause investigation, pattern analysis, hypothesis testing, implementation) that ensures understanding before attempting solutions. (project) |
Systematic Debugging
The Iron Law
NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST
The Four Phases
Phase 1: Root Cause Investigation
- Read Error Messages Carefully
- Reproduce Consistently
- Check Recent Changes
- Gather Evidence in Multi-Component Systems
- Trace Data Flow
Phase 2: Pattern Analysis
- Find Working Examples
- Compare Against References
- Identify Differences
- Understand Dependencies
Phase 3: Hypothesis and Testing
- Form Single Hypothesis
- Test Minimally
- Verify Before Continuing
Phase 4: Implementation
- Create Failing Test Case
- Implement Single Fix
- Verify Fix
- If 3+ Fixes Failed: Question Architecture
Red Flags - STOP and Follow Process
- "Quick fix for now, investigate later"
- "Just try changing X and see if it works"
- "I don't fully understand but this might work"
- Proposing solutions before tracing data flow
Quick Reference
| Phase | Key Activities | Success Criteria |
|---|
| 1. Root Cause | Read errors, reproduce, check changes | Understand WHAT and WHY |
| 2. Pattern | Find working examples, compare | Identify differences |
| 3. Hypothesis | Form theory, test minimally | Confirmed or new hypothesis |
| 4. Implementation | Create test, fix, verify | Bug resolved, tests pass |
