// Systematic debugging with 4-phase root cause analysis. Triggers when bugs are reported, errors encountered, or unexpected behavior observed.
Proactive code quality review. Triggers on significant code changes to check security, performance, architecture, and project patterns.
Capture learnings after tasks. Triggers on task completion, repeated mistakes, retrospective requests, or "what did I learn".
SDLC workflow with MCP tools. Triggers on "start", "implement", "work on", or unclear workflow.
Git workflow management. Triggers when creating branches, preparing PRs, or managing merge decisions.
Proactive OpenAPI workflow. Triggers when OpenAPI spec files are modified to validate, regenerate code, and verify builds.
Proactive security scanning. Triggers when modifying auth, API endpoints, user data, or sensitive operations.
| name | systematic-debugging |
| description | Systematic debugging with 4-phase root cause analysis. Triggers when bugs are reported, errors encountered, or unexpected behavior observed. |
Apply structured 4-phase debugging to find root causes, not just symptoms.
This skill should activate when:
Before fixing anything:
1. Understand the expected behavior
2. Understand the actual behavior
3. Find reliable reproduction steps
4. Identify the exact error/symptom
Questions to answer:
Narrow down the problem:
1. Find the smallest reproduction case
2. Identify which component/layer fails
3. Check recent changes (git log, git diff)
4. Add logging/debugging to trace execution
Techniques:
Find the actual cause, not symptoms:
1. Follow the data flow
2. Check assumptions
3. Verify inputs/outputs at each step
4. Ask "why" 5 times
Common root causes:
| Symptom | Likely Root Cause |
|---|---|
| 404 on API | Route not registered |
| Type mismatch | Wrong type conversion |
| Null pointer | Uninitialized variable |
| Race condition | Missing synchronization |
| Auth failure | Token/session expired |
Fix properly:
1. Write a test that reproduces the bug
2. Implement the fix
3. Verify the test passes
4. Check for similar issues elsewhere
5. Prevent regression
# Run with verbose logging
go run ./cmd/api/main.go
# Run specific test with verbose output
go test -v -run TestName ./...
# Add debug logging
zap.L().Debug("checkpoint", zap.Any("data", data))
// Debug print (visible in Xcode console)
#if DEBUG
print("DEBUG: \(variable)")
#endif
// Debug logging
Log.d("TAG", "Debug: $variable")
## Bug Analysis
**Symptom**: [what user reported]
**Reproduction**: [steps to reproduce]
### Investigation
- [ ] Reproduced: [yes/no]
- [ ] Isolated to: [component/file]
- [ ] Root cause: [actual cause]
### Fix
- **File**: [file:line]
- **Change**: [what was changed]
- **Test**: [test that prevents regression]
### Verification
- [ ] Original issue fixed
- [ ] No new issues introduced
- [ ] Similar code checked