| name | debug |
| description | Use when fixing a bug, investigating a failure, or troubleshooting unexpected behavior. Enforces root-cause investigation before any fix attempt. |
| version | 1.0.0 |
Debug
Find root cause before fixing. No guessing.
The Rule
Do not attempt a fix until you understand why it's broken. If you haven't read the error, reproduced it, and traced the cause — you're guessing.
Process
1. Investigate
- Read the error. Full stack trace, line numbers, error codes. The answer is often right there.
- Reproduce it. Can you trigger it reliably? If not, gather more data.
- Check what changed. Git diff, recent commits, new dependencies.
- Trace the data. Where does the bad value come from? Follow it backward to the source.
If the task description includes an error message or log, start there. If not, use ask_user to get the exact error.
2. Find the Pattern
- Find similar working code in the codebase
- Compare working vs. broken — list every difference
- Don't assume any difference "can't matter"
3. Hypothesize and Test
- State your hypothesis: "X is broken because Y"
- Make the smallest possible change to test it
- One variable at a time — never bundle multiple fixes
- If it didn't work, form a new hypothesis (don't pile on more changes)
4. Fix
- Write a failing test that reproduces the bug
- Implement the single fix for the root cause
- Verify: test passes, no other tests broken
- Set commit message explaining the root cause and fix
5. If Stuck After 3 Attempts
Stop. Use ask_user to explain:
- What you investigated
- What you tried and why it didn't work
- What you think the underlying issue might be
Three failed fixes usually means an architectural issue, not a code issue.
Red Flags
If you catch yourself thinking any of these, stop and go back to step 1:
- "Quick fix, investigate later"
- "Just try changing X"
- "I don't fully understand but this might work"
- "Let me fix multiple things at once"
