debug

name	debug
description	Systematic debugging - reproduce, isolate, understand, fix. Use when the user reports a bug, error, crash, unexpected behavior, or says something 'doesn't work' or 'is broken'.
user-invocable	true

Debug

Debug a problem systematically. No shotgun fixes.

Process

1. Reproduce the bug. If you can't reproduce it, you can't verify the fix. Get the exact steps, input, and environment.
2. Isolate the cause. Binary search through the code path. Add logging at key points. Narrow down: which function, which line, which condition?
3. Understand why it happens. Don't just find the broken line. Understand the root cause. "It crashes here" is not a root cause. "This value is null because the API returns an empty body on 204 responses and we don't check for that" is a root cause.
4. Fix the root cause, not the symptom. If you add a null check without understanding why it's null, you've hidden the bug, not fixed it.
5. Verify the fix resolves the original reproduction steps.
6. Write a regression test that would have caught this bug.

Rules

• Never fix something you can't reproduce. You're guessing.
• One fix per commit. If you found two bugs, that's two commits.
• Read the error message carefully. The answer is often right there.
• Check recent changes first: git log --oneline -10 and git diff HEAD~5.
• If the same approach fails twice, reassess your assumptions. Explain the problem from scratch. What are you taking for granted?