debuglisted

# Debug ## Core Rule Form a single hypothesis at a time. Validate with a falsifiable test before fixing. Never patch a symptom you haven't reproduced. ## When to Use Invoke with `/debug` when: - A bug has been reported or observed and needs systematic investigation - A test is failing and the cause isn't obvious - Something "just stopped working" and you need to find out why - Previous fix attempts haven't resolved the issue - You want to ensure the fix includes a regression test ## Process ### Phase 1: Reproduce Before investigating, establish a reliable reproduction: 1. **Get the symptoms** — exact error message, stack trace, unexpected behavior 2. **Get the trigger** — what action causes the bug? What input? 3. **Reproduce locally** — can you make it happen on demand? 4. **Identify consistency** — does it always happen, or is it intermittent? If you cannot reproduce the bug, do NOT guess at fixes. Instead, add logging/instrumentation to gather more data. ### Phase 2: Hypothesize Form hypotheses based on evidence, not intuition: 1. **Read the error** — what does the error message actually say? 2. **Read the stack trace** — where exactly does it fail? 3. **Check recent changes** — `git log --since='3 days ago'` — did something change? 4. **Check the language pattern lookup** — if the error matches a category in `references/error-patterns.md`, use it to seed hypotheses (do not blindly accept; verify against the actual code) 5. **Form 2-3 hypotheses** — rank by li