bug-investigationlisted
Install: claude install-skill lklimek/claudius
# Bug Investigation
Default discipline for diagnosing a reported bug. The user's reproducible observation is ground truth — the analysis must explain it, not explain it away.
## Rules
1. **Observation over theory** — the user's reproducible facts are ground truth to explain; their causal explanation is only a hypothesis. Refuting the theory ≠ explaining the observation. (User imprecision usually lives in the explanation, not the observation.)
2. **Entry point over name** — statically trace the call graph from the actual UI/CLI entry point (the thing the user clicked/ran) down to the outcome. Never anchor on a function whose name merely matches the feature.
3. **The exercised path, not a correct path** — when ≥2 plausible code paths exist, verify the one actually hit. Proving a correct path exists is not proving the user's path is correct.
4. **Reproduce or it's unsolved** — if your analysis cannot reproduce the user's concrete observation, it is INCOMPLETE. Never conclude "not a bug" until the observation is explained. A clash between your analysis and a user-observed fact is a STOP signal, not a footnote.
5. **Brief with the literal reproduction** (coordinator-facing) — investigation spawn prompts MUST quote the user's exact reproduction steps and the literal entry point, and require: "trace from this entry point; if you can't reproduce the observed symptom, you haven't found the cause."
## Failure Mode (worked example)
A real funds-safety bug (a receive address derived