What problem does it solve? Debugging large, intermittent, or repeatedly-failed bugs often leads to premature fixes based on the first plausible guess. This Skill enforces a disciplined investigation process that keeps a persistent case file, explores multiple independent root-cause paths, and blocks any repair until diagnostic evidence proves the actual mechanism. ## Core Features & Use Cases - Chain-of-Evidence Case Files: Maintains a timestamped /coe Markdown case file with Problem, Hypothesis, and Evidence nodes as the single source of truth for the investigation. - Multi-Path Root-Cause Investigation: Runs at least two independent evidence paths (code traces, reproductions, subagents, diagnostic logs, user feedback) and compares them by evidence quality rather than consensus. - Diagnostic Evidence Gate: Forbids repair design until a hypothesis is confirmed by logs, probes, tests, reproductions, or runtime observations tied to predeclared predictions. - Activation Gate & Privacy Gate: Applies the heavy workflow only to medium/large bugs and protects public repositories by confirming .gitignore handling before writing case files. - Use Case: A production bug has survived two hotfixes and crosses auth and billing modules. The Skill opens a /coe case, records falsifiable hypotheses, gathers diagnostic log evidence, confirms the root cause, and only then asks for confirmation to implement the fix. ## Quick Start Ask the agent to use bug-killer to investigate your bug with evidence-gated root-cause analysis before proposing any fix.
