What problem does it solve? Debugging often devolves into guesswork, speculative changes, and fixes that mask symptoms instead of resolving root causes. This Skill enforces a disciplined observe-hypothesize-test-fix-verify cycle so failures are reproduced, root causes are proven with evidence, and fixes are validated before being persisted. ## Core Features & Use Cases - Hypothesis-driven diagnosis: Tests one root-cause hypothesis at a time, escalating to data-flow tracing after three rejections. - Evidence-gated fixes: Requires a failing test reproducing the root cause before applying the smallest safe fix. - Self-cleanup enforcement: Audits the task's own git diff for debug output, dead code, and orphan files before persisting. - Use Case: A CI build fails with a flaky test. Invoke the Skill with the failing test output; it reproduces the failure, isolates the race condition, writes a regression test, applies the fix, and verifies the full suite passes. ## Quick Start Ask the agent to troubleshoot the failing test or error message you are seeing and find the root cause.