What problem does it solve? Debugging sessions often devolve into guess-and-check thrashing: fixes applied without a root cause, flaky tests dismissed, and symptoms patched at the crash site instead of the origin. This Skill enforces a disciplined seven-phase workflow that turns any observed misbehaviour into a verified, root-cause fix. ## Core Features & Use Cases - Loop-first diagnosis: Build a fast, deterministic, red-capable reproduction loop before forming any theory, using ten proven constructions from failing tests to artifact replay. - Structured hypothesis testing: Rank three to five falsifiable hypotheses, probe one variable at a time with tagged instrumentation, and fix at the producer rather than the consumer. - Triage and tracing references: Decision trees for non-reproducible, test, build, and runtime failures, plus backward call-chain tracing and git bisect recipes. - Use Case: A test fails in CI but passes locally. The Skill raises the reproduction rate with repeated parallel runs, identifies an arbitrary sleep as the defect, replaces it with condition-based waiting, and verifies the fix across hundreds of iterations. ## Quick Start Ask the agent to diagnose why your failing test or broken build is happening and fix the root cause using the debugging skill.