What problem does it solve? When a test fails for a non-obvious reason or behavior is unexpected, developers often patch symptoms instead of causes. This Skill runs a disciplined root cause investigation so the actual bug is found, proven with evidence, and fixed with the smallest possible change. ## Core Features & Use Cases - Structured investigation loop: Reproduce the bug deterministically, localize it by bisecting code or git history, then test one falsifiable hypothesis at a time until the cause is confirmed. - Minimal root cause fix: Applies only the targeted change that addresses the proven cause, with no opportunistic refactors or scope creep. - Regression protection: Verifies the fix against the original reproduction and the surrounding test suite, then adds or hands off a regression test so the bug cannot silently return. - Use Case: A date cutoff test fails only in certain timezones. The Skill reproduces the failure, instruments the parsing boundary, confirms the date is parsed as local time, fixes the parsing, and adds a regression test. ## Quick Start Run the debug skill to find and fix the root cause of this failing test, then add a regression test for it.
