What problem does it solve? Hard bugs and performance regressions resist casual debugging: without a deterministic reproduction signal, developers guess at causes and apply fixes that don't stick. This Skill enforces a disciplined six-phase loop that turns vague failure reports into verified fixes with regression tests. ## Core Features & Use Cases - Feedback loop construction: Builds a fast, deterministic pass/fail signal using failing tests, curl scripts, CLI fixtures, headless browser runs, trace replays, fuzz loops, or git bisect harnesses. - Ranked hypothesis testing: Generates 3-5 falsifiable hypotheses, instruments one variable at a time with tagged debug logs, and measures baselines for performance regressions. - Regression lockdown and post-mortem: Writes the regression test before the fix at a correct seam, cleans up all instrumentation, and hands architectural findings off for follow-up. - Use Case: A user reports that an export button intermittently throws an error. The Skill builds a reproduction loop (using the included human-in-the-loop bash template if needed), reproduces the failure, tests ranked hypotheses, applies the fix, and leaves a regression test behind. ## Quick Start Ask the agent to diagnose the bug where the export button intermittently throws an error and have it build a reproduction loop first.
