What problem does it solve? Hard bugs and performance regressions resist casual code reading; without a reproducible failing signal, debugging devolves into guesswork. This Skill enforces a disciplined diagnosis loop that builds a tight, red-capable feedback signal before any hypothesis is tested. ## Core Features & Use Cases - Feedback Loop Construction: Builds a deterministic pass/fail signal via failing tests, curl scripts, CLI fixtures, headless browser runs, trace replays, fuzz loops, or bisection harnesses. - Structured Six-Phase Process: Guides reproduction, minimization, ranked falsifiable hypotheses, targeted instrumentation with tagged debug logs, regression testing, and cleanup with post-mortem. - Human-in-the-Loop Fallback: Ships a bash template (scripts/hitl-loop.template.sh) that drives a human through manual reproduction steps and captures structured output. - Use Case: A user reports that an export button intermittently throws an error. The Skill builds a Playwright loop that reproduces the failure, minimizes the scenario, tests ranked hypotheses one variable at a time, and lands a fix with a regression test. ## Quick Start Ask the agent to diagnose the bug where the export button throws an error, and have it build a failing reproduction loop before proposing any fix.
