What problem does it solve? Hard bugs and performance regressions resist casual code reading; without a reproducible signal, debugging devolves into guessing. This Skill enforces a disciplined diagnosis loop that builds a tight pass/fail feedback signal first, then reproduces, minimizes, hypothesizes, instruments, fixes, and cleans up. ## Core Features & Use Cases - Feedback loop construction: Builds a red-capable, deterministic, fast command (failing test, curl script, headless browser, replayed trace, fuzz loop, or bisection harness) that catches the exact reported symptom. - Structured hypothesis testing: Generates 3-5 ranked falsifiable hypotheses, then instruments with tagged debug logs or profilers, changing one variable at a time. - Regression test and post-mortem: Writes the regression test before the fix at a correct seam, removes all debug instrumentation, and records the confirmed root cause in the commit message. - Use Case: A user reports that the export endpoint intermittently returns empty files in production. The Skill guides building a replay loop from a captured request, minimizing the repro, testing ranked hypotheses, and landing a fix with a regression test. ## Quick Start Ask the agent to diagnose the bug where the export button intermittently throws an error, and have it build a reproducible feedback loop before proposing any fix.
