Diagnose

This is a structured debugging protocol that forces you to build a fast feedback loop before you do anything else. The core insight is that if you can construct a deterministic, agent-runnable pass/fail signal for a bug, the rest of the work becomes mechanical. It walks through building test harnesses, curl scripts, headless browser automation, whatever it takes to get that loop, then uses it to reproduce, hypothesize, instrument, and fix. The discipline shines on hard bugs where your first instinct is to stare at code and guess. It's opinionated about not proceeding without a loop, generating multiple ranked hypotheses before testing, and treating non-deterministic bugs as "raise the reproduction rate until debuggable" problems. Worth reaching for when normal debugging instincts aren't cutting it.

Install to Claude Code

npx -y skills add mattpocock/skills --skill diagnose --agent claude-code