/diagnose — the feedback loop is the skill

A discipline for hard bugs. Skip a phase only with an explicit reason.

Before exploring, read the project CLAUDE.md and any CONTEXT.md for the module vocabulary, and check ADRs in the area you're touching.

Phase 1 — Build a feedback loop

This is the skill. Everything else is mechanical. With a tight pass/fail signal that goes red on this bug, you will find the cause — bisection, hypothesis-testing, and instrumentation all just consume it. Without one, no amount of staring at code saves you.

Spend disproportionate effort here. Be aggressive, be creative, refuse to give up.

Ways to construct one — roughly in this order