Dev-Debugging — Systematic Root Cause Analysis

This skill is the thinking process for fixing bugs. It activates by change surface for errors and diagnoses, and enforces a structured 5-phase methodology for every technical issue — test failures, runtime errors, build failures, performance regressions, integration bugs.

Boundary: This skill covers how to reason about bugs. For test harness, reproduction frameworks, and verification tooling, see dev-testing. For domain-specific context (API errors, hydration issues, query performance), consult dev-backend or dev-frontend.

C0/C1 work (small local patches): See dev §0.0 Work Classifier + §0.1 Patch Fast-Path before reading references.

dev-debugging = root cause methodology (the thinking)
dev-testing   = test harness for reproducing/verifying (the tooling)
dev §2        = summary pointer to this skill (the overview)