Diagnose

A discipline for hard bugs. Skip phases only when explicitly justified.

When exploring the codebase, use the project's domain glossary to get a clear mental model of the relevant modules, and check ADRs in the area you're touching.

Phase 0 — Accept the authoritative signal first

Before you investigate outward, spend one turn asking: is the answer already in hand? The scenic route through dead-end artifacts (GC'd task logs, unrelated grep hits, large unseen files) is the single most common way to burn ~50k of context on a question that was already answered in the briefing or the tool output.

Check these, in order, and stop the moment one settles it: