System audit — "what works / what drifts / what is missing / what to delete"

An agent system accretes. Good patterns and bad ones, dead rules nobody reads, facts restated in five places with three of them stale, tools that only ran once. This skill is the periodic sweep that keeps it evolving without inflating: it measures which layers actually fire, deletes what doesn't, and reports findings that carry evidence rather than impressions.

The one thing that makes this audit different from a checklist: every claim must be backed by something you touched with your own hands — a file:line, a command's output, a query result. An unverified observation is labelled hypothesis and never counted in the verdict.

Step 0 — Scope, depth, delta (2 minutes, always)