check
Read-only drift detector. Diffs SPEC.md against current code and reports violations grouped by severity. Writes nothing — suggests remedies via the spec or build skills but never invokes them. Triggers when the user asks to check drift, audit the spec, verify invariants, or ask whether code still matches the spec. Phrasings: "check drift", "audit the spec", "does the code still match §V", "check invariants", "spec vs code".
Install
Install this Claude and Codex skill with the command below. The command stays visible even when copy support is unavailable.
git clone https://github.com/JuliusBrussee/cavekit /tmp/cavekit && ln -s /tmp/cavekit/skills/check ~/.claude/skills/checkFrom README
check — drift report Pure diagnostic. Reports violations. Writes nothing. User decides remedy. Spec drifting silently from code is the #1 SDD failure mode. check is the detector. Run it after each /build and before each ship — drift caught here is a diff; drift caught in prod is a §B. LOAD Read SPEC.md. If missing → "no spec, nothing to check." Stop. Parse invocation args: §V → check invariants only (default) §I → check interfaces §T → audit task status vs code --all → all three CHECK §V — invariants For each V : Translate invariant into verifiable claim about code. Grep / read relevant files. Classify: HOLD / VIOLATE / UNVERIFIABLE. Record address + file:line evidence. CHECK §I — interfaces For each I item: Locate implementation. Classify: MATCH — shape in code = shape in spec. DRIFT — impl exists, shape differs. MISSING — impl absent. EXTRA — code exposes surface not in §I. CHECK §T — tasks For each T : If x: verify claimed work present. If : note as in-progress.