How to install check
npx skills add https://github.com/juliusbrussee/cavekit --skill checkClaude Code
Cursor
Windsurf
Cline
Full instructions (SKILL.md)
Source of truth, from juliusbrussee/cavekit.
name: check description: | 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".
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<n>:
- 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<n>:
- If
x: verify claimed work present. - If
~: note as in-progress. - If
.: note as pending. - Flag
xrows with no evidence as STALE.
REPORT
Caveman. Grouped by severity.
## §V drift
V2 VIOLATE: auth/mw.go:47 uses `<` not `≤`. see §B.1.
V5 UNVERIFIABLE: no test covers ∀ req path.
## §I drift
I.api DRIFT: POST /x returns `{result}` not `{id}`. route.go:112.
I.cmd MISSING: `foo bar` absent from cli/*.go.
## §T drift
T3 STALE: status `x`, no middleware file exists.
## summary
2 violate. 1 missing. 1 stale. 1 unverifiable.
next: spec skill with `bug:` or fix code at cited lines.
REMEDY HINTS (not actions)
End report with one-line hint per class:
- VIOLATE / DRIFT → invoke spec skill
bug: <V.n>or fix code. - MISSING → invoke build skill on
§T.nif task exists; else spec skillamend §T. - STALE → spec skill
amend §Tto uncheck. - EXTRA → spec skill
amend §Ito document, or delete code.
Never invoke fixes. Report only.
NON-GOALS
- Zero writes. No SPEC.md edits. No code edits.
- No sub-agents. Main thread reads.
- No scores, no grades. Binary per item: holds or drifts.
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