How do I install the Check skill?

Run npx skillmds@latest add om-scogo/check-2 in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Check safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Check?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Check free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

om-scogo (@om-scogo) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Check by om-scogo — Agent Skill

Name: Check
Author: om-scogo

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".

om-scogo Updated Sep 21, 2026 0 repo stars

File contents

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.
If .: note as pending.
Flag x rows 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.n if task exists; else spec skill amend §T.
STALE → spec skill amend §T to uncheck.
EXTRA → spec skill amend §I to 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.

---name: check-2description: 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 reportPure diagnostic. Reports violations. Writes nothing. User decides remedy.Spec drifting silently from code is the #1 SDD failure mode. check is thedetector. Run it after each `/build` and before each ship — drift caught here isa diff; drift caught in prod is a §B.## LOAD1. Read `SPEC.md`. If missing → "no spec, nothing to check." Stop.2. Parse invocation args: - `§V` → check invariants only (default) - `§I` → check interfaces - `§T` → audit task status vs code - `--all` → all three## CHECK §V — invariantsFor each V<n>:1. Translate invariant into verifiable claim about code.2. Grep / read relevant files.3. Classify: **HOLD** / **VIOLATE** / **UNVERIFIABLE**.4. Record address + file:line evidence.## CHECK §I — interfacesFor each I item:1. Locate implementation.2. 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 — tasksFor each T<n>:1. If `x`: verify claimed work present.2. If `~`: note as in-progress.3. If `.`: note as pending.4. Flag `x` rows with no evidence as **STALE**.## REPORTCaveman. Grouped by severity.```## §V driftV2 VIOLATE: auth/mw.go:47 uses `<` not `≤`. see §B.1.V5 UNVERIFIABLE: no test covers ∀ req path.## §I driftI.api DRIFT: POST /x returns `{result}` not `{id}`. route.go:112.I.cmd MISSING: `foo bar` absent from cli/*.go.## §T driftT3 STALE: status `x`, no middleware file exists.## summary2 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.n` if task exists; else spec skill `amend §T`.- STALE → spec skill `amend §T` to uncheck.- EXTRA → spec skill `amend §I` to 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.

Frequently asked questions