skill-validation

A rule set for validating modified skills. A skill is a reusable set of instructions that guides a coding agent through a type of work.

In plain words
What is it for?
Use it after editing a `SKILL.md` to run the appropriate validator and audit, check the instruction count, and confirm that alternative skills are named where needed.
Why use it?
It makes sure changed skills meet checks for structure, length, description quality, exclusions, and an audit score.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/wyattowalsh/agents/skill-validation
Clone the repo
git clone --depth 1 https://github.com/wyattowalsh/agents

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 149 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00149
Opus 5 $0.00000 $0.00075
Sonnet 5 $0.00000 $0.00030
Haiku 4.5 $0.00000 $0.00015

Measured 2d ago against content hash 36ac47ab754e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

skill-validation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/skill-validation.mdc · 12 lines

What it actually says

After modifying any SKILL.md:

  1. Run uv run python skills/<name>/scripts/check.py when present, otherwise uv run python skills/skill-creator/scripts/asset_toolkit/validate_skill.py skills/<name>
  2. Run uv run python skills/skill-creator/scripts/audit.py <skill-name> — score >= 80
  3. Verify body under 500 lines (below frontmatter)
  4. Verify description under 200 characters
  5. NOT-for exclusions must name the correct alternative skill in parentheses — e.g., NOT for CI/CD pipelines (devops-engineer)
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 12 lines · 149 tokens per session scan A 36ac47ab754e

Subscribe to this mod's changes

skill-validation is a cursor rule published in the GitHub repository wyattowalsh/agents (5 stars, last pushed 11d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 149 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.