Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/Everyone-Needs-A-Copilot/claude-copilotnpx agentmods add skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validationWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validation)<a href="https://agentmods.dev/skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validation"><img src="https://agentmods.dev/badge/skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validation"><img src="https://agentmods.dev/badge/skills/everyone-needs-a-copilot/claude-copilot/frontmatter-validation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00057 | $0.01476 |
| Opus 5.5 | $0.00023 | $0.00590 |
| Sonnet 5.5 | $0.00011 | $0.00295 |
| Haiku 4.5 | $0.00006 | $0.00148 |
Grade A, and why
frontmatter-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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 195 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontmatter Validation
Validate and fix YAML frontmatter metadata in markdown documentation files.
Purpose
Frontmatter enables efficient AI navigation of documentation. This skill ensures all files have correct, complete metadata for their document type.
Frontmatter Schemas by Document Type
Tier 1: Skills (SKILL.md)
---
name: forces-analysis # required, kebab-case
description: >- # required, trigger-rich — used by `cc skill search` for keyword matching
One-line description covering use cases and when to invoke this skill.
version: 1.2 # required, semver
allowed-tools: [Read, Write, Edit] # required, array
tags: [forces, organization] # required, array
---
Tier 2: Product Documentation
---
product: Insights Copilot # required
status: active # required: active, beta, deprecated
last_updated: 2025-01-15 # required, ISO date
owner: Platform Team # required
token_estimate: 650 # required, integer
doc_type: architecture # required: overview, architecture, api, integration, security
source_of_truth: ../repo/docs/... # optional, path to canonical doc
dependencies: [product-a, product-b] # optional, array
summary: Brief description # optional, 1-2 sentences
key_entities: [Force, Pattern] # optional, domain entities
integration_endpoints: [POST /api/x] # optional, for API docs
---
Tier 3: Operational Documentation
---
title: Documentation Strategy Guide # required
doc_type: guide # required: guide, standard, reference, runbook
category: operations # required: operations, security, development
last_updated: 2025-01-15 # required, ISO date
version: 2.1 # optional
status: active # required: active, deprecated, draft
primary_audience: [developers] # optional, array
required_reading: false # optional, boolean
token_estimate: 2500 # required, integer
replaces: _archive/old-doc.md # optional, path to replaced doc
related: [other-doc.md] # optional, array
---
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.
- 1mo ago First seen · 195 lines · 57 tokens per session scan A 89c6190bccd4
frontmatter-validation is a skill published in the GitHub repository Everyone-Needs-A-Copilot/claude-copilot (14 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 1,476 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-04.
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