What is doc-frontmatter?

A tool for creating and checking YAML frontmatter, which is metadata placed at the top of documents in a docs folder.

Use it to add or update frontmatter and validate existing documents against a defined schema.

It helps keep document metadata complete and in the required format, without checking each file by hand.

How practical-stack/ai-lab configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to practical-stack/ai-lab. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/practical-stack/ai-lab/main/.claude/skills/doc-frontmatter/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/practical-stack/ai-lab

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/practical-stack/ai-lab/doc-frontmatter/github.svg)](https://agentmods.dev/skills/practical-stack/ai-lab/doc-frontmatter)

Your own site

<a href="https://agentmods.dev/skills/practical-stack/ai-lab/doc-frontmatter"><img src="https://agentmods.dev/badge/skills/practical-stack/ai-lab/doc-frontmatter/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/practical-stack/ai-lab/doc-frontmatter"><img src="https://agentmods.dev/badge/skills/practical-stack/ai-lab/doc-frontmatter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 457 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin unknown 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.

Model	Per session	Once invoked
Fable 5.1	$0.00042	$0.00457
Opus 5.5	$0.00017	$0.00183
Sonnet 5.5	$0.00008	$0.00091
Haiku 4.5	$0.00004	$0.00046

Measured 2mo ago against content hash f834c42bc2c0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

doc-frontmatter 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 2mo ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/generate-frontmatter.ts, scripts/validate-frontmatter.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/doc-frontmatter/SKILL.md · 61 lines

The source is not reproduced here

No licence file

Read it on GitHub

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2mo ago First seen · 61 lines · 42 tokens per session scan A f834c42bc2c0

Subscribe to this mod's changes

doc-frontmatter is a skill published in the GitHub repository practical-stack/ai-lab (2 stars, last pushed 8mo ago), with no licence file. It adds 42 tokens to every session and 457 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 2026-08-31.

Documents Writing and docs

doc-frontmatter next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
doc-frontmatterpractical-stack/ai-lab	Skill	2	8mo ago	none	A	42	Claude Code
orbit-notionnexu-io/open-design	Skill	106k	yesterday	Apache-2.0	A	117	Claude Code, Codex
instrument-data-to-allotropeanthropics/knowledge-work-plugins	Skill	35k	2d ago	Apache-2.0	A	123	Claude Code
apify-youtube-transcript-scrapersickn33/agentic-awesome-skills	Skill	49k	yesterday	MIT	A	48	Claude Code
legal-holdanthropics/claude-for-legal	Skill	9.9k	3d ago	Apache-2.0	A	68	Claude Code
ppt-reviewOrkas-AI/Orkas	Skill	9.0k	yesterday	MIT	A	2	Claude Code, Codex
feishuHmbown/CodeWhale	Skill	41k	5d ago	MIT	A	33	Claude Code, Codex

ai-lab: Skill for Claude Code