packmind: Skill for Claude Code

.agents/skills/agent-skill-frontmatter-audit/SKILL.md

agent-skill-frontmatter-audit is a skill for Claude Code, Codex from PackmindHub/packmind. It costs 38 tokens per session (3,982 once invoked), scanned A, original, Apache-2.0.

A compatibility audit for the YAML front matter in SKILL.md files, which are instruction files installed for AI coding agents. It compares Packmind's output with the shared Agent Skills specification and each agent's own documented fields.

In plain words
What is it for?
It checks each supported agent against the baseline specification and its official documentation, then creates a dated report at the project root.
Why use it?
It finds differences between the fields agents support and the fields Packmind produces, so changes or outdated fields can be tracked over time.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths; mentions Claude Code; installed under .agents/ (shared by several agents).

This is PackmindHub/packmind's own configuration. It tells Claude Code and Codex how to work on packmind itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything packmind configures →

Reuse

Borrowing it

Nothing to install: this file belongs to PackmindHub/packmind. 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/PackmindHub/packmind/main/.agents/skills/agent-skill-frontmatter-audit/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/PackmindHub/packmind

Made for: Claude Code, Codex.

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.

agentmods badge for agent-skill-frontmatter-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/packmindhub/packmind/agent-skill-frontmatter-audit/github.svg)](https://agentmods.dev/skills/packmindhub/packmind/agent-skill-frontmatter-audit)
Your own site
<a href="https://agentmods.dev/skills/packmindhub/packmind/agent-skill-frontmatter-audit"><img src="https://agentmods.dev/badge/skills/packmindhub/packmind/agent-skill-frontmatter-audit/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.

agentmods 80×15 button for agent-skill-frontmatter-audit

Your own site · 80×15
<a href="https://agentmods.dev/skills/packmindhub/packmind/agent-skill-frontmatter-audit"><img src="https://agentmods.dev/badge/skills/packmindhub/packmind/agent-skill-frontmatter-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,982 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 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 5.1 $0.00038 $0.03982
Opus 5.5 $0.00015 $0.01593
Sonnet 5.5 $0.00008 $0.00796
Haiku 4.5 $0.00004 $0.00398

Measured 1mo ago against content hash 238539f34b6b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

agent-skill-frontmatter-audit 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.

.agents/skills/agent-skill-frontmatter-audit/SKILL.md · 234 lines

How it starts

The opening of the file, as written. The whole thing — 234 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Skill Frontmatter Audit

Packmind renders skills (one of the three artefact types along with standards and commands) as a SKILL.md file with YAML frontmatter deployed into each AI coding agent's expected folder (.claude/skills/, .cursor/skills/, .github/skills/, .agents/skills/, .opencode/skills/, etc.).

There is a shared Agent Skills baseline specification that all supporting agents commit to (the "core" fields every agent understands), and then each agent may publish its own documentation extending that baseline with agent-specific "additional properties". Both layers evolve over time: the baseline spec ships new versions, and vendors add, rename, or deprecate extensions.

This skill audits Packmind's rendering against both layers and produces a dated report at the project root so drift can be tracked release over release.

Context

The audit is a four-way comparison per agent:

  1. Baseline spec — the current Agent Skills specification at https://agentskills.io/specification.md. Defines the set of fields every compliant agent is expected to accept (typically name, description, and similar core keys).
  2. Upstream agent spec — the agent's own public documentation page. May extend the baseline with agent-specific properties, or may be baseline-only.
  3. Packmind declared support — the per-agent constants in packages/types/src/skills/skillAdditionalProperties.ts.
  4. Packmind actual rendering — what each agent's deployer in packages/coding-agent/src/infra/repositories/{agent}/{Agent}Deployer.ts actually writes into the YAML frontmatter.

The four pairs can disagree silently:

  • Baseline vs. upstream — a vendor page that omits a field the baseline requires is a vendor bug to note, not a Packmind action item.

  • Upstream vs. constants — Packmind is behind (or ahead of) the vendor on agent-specific fields.

  • Constants vs. deployer — internal drift; the "supported" promise in the codebase is a lie.

  • A dead doc URL — the audit can no longer be trusted automatically for that agent.

Read the full file on GitHub · 234 lines

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. 1mo ago First seen · 234 lines · 38 tokens per session scan A 238539f34b6b

Subscribe to this mod's changes

agent-skill-frontmatter-audit is a skill published in the GitHub repository PackmindHub/packmind (319 stars, last pushed 4d ago), licensed Apache-2.0. It adds 38 tokens to every session and 3,982 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 2026-09-22.

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