missing-frontmatter

missing-frontmatter is a skill for Claude Code, Codex from akshay5995/agent-skill-evals. It costs 0 tokens per session (18 once invoked), scanned A, original, MIT.

A test fixture for an agent skill that deliberately has no routing metadata at the top of its file.

In plain words
What is it for?
It is for testing how Agent Skill Evals handles skills whose required frontmatter is absent.
Why use it?
It is used to represent or detect a skill with missing frontmatter, the metadata block used for routing.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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 skills/akshay5995/agent-skill-evals/missing-frontmatter
Any agent
npx skills add akshay5995/agent-skill-evals --skill missing-frontmatter
Clone the repo
git clone --depth 1 https://github.com/akshay5995/agent-skill-evals

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 missing-frontmatter

README.md
[![agentmods](https://agentmods.dev/badge/skills/akshay5995/agent-skill-evals/missing-frontmatter.svg)](https://agentmods.dev/skills/akshay5995/agent-skill-evals/missing-frontmatter)
Your own site
<a href="https://agentmods.dev/skills/akshay5995/agent-skill-evals/missing-frontmatter"><img src="https://agentmods.dev/badge/skills/akshay5995/agent-skill-evals/missing-frontmatter.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 18 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 5.1 $0.00000 $0.00018
Opus 5 $0.00000 $0.00009
Sonnet 5 $0.00000 $0.00004
Haiku 4.5 $0.00000 $0.00002

Measured 5d ago against content hash 5e3619aa3d6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

missing-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 5d 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.

packages/promptfoo/integration/fixtures/invalid-skill-metadata/skills/missing-frontmatter/SKILL.md · 4 lines

What it actually says

missing-frontmatter

This fixture intentionally omits Agent Skill Evals routing frontmatter.

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. 5d ago First seen · 4 lines · 0 tokens per session scan A 5e3619aa3d6d

Subscribe to this mod's changes

missing-frontmatter is a skill published in the GitHub repository akshay5995/agent-skill-evals (2 stars, last pushed 1mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 18 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.

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