sk-create-frontmatter

sk-create-frontmatter is a skill for Claude Code, OpenCode from MichelKerkmeester/skilled-agent-harness_spec-driven-loops. It costs 0 tokens per session (3,161 once invoked), scanned A, original, MIT.

A documentation workflow that defines the required YAML frontmatter fields and version format for different document types.

In plain words
What is it for?
Use it when adding, checking, shortening, or updating frontmatter fields such as triggers, importance, context type, or version.
Why use it?
It prevents documents from using inconsistent metadata or exceeding the allowed description format.

Skill for Claude CodeOpenCode

Written for Claude Code and OpenCode: allowed-tools in frontmatter, but also installed under .opencode/. Also seen: mentions OpenCode.

Good fit Use it when adding, checking, shortening, or updating frontmatter fields such as triggers, importance, context type, or version.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter
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.

Any agent
npx skills add MichelKerkmeester/skilled-agent-harness_spec-driven-loops --skill sk-create-frontmatter
Clone the repo
git clone --depth 1 https://github.com/MichelKerkmeester/skilled-agent-harness_spec-driven-loops

Made for: Claude Code, OpenCode.

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 sk-create-frontmatter

README.md
[![agentmods](https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter/github.svg)](https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter)
Your own site
<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-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.

agentmods 80×15 button for sk-create-frontmatter

Your own site · 80×15
<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/sk-create-frontmatter.svg" alt="Reviewed on agentmods" width="80" 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 3,161 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Prompt Injection · line 8
    Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.
    Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
How audits are shown
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 $0.03161
Opus 5 $0.00000 $0.01580
Sonnet 5 $0.00000 $0.00632
Haiku 4.5 $0.00000 $0.00316

Measured 4d ago against content hash 2b07dacf2276, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

sk-create-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 4d 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.

.opencode/skills/sk-doc/sk-create-frontmatter/SKILL.md · 245 lines

How it starts

The opening of the file, as written. The whole thing — 245 lines — stays where its author put it; the contents beside it link to each section on GitHub.

create-frontmatter

create-frontmatter is the frontmatter workflow packet of the sk-doc family. It owns the contract every other mode writes against: which fields a document class carries, what each field may contain, and how the 4-part version field is derived and inserted.

Six sibling modes emit frontmatter. None of them decides what a frontmatter block is. This mode does, and they cite it.

This mode owns rules, not enforcement. The validators and the versioning engine live in the hub's shared tier because a post-edit hook outside this hub resolves them by path. This mode is where you find out what the validators are checking for and why.


1. WHEN TO USE

Activation Triggers

  • A document needs a frontmatter block and you do not know which fields its class carries.
  • A validator rejected a frontmatter block and the message names a field rather than a fix.
  • A description is over budget and needs trimming without losing its routing signal.
  • A version field needs deriving, inserting or reconciling against a changelog anchor.
  • Someone asks what trigger_phrases, importance_tier or contextType are for.
  • A document class is being added and needs a frontmatter rule of its own.

Keyword triggers: yaml frontmatter, frontmatter block, frontmatter template, frontmatter field, frontmatter fields, trigger_phrases, trigger phrases, importance_tier, contextType, description budget, 4-part version, X.Y.Z.W, frontmatter versioning, frontmatter version, version field, frontmatter validation, missing frontmatter, frontmatter contract, yaml header, goes at the top of the file, version number at the top, importance tier, versioning pass, stopped showing up in suggestions, validator says my file is missing, description too long, edit count, field the validator wants.

Read the full file on GitHub · 245 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. 4d ago Changed · +21 lines 2b07dacf2276
  2. 6d ago Changed · +5 lines a4e1a01a9754
  3. 8d ago First seen · 219 lines · 0 tokens per session scan A 5af95ced2b47

Subscribe to this mod's changes

sk-create-frontmatter is a skill published in the GitHub repository MichelKerkmeester/skilled-agent-harness_spec-driven-loops (35 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 3,161 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 2026-09-03.

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