# Unknown Frontmatter

> validator, fixture

- Skill: `lost-rob0t/unknown-frontmatter` (Agent Skill)
- Install (CLI): `npx skillmds@latest add lost-rob0t/unknown-frontmatter`
- Raw SKILL.md: https://api.skillmd.com/api/skills/lost-rob0t/unknown-frontmatter/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: lost-rob0t (https://skillmd.com/u/lost-rob0t)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/lost-rob0t/unknown-frontmatter

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# Unknown frontmatter fixture

This fixture must fail canonical skill validation because its frontmatter contains an unknown key.