Agent Skills Has No Integrity Layer. We Built One.

The Agent Skills specification defines six fields for a SKILL.md frontmatter: name, description, license, compatibility, metadata, and allowed-tools. None of them are cryptographic. There is no hash. No signature. No way to tell, after a skill reaches your agent, whether it is the bytes the publisher originally wrote. This is not a criticism. The format solved a different problem first: interoperability across 35+ agent runtimes. Claude Code, Cursor, Codex CLI, Gemini CLI, GitHub Copilot, and others all load SKILL.md and it works. That is a genuine achievement.