Agent Skill format

Agent Skill directories and the SKILL.md format

A skill is valuable only when an agent can discover, load, and execute it correctly. The minimum unit is a directory containing SKILL.md.

Keep the minimum structure stable

Use a stable lowercase, hyphenated directory name and put SKILL.md at its root. Move long background material into references.

  • skill-name/SKILL.md
  • Optional agents/openai.yaml
  • Optional references/*.md
  • Optional scripts/ and assets/

The description controls discovery

Frontmatter should say what the skill does and when the user needs it. Broad descriptions over-trigger; noun lists are hard to discover.

  • Use verbs for the capability
  • Name typical tasks or inputs
  • State important boundaries
  • Differentiate neighboring skills

Write the body for execution

Prioritize prerequisites, ordered steps, output format, and validation. Keep only the theory that changes execution in the main file.

  • Start with use cases
  • Provide executable steps
  • Include failure branches and checks
  • Give a minimal example
  • Keep the main file compact

Common questions

Is a longer SKILL.md better?

No. It should guide execution without loading every reference into context.

Can the skill body use another language?

Yes. A stable English slug is still helpful for scripts and cross-platform use.

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