Agent Skills Spec

Agent Skills Spec

A skill is a folder of instructions, scripts, and resources that agents can discover and load dynamically to perform better at specific tasks. In order for the folder to be recognized as a skill, it must contain a `SKILL.md` file.

Skill Folder Layout

A minimal skill folder looks like this:

my-skill/
  - SKILL.md

More complex skills can add additional directories and files as needed.

The SKILL.md file

The skill's "entrypoint" is the `SKILL.md` file. It is the only file required to exist. The file must start with a YAML frontmatter followed by regular Markdown.

YAML Frontmatter

The YAML frontmatter has 2 required properties:

• name
  • The name of the skill in hyphen-case
  • Restricted to lowercase Unicode alphanumeric + hyphen
  • Must match the name of the directory containing the SKILL.md
• description
  • Description of what the skill does and when Claude should use it

There are 3 optional properties:

• license
  • The license applied to the skill
  • We recommend keeping it short (either the name of a license or the name of a bundled license file)
• allowed-tools
  • A list of tools that are pre-approved to run
  • Currently only supported in Claude Code
• metadata
  • A map from string keys to string values
  • Clients can use this to store additional properties not defined by the Agent Skills Spec
  • We recommend making your key names reasonably unique to avoid accidental conflicts

Markdown Body

The Markdown body has no restrictions on it.

Additional Information

For a minimal example, see the `template-skill` example.

Version History

• 1.0 (2025-10-16) Public Launch