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Agent Skills Specification

Source

This directory contains the specification for Agent Skills.

The full specification is maintained at: https://agentskills.io/specification

Quick Reference

Required Frontmatter Fields

  • name — Unique skill identifier (max 64 chars, kebab-case, must match directory name)
  • description — What the skill does and when to trigger it (max 1024 chars)

Optional Frontmatter Fields

  • license — License name or reference
  • metadata — Flat key-value map of strings (e.g., author: "Name")
  • compatibility — Environment requirements (string, max 500 chars)
  • allowed-tools — Space-delimited list of pre-approved tools

Size Guidelines

  • SKILL.md body: under 500 lines, under 5000 tokens recommended
  • Use separate references/, scripts/, or assets/ directories for supplementary content