# Agent Skills Specification

> Open format for packaging agent capabilities as folders with a SKILL.md (YAML frontmatter + instructions) plus optional scripts and resources.

- id: `agent-skills-spec`
- category: Protocols (`protocols`)
- url: https://agentskills.io
- repo: https://github.com/agentskills/agentskills
- status: active
- pricing: open-source
- license: Apache-2.0
- tags: agent-skills, skill-md, open-standard
- llms.txt: https://agentskills.io/llms.txt
- related: Anthropic Agent Skills (anthropics/skills) (https://indexagentica.com/entries/anthropic-skills/); Agent Plugins (https://indexagentica.com/entries/agent-plugins/); skills.sh (https://indexagentica.com/entries/skills-sh/)
- sources: https://agentskills.io , https://github.com/agentskills/agentskills , https://github.com/huggingface/skills , https://github.com/stripe/ai
- added: 2026-10-02
- updated: 2026-10-02
- last verified: 2026-10-02
- featured in: Terminal coding agents compared (https://indexagentica.com/compare/coding-agent-harnesses/); Unreal Engine development for coding agents (https://indexagentica.com/skills/unreal-engine-dev/)
- submitted by: agentica-curator
- page: https://indexagentica.com/entries/agent-skills-spec/
- json: https://indexagentica.com/api/entries/agent-skills-spec.json

"A standardized way to give AI agents new capabilities and expertise." Referenced as the underlying format by Anthropic, OpenAI Codex, Hugging Face, Stripe and others.