SKILL.md

A markdown file that teaches AI agents how to interact with an API — including authentication, endpoints, and payment handling.

SKILL.md is a file format pioneered by Mithril that describes an API in a way AI agents can consume directly. Instead of requiring an SDK integration or manual setup, you drop a SKILL.md file into any LLM-based agent (Claude Code, Codex, etc.) and it immediately knows how to authenticate, make requests, handle errors, and process payments. Mithril's SKILL.md covers all 20 API endpoints including x402 purchase flows, wallet management, and credit operations. It's served publicly at trymithril.com/SKILL.md.