AI coding glossary
Skill (Agent Skill)
Also known as: agent skill, ai skill, skill.md
In one sentence
A reusable, versioned, natural-language instruction set for AI coding assistants, packaged as a SKILL.md file with YAML frontmatter.
Full definition
An Agent Skill is the unit of reusable AI instruction in the open Agent Skills standard. A skill is a SKILL.md file, Markdown with YAML frontmatter declaring `name`, `description`, `version`, `category`, and optional `platforms`. The body is natural-language instructions the AI follows when the skill is triggered. Skills load on demand (slash command, keyword, or path matcher), so they don't bloat every conversation the way ambient rules do. The same SKILL.md runs unchanged across Claude Code, Cursor, OpenAI Codex CLI, Windsurf, GitHub Copilot, Cline, AWS Kiro, Google Antigravity 2.0, and any MCP-compatible tool.