Definition
An Agent Skill is a plain folder: a
SKILL.mdwith a YAML header (name and description, both required) and instructions, plus optional reference files and runnable scripts. It turns a generalist agent into a specialist for a team’s procedures and formats.
Progressive disclosure: (1) only name and description are preloaded; (2) the SKILL.md body loads when the agent judges the skill relevant; (3) bundled files and scripts are read or run only when needed. The agent pays context only for what it opens, so a skill’s effective size is essentially unbounded relative to the context window. Skills capture the workflow and can call MCP tools.
Appears in
- Lecture 8, Agent Skills
- Lecture 8, progressive disclosure
- Lecture 9, Skill-Inject: skills as a supply-chain attack surface