Skill

Skill

Also called: 技能包 · Agent Skill

A reusable unit packaging instructions, scripts, and reference material for an agent to load on demand; Claude Skills is the canonical implementation.

Skill (folder)SKILL.mdscripts/reference files (loaded on demand)
Schematic (simplified)

What it solves

A model cannot hold every specialised procedure in its weights, nor cram every instruction into context at once. A Skill packages "the full know-how for a class of task" into files: normally the model sees only its short description, and the details and scripts expand only when it is actually used. This lets a model "hold" hundreds of specialities without overflowing context.

Difference from neighbouring concepts

  • Tool: one function call — "an action you can take."
  • Skill: instructions + resources — "a method for a class of task," which may use several tools internally.
  • MCP server: an external service reached over a protocol.

A Skill loads into the model side; an MCP server runs outside the model.

Common misconceptions

  • A Skill is mainly "a manual for the model," not an executable program (though it can bundle scripts).
  • Installing many Skills does not scale context cost linearly — an untriggered Skill costs only its one-line description.

Related terms

Sources

  1. Anthropic Engineering — Equipping agents for the real world with Agent Skills (2025)
  2. Anthropic — Claude Docs: Agent Skills overview

Compiled 2026-08-29 · This glossary is compiled from public papers, official specifications, and common industry definitions, and is updated as the field evolves. Corrections welcome.