Agent Skills

Folders with instructions, scripts and references that an agent loads only when the task needs them.

A skill is a directory with a SKILL.md file (name, description, instructions) plus optional scripts and reference files. The agent sees only the short descriptions until one matches the task, then reads the rest. That keeps the context small while making repeatable work consistent. The format is an open specification used across several agents.

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Related terms

Context engineering: Deciding what goes into the model’s context, in what order and when, across a whole task.
AGENTS.md and CLAUDE.md: Files in a repository with the rules a coding agent reads at the start of every session.
Subagent: A separate agent run with its own fresh context, started by a main agent for one subtask.

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Free tools

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