Agent Skill

An Agent Skill is a folder containing a SKILL.md plus any supporting files, which extends what an AI agent can do. Claude Code skills follow the Agent Skills open standard, which works across multiple AI tools. Claude Code extends this standard with additional features like invocation control, subagent execution, and dynamic context injection.

Create a skill when you find yourself repeatedly pasting the same instructions, checklist, or multi-step procedure into chat. It's also a good candidate when a section of CLAUDE.md has evolved into a procedure rather than a simple statement of fact.

Unlike CLAUDE.md content, a skill's body loads only when it is used. This means long reference material costs almost nothing until it's actually needed. Claude uses skills when it determines they are relevant, or you can invoke one directly using the /skill-name command.

SkillProof's perspective is that a skill is only as good as its real-world behavior. This is why each listing includes an install/trigger/output/docs score, rather than a generic star rating. For example, the Skill Creator skill helps you build, test, and optimize your own skills, while the Agent Skills Guide serves as a reference for authoring and debugging SKILL.md files. If you're looking for existing skills, Find Skill searches multiple marketplaces.

Skills offer a structured way to package reusable logic, moving beyond simple prompts and enabling more complex workflows. They are a key component in building more capable and modular AI systems, contrasting with the more static nature of a basic skill-vs-prompt. This approach aligns with principles of progressive disclosure, where functionality is revealed and loaded on demand.