Skill

A skill is a SKILL.md file with instructions that Claude adds to its toolkit. Claude uses a skill when it is relevant, or you can invoke one directly with /skill-name.

A skill’s body only loads when it is used, so long reference material costs little context until it is needed. Claude Code skills follow the open Agent Skills standard.

Vendor skills matter for SaaS building blocks because they teach the agent the current SDK patterns, so it is less likely to write code against outdated APIs. We count the SKILL.md files in each official plugin.