If you're building skills for Claude, this is your starting point. It walks through the three-tier loading system (metadata, SKILL.md, bundled resources), explains when to use scripts versus reference docs versus assets, and pushes hard on keeping things concise since skills share context with everything else. The progressive disclosure patterns are especially useful: keep SKILL.md under 500 lines and split variant-specific details into separate files that Claude loads only when needed. It's prescriptive about structure but flexible about content, which feels right. Think of it as the spec for how to write good onboarding docs that don't waste tokens.
npx skills add https://github.com/anthropics/financial-services-plugins --skill skill-creator