Web Core Skill
The web core skill gives Claude deep knowledge of web fundamentals — semantic HTML, modern CSS features, and vanilla JavaScript patterns.
When It’s Active
Section titled “When It’s Active”Activated automatically when working with semantic HTML, modern CSS features, or vanilla JS patterns.
What It Teaches Claude
Section titled “What It Teaches Claude”- Semantic HTML elements (section, article, nav, dialog, details)
- Modern CSS features (nesting, :has(), container queries, @layer, light-dark())
- Vanilla JS patterns (event delegation, IntersectionObserver, custom elements)
- Template element for client-side templating
- HTML validation with html-validate