Lit Component Development for Common UI

This skill provides guidance for developing Lit web components within the Common UI v2 component library (packages/ui/src/v2).

When to Use This Skill

Use this skill when:

• Creating new cf- prefixed components in the UI package
• Modifying existing Common UI v2 components
• Implementing theme-aware components
• Integrating components with Cell abstractions from the runtime
• Building reactive components for pattern UIs
• Debugging component lifecycle or reactivity issues

Do NOT use this skill when authoring or styling pattern UIs that consume cf- components — that's pattern-ui's job. Patterns must never touch component internals, and pattern JSX uses theme={...}, not Lit's .theme=${...}.