Xstate

This is a comprehensive XState v5 skill that guides you through designing, implementing, and migrating state machines in TypeScript. It knows when to recommend the simpler @xstate/store instead of a full machine, which is refreshingly practical. The skill emphasizes modeling first and API correctness second, walking you through the right questions before you write code: what are the finite states, what belongs in context, should this be a guard or a separate state. It handles three distinct modes (new code, local edits, migrations) and adjusts its opinionation accordingly, so it won't bulldoze your existing codebase with unnecessary refactors. Particularly strong on v5-specific patterns like setup scoped actions, tags for UI semantics, and choosing the right actor type for your async work.