Vitest

This generates a complete Vitest setup tailored to your project type. It detects whether you're running Cloudflare Workers, React, Hono APIs, or a library, then scaffolds the right config, test utilities, and a working sample test. The skill extends existing vite.config.ts files instead of creating conflicts, handles Jest migrations, and picks a real file from your codebase to demonstrate testing patterns. It's thorough about the details that break most test setups: TypeScript globals, jsdom vs node environments, Workers pool configuration. Use it when you're starting fresh with Vitest or fixing a broken test infrastructure. The generated files actually run, which is rarer than it should be.