Nodejs Backend

This one teaches Claude clean Node.js backend architecture with Express or Fastify. It pushes dependency injection at the composition root, separates pure business logic from infrastructure concerns, and enforces the repository pattern for data access. You get route handler templates, Zod validation at boundaries, domain error classes that map to HTTP status codes, and transaction examples with Kysely. The anti-patterns list is worth reading: it calls out callback hell, SQL concatenation, and monolithic route files. Fires automatically when you're touching API routes, middleware, or server setup files. If you've inherited a messy Express app, this will nudge you toward testable patterns.