Medusa

This teaches Claude how to build with Medusa, the open-source headless commerce platform built on Node.js and TypeScript. You'd reach for this when you need an e-commerce backend that doesn't lock you into Shopify or similar hosted solutions. It covers the full stack: scaffolding projects with create-medusa-app, writing custom API routes in the src/api directory structure, building modules for business logic like reviews or loyalty systems, and creating workflows for multi-step processes like order fulfillment with rollback support. The skill includes realistic examples like calculating revenue analytics through the order service and setting up CORS for your Next.js storefront. If you want programmatic control over your commerce layer without rebuilding everything from scratch, this is the reference.