Use when users ask how to build, explain, configure, secure, test, deploy, or troubleshoot NestJS applications, including modules, controllers, providers, dependency injection, middleware, guards, pipes, interceptors, exception filters, configuration, databases, validation, caching, queues, GraphQL, microservices, WebSockets, OpenAPI/Swagger, CLI, or platform adapters (Express/Fastify), especially when they need official NestJS documentation, exact links, or docs-grounded TypeScript guidance.
