Use when implementing features across frontend and backend, building APIs with UI, or creating end-to-end data flows. Invoke for feature implementation, API development, UI building, cross-stack work.

Use when building high-performance async Python APIs with FastAPI and Pydantic V2. Invoke for async SQLAlchemy, JWT authentication, WebSockets, OpenAPI documentation.

Use when building CLI tools, implementing argument parsing, or adding interactive prompts. Invoke for CLI design, argument parsing, interactive prompts, progress indicators, shell completions.

Use when developing firmware for microcontrollers, implementing RTOS applications, or optimizing power consumption. Invoke for STM32, ESP32, FreeRTOS, bare-metal, power optimization, real-time systems.

Use when building Django web applications or REST APIs with Django REST Framework. Invoke for Django models, ORM optimization, DRF serializers, viewsets, authentication with JWT.

Dependency injection workflow for Spring Boot projects covering constructor-first patterns, optional collaborator handling, bean selection, and validation practices.

Comprehensive React 19 patterns expert covering Server Components, Actions, use() hook, useOptimistic, useFormStatus, useFormState, React Compiler, concurrent features, Suspense, and modern TypeScript development. Proactively use for any React development, component architecture, state management, performance optimization, or when implementing React 19's latest features.

UI design system toolkit for Senior UI Designer including design token generation, component documentation, responsive design calculations, and developer handoff tools. Use for creating design systems, maintaining visual consistency, and facilitating design-dev collaboration.

Implement proven backend architecture patterns including Clean Architecture, Hexagonal Architecture, and Domain-Driven Design. Use when architecting complex backend systems or refactoring existing applications for better maintainability.

Use when you have a spec or requirements for a multi-step task, before touching code

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.