Backend

Expert in React Native 0.83+ performance optimization including Hermes V1, React 19.2 concurrent features, Intersection Observer, Web Performance APIs, bundle size reduction, memory management, rendering optimization, FlashList, expo-image v2, memoization, lazy loading, code splitting. Activates for performance, slow app, lag, memory leak, bundle size, optimization, flatlist performance, re-render, fps, jank, startup time, app size, hermes, concurrent rendering.

.NET/C# backend developer for ASP.NET Core APIs with Entity Framework Core. Builds REST APIs, minimal APIs, gRPC services, authentication with Identity/JWT, authorization, database operations, background services, SignalR real-time features. Activates for: .NET, C#, ASP.NET Core, Entity Framework Core, EF Core, .NET Core, minimal API, Web API, gRPC, authentication .NET, Identity, JWT .NET, authorization, LINQ, async/await C#, background service, IHostedService, SignalR, SQL Server, PostgreSQL .NET, dependency injection, middleware .NET.

Node.js/TypeScript backend developer. Builds Express.js, Fastify, NestJS APIs with Prisma ORM, TypeORM, Mongoose. Implements REST APIs, GraphQL, authentication (JWT, session, OAuth), authorization, database operations, background jobs, WebSockets, real-time features, API validation, error handling, middleware. Activates for: Node.js, NodeJS, Express, Fastify, NestJS, TypeScript backend, API, REST API, GraphQL, Prisma, TypeORM, Mongoose, MongoDB, PostgreSQL with Node, MySQL with Node, authentication backend, JWT, passport.js, bcrypt, async/await, promises, middleware, error handling, validation, Zod, class-validator, background jobs, Bull, BullMQ, Redis, WebSocket, Socket.io, real-time.

n8n workflow automation with Kafka integration expert. Covers Kafka trigger node, producer node, event-driven workflows, error handling, retries, and no-code/low-code event processing patterns. Activates for n8n kafka, kafka trigger, kafka producer, n8n workflows, event-driven automation, no-code kafka, workflow patterns.

Python backend developer for FastAPI, Django, Flask APIs with SQLAlchemy, Django ORM, Pydantic validation. Implements REST APIs, async operations, database integration, authentication, data processing with pandas/numpy, machine learning integration, background tasks with Celery, API documentation with OpenAPI/Swagger. Activates for: Python, Python backend, FastAPI, Django, Flask, SQLAlchemy, Django ORM, Pydantic, async Python, asyncio, uvicorn, REST API Python, authentication Python, pandas, numpy, data processing, machine learning, ML API, Celery, Redis Python, PostgreSQL Python, MongoDB Python, type hints, Python typing.

Comprehensive Playwright end-to-end testing expertise covering browser automation, cross-browser testing, visual regression, API testing, mobile emulation, accessibility testing, test architecture, page object models, fixtures, parallel execution, CI/CD integration, debugging strategies, and production-grade E2E test patterns. Activates for playwright, e2e testing, end-to-end testing, browser automation, cross-browser testing, visual testing, screenshot testing, API testing, mobile testing, accessibility testing, test fixtures, page object model, POM, test architecture, parallel testing, playwright config, trace viewer, codegen, test debugging, flaky tests, CI integration, playwright best practices.

Software architecture patterns and alternatives expert. Covers monolith vs microservices, serverless, event-driven, CQRS, hexagonal architecture, clean architecture, DDD, and architecture decision frameworks. Activates for architecture patterns, monolith, microservices, serverless, event-driven, CQRS, hexagonal architecture, clean architecture, DDD, architecture decisions, system design, scalability patterns.

Expert in analyzing and recommending release strategies for software projects. Detects existing release patterns in brownfield projects (git tags, CI/CD workflows, changelogs, version files). Suggests optimal strategies based on architecture (single-repo, multi-repo, monorepo, microservices), team size, deployment frequency, and dependencies. Creates comprehensive release-strategy.md in living docs (.specweave/docs/internal/delivery/ or projects/{id}/delivery/). Activates for release strategy, versioning strategy, multi-repo releases, monorepo versioning, semantic versioning, coordinated releases, independent releases, release planning, version alignment, brownfield release analysis, deployment strategy, CI/CD release, how to version, release best practices.

Backend architecture policy. Use when building APIs, services, data access, or any backend work. Prevents over-engineering.

Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).

Teaches effective documentation search using the blz CLI tool. Use when searching documentation with blz, looking up APIs, finding code examples, retrieving citations, or when questions mention libraries, frameworks, "how to", or documentation topics. Covers BM25 full-text search patterns, citation retrieval, and efficient querying.

Write or update backend feature documentation that follows a repo's DOCUMENTATION_GUIDELINES.md (or equivalent) across any project. Use when asked to create/update module docs, API contracts, or backend documentation that must include architecture, endpoints, payloads, Mermaid diagrams, and seeding instructions.

Orchestrates /init-project command execution through interactive questionnaire (15 questions), brownfield codebase scanning (tech stack detection, ERD from migrations), and 8-document generation (overview, architecture, tech-stack, data, API, capacity, deployment, workflow). Use when user runs /init-project, requests project documentation generation, or asks about architecture setup for greenfield/brownfield projects. (project)

Cache expensive operations to avoid redundant work across workflow phases. Caches project docs (15min TTL), npm info (60min), grep results (30min), token counts (until file modified), web searches (15min). Auto-triggers when detecting repeated reads of same files or repeated API calls. Saves 20-40% execution time.

Design effective MCP tools and Claude Code integrations using the consolidation principle. Fewer, better-designed tools dramatically improve agent success rates. Use when creating MCP servers, designing tool interfaces, optimizing tool sets, or when user mentions 'tool design', 'MCP', 'fewer tools', 'tool consolidation', 'tool architecture', or 'tool optimization'.

Create comprehensive ontological documentation for Grey Haven systems - extract domain concepts from TanStack Start and FastAPI codebases, model semantic relationships, generate visual representations of system architecture, and document business domains. Use when onboarding, documenting architecture, or analyzing legacy systems.

硅基流动（SiliconFlow）云服务平台文档。用于大语言模型 API 调用、图片生成、向量模型、在 Claude Code 中使用硅基流动、Chat Completions API、Stream 模式等。

Organize Grey Haven projects following standard structures for TanStack Start (frontend) and FastAPI (backend). Use when creating new projects, organizing files, or refactoring project layout.

Rails-AI introduction - explains how rails-ai (Rails domain layer) integrates with superpowers (universal workflows) for Rails development

Use when adding interactivity to Rails views - Hotwire Turbo (Drive, Frames, Streams, Morph) and Stimulus controllers