Design

Build MCP servers in Python with FastMCP to expose tools, resources, and prompts to LLMs. Supports storage backends, middleware, OAuth Proxy, OpenAPI integration, and FastMCP Cloud deployment. Prevents 25+ errors. Use when: creating MCP servers, or troubleshooting module-level server, storage, lifespan, middleware, or OAuth errors.

Set up Tailwind v4 with shadcn/ui using @theme inline pattern and CSS variable architecture. Four-step pattern: CSS variables, Tailwind mapping, base styles, automatic dark mode. Use when initializing React projects with Tailwind v4, or fixing colors not working, tw-animate-css errors, v3 migration.

Build semantic search with Cloudflare Vectorize V2. Covers async mutations, 5M vectors/index, 31ms latency, returnMetadata enum changes, and V1 deprecation. Prevents 8 errors including dimension mismatches. Use when: building RAG or semantic search, troubleshooting returnMetadata, V2 timing, metadata index, or dimension errors.

Build MCP servers on Cloudflare Workers - the only platform with official remote MCP support. TypeScript-based with OAuth, Durable Objects, and WebSocket hibernation. Prevents 22 documented errors. Use when: deploying remote MCP servers, implementing OAuth, or troubleshooting URL path mismatches, McpAgent exports, CORS issues.

Nine integrated slash commands for complete project lifecycle: /explore-idea, /plan-project, /plan-feature, /wrap-session, /continue-session, /workflow, /release, /brief, /reflect. Use when starting projects, managing sessions across context windows, capturing learnings, or preparing releases. Saves 35-55 minutes per lifecycle.

Build type-safe global state in React with Zustand. Supports TypeScript, persist middleware, devtools, slices pattern, and Next.js SSR with hydration handling. Use when setting up React state, migrating from Redux/Context, or troubleshooting hydration errors, TypeScript inference, or infinite render loops.

Build type-safe D1 databases with Drizzle ORM. Includes schema definition, migrations with Drizzle Kit, relations, and D1 batch API patterns. Prevents 12 errors including SQL BEGIN failures and foreign key issues. Use when: defining D1 schemas, managing migrations, or troubleshooting D1_ERROR, BEGIN TRANSACTION, foreign keys.

Build CLI scripts alongside MCP servers for terminal environments. File I/O, batch processing, caching, richer output formats. Templates for TypeScript scripts and SCRIPTS.md. Use when: MCP companion scripts, batch processing, saving results to files, CLI API wrappers. Troubleshoot: context too large, no file access, batch input.

Build content-heavy sites with Git-backed TinaCMS. Provides visual editing for blogs, documentation, and marketing sites. Supports Next.js, Vite+React, and Astro with self-hosting options. Use when setting up CMS with non-technical editors or troubleshooting ESbuild compilation, module resolution, or Docker binding issues.

Build document Q&A with Gemini File Search - fully managed RAG with automatic chunking, embeddings, and citations. Upload 100+ file formats, query with natural language. Use when: document Q&A, searchable knowledge bases, semantic search. Troubleshoot: document immutability, storage quota (3x), chunking config, metadata limits (20 max), polling timeouts.

Generate structured task lists from specs or requirements. IMPORTANT: After completing ANY spec via ExitSpecMode, ALWAYS ask the user: "Would you like me to generate a task list for this spec?" Use when user confirms or explicitly requests task generation from a plan/spec/PRD.

Build headless data tables with TanStack Table v8. Server-side pagination, filtering, sorting, and virtualization for Cloudflare Workers + D1. Use when building tables with large datasets, coordinating with TanStack Query, or fixing state management or performance issues.

Build Python web apps with Flask using application factory pattern, Blueprints, and Flask-SQLAlchemy. Covers project structure, authentication, and configuration management. Use when: creating Flask projects, organizing blueprints, or troubleshooting circular imports, context errors, or registration.

Build Next.js 16 apps with App Router, Server Components/Actions, Cache Components ("use cache"), and async route params. Includes proxy.ts and React 19.2. Use when: building Next.js 16 projects, or troubleshooting async params (Promise types), "use cache" directives, parallel route 404s.

Implement or extend a user-facing workflow in a web application, integrating with existing backend APIs. Use when the feature is primarily a UI/UX change backed by existing APIs, affects only the web frontend, and requires following design system, routing, and testing conventions.

Add OAuth authentication to MCP servers on Cloudflare Workers. Uses @cloudflare/workers-oauth-provider with Google OAuth for Claude.ai-compatible authentication. Use when building MCP servers that need user authentication, implementing Dynamic Client Registration (DCR) for Claude.ai, or replacing static auth tokens with OAuth flows. Prevents CSRF vulnerabilities, state validation errors, and OAuth misconfiguration.

Build Python APIs on Cloudflare Workers using pywrangler CLI and WorkerEntrypoint class pattern. Includes Python Workflows for multi-step DAG automation. Prevents 8 documented errors. Use when: building Python serverless APIs, migrating Python to edge, or troubleshooting async errors, package compatibility, handler pattern mistakes.

Build stateful Durable Objects for real-time apps, WebSocket servers, coordination, and persistent state. Use when: implementing chat rooms, multiplayer games, rate limiting, session management, WebSocket hibernation, or troubleshooting class export, migration, WebSocket state loss, or binding errors.

Run LLMs and AI models on Cloudflare's GPU network with Workers AI. Includes Llama 4, Gemma 3, Mistral 3.1, Flux images, BGE embeddings, streaming, and AI Gateway. Handles 2025 breaking changes. Use when: implementing LLM inference, images, RAG, or troubleshooting AI_ERROR, rate limits, max_tokens, BGE pooling.

Build integrations with Google Workspace APIs (Gmail, Calendar, Drive, Sheets, Docs, Chat, Meet, Forms, Tasks, Admin SDK). Covers OAuth 2.0, service accounts, rate limits, batch operations, and Cloudflare Workers patterns. Use when building MCP servers, automation tools, or integrations with any Google Workspace API, or troubleshooting OAuth errors, rate limit 429 errors, scope issues, or API-specific gotchas.