Build with D1 serverless SQLite database on Cloudflare's edge. Use when: creating databases, writing SQL migrations, querying D1 from Workers, handling relational data, or troubleshooting D1_ERROR, statement too long, migration failures, or query performance issues.
Build autonomous AI agents with Claude Agent SDK. Structured outputs guarantee JSON schema validation, with plugins system and hooks for event-driven workflows. Prevents 12 documented errors. Use when: building coding agents, SRE systems, security auditors, or troubleshooting CLI not found, structured output validation, session forking errors.
Zero-config animations for React, Vue, Solid, Svelte, Preact with @formkit/auto-animate (3.28kb). Prevents 10+ documented errors including SSR imports, conditional parents, missing keys, and CSS conflicts. Use when: animating lists/accordions/toasts, troubleshooting SSR animation errors, or need accessible drop-in transitions with auto prefers-reduced-motion.
Build AI applications with OpenAI Agents SDK - text agents, voice agents, multi-agent handoffs, tools with Zod schemas, guardrails, and streaming. Use when: building agents with tools, voice agents with WebRTC, multi-agent workflows, or troubleshooting MaxTurnsExceededError, tool call failures.
Connect Workers to PostgreSQL/MySQL with Hyperdrive's global pooling and caching. Use when: connecting to existing databases, setting up connection pools, using node-postgres/mysql2, integrating Drizzle/Prisma, or troubleshooting pool acquisition failures, TLS errors, or nodejs_compat missing.
Build agentic AI with OpenAI Responses API - stateful conversations with preserved reasoning, built-in tools (Code Interpreter, File Search, Web Search), and MCP integration. Use when: building agents with persistent reasoning, using server-side tools, or migrating from Chat Completions for better multi-turn performance.
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 AI agents with Cloudflare Agents SDK on Workers + Durable Objects. Provides WebSockets, state persistence, scheduling, and multi-agent coordination. Prevents 16 documented errors. Use when: building WebSocket agents, RAG with Vectorize, MCP servers, or troubleshooting "Agent class must extend", "new_sqlite_classes", binding errors.
Integrate Gemini API with @google/genai SDK (NOT deprecated @google/generative-ai). Text generation, multimodal (images/video/audio/PDFs), function calling, thinking mode, streaming. 1M input tokens. Use when: Gemini integration, multimodal AI, reasoning with thinking mode. Troubleshoot: SDK deprecation, model not found, context window, function calling errors.
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.
Manage server state in React with TanStack Query v5. Covers useMutationState, simplified optimistic updates, throwOnError, network mode (offline/PWA), and infiniteQueryOptions. Use when setting up data fetching, or fixing v4→v5 migration errors (object syntax, gcTime, isPending, keepPreviousData).
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 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.
Self-hosted auth for TypeScript/Cloudflare Workers with social auth, 2FA, passkeys, organizations, RBAC, and 15+ plugins. Requires Drizzle ORM or Kysely for D1 (no direct adapter). Self-hosted alternative to Clerk/Auth.js. Use when: self-hosting auth on D1, building OAuth provider, multi-tenant SaaS, or troubleshooting D1 adapter errors, session caching, rate limits.
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 conversational AI voice agents with ElevenLabs Platform. Configure agents, tools, RAG knowledge bases, multi-voice, and Scribe STT across React, React Native, or Swift. Prevents 27 documented errors. Use when: building voice agents, AI phone systems, or troubleshooting @11labs deprecated, webhook errors, CSP violations.
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 Cloudflare Workers with Hono routing, Vite plugin, and Static Assets. Prevents 8 errors including export syntax, routing conflicts, HMR crashes, and free tier 429s. Use when: creating Workers projects, configuring Hono/Vite, or troubleshooting export syntax, API route conflicts, or HMR issues.
Build RAG systems and semantic search with Gemini embeddings (gemini-embedding-001). 768-3072 dimension vectors, 8 task types, Cloudflare Vectorize integration. Use when: vector search, RAG systems, semantic search, document clustering. Troubleshoot: dimension mismatch, wrong task type, rate limits (100 RPM), text truncation (2048 tokens).
Integrate Redis-compatible Vercel KV for caching, session management, and rate limiting in Next.js. Powered by Upstash with strong consistency and TTL support. Use when implementing cache strategies, rate limiters, or troubleshooting environment variables, serialization errors, or rate limit issues.
Add bot protection with Turnstile (CAPTCHA alternative). Use when: protecting forms, securing login/signup, preventing spam, migrating from reCAPTCHA, integrating with React/Next.js/Hono, implementing E2E tests, or debugging CSP errors, token validation failures, or error codes 100*/300*/600*.
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 full-stack React apps with TanStack Start on Cloudflare Workers. Type-safe routing, server functions, SSR/streaming, D1/KV/R2 integration. Use when building full-stack React apps with SSR, or migrating from Next.js. RC status - monitor #5734 before production.
Build with OpenAI stateless APIs - Chat Completions (GPT-5.2, o3), Realtime voice, Batch API (50% savings), Embeddings, DALL-E 3, Whisper, and TTS. Use when: implementing GPT-5 chat, streaming, function calling, embeddings for RAG, or troubleshooting rate limits (429), API errors.
