What problem does it solve? Building production LLM features requires handling provider outages, streaming responses, tool calling, cost tracking, and rate limiting across multiple vendors, which is complex to implement correctly from scratch. ## Core Features & Use Cases - Multi-Provider Routing: Configure LiteLLM or Vercel AI Gateway with automatic failover between Anthropic Claude and OpenAI GPT models, including retry logic and router configuration. - Streaming & Tool Calling: Implement server-side streaming with the Vercel AI SDK, define typed tools with Zod schemas, and render tool calls in React using AI Elements. - Production Hardening: Add Redis caching, token-based cost tracking, per-user rate limiting with Upstash, exponential backoff retries, and durable agents via Workflow DevKit. - Use Case: You are building a chat feature in a Next.js SaaS app and need Claude as the primary model with GPT fallback, streaming UI, and per-user daily request limits. ## Quick Start Set up a streaming chat endpoint in my Next.js app using the AI SDK with Claude as the primary model and GPT as a fallback.