tl;dr: Anthropic's Claude Cookbook is a growing collection of practical notebooks and guides covering agent patterns, tool use, RAG, evals, multimodal workflows, prompt caching, fine-tuning, and integrations with services like Pinecone, LangChain, and ElevenLabs. Recent entries focus heavily on the Claude Agent SDK and Managed Agents—covering multi-agent orchestration, memory/context compaction, self-verifying outcomes, SRE and vulnerability-detection agents, and production deployment patterns. Older recipes cover fundamentals like JSON extraction, SQL generation, vision, classification, and summarization.