Reference for building directly on Anthropic's Messages API: request anatomy, multi-turn state, system prompts, temperature, streaming, forced structured output via prefill+stop sequences, prompt evaluation (datasets, model/code graders), prompt engineering technique, custom tool use end-to-end (sch
Reference for building directly on Anthropic's Messages API: request anatomy, multi-turn state, system prompts, temperature, streaming, forced structured output via prefill+stop sequences, prompt evaluation (datasets, model/code graders), prompt engineering technique, custom tool use end-to-end (schemas, message blocks, multi-turn loops, text-editor and web-search built-in tools), RAG (chunking, e