Claude Code SDK and API

Drive Claude from code: the Messages API and Agent SDK end to end. Typed responses, system and roles, streaming, tool use, the agent loop (tool_runner), structured output, prompt caching and token counting, then a small shippable app.

1. 1The Messages API: one endpoint, one shape3 q
2. 2System prompts, roles, and a stateless API3 q
3. 3Streaming responses3 q
4. 4Tool use and function calling3 q
5. 5The agent loop and the tool runner3 q
6. 6Structured output you can trust3 q
7. 7Prompt caching and token counting3 q
8. 8Build a small app with the SDK3 q