Anthropic SDK Patterns

Quick Guide: Use the official @anthropic-ai/sdk package to interact with Claude models directly. Use client.messages.create() for single-turn and multi-turn conversations. Use client.messages.stream() for streaming with event-based consumption. max_tokens is always required. Content blocks are typed unions (text, tool_use, thinking). Use client.messages.parse() with zodOutputFormat() for structured outputs. Tool use requires a tool-result loop -- Claude returns tool_use blocks, you execute the tool and send back tool_result blocks. Extended thinking adds thinking content blocks before the response.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST always provide max_tokens in every messages.create() / messages.stream() call -- it is required and has no default)

(You MUST handle the stop_reason field to detect end_turn, max_tokens, tool_use, and stop_sequence -- ignoring it causes silent truncation or broken tool loops)

(You MUST iterate over response.content blocks (not assume a single text block) -- responses can contain text, tool_use, and thinking blocks mixed together)

(You MUST handle errors using Anthropic.APIError and its subclasses -- never use bare catch blocks without error type checking)