Anthropic Claude SDK

Expert assistance with the Anthropic Python SDK (anthropic package) and Claude API. Covers the Messages API, tool use, streaming, prompt caching, cost estimation, and model selection for coding workloads.

When to Use This Skill

• Calling Claude models directly via the Anthropic API
• Implementing tool use / function calling with Claude
• Streaming responses for real-time UX
• Estimating token costs before making a call
• Choosing between Fable 5, Opus 4.8, Sonnet 4.6, and Haiku 4.5
• Setting up prompt caching for long repeated contexts
• Debugging stop_reason, usage, and content block responses

Pre-flight Checklist

Before writing any API code, verify these in order: