Anthropic Core Workflow A — Tool Use (Function Calling)

Overview

Implement Claude's tool use capability where the model can call functions you define. Claude returns tool_use content blocks with structured JSON inputs; your code executes the function and returns tool_result blocks. This is the foundation for building AI agents.

Prerequisites

• Completed anth-install-auth setup
• Understanding of the Messages API request/response cycle
• Functions or APIs you want Claude to call

Instructions

Step 1: Define Tools

import anthropic

client = anthropic.Anthropic()