Tool Use

Understand how tool descriptions and input_schema shape Claude's tool_use decisions.

Define one tool and handle its tool_use and tool_result round trip.

Write a precise JSON Schema so Claude calls your tool correctly.

Execute the requested tool and return a matching tool_result content block.

Reference table for auto, any, tool, and none tool_choice settings.

Loop tool_use and tool_result exchanges until Claude returns an end_turn.

Reference for defer_loading, tool_search_tool_regex, and tool_search_tool_bm25 configuration options.

Numbered practices for schema design, error handling, and multi-turn tool loops.