Tool Use
Tool use with the Claude API — how function calling works, structured outputs, and best practices.
4 articles
Claude API Tool Definitions: Naming and Description Rules Without the Guesswork
A beginner-friendly walkthrough of how to name and describe tools in the Claude API so Claude calls the right one at the right time, based on official documentation.
Claude API Tool Use Best Practices: Definitions, Errors, Parallel Calls
A practical guide to reliable Claude API tool use: tool definitions (description, strict), is_error handling, the agent loop, parallel result formatting rules, Tool Runner and Tool Search — per official docs.
Claude API structured outputs — guarantee output with a JSON schema
"Answer in JSON" sometimes breaks. Structured outputs guarantee a schema via two modes (JSON output, strict tools), constrained decoding, plus incompatibilities and pitfalls — per the official docs.
Claude API Tool Use Guide: How Function Calling Works
How tool use (function calling) works in the Claude API: the three places tools run, the agentic loop, defining tools (name, description, input_schema), and server tools with pause_turn — based on official docs.