Claude's tool use allows models to call external functions during conversations. Define tools with schemas. Claude decides when and how to use them. Execute tool calls and return results for continued reasoning.
Tool Definition
Define tools with names, descriptions, and input schemas. Clear descriptions help Claude understand when to use tools. JSON schemas specify parameter types and requirements.
- Write clear tool descriptions explaining purpose and usage
- Define comprehensive input schemas with descriptions
- Handle tool execution errors gracefully
- Return structured results for Claude to interpret
- Implement multiple tools for complex workflows
Workflow Patterns
Sequential tool calls build on previous results. Parallel tool use retrieves multiple data sources. Error handling guides Claude to retry or use alternatives.