Anthropic Claude tool-use integration profile

Evidence-backed facts

1. For client tools, Claude returns a structured tool_use block; the application executes the operation and sends a tool_result back in a later Messages API request. informative
2. Anthropic server tools execute on Anthropic infrastructure, while application-defined client tools execute in the integrating application. informative
3. A custom tool definition can request strict schema conformance, but the application remains responsible for authorization and the consequences of client-side execution. informative

Primary sources