Tool call

A tool call is the structured output a model emits to invoke a tool.

A tool call is the structured output that a model emits to invoke a tool. Models do not call SDKs. A model sees each tool as a name, a natural-language description, and a schema for its arguments. The model decides to call a tool by emitting structured output, the agent harness executes the call, and the result is fed back as text or images.