Arguments the model wants to pass to the tool, as a key-value map. Deserialize and validate these against the tool's input schema before executing.
Unique identifier for this tool call, assigned by the model. Use this value as id when submitting the corresponding tool result.
Name of the tool or function the model wants to invoke, e.g. "web_search" or "run_code".
Optionalthought_Opaque signature representing the model's internal reasoning that led to this tool call. null when the provider does not expose chain-of-thought data.
A tool (function) call emitted by the assistant within an AI message. Mirrors the OpenAI tool-call object format.