Tool details that the model may use to generate response.

A Tool is a piece of code that enables the system to interact with external systems to perform an action, or set of actions, outside of knowledge and scope of the model.

function_declarations MutableSequence[]

Optional. A list of FunctionDeclarations available to the model that can be used for function calling.

The model or system does not execute the function. Instead the defined function may be returned as a [FunctionCall][content.part.function_call] with arguments to the client side for execution. The model may decide to call a subset of these functions by populating [FunctionCall][content.part.function_call] in the response. The next conversation turn may contain a [FunctionResponse][content.part.function_response] with the [content.role] "function" generation context for the next model turn.