{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "title": "ToolInvocationStartData",
    "description": "Schema for the data part of a tool invocation start signal.",
    "type": "object",
    "properties": {
        "type": {
            "type": "string",
            "const": "tool_invocation_start",
            "description": "The constant type for this data part."
        },
        "tool_name": {
            "type": "string",
            "description": "The name of the tool being called."
        },
        "tool_args": {
            "type": "object",
            "description": "The arguments passed to the tool."
        },
        "function_call_id": {
            "type": "string",
            "description": "The ID from the LLM's function call."
        }
    },
    "required": ["type", "tool_name", "tool_args", "function_call_id"]
}
