Example

{
    "event_id": "event_6201",
    "type": "response.mcp_call_arguments.delta",
    "response_id": "resp_001",
    "item_id": "mcp_call_001",
    "output_index": 0,
    "delta": "{\"partial\":true}"
}

response.mcp_call_arguments.done

Returned when MCP tool call arguments are finalized during response generation.