What happens when you enable json_response in StreamableHTTP?

Setting json_response to true disables streaming for POST request responses. Instead of receiving multiple SSE messages as a tool executes, showing intermediate progress and log updates, the client gets only the final result as a plain JSON response. This means no intermediate progress messages, no log statements during execution, and just the final tool result delivered at once. This flag is simpler to integrate with systems that expect standard JSON HTTP responses but sacrifices the real-time feedback that makes long-running tool operations user-friendly. ---