Question regarding: middle_tier_tool_response

[gcalabria]

Hello langchain team 👋

first of all, thank you very much for all the amazing works you are doing on the AI scene! I don't miss one post :)

I was playing with the code of this prototype and I came across the response type extension.middle_tier_tool_response. I did some more digging and even tried to google where this comes from, but I haven't found a single documentation about it. Is this a custom response type that you have created or is this something that comes directly from OpenAI's API?

I appreciate any hints of where to look for this. I really would like to understand how it works.

Once again, thanks a lot 👌