How to define the function for Assistant function calling for Zapier


I have an assistant built out to answer my user’s queries and have it linked to Zapier to respond via SMS. I want to define a custom function to run some calculations every time a user asks a specific question. I believe this can be done via the “Function Calling” functionality of the assistant, but I am not sure how I would pass the said function (body of the function that needs to be executed) to the assistant.

Every piece of document I see, asks me to invoke a new thread in a python script and call the custom function from there when the response has some tool_calls. That would involve me moving the assistant out of Zapier and handling everything through python. But I don’t want to do that. I would like to define the custom function that runs every time the user sends a specific query (via Zapier) to my assistant.

I am not sure if I am not able to get to the right piece of documentation, or if I am missing something, but any help would be greatly appreciated.