that is an option, but I am not even getting a basic json like this to be interpreted by VAPI { "results": [ { "toolCallId": "call_KEhwN0E8gdUqpRpOd1qe8H6P", "result": "That timeslot is not available" } ] } The only message that appears to be interpreted by VAPI is a positive message, like below: { "results": [ { "toolCallId": "call_KEhwN0E8gdUqpRpOd1qe8H6P", "result": "The appointment was successfully booked." } ] } It this working for you?