I have experienced this issue with make.com with the payload VAPI sends, it can be a bit tricky with mapping of the keys. Setting the webhook back to "redetermine for data structure", then get the voice agent to action your tool and it should help get mappings defined in make? If there is nothing in there from VAPI from the tool, but webhook is firing OK, then could be a system prompt thing: I.e Help AI understand the tool/ parameter, maybe name the tool clearly in the system prompt, name the property etc.