I'd like to make contextual requests to my API and be able to respond with information related to the caller or the number he's calling. How can I pass some context to the tool call ? (call_id seemed like the most obvious)

Either extract it from the [message.call](http://message.call) payload in your webhook or use the built-in get_call tool within the assistant to fetch and forward it as parameters..

I don't receive any message.call on my API when receiving the API Request call, only the fields specified in the tool settings

Ensure the tool is registered in your assistant and invoked inside the actual call flow, not outside or prematurely..