yes but how to set this pls?

Configure an assistant selector webhook to extract the caller’s number from the SIP “From” header, pass it as callerId via assistantOverrides, create a lookup_contact tool that queries your database, add it to your assistant, and in the prompt, instruct the agent to call the tool using callerId and greet the caller by name if a match is found.. https://docs.vapi.ai/tools/custom-tools

thks !