curl --request POST \
  --url http://localhost:8000/api/telephony/numbers/buy \
  --header 'Content-Type: application/json' \
  --data '
{
  "agent_id": "<string>",
  "phone_number": "<string>"
}
'

{
  "phone_number": "<string>",
  "twilio_sid": "<string>",
  "agent_id": "<string>"
}