curl --request POST \
  --url https://api.example.com/v1/calls \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "agent_id": "<string>",
  "tags": {},
  "livekit_username": "User"
}
'

{
  "id": "<string>",
  "agent_id": "<string>",
  "started_at": "<string>",
  "ended_at": "<string>",
  "livekit_url": "<string>",
  "livekit_token": "<string>",
  "tags": {}
}