curl --request POST \
  --url https://api.utage-system.com/v1/accounts/{account_id}/scenarios/{scenario_id}/readers/{reader_id}/labels \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "label_id": "<string>"
}
'

{
  "data": {
    "id": "<string>",
    "assigned_at": "<string>"
  }
}