curl --request POST \
  --url https://{host}/me/v1/authentication-methods \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "phone",
  "phone_number": "+15551234567",
  "preferred_authentication_method": "sms"
}
'

{
  "id": "phone|dev_XXXXXXXXXXXXXXXX",
  "auth_session": "Fe26.2**05c400ed..."
}