curl --request POST \
  --url https://api.gospott.com/lists/{id}/client-contacts/_link \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "selection": {
    "type": "included",
    "ids": {
      "include": [
        "<string>"
      ]
    }
  }
}
'

{
  "error": {
    "type": "LIST_SIZE_LIMIT_EXCEEDED",
    "message": "<string>",
    "listId": "<string>"
  }
}