Hello Jake,
Thanks for sending the result. I believe that the tool is working well. It seems that there is an issue on my end. I created a new feature class and divided it in two parts. So, the second part is appended to the first part by the tool. I published the first part as "Hosted Feature Layer" on both ArcGIS Online and Enterprise. I executed the tool, but I received two different error messages.
For ArcGIS Online, it looks that everything is working well, but no new row is appended to the hosted feature layer. I checked the tool twice. One time with defining a field value and the other time with no field value. Both had the following error.
This is the error message.
For ArcGIS Enterprise, there is a problem in connection.
It is "ConnectionError: HTTPSConnectionPool(host=' ', port=7443): Max retries with url: /arcgis/sharing/rest/generateToken
Thank you