This sounds a lot like Spiceworks on-prem where you could put commands in a ticket response that would cause something to happen but the commands wouldn't show for the ticket users. Things like #close, #cc, #assign.
I miss #close, we had a canned response that put a comment in the ticket reply as well as the #close, and it was closed. We have a similar canned response in osT but will forget to take the additional step to change the dropdown to Closed.