Klipper help sought: fully automatic action to replace a clipboard entry

[J.B. Nicholson]

I didn't notice a more appropriate mailing list to ask about this. If there 
is one, please point me to that mailing list.

I'd like to fully automatically modify a textual clipboard item using 
Klipper and put the modified item back on the clipboard in its modified 
state so I can paste that item where needed.

I'd like to do all of this without answering any prompt from Klipper. I 
don't want to manually start the command, I want the command to run anytime 
the top (most recently copied) text item matches a command's regular 
expression.

Just in case this sounds like it could trigger an endless loop: I've made 
sure that the matching regular expression will never match the modified 
output so there will be no endless loop resulting from this modification 
putting matching text back on the clipboard.

I've also got only one command in my list of commands so there's no 
question which command should run -- if the copied text matches, the 
command I've got is the command to run.

Can Klipper do this?

If so, how do I make Klipper run the command for the matching regular 
expression and not prompt me?

Thanks for your help.