Hello, i think this is what you meant correct me if im wrong.
options:
prefix: &4Coke&cDupe &8| &cItem &4Duped!
command /dupe:
trigger:
set {_item} to player's tool
if {_item}'s lore does not contain "&fUndupable":
give {_item} to player
send "{@prefix}"
stop
else:
send "&cYou can't dupe this item." // feel free to edit this