just tried it out with unix pass which is what I use mostly and somewhat understandably it didn't manage to stop it recording it in the clipboard history. Not sure how well it can work with pure terminal apps like that.
function pass() { defaults write org.p0deje.Maccy ignoreEvents true ; sleep 1; /opt/local/bin/pass -c "$@" ; echo "Copied password to clipboard for $*"; sleep 1; defaults write org.p0deje.Maccy ignoreEvents false; }