Obviously the two tags should be made synonyms, I'm asking which one we should use. @Drew recently pointed to me, we had a question tagged as interactive-command, which is obviously a pleonasm.
The tag should be
commands. It could have
interactive-function as a synonym, but I doubt that that will prove useful at all.
interactive is a Lisp special form. While some questions about
commands (aka interactive functions) will also be about "function"
interactive, and some questions about
interactive will also be about commands, the two are not the same thing.
Another tag might be
interactivity, which would deal with questions involving different ways to interact with users. (It would not be limited to dealing with commands.) But that is quite general, and it might be better to stick with tags for different kinds or topics of interactivity (