Ive tried -negative efficiency, that didn't work. I tried a couple other things I cant remember. is there a easy way to make it so people cant mine with a certain pic besides creating a listener?
I don't think so unless they are in adventure mode maybe you could make it break every other block beside a few. What's the problem with using a listener?
because it would be slightly more server efficient if there was a like a item attribute that I could change
If you're literally adding one line of code in a listener that checks what item and then the block, the effect it will have on performance won't even be noticeable.
