Forge will let you start the game with RockyCore installed and MTLib not installed (and then give a crafttweaker script error upon world join for any anvil recipes)

I see the dep in your code...I've never had more than one dep in any of my mods, but maybe the correct format is "required-after" for each entry, and not just the first one?

Apparently this was a mistake on my part; the dependencies seem to be registering fine. Sorry for the false alarm