Yeah, forgot about that. Such Faustian clauses are evil, and shouldn't be possible in the first place.

Nevertheless, this doesn't look like a Non-Compete Agreement violation, or we would probably have seen those words in the article. My guess is, Carmack haven't signed one (75% probability).

I agree that Carmack probably didn't not sign one. But they are very common among companies in the tech sector and they can be just as horrible as you imagine.