Hard to tell from a highlight vid, but if I were to pick apart his tools, I'd harp on:
- Limited athleticism/weak lower body: judging from the way he gets up (or, rather, doesn't), he reminds me of Oriakhi, who had a notoriously weak lower body and generated minimal lift in getting off the ground; if you recall, most of Oriakhi's dunks were two-handed, with arms extended almost completely straight up to get the ball over the rim. Stone looks similar. Of course, Stone is a junior in high school, not a junior in college, and will have time to get stronger.
- Lousy shooting mechanics: yes, they let him take 3's, and yes, he apparently made a couple, but his shot form is awful and I'd be shocked if the coaching staff would let him shoot from beyond the free throw line; this is also something he has time to work on.
He does seem to have some nice touch and a few rudimentary post moves, so right now if I were evaluating him (on very limited info), I'd describe him as a skilled plodder, kind of the anti-Drummond, which isn't necessarily a bad thing.