Hmm. Tomorrow, Azami's Familiar and Aladdin's Lamp can replace card draw with looking at top cards. That means this will sometimes be very hard to predict whether it should counter a spell or not. For example, Fiery Gambit!

Would it be clearer to template it as "instead they don't"? Does that cause any problems with resolutions of abilities?

Erk. Yeah, I think there'll be a bunch of effects that say things like "Look at the top card of your library. If it's a land card, you may put it onto the battlefield..." Or Kinship abilities like on Leaf-Crowned Elder would have difficulties if you can't tell whether the top card meets the criterion or not.

Yeah, I thought you'd probably wasn't workable. I just thought I'd pop it out there anyway.

Although, don't "look at the top card of your library" effects have to cope with an empty library? I assume in that case it's just treated as if you can't do any of the things which depend on it. Does that mean this could be templated the same way (and be unambiguous, even if it might be too confusing)

They do, but it's usually a lot easier to tell what the default action is in those cases. (Leaf-Crowned Elder doesn't put anything onto the battlefield, Kithkin Zephyrnaut doesn't get bigger etc). If the card exists, and has some characteristics, but they're unknown because the card can't be seen? That's more fiddly. I think the game will treat all such characteristics as unknown. Which I think in turn means that even with a Courser of Kruphix out, Leaf-Crowned Elder couldn't put another Treefolk out. Which is pretty odd.

"Which is pretty odd."

I think that's about what I expected -- it means the rest of the ability doesn't happen. But I admit, it would need to be clearer than that to be published.

Yeah, I don't think this is really publishable. As you've said, it's quite confusing, and then on top of that, it's incredibly niche.