I make all of my custom moves with the players, and if I don't, I text it to them during the week so they can chime in. I might not tell them who exactly has got it, but they know when I do. I don't really see any value in surprising them of a risk or challenge, its already risky and challenging, they might as well know the stakes. I have made many many many custom moves however, and in every case where I didnt tell anyone, they often never did the thing to trigger it either.
AW isnt about the mystery behind that door. Its not really suppose to function like: "open the door and roll+weird cause... choose 2." It's suppose to be like, everything in this place is old and dead and battered... except that door to the office right there. It's like... brand-new hardwood, all glossy and immune. It's weird ass shit and doesnt belong. You can even look into the room behind it through the shattered glass, it's crap like out here. But the door... You dont know what to think about that.
That's weird.
I wouldn't have a custom move however, I might just have them open their brains if they open that door. Barth forth weird shit, and ask my questions to form what they see and have them guess why its significant, well have them decide--really. My job is to keep make the world seem real, so whatever this is, it will make some sense from the world's internal logic; probably building on previous weirdness.
Honestly, I've found my players like to be involved with the making of moves anyway. They like to have a say, and the options should feel both scary and rewarding to them. So it works out well. I dont want them to hita roll they didnt know they had to make, to get soemthing they didnt really want anyway. I dont bother rolling to see if they run into trouble, I just think... has anything interesting been happening? Nope? Well then... Time to make something more complicated then they expected or... did they miss a roll? Well time to make things complicated.
There are exceptions.. The people that can get into other people's mind that listed as an example custom move... that I told them about narratively the first time they got touched. (was my first game ever) I told them the implications very clearly, they felt shit happen. But I didnt have them roll that time, nah. I had them roll the time later when they pissed one of those people off. And that, that was scary fun for them. Just the threat and the weirdness made it cool. And telling them in advance would have made it less cool. This is the only time I would withhold that type of information--and I would release most of it before making them roll, even if they didnt see the move itself until they did.