In Betrayal At House On The Hill, the explorers will eventually reveal one too many Omens, causing some (random) explorer to become the Traitor and try to do something terrible to the remaining players (who are then called Heroes). There are 50 different scenarios that might happen, and each scenario has special rules for the Traitor, and different special rules for the Heroes. (Among other things, these rules say how each side can win.) The rules for each side are not to be revealed to the other side; instead, each side has a small paragraph in their rules about "What the other team knows".
During play, those special rules come up repeatedly: how the Traitor is permitted to move the Zombies, the deterministic rules on how the Banshee moves, special attacks, special defenses, special items required, etc.
How much of the special rules is each side required to reveal when using them? For example, several scenarios require that the Heroes perform a ritual/exorcism/silly dance with particular items and/or in particular locations, using a skill check. How much should the Heroes reveal while doing this? Should a Hero say "I'm searching for voodoo supplies here in the bedroom, which requires me to roll at least a 4 on Sanity" or simply "I'm making a skill check" (or even say nothing and just roll the dice)? When Heroes have a special way of defeating monsters, do they have to describe the action ("I'm throwing a torch at the monster"), or simply roll an attack ("I'm attacking you with Speed.")?
In play, I've usually described only things that would be obvious: "Roll a Sanity check. Okay, you failed (I don't mention the target number); the Zombie won't act for the rest of the game" or "I throw a torch, it's a Speed attack." In the first case, the reason the Zombie shut down is only known to the Zombie itself, and it isn't communicating anymore. In the second case, it's obvious to the monster that I'm throwing a torch at it. Am I doing it right?