Sword of the Seer: Weapon, 2 Vorpal. Draw a card. Each other player must show you their hand.
Are you not normally allowed to tell your teammates what cards you have? The game is cooperative rather than competitive so this seems out of place, and looking at the next card in the foe or encounter deck would have still been thematic with the card and really useful.
I got the impression that it's not quite as cooperative as you seem to think it is. I think I'd probably put this in the semi-cooperative category. While you can't attack any other players directly, you aren't under any obligation to help them. If you read through the rulebook, especially with regards to conquering the spire, you see that there's an element of "every runelord for themself" at play. The only real cooperative element is the madness track.