What happens when you try to reveal/look at the top X cards of your deck but have fewer than X cards remaining?

Ruling: You reveal/look at as many cards as you can and resolve the effect normally. You do not deck out because the cards you're looking at are still part of your main deck.

Sequence:

• Reveal/look at as many cards as are available in your deck
• Resolve the card effect with those cards
• The revealed cards remain part of your main deck during this process

Nuances:

• You only deck out if there are 0 cards in your deck when you use the effect
• The deck-out rule requires your main deck to be empty, which is not satisfied when cards are being revealed/looked at since they're still part of the deck