Are you required to search your deck when playing a search card?
Yes. (Unless the card says &quot;You may search your library for ... If you do, shuffle it afterwards.)

608.2c The controller of the spell or ability follows its instructions in the order written.

If the spell tells you to search your library, you search your library. Most of these place restrictions on what cards you search for; in those cases, actually finding a card is not required:

701.19a To search for a card in a zone, look at all cards in that zone (even if it’s a hidden zone) and find a card that matches the given description.


701.19b If a player is searching a hidden zone for cards with a stated quality, such as a card with a certain card type or color, that player isn’t required to find some or all of those cards even if they’re present in that zone.


701.19d If a player is searching a hidden zone simply for a quantity of cards, such as “a card” or “three cards,” that player must find that many cards (or as many as possible, if the zone doesn’t contain enough cards).