|Type(s)||Action - Attack|
Each player (including you) reveals the top card of his deck and either discards it or puts it back, your choice.
Spy is an Action-Attack card from the first edition of the Base set. It is a cantrip, meaning it provides +1 Card/+1 Action, and so it doesn't prevent you from drawing or playing other Action cards too. It helps you by allowing you to discard bad cards off of your deck, and hurts your opponents by letting you inspect and discard their good cards (a deck inspection attack). It combos with other cards that care about the top of your opponent's deck, like Thief.
 Official FAQ
- Spy causes all players, including the one who played it, to reveal the top card of their Deck.
- Note that you draw your card for playing Spy before any cards are revealed.
- Anyone who does not have any cards left in their Deck shuffles in order to have something to reveal. Anyone who still has no cards to reveal doesn't reveal one.
- If players care about the order in which things happen for this, you do yourself first, then each other player in turn order.
- Revealed cards that aren't discarded are returned to the top of their players' Decks.
 Other Rules clarifications
- In a strict interpretation of the rules, each player reveals their card and returns it or discards it before the next player does, and for certain cards (such as Chariot Race), this can matter when it comes to deciding which each player should do. However, in practice, it's usually fine for all players to reveal their cards at the same time for efficiency's sake, provided there's no effect in the game that cares about the order of revealing.
 Strategy Article
Spy is a generally weak card, especially compared to other cantrip, its opportunity cost often makes it not worth buying. This has particularly become the case as later expansions have introduced new (and better) cantrips. Spy is usually the worst buy in Big Money strategies, especially terminal draw big money. It is usually a slightly better buy in engines.-cost cards, and is usually not worth buying unless there are specific synergies with other cards in your deck. The attack is weak and the benefit to you is also fairly weak. Even though Spy is a
 Spy's Attack
The attack of Spy is weak, and more notably, on average, becomes weaker with successive plays of the card. This is because once you hit a bad card that you choose to keep on top of the opponent's deck, future attacks are useless. Further attacks only have use if you hit and discard good cards. In the case that you discard a bunch of cards with Spy, however, the strength of the attack is mitigated by the fact that you are cycling your opponent's deck.
Spy's attack becomes much stronger when paired with top-deck attacks. Swindler is probably the strongest synergy; Spy can make it more likely that your Swindler hits a Copper and not an Estate, helping reduce the swinginess of Swindler's attack.
 Your deck inspection
On the other hand, the benefit to you from Spy becomes greater with successive plays. A single Spy only lets you set up a card for future draw, but a double Spy lets you set up and then draw a card immediately, and set up a future card. A chain of Spies will let you draw a bunch of cards that are a better than what you would draw on your own.
The deck inspection function of Spy is strongest in decks which have a highly heterogeneous composition. Strong trashing thus makes Spy less useful, but the card becomes more useful in decks with a lot of VP cards, Curses that cannot be trashed, or other junk cards.
- Your top-deck attacks such as Swindler, Jester, Thief, Noble Brigand, and Pirate Ship.
- Useful when you need Action density, such as for Scrying Pool or Conspirator.
- Useful if available alongside Tunnel, as it enables top-deck discard to trigger Tunnel's effect.
- Opponent's discard attacks
- Opponent's Farming Village
- Terminal draw Big Money
- In the absence of +Buy or gainers, it's hard to find a good time to buy a Spy.
- Sea Hag
 English versions
|+1 Card. +1 Action. Each player (including you) reveals the top card of his deck and either discards it or puts it back, your choice.||Dominion 1st Edition||October 2008|
 Other language versions
 Secret History
 Why does Spy cost 4?and people bought it and you didn't have to. These days I wouldn't make it at all - it's too slow for what you get, and charging less doesn't fix that.
 Second Edition Removal