Exhaust, ready, buff, XP and the other limited actions

Game actions come in two kinds. A Discretionary Action is one you may take whenever you like during your own turn in a Neutral Open State, as long as its conditions and costs are met: playing a card and making a Standard Move are examples (rule 411.1.a, rule 411.1.b, rule 420.2 and rule 411.1.b.3). A Limited Action is one that a spell, an ability or the turn's own progression makes you perform, and you cannot do it at will (rule 411.2.a and rule 411.2.b). Nearly everything in this lesson is Limited: Exhaust, Ready, Buff, Discard, Predict and Skip are each declared Limited Actions in their own rules (rule 415.3, rule 416.3, rule 427.2, rule 423.2, rule 437.2 and rule 444.3). The player who performs an action is responsible for it, and an ability that triggers when "you" do something looks for actions you are responsible for (rule 412.1 and rule 412.4). If an opponent discards because of your spell, they are the ones performing it, so your "when you discard" ability does not trigger (rule 423.1.a).

Exhausted and Ready are both actions and states. Exhausting marks a non-spell game object as spent, and an object that is already exhausted cannot be exhausted again; as a cost the action must be able to be completed, so an exhausted object cannot pay an Exhaust cost (rule 415.1, rule 415.1.b, rule 415.2 and rule 415.4). Readying works the other way, and readying a unit that is already ready changes nothing (rule 416.1 and rule 416.1.c). Each Awaken Phase the Turn Player readies every game object they control that can be readied, runes and gear as well as units (rule 315.1.b).

Here is a worked example. Honeyfruit is a gear that enters exhausted and has a Reaction ability whose cost is to exhaust it. Its controller plays it during their Main Phase and wants its Add right away. They cannot: the gear is already exhausted, so the cost cannot be completed (rule 415.4). It will ready in their next Awaken Phase, and the ability is usable from then on.

A Buff is a counter on a unit. A unit can hold only one, and buffing a unit that already has one places nothing (rule 702.2.a, rule 702.3 and rule 702.3.a). Such a unit can still be chosen, but it will not be buffed, so an effect that depends on the unit having been buffed does nothing (rule 427.1.b.1 and rule 427.1.c). Each Buff adds 1 Might (rule 703). Spending a Buff removes the counter, and you can spend only buffs on units you control (rule 702.2.b and rule 702.2.b.2). When a unit leaves play, its Buffs go with it (rule 705).

XP is a number kept on a player. You Gain it by raising the marked value and Spend it by lowering it (rule 730.1 and rule 730.2). It is public information, it is not a game object, so it cannot be targeted, readied or exhausted, it is not shared with teammates in team modes, and it has no upper limit (rule 729.2, rule 731, rule 731.1, rule 732 and rule 733). Keywords such as Hunt and Level are built on it.

Three smaller actions come up often. When Discarding is a cost, you must be able to discard the full amount to pay it. When it is part of an effect you discard as many as you can, and the remaining discard is negated (rule 423.3 and rule 423.4). Predicting with fewer cards in your Main Deck than the number asked for looks at as many as it can, and does not cause a burn out (rule 437.4 and rule 437.4.a). Skip replaces an event or a phase of the turn with nothing, so anything that would have happened in it does not happen (rule 444.1, rule 444.2 and rule 444.4).

At a tournament, players track their own XP in a clear way, and anyone who notices a discrepancy must tell everyone at once and call a judge if it cannot be settled easily (TR 415.4 and TR 415.4.b). Forgetting to ready during the Awaken Phase has no penalty. If it is still that turn, the judge readies everything that should have been readied, and if the turn is over, play continues with objects as they are (TR 702.15, TR 702.15.a.1 and TR 702.15.a.2). It becomes a Warning if forgetting was advantageous (TR 702.15.b).