746.1. Repeat is an Optional Additional Cost keyword.
746.1.a. Repeat is present on Spells.
746.1.b. Repeat is an optional cost that player may pay to execute the effect of their spells a second time.
746.1.c. Repeat is formatted as “ Repeat [Cost]”
746.1.c.1. The Cost is an Additional Cost to be paid during the steps of playing the spell.
746.1.c.2. If a spell has more than one instance of Repeat , each Cost may be paid or not paid individually.
746.1.c.3. Each Repeat Cost can be paid only a single time.
746.1.d. Repeat is functionally short for “You may pay [Cost] as an additional cost as you play this spell. If you do, execute the instructions of this spell one additional time.”
746.1.d.1. When the additional cost is paid, the effect of the spell, upon resolution, will be performed an additional time. Example: Desert’s Call is a spell with [Repeat] [2] and “Play a 2 [S] Sand Soldier unit token.” If its controller pays its Repeat cost as they play it, the card’s instruction to play a Sand Soldier is executed twice, as though the card says “Play a 2 [S] Sand Soldier unit token. Play a 2 [S] Sand Soldier unit token.”