Spell Speed

There are two spell speeds on Dimensional Rift; slow means "sorcery" speed, while fast means "instant" speed.

• Slow Speed: actions, summoning cards from your hand or Fables Deck
• Fast Speed: any activation and trigger effects, proactively flipping artifacts or creatures with Ambush

As in MTG, Slow speed effects can only be activated during your own Deployment Phase (for summons) or Event Phase (for actions); when the stack is empty; and you have priority.