Rule 329

Cards, tokens, and abilities added to the chain are added as Pending Chain Items that become Finalized Chain Items.

• 329.1 Pending Items are on the Chain.
• 329.2 Chain Items are Pending until the “Check Legality” step of playing a card. See rule 349. Playing Cards for more…
• 329.3 When a Pending Chain Item is no longer Pending it is finalized and becomes a Finalized Chain Item.

Official Core Rules