Can you add a reaction to a chain that's already resolving? Specifically, if you draw a card from a resolving reaction spell (like Consult the Past), can you immediately play that card to respond to something earlier in the chain?

Ruling: Yes, you can add reactions to a chain that is resolving. After each spell or ability resolves from the chain, both players get priority again to add more items to the chain before the next item resolves.

Sequence:

• Both players pass priority, so the last item on the chain resolves
• After it resolves, the player who controls the next item on the chain gets priority first
• That player can play cards/abilities or pass
• Then the other player gets priority to play cards/abilities or pass
• If both players pass, the next item on the chain resolves
• This process repeats for each item until the entire chain has resolved

Nuances:

• The player who controls the most recent item on the chain retains priority to add more items before passing to their opponent
• A player can add multiple items to the chain in a row before passing priority
• You cannot respond to a spell the moment it's played - only after you receive priority
• This is different from Yu-Gi-Oh where the entire chain resolves without being able to add to it