Extort triggers off of any spell you cast, not just spells cast from your hand. And once you’ve encoded one of your creatures with a cipher spell and that creature deals combat damage to a player, you get to cast a copy of that encoded spell. Since you’re casting the encoded spell, all of your extort abilities will trigger.
For instance, let’s say you control two creatures with extort, and one of them is encoded with Last Thoughts. If that creature deals combat damage to a player, you get to cast a copy of the Thoughts. Since you’re casting the copy, both of your creature’s extort abilties will trigger. So not only do you get to draw a card from the Thoughts, but you can drain your opponents twice. I guess that just shows that there’s a tax for being sneaky, and it’s your opponents who are going to pay.
Today’s Rules Tip written by Nate Long