Jeskai Ephemerate leans on value engines like Ephemerate rebound loops with Mulldrifter/Archaeomancer, plus card draw sorceries (Preordain, Lorien Revealed). Envelop only counters sorcery spells, so it can't answer Ephemerate, Mulldrifter, or Archaeomancer. It is well-positioned against Lorien Revealed, Preordain, and Fanged Flames, which cuts into their card flow. Toxin Analysis and a copy of Cast Down are cut since their creatures (Murmuring Mystic, Augur of Bolas) aren't big threats requiring removal as much as we need to slow their card-draw sorceries. We keep our proactive plan intact to pressure them before they stabilize with repeated Mulldrifter and Archaeomancer value.