Dimir Tempo relies on cantrips and free countermagic like Force of Will and Daze, so Disruptor Flute is the best sideboard tool here. Naming Daze or Brainstorm makes those spells cost {3} more, which blunts their free countermagic and their card selection and slows their Thoughtseize-into-threat plan. Avoid naming Wasteland, since the Flute would also shut off your own Wastelands. Goblin Bombardment is weak here since they have few sacrifice synergies to punish, so both copies come out. Karakas stays in, because Bilbo, Thief in the Night is a legendary creature it can bounce, as is Kaito, Bane of Nightmares while it is a creature on their turn. Keep the Thoughtseize/Cabal Therapy suite fully intact to fight the disruption mirror and race before their lock pieces land.