Summary Judgment
Instant
Summary Judgment deals 3 damage to target tapped creature.
Addendum — If you cast this spell during your main phase, it deals 5 damage instead.
Any challenge to Azorius authority is met with swift and potent retribution.
Illustrated by
Ravnica Remastered#27CommonEnglishLegality
Rulings
Jan 25, 2019
Addendum abilities of instant spells apply while the spell is resolving, not immediately after casting it. If the spell is countered, you don’t get the addendum bonus. For example, if you cast Sphinx’s Insight during your main phase, you gain 2 life during its resolution, after you draw two cards.
Jan 25, 2019
If a spell with an addendum ability is copied, the copy won’t give you the addendum bonus. This is because the copy wasn’t cast at all.