Can you react to Beginning Phase activated abilities, and specifically can you use Gust to move a unit to hand in response to Jinx Leader's trigger to prevent the extra draw?

Ruling: Yes, you can react to Beginning Phase triggered abilities. Using Gust in response to Jinx's trigger will prevent the draw if it brings the hand to 2 cards, because Jinx's ability always triggers at the Beginning Phase but checks the number of cards in hand when it resolves.

Sequence:

• At the Beginning Phase, Jinx's trigger is created and added to the chain
• You can respond with Gust, which resolves first
• Gust moves a unit to hand, bringing total to 2 cards
• Jinx's trigger resolves next, sees 2 cards in hand, and does not draw

Nuances:

• Jinx's ability always triggers at the Beginning Phase regardless of current hand size
• The hand size condition is checked at resolution, not when the trigger is created
• Gusting a unit at this point also prevents scoring