Can an opponent play Gust in response to Wielder of Water attacking alone, or does Wielder of Water's 'while I'm attacking' ability make it count as 4 might immediately?

Ruling: Wielder of Water's "while I'm attacking" ability is a passive ability that applies immediately when attacking, so the opponent cannot react with Gust before it takes effect.

Nuances:

• "While I'm attacking" abilities are passive and always active during the attack, similar to assault tags
• This is different from "When I attack" abilities, which are triggered abilities that start a chain and allow responses