The event is not cancelable.

The event does not have a result.

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import at the very top of the file.

ZenScript
 Copy
import crafttweaker.forge.api.event.entity.living.effect.MobEffectAddedEvent;

MobEffectAddedEvent extends MobEffectEvent. That means all methods available in MobEffectEvent are also available in MobEffectAddedEvent

Name	Type	Has Getter	Has Setter
Name effectInstance	Type MobEffectInstance	Has Getter true	Has Setter false
Name effectSource	Type Entity?	Has Getter true	Has Setter false
Name oldEffectInstance	Type MobEffectInstance?	Has Getter true	Has Setter false