Subrule · Chapter 6
cr:6.4.10b
If the prevention amount is not explicitly specified, the prevention amount is defined as the amount of damage in the damage event.
Example: Feign Death has the text “The next time you would be dealt damage this turn, prevent it,” which does not explicitly specify the prevention amount. If the damage event that Feign Death will apply to is 3 damage, then the prevention amount of this effect is considered to be 3.