Block spell effects when buffs aren't running

Simple example:

spell:

name: Shoot Poison from Eyes​

requireBuff: Vile Poison​

... rest of spell ...​

to make sure that Shoot Poison from Eyes does nothing unless the caster has the Vile Poison buff.

This could also be specified in the requirements for spells, allowing the game to gray out a skill as unusable if the appropriate buff to use it isn't running.

 

A similar function would be to allow buffs, etc. to grant spells/powers temporarily.

 

Further on this related wishlist: buffs granting access to recipes temporarily.