Tome of the Guildpact
{5}
Artifact
Oracle Text
Whenever you cast a multicolored spell, draw a card.
{T}: Add one mana of any color.
Watch Out
Cast trigger fires even if counteredWatch Out
This triggers when the spell is cast, before it resolves. Even if the spell is countered, the cast trigger still resolves. Copies of spells are not cast, so they won't trigger this.
Mana abilities don't use the stackRules Note
If this card's activated ability produces mana and doesn't target, it's a mana ability. Mana abilities resolve immediately without using the stack — opponents can't respond to them. However, abilities that target (even if they produce mana) aren't mana abilities.