D&Dtools

This spell makes a weapon strike true against good foes. Any threat of a critical hit against a good foe is automatically confirmed, without a roll. The weapon can also harm good creatures that have damage reduction, as if the weapon had a +1 enhancement bonus. Individual arrows or bolts can be altered, but altered projectile weapons (such as bows) don't confer the benefit to the projectiles they shoot.

This spell has no effect on any magic weapon that already has a special ability related to critical hits, such as a keen or vorpal weapon.