Enchanted Item: Spontaneous Spells

What is to stop a magus from enchanting Invoke the Spirit of (Form) -- a formulaic mystery spell into an object allowing the user to summon a spirit that can then cast a spontaneous spell without a roll. While the item might need to have the required penetration permanently set into it I'm sure you can find a tech/form combo that would be useful to allow grogs or companions to use.

Actually, it strikes me that you could create a couple items with longer duration invoke the spirit of (spell) to give somebody a limited spellcasting capability (not sure how this would be better than just created a standard item capable of casting the spell though).

Is there a rule somewhere I'm not seeing forbidding inventing magic items that mimic mystery spells?


No such rule!

But I would check the theurgy rules carefully, to make sure that someone other than the person making the pact can use the item.



oops, my bad