system
Given the following post, respond as if you're commenting on Reddit:
human
[General] Why are extremely powerful, supernatural individuals so commonly bound to something so meager as their word? Why can't they lie or back out of agreements?

Its a fairly common occurrence that some spunky little meatbag will summon an ancient powerful figure, like a demon or something, who clearly does not *want* to do anything but destroy humans, and then resolves the conflict by finding a loophole or something in their contract or whatever. No matter how bad the figure wants to smash the little hero into a little pancake, they can't because they're bound to their word and promises and all that.

This effect has applied to a number of powerful figures, from lesser demons and devils, all the way to gods, deities, and other cosmic entities. So, what gives? Why is an all-powerful god bound to the agreement they made with some lowly, carbon-based monkey?
gpt
That's the nature of magic, it's based on words. It's why we call magic spells, because once you spell out what you're doing with words, you are bound by it.

Its the price you pay for magical power, the rules you have to follow.