Sounds cool and all.
Will it be like a slice of life with added japanese god familiars and also the fact that magic exists because we are or will become mages?
Other questions:
How will magic really exist in this story? How will it be used?
Maybe magic will either be learned through books or be inherent in an individual as a talent(s) that they can control/summon/use to transform thing(s) from the time that they are born.
Perhaps individuals who are born with it are called wilders and the ones that have first learnt it through books are called adepts.
Another thing is how will/where will the magic manifest?
Could magic be apart of the environment where an individual or everybody could manipulate the cell structure of a substance. The process of changing that substance's shape, the very act of that could take away from the substance until there is nothing left.
Also added on to the paragraph right above this one ^, perhaps there could be the idea of (Got this from full metal alchemist) the idea of equivalent exchange where if you manage to manipulate something of the environment then it would cost you something. Perhaps the cost would only be energy leading to your exhaustion or perhaps something more.
^ Perhaps this would be one of the talents of magic users.
Maybe another talent of magic would be summoning, through the use of incantations or sheer power of will, depending upon what you wish to summon. For example in order to summon a fireball, perhaps a few appropriate words spoken would be enough to do this, but if it was to summon an animal that exists somewhere else it would require a very long incantation or someone with a very strong will that truly desires with total focus to summon the beast. The cost of this would be higher than the manipulation talent because your working with less and usually doing more.
Another talent of magic could be transformation magic. The ability to alter the composition and or the appearance of an object or living being. The cost of this would be higher then the manipulation or summoning talents because it is more difficult to change something or others or yourself into something completely different. It requires intense concentration and being detail oriented.
These are just suggestions that I thought might help.