For those who don't want to use PSI's armor, you could add some baubles that can hold one or two bullets apiece, with autocasting triggers similar to the exosuit armor pieces (& psimetal tools?).

Perhaps: Charm for taking damage, amulet for continuous cast (or vice versa), body item with a slot for helmet sensors, belt for jump? Or perhaps some different triggers....

Perhaps even just some spell storage that you could access to swap the spells from your CAD