I'm pretty sure `pass edit foo` does more or less what you seek: it launches $EDITOR with the full contents of whatever's in foo, and would therefore naturally

I'm pretty sure `pass edit foo` does more or less what you seek: it launches $EDITOR with the full contents of whatever's in foo, and would therefore naturally support whatever markup or editor shenanigans you want for your preferred workflow. Or `pass show foo`, which you could pipe any which way for whatever processing you see fit.