Sure, it’s scary to send your writing to a literary agent. But pity the poor agent who must wade through hundreds of terrible query letters a week! One of them shares excerpts from those hilariously bad query letters on a blog called SlushPile...
All’s, as in the common clause all’s you have to do, isn’t grammatically incorrect. It’s a valid contraction of the archaic construction all as. This is part of a complete episode.