What arrives
The letter
Two levels. First the handful of things that are structural or run through everything, then the rest, ordered so you can work through it rather than drown in it. It closes with what to do first, because a cloud of possibilities is how writers end up doing nothing at all.
What works, in the same detail
Knowing why a passage lands is the fastest route to more of them, and it is craft rather than courtesy. "Great voice" has never helped anybody. "The line stands alone with nothing explaining it afterwards, and that is why it lands" might.
A summary you can print
Your own answers about the book, arranged in the order an editor reads them: premise, protagonist, what it is about underneath. Nothing in it is generated; it is your brief, made to print and to put in front of somebody else. It comes free, as thanks for filling the form in properly.
Somewhere to push back
Every note is something you can argue with. Mark what helped and what did not, write back on a finding, and ask for the one revision of the letter that comes with each read. Being told what a book is actually trying to do is worth more to me than anything else you could send back.
See it in action
A page from my own draft, with the letter's notes marked on it: red for what should change, yellow for what works and should stay. Tap or hover a mark and the note follows.
See the example on the front page