I do assume that Dumbles operates on extensive access to prophecy as well as his own plotting, so it's possible that he gave Harry the cloak because he know this is required even if he doesn't know why.
One possibility I've been kicking around is that Harry will destroy this world with Quirrell in it (and the stars themselves) to take out all of his horcruxes, but will transport himself and much of the rest of the world into a mirror realm first. The mirror and it's contents will survive, and Quirrell will be left out of the mirror world escape because the cloak is covering him. I can't really make the details work in my head, but it's a scenario where the cloak becomes a liability to Quirrell.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 110.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: