Carrie Ulrich is working on some neat investigation mechanics for a CoC-style PbtA hack. I was pleased to see that she didn’t just throw in Read a Sitch and figure it would work out. 😀
I think we have only cracked the surface of what the engine can do with mysteries, but we’re going to need to develop some new tools in order to make them really work. When I eventually return to By the Book, I might make some progress!