The idea seems so similar to the classical AMB ambiguous operator introduced by John McCarthy [0]. The implementation seems similar to what I've done a while ago, too, just in Lisp and using Lisp primitives rather than function decorators.
Yep, Screamer is the "enterprise" quality of nondeterministic programming - think efficient and optimized Prolog-esque primitives, but in Lisp.
My implementation of AMB is purposefully small (70 LOC, not counting docstrings and tests and system definition), so that it can fit on a page of paper and be easily understood.
The cool stuff here is the simplicity of the interface to it and its integration thanks to high order functional constructs (decorator).