Really intriguing set of techniques to improve accuracy by generating multiple solutions. Even with the work to predict the most likely solutions, it's not clear to me based on the description how this could all be done efficiently. Would definitely be really impressive if it pans out on real-world use cases. Will look to kick the tires on this if I can get some time.
Seems like the key insight is to train a small model that acts as a heuristic for embeddings that resemble quality code. I imagine a lot depends on how well this model is trained. And you could probably create specialized versions for different languages and domains.
Another interesting approach could be to use this set up with a language like Clojure or Common Lisp which facilitates interactive development. If you could hook up the agent directly to a REPL in a running program, then it could run tests with a lot less overhead.