Yes, that matches my understanding too — the inversion itself is inherently ambiguous, which is probably why there isn’t a clean general solution.
My admittedly naive approach is to follow the engineering path and see which building blocks are actually required to move towards something workable, in KMP context. Your idea of using vector arithmetic to constrain or steer the expected reconstruction also sounds like an interesting direction to explore.
Even at this early stage, the exercise has already been useful for SKaiNET: it pushed me to add support for more advanced embedding models such as T5, and it also exposed a gap in our KV-cache implementation that we’ll address soon.
So regardless of whether embedding inversion itself turns out to be practical, exploring the problem is already helping improve the framework. I’m curious to see how far the idea can be pushed.