(If it is, this really feels like it should be a separate general purpose local extension mechanism into which random functions can be added, instead of something tied to this use case... maybe I want to add some locally-executed string parsing function, for example...)
(...but, the entire concept of having some functions be "locally" executed also feels really awkward/limited and will involve a ridiculous amount of work to make, at the end of the day, it only sort of work in some places in the query, so I bet you don't mean what I do when I say "locally", right?)
(But, like... doing it remotely--on the database server as part of the query plan--frankly seems kind of crazy to me, as it is going to be so slow and add a massive CPU load to what should be an I/O workload. Makes for good demos I bet, but otherwise unusable in a database context.)
(Regardless, the premise of seeing this as a feature kind of squicks me... like, it honestly gives me strong apprehensions about using your extension at all, as I can see--very clearly--the mission creep it is going cause as you deal with demands to drag more and more popular embedding models with lots of execution dependencies as part of the extension that has to be loaded into the server, as well as fielding distracting discussions about the performance of the embedding helpers...)
(...this frankly shouldn't be part of the same extension: it should be another extension that happens to return this extensions data type--or even potentially returns some more generic one, like an array of float, making it drop-in compatible with other extensions for vector indexing--and there should then almost certainly be separate such extensions for each major model you want to support.)
