openai and langchain natively support all of that or expose the hooks to do it

all that stuff is what we needed to do to support multiple providers vs hard-coding a single one. none of it is specific to our codebase. if we were going to take on a third-party dependency, we'd need it to be serious about this kind of thing, else we have an external dependency to work around on our critical path

Edit: As an example, if the switching layer doesn't implement model negotiation and doesn't expose key model details (which vary by model provider service, and often require REST calls to introspect), we can't add model negotiation / retries / etc on top, and would have to edit the innards to enable that, which opens up all sorts of questions