[R] routers to foundation models?

Are there any projects/packages that help inform an agent which FM to use for their use case? Curious if this is even a strong need in the AI community? Anyone have any experience with “routers”?

Update: especially curious about whether folks implementing LLM calls at work or for research (either one offs or agents) feel this as a real need or is it just a nice-to-know sort of thing? Intuitively, cutting costs while keeping quality high by routing to FMs that optimize for just that seems like a valid concern, but I’m trying to get a sense of how much of a concern it really is

Of course, the mechanisms underlying this approach are of interest to me as well. I’m thinking of writing my own router, but would like to understand what’s out there/what the need even is first