> Echo does not disclose its per-request routing decision because that policy is the product

My honest advice: that's going to pull away a decent amount of potential customers, even though I think your idea/concept is fantastic.

For example, if we were to consider it for Canva, observerability and full transparency is critical requirement; we can't accept not knowing which model serves a request. Both for legal/contract reasons, co-ordinated capacity planning with API providers, or even just evaluating our prompts and harnesses; and debugging/tracing results that went wrong. So that renders it out of consideration; and also suggests some kind of adversarial relationship where customers aren't trusted with critical information.

I definitely understand you need to keep business value, but I don't think hiding which model a request is routed to, is the right one, or at least if you want to expand to bigger potential customers / more advanced LLM deployments.