Provider selection for proprietary models
Even for Claude and Gemini models, there are a few different providers available and OpenRouter allows to choose between them. This is useful, because for example Google Vertex tends to be less censored than AI Studio or Anthropic (or at the very least it allows users to judge if a specific provider works better for their needs). They also have different data retention policies which one could compare if it was transparent who the requests are routed to. I don't know why the option to set provider preferences is exclusive to open source models. Additionally, the reasoning for not showing the provider used for each request on auto routing does not seem to apply here, because the prices billed for these models are apparently identical with all providers (on the consumer's end, which is what matters regarding the possible disclosure of discounts). So I'd like to be able to specify the provider for Gemini and Claude models and for auto routing to report which provider served these models for each request.