Smart routing

The default policy

On each request the gateway collects every candidate provider for the model, then filters and ranks them:

1. Availability filter — skip providers that are cooling down, at capacity or failing repeatedly.
2. Capability filter — skip providers that can't do what this request needs (an image attachment on a text-only provider, say).
3. Ranking — order by the provider priority the platform configured for the model, then nudge by recent performance: providers doing worse move down.
4. Call the top candidate, and on failure continue per the failover rules.

Keeping a conversation on one provider

For some models, one conversation stays on the same provider for a while to avoid bouncing between them. If that provider degrades, the gateway moves away at once — consistency never wins over availability.

What you need to do

Nothing. Provider choice, ranking and switching are maintained by the platform; requests don't need to — and can't — name a provider. You only pick the model.