Design one provider-neutral gateway

Cursor's current job description says every agent session, Tab completion and chat message flows through the Model Routing and Inference team's stack. One example project is a single abstraction over every provider's API so onboarding a model becomes a configuration change.

Providers differ in authentication, request fields, response fields, streaming events and error meanings. The gateway translates those differences so callers can use one model interface.

Use a small adapter for each provider's wire format. Keep shared behavior such as timeouts, retry budgets, tracing, token accounting and idempotency in the gateway core. Make the shared request capability-aware. A caller should state whether it needs tools, images, structured output or a particular context size. Routing can then reject an incompatible model before sending work. Run the same contract fixtures against every adapter and verify request mapping, stream events, error categories and usage records.