The caller specifies the model in the request body (just like a normal OpenAI API call). OCP maps it to the corresponding Claude CLI flag:

- claude-sonnet-4-6 → claude -p --model sonnet - claude-opus-4-6 → claude -p --model opus

If you don't specify, it defaults to Sonnet. There's no automatic model selection yet — that's coming in v4 with agent-aware routing (different agents get different models based on their role).