OpenAI's GPT-5.5 model is now available as a managed LLM in the Voice Agent API. GPT-5.5 is an Advanced tier model. Set the model in your agent configuration: { "agent": { "think": { "provider": { "type": "open_ai", "model": "gpt-5.5", "temperature": 0.7 } } } } For the full list of supported models and pricing tiers, see the Voice Agent LLM Models...