GPT-5.2 Pro is our previous pro model for complex professional work. We recommend using GPT-5.5 Pro for the latest pro model. GPT-5.2 Pro is available in the Responses API only to enable support for multi-turn model interactions before responding to API requests, and other advanced API features in the future. Since GPT-5.2 Pro is designed to tackle tough problems, some requests may take several minutes to finish. To avoid timeouts, try using background mode. GPT-5.2 Pro supports reasoning.effort: medium, high, xhigh.