GPT-5.6 Sol outperforms physicians on medical accuracy, communication & decisions

OpenAI said Friday it is limiting the release of its newest GPT-5.6 model lineup to a small group of trusted partners at the request of the U.S. government. The company announced the restriction in a blog post Friday. The lineup includes Sol, described as the flagship and most powerful model; Terra, a balanced model for everyday use; and Luna, a faster, lower-cost option. OpenAI said the preview is limited to partners whose participation has been shared with the government. The administration's request comes as it puts new pressure on AI companies to restrict their most advanced systems. OpenAI said it does not believe the government access process should become the long-term default, adding that it keeps the best tools from users, developers, enterprises, cyber defenders and global partners who need them. The company called the preview a short-term step toward broader availability in the coming weeks as it works with the administration to develop a new executive order framework on cybersecurity and a repeatable process for future model releases. OpenAI said GPT-5.6 Sol features improved agentic capabilities in coding, biology and cybersecurity and includes a max reasoning effort mode and an ultra mode using coordinated subagents. Pricing for Sol is set at $5 per million input tokens and $30 per million output tokens.