OpenAI Previews GPT-5.6 Sol With Restricted Access and Stronger Cyber Safeguards

OpenAI has released a limited preview of three GPT-5.6 versions, known as Sol, Terra, and Luna, to a small group of companies as part of its work with the US government. Sol is the most powerful model, while Terra balances efficiency and power, and Luna is optimized for speed and affordability. The Sol model is the flagship version and features stronger cyber safeguards. The release is part of an ongoing collaboration with the US government. OpenAI has restricted access to these models for now. The company is highlighting the enhanced security features of the Sol model.