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

OpenAI released three GPT-5.6 variants—Sol, Terra, and Luna—as a limited preview for select companies in partnership with the U.S. government. Sol, the most powerful, is touted as the most capable model for cybersecurity, competing with Anthropic Mythos Preview on ExploitBench while using one-third the output tokens. OpenAI warns that safeguards may block legitimate requests during the preview.