OpenAI unveils GPT-5.6 Sol, Terra and Luna models — but only accessible to limited preview partners for now, per US Gov

OpenAI is announcing a limited preview of its next-generation GPT-5.6 model series today, introducing three distinct, capability-tiered models—Sol, Terra, and Luna—designed to re-engineer developer and enterprise workflows. OpenAI says the GPT-5.6 series improves upon its predecessors by offering superior token efficiency and enhanced reasoning, completing more complex tasks with significantly fewer resources, and is suited for software engineering, scientific research, and cybersecurity. The initial rollout is available through the API and Codex to a narrow set of approximately 20 total organizations after OpenAI shared the models and release plans with the U.S. government, with a general release planned for "the coming weeks."The staggered release follows an executive order issued by Pr