OpenAI previews GPT-5.6 Sol, Terra and Luna

OpenAI has begun a limited preview of GPT5.6, a new model family that includes Sol, Terra and Luna. The company says Sol is its flagship model, Terra is designed for everyday work, and Luna is the lowestcost option in the lineup. According to OpenAI, the preview is starting with select trusted partners before a broader rollout in the coming weeks. The company says the staged release is tied to coordination with the U.S. government and ongoing work on a cyber safety framework. OpenAI says GPT5.6 Sol improves performance in coding, biology and cybersecurity tasks, while also adding a stronger safety stack. The company also said the models include new reasoning modes, updated pricing, and planned availability through ChatGPT, Codex and the API.