Previewing GPT-5.6 Sol: A Next-Generation Model
OpenAI, Friday, June 26th, 2026
OpenAI begins a limited preview of GPT-5.6 Sol, Terra, and Luna with new reasoning modes.
OpenAI began a limited preview of its GPT-5.6 series: Sol, the flagship; Terra, a balanced everyday model; and Luna, a fast, affordable model.
GPT-5.6 Sol is OpenAI's strongest model yet, with improved agentic capabilities in coding, biology, and cybersecurity, plus a new max reasoning effort and an ultra mode that uses subagents for complex work. Sol launches with OpenAI's most robust safety stack to date.
The preview is restricted to around 20 government-approved partner companies, with broader and general availability planned in the coming weeks.