GPT-5.6 was released publicly on July 9, 2026, as a family of models that comes in three distinct variants, ranked from least to most capable: Luna, Terra, and Sol. The flagship model, Sol, is considered its workhorse, suited for complex agentic capabilities in coding, biology, and cybersecurity. GPT-5.6 Sol, Terra, and Luna are generally available across ChatGPT, Codex, and the OpenAI API. Alongside the models, OpenAI also launched ChatGPT Work, a new mode for complex tasks. The defining shift of July 2026, across the whole model landscape, may be the move from “best model wins” to “best fit wins.”