OpenAI Launches Revolutionary GPT-5.6 Model Family: Sol, Terra, and Luna
In a landmark event in the history of AI models, OpenAI has unveiled its highly anticipated GPT-5.6 model family — Sol, Terra, and Luna — to the public on July 9, 2026. This follows a closely guarded preview period that started on June 26 and was confined to approximately 20 government-approved partner organizations. The U.S. Department of Commerce has now sanctioned a wide-ranging global launch.
GPT-5.6 Sol, the flagship model, is specifically designed for complex reasoning, advanced coding, scientific research, and long-horizon agentic workflows. It leads the Terminal-Bench 2.1 leaderboard with a remarkable 91.9% score in its Ultra mode, which accommodates subagents for multi-step tasks. Terra delivers performance on par with GPT-5.5 at half the price, while Luna is the quickest and most cost-effective tier in the family.
The pricing for API access is tiered as follows:
- Sol: $5 per million input tokens and $30 per million output tokens
- Terra: $2.50 per million input tokens and $15 per million output tokens
- Luna: $1 per million input tokens and $6 per million output tokens
In addition, OpenAI is launching Sol on Cerebras hardware at up to 750 tokens per second in July, targeting real-time interactive AI applications. The GPT-5.6 series also brings enhanced prompt caching with explicit cache breakpoints and a minimum cache life of 30 minutes.
The release is accompanied by what OpenAI terms its most robust safety stack to date, addressing cyber, biological, and destructive-action risks — a testament to the model’s unparalleled capabilities.
Source: Neowin — OpenAI to release GPT-5.6 Sol, Terra and Luna on July 9