WHY THIS MATTERS
OpenAI announced a limited preview of the GPT-5.6 family (Sol, Terra and Luna) on June 26, currently available to only about 20 companies approved by the US government.In this article
Three models, one launch
On June 26, 2026, OpenAI announced a preview of the GPT-5.6 series: Sol (flagship model), Terra (a balance of cost and performance, roughly half the price of GPT-5.5 with competitive results) and Luna (the cheapest and fastest of the family).
Stronger safety stack
According to OpenAI, GPT-5.6 Sol ships with the company's most robust safety stack to date, with added protections for higher-risk activity and sensitive cybersecurity requests.
Government-controlled access
The preview is currently available to about 20 companies, all approved by the US government — OpenAI says it is working with the administration to establish a repeatable model-assessment process ahead of future releases.