OpenAI Unveils GPT-5.6 Models (Sol, Terra, Luna); Limited Access Initially, Broader Rollout Expected

According to OpenAI, the company unveiled GPT-5.6 family on June 26, comprising three models—Sol (flagship), Terra (balanced performance), and Luna (cost-efficient)—with initial access limited to government-approved partners only.

Sol delivers significant improvements over GPT-5.5 in advanced reasoning and agentic workflows. Terra offers performance competitive to GPT-5.5 at half the cost, while Luna is designed as the most cost-efficient option for high-volume tasks. OpenAI expects broader access to GPT-5.6 in the coming weeks, pending completion of the government-supervised preview period.