Sol

OpenAI cut GPT-5.6 Luna pricing by 80% to $0.20/$1.20 per million tokens and GPT-5.6 Terra by 20% to $2/$12, while adding a 2.5x-faster mode for Sol at double the price. The company says GPT-5.6 itself rewrote production inference kernels and tuned its own speculative decoding pipeline to enable the cuts.

OpenAI has released its latest advanced model, Sol, for public access after government review, but researchers and industry figures say the approval process remains opaque. The model is considered comparable to Anthropic's Fable, which was briefly banned from public access, yet details of how either model received clearance are unclear.

OpenAI released GPT-5.6 on July 9, 2026, introducing a new three-tier model naming system: Sol (flagship), Terra (balanced for everyday work), and Luna (fast and affordable). The company integrated Codex development workflows directly into the main ChatGPT app and launched ChatGPT Work for enterprise users.

OpenAI released GPT-5.6, a three-model suite consisting of Sol (flagship), Terra (medium-tier), and Luna (fast/affordable). Sol is priced at $5 input/$30 output per million tokens—nearly half the cost of Anthropic's Claude Fable 5. The release follows Trump administration involvement in approval process.