Terra

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 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.