OpenAI launches GPT-5.6 family: Sol, Terra, and Luna

Sol is the flagship model with a step-function improvement over GPT-5.5, priced at $5/$30. Terra delivers GPT-5.5-level performance at $2.5/$15, and Luna is the most cost-efficient at $1/$6. The models are rolling out across ChatGPT, Codex, and the API starting today.