OpenAI introduced its GPT-5.6 family on June 26, split into three durable tiers instead of one adjustable model: Sol (flagship), Terra (balanced), and Luna (fast and affordable). Pricing is set at $5/$30 per million input/output tokens for Sol, $2.50/$15 for Terra, and $1/$6 for Luna — with Terra landing at roughly half the cost of GPT-5.5.
Sol and Terra set new benchmark records in coding, cybersecurity, and genomics, while Luna performs close to GPT-5.5 levels despite its lower price. The models add a "max" reasoning mode for deeper inference and an "ultra" mode that coordinates multiple subagents on complex tasks.
Rollout is unusually restricted: at the request of the US government, OpenAI limited initial access to around 20 trusted partner organizations, sharing their participation list with officials. The move follows a June 2 executive order requiring federal agencies to benchmark frontier AI models for safety before wide release. OpenAI says general availability is planned "in the coming weeks," with a Cerebras-powered deployment reaching up to 750 tokens per second for select customers arriving in July.