OpenAI previews GPT-5.6 family with three models: Sol, Terra, and Luna
OpenAI has released GPT-5.6 Sol, its most powerful model to date, alongside two cheaper variants, Terra and Luna. Currently, access is restricted to approximately 20 vetted partners at the request of the U.S. government. Sol features a 'max reasoning effort' and an 'ultra' mode that spawns parallel subagents to handle complex tasks.