GPT-5.6 Sol is OpenAI's strongest model with enhanced agentic capabilities, new max and ultra reasoning modes, and improved security hardening. Released in restricted preview to government-approved partners only.
OpenAI released its GPT-5.6 model lineup to a limited group of "trusted partners" after the U.S. government requested restrictions on the rollout. The company released three models—Sol ($5/$30 per million tokens), Terra ($2.50/$15), and Luna ($1/$6)—but said the government-mandated preview "shouldn't become the long-term default."
OpenAI announced GPT-5.6, a three-tier model series launching through a limited preview coordinated with the U.S. government. The models—Sol, Terra, and Luna—are priced from $1/$6 to $5/$30 per million input/output tokens and introduce new max and ultra reasoning modes.
OpenAI has begun a limited preview of its GPT-5.6 series, introducing three models: Sol (flagship), Terra (2x cheaper than GPT-5.5 with competitive performance), and Luna (lowest cost option). The models are launching first with trusted partners before general availability in coming weeks, following U.S. government preview requirements.
OpenAI announced three new models—GPT-5.6 Sol, Terra, and Luna—on June 26, 2026, but is limiting initial access to a "small group of trusted partners" following a U.S. government request. The company says it plans to make the models generally available "in the coming weeks."
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.