OpenAI unveiled GPT-5.6 Sol, Terra, and Luna on June 26, 2026 with limited preview before broader release. Terra has competitive GPT-5.5 performance at 2x lower cost; Luna at lowest cost tier.
Pricing (per 1M tokens): Sol 30 output; Terra 15; Luna 6. Models available via API and Codex to select partners during preview. GPT-5.6 Sol Terminal-Bench 2.1 SOTA. Cerebras deployment July 2026 at 750 tokens/sec.
OpenAI shared models with U.S. government ahead of launch; starting limited preview at administration request while developing cyber EO framework. Plans general availability in coming weeks.