OpenAI officially launches GPT-5.6 trio: Sol, Terra, Luna

OpenAI released the GPT-5.6 series on July 9, including flagship Sol, balanced Terra, and economy Luna. Terra matches GPT-5.5 in multiple benchmarks with approximately 50% lower inference cost; Sol leads all public models at 91.9% on Terminal-Bench 2.1. Initial access is limited to approximately 20 US government-approved organizations via API and Codex, with public GA expected in late July.