GPT-5.6 Sol, Terra & Luna: The Complete Developer Guide to OpenAI's Three-Tier Frontier
Sol at 91.9% TerminalBench 2.1, Terra at 2× lower cost, Luna for volume — and a U.S. government-gated preview that limits Sol to ~20 partners. Full breakdown of benchmarks, pricing ($1/$6 to $15/$60 per million tokens), Ultra/Max reasoning modes, tier routing strategy, and a migration playbook from GPT-5.5, o3, and GPT-4.5.
Read Full Article →