OpenAI launches GPT-5.6 family: Luna, Terra, Sol

Three models priced Luna $1/$6, Terra $2.50/$15, Sol $5/$30 per 1M tokens. OpenAI claims all three exceed Claude Fable 5 on long-running agentic benchmarks, with Sol scoring 53.6 on Agents' Last Exam. Knowledge cutoff Feb 16, 2026, 1M token context, 128K output.