OpenAI releases GPT-5.6 Sol, Terra, and Luna models with improved cost-efficiency
Model release Provisional 72% confidence first seen
OpenAI released three new models: GPT-5.6 Sol (priced at $5/$30 per million tokens), Terra ($2.50/$15), and Luna ($1/$6), positioned as cost-effective alternatives to existing models. Sol demonstrated significant capabilities including proving the 50-year-old Cycle Double Cover Conjecture using 64 subagents and outperforming physician-written responses in healthcare evaluations, though it trails some existing models on certain benchmarks.