kapynAI / Models

The new GPT-5.6 family: Luna, Terra, Sol

OpenAI unveils GPT-5.6, a new flagship model family released in three sizes: Luna, Terra, and Sol. These models offer competitive pricing and claim significant advancements in long-running agentic performance, outperforming competitors like Claude Fable 5 on benchmarks like Agents' Last Exam. OpenAI also addresses potential benchmark issues, particularly with SWE-Bench Pro.

Simon Willison·Jul 9, 2026

Opening Kapyn…