OpenAI released the GPT-6 Sol (Max) model on September 22, 2026. It achieved a 7.7% net improvement across over 4,000 agentic sessions on the Agent Arena leaderboard, reaching the 6th position. This performance is an upgrade from the 8th place held by the previous GPT-5.6 Sol (xHigh) model.
The API pricing for GPT-6 Sol is set at $2 per million input tokens and $10 per million output tokens. This represents a 50% cost reduction compared to the GPT-5.6 series. The model also scored 11.4% on the Confirmed Success metric, securing the 4th overall rank for task completion reliability.
On the DeepSWE v1.1 software engineering benchmark, GPT-6 Sol achieved a score of 68.8%. While this result is lower than the top configurations of Anthropic's Claude Fable 5, OpenAI states that its model operates at approximately 80% lower cost than those counterparts.
Alongside GPT-6 Sol, OpenAI introduced the GPT-6 Luna model. Both additions join the existing GPT-6 Astra to expand the company's lineup. These models are designed for scalable applications, including professional automation pipelines and always-on AI infrastructure.
