OpenAI says GPT-6.1 Terra cut GPT-5.6 Terra's error rate on OpenAI's internal error-inducing prompts from 53.6% to 16.7% at low reasoning effort

OpenAI's fast, efficient GPT-6 series model for visual reasoning and computer use, released on October 26, 2026 at $1 per million input tokens and $5 per million output tokens, half the price of GPT-5.6 Terra and GPT-6.1 Sol.