OpenAI began rolling out GPT-6 Astra on September 3, 2026 to ChatGPT Plus, Pro, Business, and Enterprise plus the API. It sits atop OpenAI's Astra > Sol > Terra > Luna naming scale. Independent Artificial Analysis scores put it behind Claude Fable 5.1 on the Intelligence Index while OpenAI-reported tables and demos emphasize computer use (OSWorld), math (FrontierMath), ExploitBench, and token efficiency. Headline API pricing matches Fable 5.1 at $10 input / $50 output per million tokens.