OpenAI Launches Cheaper GPT-6 Sol and Luna Models Minutes After Anthropic's Claude Opus 5.5

OpenAI released two new AI models, GPT-6 Sol and GPT-6 Luna, on Tuesday, Sept. 22, 2026, minutes after Anthropic launched its flagship Claude Opus 5.5. The models are positioned below GPT-6 Astra, OpenAI's top-tier release from September 3. OpenAI cut API pricing by 50% versus GPT-5.6 promotional rates. Sol costs $2 per million input tokens and $10 per million output tokens, down from $4 and $20. Luna drops to $0.10 and $0.50, down from $0.20 and $1.20. On Zapier's AutomationBench, Sol scored a 33.2% pass rate at $0.27 per task, versus Claude Opus 5's 26.9% at more than 11 times the cost. On Agents' Last Exam, Sol scored 56.4%. Both models are live in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise, and Edu subscribers; Luna also reaches free and Go users. Neither is in the standard ChatGPT app yet.