OpenAI's new Sol and Luna ship at half price, reliability claims still self-tested
GPT-6 Sol and Luna cut API pricing to half of the 5.6 series; the factuality gain comes from an internal eval, pending third-party verification.
Original event 2026-09-22
This is an archived article. Forecasts, prices and upcoming events refer to its original time period.
OpenAI released GPT-6 Sol and Luna on September 22, pricing the API at half the cost of the 5.6-series equivalents, which the company attributes to improvements in caching and inference.
Sol targets complex tasks like coding; Luna handles high-volume clerical work such as summarizing and extraction. Both are live in ChatGPT Work, Codex and the API, and Luna will also reach Free and Go users.
The reliability claim deserves a discount: the reported halving of mistakes comes from OpenAI's internal evaluation based on user-flagged conversations, not third-party testing. Anthropic shipped Opus 5.5 just 90 minutes earlier, and the pricing race between the two is clearly deliberate.