Earlier this month, OpenAI launched GPT-6 Astra, which it announced as its most powerful and capable model yet, and the “world’s best model” for a variety of activities, including computer work and coding. Now, the lab is expanding the GPT-6 generation with updated versions of the smaller Sol and Luna models. “GPT-6 Astra introduced a new generation of intelligence; these models expand its benefits by making that intelligence more efficient and accessible,” the company writes. The first Sun and Moon series models were introduced earlier this year and represent different levels in the OpenAI model hierarchy. Sol is designed for complex tasks like coding, while OpenAI says Luna is best suited for administrative work: “high-volume tasks with a clear goal, such as summarizing documents, extracting information, or answering quick questions.” OpenAI is also emphasizing big improvements in efficiency and affordability, in particular through a substantial drop in the price of API access. The Series 6 models will be available at half the cost of the Sun and Moon Series 5.6, a price drop that OpenAI attributes to improvements in caching and inference. OpenAI also claims that its newer models are better at producing objectively accurate responses and notes that they have a lower error rate when it comes to coding. “In our internal feasibility evaluation, which is based on anonymous real-world conversations in which users pointed out errors in our models, GPT-6 Sol makes about half as many errors as its predecessor, achieving Astra-level reliability at a much lower cost,” the announcement reads. As is typical with new OpenAI model releases, the company claims that its latest offerings dwarf those of its main competitor, Anthropic. The company repeatedly claims that the GPT-6 Sol and Luna handle tasks substantially better than Anthropic’s best models, such as the Fable and Opus. Notably, Anthropic released a new version of Opus 5.5 just 90 minutes before the launch of OpenAI, reflecting the intense competition between the two companies. The new versions of Sol y Luna are now available in ChatGPT Work and Codex for most paid accounts, and in the ChatGPT API, while Luna will be available in the desktop app and for Free and Go users. OpenAI expects to deploy the models to ChatGPT (the app and the website) gradually throughout the day. When you buy through links in our articles, we may earn a small commission. This does not affect our editorial independence.
