OpenAI launches GPT-6 Sol and Luna models

OpenAI announced the launch of GPT-6 Sol and Luna, expanding its newest model generation following the rollout of GPT-6 Astra. The updated offerings represent smaller, more accessible tiers within the company's lineup, with Sol tailored for complex tasks such as coding and Luna built for high-volume clerical work like summarizing text and answering direct questions.

The company cut API access pricing for the new models to half the cost of the prior 5.6 series of Sol and Luna. OpenAI attributed this reduction to improvements in caching and inference efficiency.

OpenAI reported that GPT-6 Sol makes about half as many mistakes as its predecessor on internal factuality benchmarks based on de-identified user conversations, achieving lower error rates in coding tasks. OpenAI also stated that the new models outperform competitor models such as Anthropic's Fable and Opus. Anthropic released an updated Opus 5.5 model 90 minutes before OpenAI's announcement.

Both models are available in the ChatGPT API as well as ChatGPT Work and Codex for most paid accounts. Luna is also rolling out to the desktop application and to Free and Go users, with broader availability across the ChatGPT web and mobile apps expanding gradually.