GPT-6 Sol and Luna are OpenAI models extending the GPT-6 generation. Sol targets complex tasks such as coding; Luna targets high-volume work like summarizing documents, extracting information and answering quick questions. Priced at half the cost of the previous 5.6 series. OpenAI says Sol makes about half as many mistakes as its predecessor. Available in ChatGPT Work, Codex and the API; Luna also reaches Free and Go users.