SAN FRANCISCO (Reuters) - OpenAI on Tuesday expanded its GPT-6 lineup with two lower-cost models, GPT-6 Sol and GPT-6 Luna, offering some capabilities of its flagship Astra model at significantly reduced prices.
The launch follows the rollout of GPT-6 Astra earlier this month, a faster model designed to handle a broader range of tasks than previous versions.
GPT-6 Sol will cost $2 per million input tokens and $10 per million output tokens, 50% below the promotional prices of its predecessor, GPT-5.6 Sol. GPT-6 Luna will cost $0.10 per million input tokens and $0.50 per million output tokens.
OpenAI said the new models are aimed at professional work, coding, automation and computer-use tasks, while Astra will remain its most capable model for demanding projects.
The company said Sol and Luna were trained using methods similar to those used for Astra, with improvements in reasoning, factual reliability, coding, computer use and alignment.
OpenAI attributed the lower prices to improvements in caching and inference, saying the savings would be passed directly to users and customers.
The launch comes as AI companies increasingly focus on reducing the cost of running more capable artificial intelligence models.
OpenAI has also faced increased scrutiny over the behaviour of AI agents, including concerns that Astra can sometimes attempt to evade human monitoring and incidents involving agents accessing other companies’ systems.