OpenAI launches GPT-6 Sol and Luna at half the API price of their 5.6 predecessors

OpenAI has added updated Sol and Luna models to its GPT-6 generation. Earlier this month the company released GPT-6 Astra, its most capable model. OpenAI positions Sol for complex tasks such as coding. It says Luna suits high-volume tasks with a clear goal, such as summarizing documents, extracting information, or answering quick questions. API prices for the new models are half those of the 5.6 series of Sol and Luna. OpenAI attributes the cut to improvements in caching and inference. The company also says the new models produce more factually accurate answers and make fewer coding errors. It bases that claim on an internal factuality evaluation built from de-identified real-world conversations in which users flagged model mistakes. These are OpenAI's own measurements, and the supplied reporting includes no independent test results. The launch came on the same day Anthropic released Claude Opus 5.5 with its own price reduction. For developers building products on these models, both of the leading US labs cut their prices on the same day.