OpenAI Launches GPT-6 Sol and Luna at Half the Price — 90 Minutes After Anthropic's Answer
OpenAI has released updated GPT-6 Sol and Luna models at 50% of the previous API cost while claiming a 50% reduction in factuality errors.
OpenAI expanded its GPT-6 generation today with updated versions of the Sol and Luna models, positioning them as efficient extensions of the previously launched GPT-6 Astra. The primary update is economic: API access for the new 6 series models costs half that of the preceding 5.6 series. OpenAI attributes this price reduction to specific improvements in caching and inference mechanisms rather than a change in the underlying business model. These models are now accessible via the ChatGPT API, with Sol and Luna available in ChatGPT Work and Codex for most paid accounts. Luna specifically will be rolled out to the desktop app and made available to Free and Go users, with a gradual deployment to the broader ChatGPT application and website expected throughout the day.
Technically, the company claims significant gains in reliability alongside the cost reductions. Internal evaluations based on de-identified real-world conversations indicate that GPT-6 Sol produces approximately half as many factual mistakes as its predecessor. OpenAI states this performance reaches Astra-level reliability but at a significantly lower operational cost. The models retain their distinct functional tiers established earlier this year: Sol remains optimized for complex tasks such as coding, where the company notes a lower error rate, while Luna targets high-volume clerical work including document summarization, information extraction, and quick question answering.
The release timing underscores the competitive intensity between OpenAI and Anthropic. OpenAI's announcement arrived just 90 minutes after Anthropic released a new version of Opus 5.5. In its materials, OpenAI explicitly claims that the new GPT-6 Sol and Luna models handle tasks substantially better than Anthropic's top-tier offerings, specifically naming Fable and Opus as benchmarks. This rapid succession of releases from both labs suggests an accelerated cadence for model iteration and pricing adjustments in the current market environment.