OpenAI has expanded its GPT-6 family with two new models, GPT-6 Sol and GPT-6 Luna, which the company said bring frontier intelligence to faster, more affordable tiers.
The models were trained with similar methods to GPT-6 Astra, which OpenAI introduced earlier this month and described as "the most intelligent and aligned model in the world." Sol and Luna carry advances behind Astra's performance in professional work, factuality, coding, computer use and alignment, the company said.
OpenAI said it is cutting API prices for both models by 50% compared with their GPT-5.6 promotional pricing, citing improvements in caching and inference. Sol's input price falls from $4 to $2 per million tokens and its output price from $20 to $10, while Luna's input price drops from $0.20 to $0.10 and its output price from $1.20 to $0.50.
On AutomationBench, which tests business workflows across 47 tools, OpenAI said GPT-6 Sol at xhigh effort outperforms Claude Opus 5 at max effort at just 9% of Opus 5's cost per task. On Agents' Last Exam, Sol at max effort scores 56.4%, above Claude Opus 5's highest score at 60% lower cost per task.
On the internal factuality evaluation, based on de-identified real-world conversations where users flagged mistakes, OpenAI said Sol makes about half as many mistakes as its predecessor, approaching Astra-level reliability at much lower cost. Luna at higher effort levels matches GPT-5.6 Sol at about a hundredth its cost.
For coding, OpenAI said Sol improves substantially over GPT-5.6 Sol on FrontierCode and matches Claude Fable 5.1 xhigh at much lower cost. On DeepSWE v1.1, Sol at max effort scores 68.8%, within 1.1 percentage points of Claude Fable 5's highest score of 69.9% at approximately 80% lower cost per task.
On OSWorld 2.0 offline, Sol at xhigh effort scores 60.5% versus Claude Opus 5's 60.3% at medium effort, at roughly 80% lower cost per task. OpenAI also said it brought Astra's improved communication style to both models, expecting more clarity and fewer low-value details.
OpenAI said improved prompt caching delivers higher cache hit rates by default, with discounts of 90% on cached input-token reads, and that GitHub reports the changes reduced the share of prompt tokens requiring fresh processing by more than 50% across billions of requests.
GPT-6 Sol and GPT-6 Luna are available in ChatGPT Work and Codex starting today for all Plus, Pro, Business, Enterprise and Edu users, and in the OpenAI API as gpt-6-sol and gpt-6-luna. Free and Go users can access Luna in the desktop app. OpenAI said it plans to roll out the models in ChatGPT gradually throughout the day.
Full Article: Introducing GPT-6 Sol and Luna