Earlier this month, OpenAI introduced GPT-6 Astra, the most intelligent and aligned model in the world. While the most demanding projects still call for Astra's full depth, work happens at different scales, rhythms, and budgets. That's why OpenAI is expanding the GPT-6 universe with GPT-6 Sol and GPT-6 Luna.

GPT-6 Astra introduced a new generation of intelligence—these models help distribute the benefits of that intelligence by advancing the frontier on cost efficiency. Trained with similar methods as Astra, Sol and Luna bring advances in professional work, factuality, coding, computer use, and alignment to faster, more affordable models. Improvements in caching and inference let OpenAI serve these models at lower cost, passing savings to users by reducing API prices for Sol and Luna by 50% compared with GPT-5.6 promotional pricing.

GPT-6 Sol can take on difficult work tasks with higher usage limits and lower cost. On Automation Bench, GPT-6 Sol at xhigh effort outperforms Claude Opus 5 at max effort at just 9% of Opus 5's cost per task. At high effort, GPT-6 Luna improves on its predecessor by 5.4 percentage points at 58% lower cost per task. On Agents' Last Exam, GPT-6 Sol at max effort scores 56.4%, above Claude Opus 5's highest score at 60% lower cost per task.

On internal factuality evaluation, GPT-6 Sol makes about half as many mistakes as its predecessor, approaching Astra-level reliability at much lower cost. GPT-6 Luna matches GPT-5.6 Sol at about a hundredth its cost. GPT-6 Astra continues to be OpenAI's best model across the board.