OpenAI launches GPT-6 Sol and Luna with 50% API price cuts

OpenAI has released two new artificial intelligence models, GPT-6 Sol and GPT-6 Luna, priced at 50% less than their GPT-5.6 predecessors, according to a company statement.

GPT-6 Sol API pricing moves from $4 to $2 per million input tokens and from $20 to $10 per million output tokens. GPT-6 Luna drops from $0.20 to $0.10 per million input tokens and from $1.20 to $0.50 per million output tokens. OpenAI attributed the reductions to improvements in caching and inference infrastructure.

The two models sit below GPT-6 Astra, which OpenAI introduced earlier this month and describes as its most capable model. Sol and Luna are positioned as faster, lower-cost alternatives trained using similar methods as Astra.

On AutomationBench, a business workflow evaluation covering 47 tools across functions including sales, finance, and HR, GPT-6 Sol at extended-high effort scored 33.2% at $0.27 per task, compared with Claude Opus 5 at maximum effort scoring 26.9% at roughly 11 times the cost per task. On the coding benchmark DeepSWE v1.1, GPT-6 Sol at maximum effort scored 68.8%, compared with Claude Fable 5's highest score of 69.9% at approximately 80% higher cost per task.

On the computer-use benchmark OSWorld 2.0, GPT-6 Sol at extended-high effort scored 60.5%, compared with Claude Opus 5 at medium effort scoring 60.3%, at approximately 80% lower cost per task.

OpenAI also reported alignment improvements, with GPT-6 Sol showing a coding deception rate of 2.8% and GPT-6 Luna at 1.3%, compared with 10.4% and 9.5% respectively for their GPT-5.6 counterparts in internal evaluations designed to elicit dishonest behavior.

On the caching side, OpenAI said GitHub reported a reduction of more than 50% in the share of prompt tokens requiring fresh processing across billions of requests over recent months, with improvements to cache hit rates and a 90% discount on cached input-token reads.

GPT-6 Sol and Luna are available in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise, and Edu subscribers. Free and Go users can access GPT-6 Luna via the desktop app. The models are available in the OpenAI API as gpt-6-sol and gpt-6-luna.

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