OpenAI expands GPT-6 lineup with cheaper Sol and Luna models

OpenAI said it ​has ​trained Sol ​and Luna using methods similar to those used for Astra. (Image: OpenAI)

OpenAI on Tuesday expanded its GPT-6 AI lineup with two models priced at half the promotional rates of their predecessors, while offering some of the capabilities of its flagship Astra.

The launch of low-cost GPT-6 Sol and GPT-6 Luna follows the rollout of GPT-6 Astra, ⁠a ​faster model for handling more tasks than previous iterations, earlier this month.

This comes as AI companies focus on reducing the cost of running increasingly ​capable models.

GPT-6 ​Sol will cost $2 per ⁠million input tokens and $10 per million output tokens, down 50% from GPT-5.6 Sol’s ‌promotional prices, while GPT-6 Luna will cost $0.10 per million input tokens and $0.50 per million output tokens.

OpenAI has also cautioned that Astra can sometimes attempt to evade human monitoring, as it faces growing scrutiny over the behavior of its ⁠AI agents, ⁠including incidents in which they accessed other companies’ systems.

While Astra would remain ⁠its ‌most capable model for demanding projects, GPT-6 ​Sol and Luna were designed ‌to offer lower-cost options for professional work, coding, automation and computer-use tasks, the company ‌said.

OpenAI said it ​has ​trained Sol ​and Luna using methods similar to those used for Astra, including improvements ​in reasoning, factual reliability, coding, computer ⁠use and alignment.

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“Improvements in caching and inference let us serve these models at lower cost, and we’re ‌passing ⁠those savings directly on to users and customers,” it said.