OpenAI Expands GPT-6 Lineup With Cheaper Sol and Luna Models

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.

"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.