GPT-6 Sol and GPT-6 Luna

2026-09-22 · Publisher : OpenAI · Domain : Artificial Intelligence

OpenAI expands the GPT-6 family with Sol and Luna, trained with the same methods as Astra but cheaper: API prices drop by 50% compared with the promotional pricing of GPT-5.6.

What changes

  • GPT-6 Sol targets complex code and agentic workflows; GPT-6 Luna targets focused high-volume tasks.
  • Astra's communication style (clearer, less jargon, shorter answers) is carried over.
  • Improved caching for GPT-6: better hit rates by default, 90% discount on cached reads.
  • Improved alignment compared with GPT-5.6, with fewer misleading claims about code work.
  • September 25 fix for an image encoding bug that degraded vision.

### Specifications - Context: 1,050,000 tokens (272,000 standard), maximum output 128,000 tokens, text and image input, text output. - Effort: none, low, medium (default), high, xhigh, max. Function calling with Chat Completions only at effort none. - Availability: ChatGPT Work and Codex (Plus and above, Luna also for Free and Go in the desktop app), API; not yet in Chat. - Identifiers: gpt-6-sol, gpt-6-luna. ### Pricing | Model | Input | Cached input | Output | | --- | --- | --- | --- | | gpt-6-sol | $2.00 | $0.20 | $10.00 | | gpt-6-luna | $0.10 | $0.01 | $0.50 | Prices per million tokens (USD). Beyond 272,000 tokens: 2x input, 1.5x output. Cache write: $2.50 and $0.125. Batch and Flex at half price, Fast mode at 2x. ### Benchmarks | Evaluation | Result | | --- | --- | | AutomationBench, Sol (xhigh) | 33.2% at $0.27 per task | | Agents' Last Exam, Sol (max) | 56.4% | | DeepSWE v1.1, Sol (max) | 68.8% | | DeepSWE v1.1, Luna (max) | 66.6% | | OSWorld 2.0 offline, Sol (xhigh) | 60.5% | Scores published by the vendor. Cost comparisons with competing models in the post. ### Key takeaways One more step toward Astra-level intelligence at reduced cost: Sol at $2 and $10 and Luna at $0.10 and $0.50 change the calculus for high-volume agents. The promotional 5.6 pricing lasted only a few weeks.

Links

Tags : LLM, OpenAI, GPT-6, Sol, Luna, Agent