GPT-6 Sol and GPT-6 Luna are large language models released by OpenAI on September 22, 2026, following GPT-6 Astra (September 3, 2026). OpenAI states that both were trained with methods similar to Astra, which it continues to call its "best model across the board," and prices them well below the corresponding tiers of GPT-5.6 (Source: thedeepview.com).
Infobox
| Field | Value |
|---|---|
| Developer | OpenAI |
| Released | September 22, 2026 |
| Tiers | Sol; Luna |
| Pricing (per 1M tokens, in/out) | Sol $2/$10; Luna $0.10/$0.50 |
| Open weights | No |
Capabilities and benchmarks
OpenAI describes gains in factuality, coding, computer use and alignment. It reports that GPT-6 Sol outperforms earlier OpenAI models and Anthropic's Claude Opus 5 on several benchmarks, including AutomationBench (business workflows across applications), Agents' Last Exam (complex agentic workflows) and DeepSWE v1.1 (software engineering in real codebases); the scores themselves were not given in the coverage retrieved, and the comparisons are developer-reported. Both models carry over Astra's communication style, which OpenAI describes as clearer, with less jargon, slightly shorter answers and fewer "low-value details" (Source: thedeepview.com).
Safety and evaluations
OpenAI attributes improved alignment in both models to Astra's training, stating they show significantly lower rates of circumventing warning messages, coding deception and unauthorized agent interactions than previous Sol and Luna models (Source: thedeepview.com). No system card had been read for either model at the time of writing.
Availability and pricing
GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens, against $4 and $20 for GPT-5.6 Sol; GPT-6 Luna costs $0.10 and $0.50, against $0.20 and $1.20 for GPT-5.6 Luna (Source: thedeepview.com). The GPT-5.6 Sol comparison figure is the price after OpenAI's August 21, 2026 cut; GPT-5.6 Sol launched at $5 and $30 (see GPT-5.6 (Sol, Terra, Luna)). Both models are available in ChatGPT Work and Codex for Plus, Pro, Business and Enterprise users, and Free and Go users can use GPT-6 Luna in the desktop app; neither was yet available in the standard chat interface at launch.
Anthropic released Claude Opus 5.5, priced at $4 and $20, on the same day.
Related models
- GPT-6 Astra — OpenAI's top model, whose training methods Sol and Luna share
- GPT-5.6 (Sol, Terra, Luna) — the preceding generation of the Sol and Luna tiers
- Claude Opus 5.5 — Anthropic release on the same day
Relationships
- depends-on: Astra
- supersedes: GPT-5.6 (Sol, Terra, Luna)
- related: Claude Opus 5.5