GPT-5.6 (Sol · Luna · Terra)
GPT-5.6 is OpenAI's frontier model family with three variants: Sol, Luna and Terra. In August 2026 OpenAI shipped rapid updates — Sol improved factuality by 68% in high-stakes domains, Luna gained extended thinking for Free and Go users, and Luna prices were cut by 80% (Terra by 20%) at the end of July 2026.
Key facts
| Developer | OpenAI |
| Category | large language model family |
| Notable for | Sol +68% factuality; Luna prices cut 80% in July 2026. |
| Available via | OpenAI |
| Tracked announcements | 5 |
Announcement timeline
GPT-5.6 Sol updated version now available in ChatGPT
OpenAI has released an updated version of GPT-5.6 Sol for Plus and Pro users in ChatGPT, available today with a new slider feature for everyday chats.
GPT-5.6 Luna adds extended thinking for Free and Go users
OpenAI has released GPT-5.6 Luna with improved intelligence and extended the "Think" button feature for deeper reasoning to Free and Go tier users, not just paid subscribers.
GPT-5.6 Sol improves factuality by 68% in high-stakes domains
OpenAI released GPT-5.6 Sol, which now powers all chats for paid users. The model shows significant improvements in factuality across finance, medicine, and law, producing 68% fewer responses with factual errors compared to GPT-5.5 Instant.
GPT-5.6 Sol and Luna expand across ChatGPT tiers
OpenAI is rolling out GPT-5.6 Sol to power both instant and deep reasoning for Plus & Pro users, while free and Go users gain unlimited text chats with GPT-5.6 Luna starting tomorrow.
OpenAI cuts GPT-5.6 Luna prices by 80%, Terra by 20%
OpenAI announced significant price reductions for GPT-5.6 Luna (80% cut) and GPT-5.6 Terra (20% cut), plus a faster option for GPT-5.6 Sol in the API, aimed at improving cost efficiency and accessibility.
FAQ
What is GPT-5.6 (Sol · Luna · Terra)?
GPT-5.6 is OpenAI's frontier model family with three variants: Sol, Luna and Terra. In August 2026 OpenAI shipped rapid updates — Sol improved factuality by 68% in high-stakes domains, Luna gained extended thinking for Free and Go users, and Luna prices were cut by 80% (Terra by 20%) at the end of July 2026.
Who makes GPT-5.6?
GPT-5.6 is developed by OpenAI. This page tracks its official announcements as they happen.
Where is GPT-5.6 available?
Based on official announcements tracked here, it is available via: OpenAI.
What is the latest GPT-5.6 news?
GPT-5.6 Sol updated version now available in ChatGPT (August 6, 2026). OpenAI has released an updated version of GPT-5.6 Sol for Plus and Pro users in ChatGPT, available today with a new slider feature for everyday chats.