Number is generation
Name is the size (Luna smallest to Astra largest)
replyThen what is Astra high-extra high-Ultra? That’s effort within each tier?
replyYes that is number of reasoning tokens used.
replyPerformance increases both with larger model (Luna vs Sol)
And with more reasoning (low vs xhigh)
Exactly
replyIt's just another step on the timeline.
replyGPT-5.6-Sol, GPT-5.6-Terra, and GPT-5.6-Luna were released in July of 2026.
The first release from the GPT-6 series was GPT-6-Astra. GPT-6-Astra happened on around September 3, 2026, and the previously-mentioned GPT-5.6-* widgets remained available.
Today, September 22, 2026, we now also have GPT-6-Sol and GPT-6-Luna added into the mix.
As I write this, all of the model identifiers I've mentioned are available to select for use within Codex.
Just released 6-Sol and 6-luna a few hours ago
reply