OpenAI's GPT-5.6 goes public today — after a month in government testing.
OpenAI's GPT-5.6 goes public today, after a month in government testing. OpenAI opened its GPT-5.6 family; Sol, Terra and Luna to ChatGPT, Codex and the API today. This comes after weeks confined to about 20 vetted partners. Terra is the cheaper everyday tier OpenAI says matches GPT-5.5 for less, Luna is the fast, cheap option, and Sol is the flagship with a new multi-agent 'ultra' reasoning mode. Prompt caching now holds for at least 30 minutes.
What it actually means
The useful part isn't the flagship. It's Terra, the cheaper middle tier OpenAI says matches GPT-5.5 for less and prompt caching that now holds for at least 30 minutes. That's a real cut to the bill on the boring, high-volume parts of a build. Swap it into one live task this week and check the quality holds before you move anything that matters. Keep Sol's new multi-agent 'ultra' mode for the hard problems, not the default.
A new flagship is the headline; a cheaper everyday tier is the thing you'll actually feel.
Source: The Hill · Thursday 9 July 2026