OpenAI previews GPT-5.6, including a cheaper Terra model
By Steven Van ·
Sol, Terra and Luna target coding, computer use and research, with Terra roughly matching GPT-5.5 at half the cost.
OpenAI is running a limited preview of the GPT-5.6 model family: Sol, the flagship model, Terra, a balanced model with performance competitive with GPT-5.5 at roughly half the cost, and Luna, a fast, low-cost model. The family targets software engineering, computer use, knowledge work, research and cybersecurity, and adds a new max reasoning effort setting.
Sol ships with what OpenAI calls its most robust safety stack to date, with strengthened protections against higher-risk activity, sensitive cyber requests and repeated misuse. The preview is available via the API and in Codex, and can be used through ChatGPT.
