OpenAI on Friday released three versions of GPT-5.6, called Sol, Terra, and Luna, as a limited preview to a small number of companies as part of an ongoing engagement with the U.S. government.
While Sol is the latest flagship model and the most powerful, Terra strikes a balance between efficiency and power, and Luna is fine-tuned for speed and affordability.
"GPT‑5.6 Sol launches with our most robust safety stack to date. We strengthened protections for higher-risk activity, sensitive cyber requests, and repeated misuse, and spent multiple weeks finding weaknesses, pressure-testing our system, and hardening it against real-world attacks," OpenAI said.
The model has also been touted as the "most capable model yet" for cybersecurity, making it much more suitable for vulnerability research and exploitation. On ExploitBench , GPT‑5.6 Sol is competitive with Anthropic Mythos Preview using only about one-third of the output tokens, OpenAI noted.
The goal, it added, is to enable access to legitimate work such as code review, vulnerability research, patch development, debugging, security education, and defensive testing, while enforcing strong guardrails that block offensive activity and swiftly remediating newly discovered jailbreaks. This includes adversarial attempts to jailbreak the model and refuse what it describes as "prohibited cyber assistance."
