ChatGPT’s powerful GPT-5.6 models arrive, but not for you

News Analysis ChatGPT’s powerful GPT-5.6 models arrive, but not for you While the wait continues for Claude Fable to return, OpenAI has released its most powerful models yet, but only in a “limited preview.” By Ben Patterson Senior Writer, PCWorld Jun 26, 2026 11:46 am PDT --> Image: Bangla Press / Shutterstock.com Summary created by Smart Answers AI In summary: OpenAI has released its most powerful GPT-5.6 models (Sol, Terra, and Luna) but only to trusted partners and organizations following a U.S. government request for limited rollout. PCWorld reports that the flagship Sol model directly competes with Anthropic’s restricted Fable and Mythos models, featuring enhanced layered safeguards against misuse. A wider public release remains uncertain due to regulatory concerns about the models’ advanced capabilities and potential security implications. The U.S. government ban on Anthropic’s powerful Fable and Mythos models has everybody spooked. That’s why it’s a little surprising that OpenAI, Anthropic’s biggest rival, is slowly rolling out its latest and most powerful GPT models. Yes, the GPT-5.6 series of models is here , but not for everyone. It comes in three flavors: the flagship Sol model, the everyday Terra, and the fast-and-efficient Luna. Those models map roughly to the Opus, Sonnet, and Haiku configuration of Anthropic’s Claude models.  That said, Sol is really more of a competitor to Fable and Mythos, the two Claude models that were slapped with expert restrictions by the Trump Administration earlier this month over fears they were too dangerous for broad release. Like Fable and particularly Mythos (which was restricted to only a small group of handpicked users and organizations even before the U.S. ban), GPT-5.6 Sol is being billed as OpenAI’s “strongest model yet,” complete with robust coding, biology, and cybersecurity capabilities. But while Anthropic put Claude Fable into general