OpenAI has unveiled the full version of its cybersecurity-focused AI model GPT-5.5-Cyber. The model is part of the company’s own cyber-defense program “Daybreak” and is explicitly aimed not at the general public but at verified security professionals. While Anthropic’s competing flagship models Mythos 5 and Fable 5 are currently offline by order of the US government, OpenAI’s new model continues to operate under access controls coordinated with the government. That GPT-5.5 may be more capable –