Closed Frontier Cyber AI vs Open Defensive Tools: Real-World Comparison 2026

Originally published on NextFuture As of May 2026, Anthropic's Mythos and OpenAI's GPT-5.5-Cyber sit behind allowlists that most engineering teams will never clear. Meanwhile, Llama Guard 3, CodeLlama Guard, and Cisco AI Defense have been in production for months—no NDAs, no federal vetting, no undisclosed pricing. We tested both stacks against four real defensive tasks: phishing detection, code audit, threat triage, and log forensics. Here is what the gap actually looks like. For the broader co