9to5mac.com › 2026 › 04 › … OpenAI unveils GPT‑5.4‑Cyber, an AI model for defensive cybersecurity - 9to5Mac … Similar to Anthropic’s Claude Mythos , this new “cyber-permissive” variant of its GPT-5.4 is built for defensive cybersecurity and not public use. … Apr 14, 2026 · Zac Hall