OpenAI counters Anthropic’s Mythos with Daybreak and three GPT-5.5 cyber models
OpenAI has launched Daybreak, a cybersecurity initiative arriving roughly a month after Anthropic’s Project Glasswing—setting up a direct contest between the two labs over AI-powered cyber defence. Daybreak pairs OpenAI’s Codex Security agent with three GPT-5.5 variants to help defenders find vulnerabilities, generate patches and verify fixes inside live repositories.
Access is tiered. Standard GPT-5.5 covers general developer work. GPT-5.5 with Trusted Access for Cyber handles secure code review, vulnerability triage, malware analysis and patch validation. GPT-5.5-Cyber sits at the top, gated behind stronger verification and reserved for authorised red teaming and penetration testing.
