OpenAI introduces Daybreak cyber platform, takes on Anthropic Mythos

OpenAI has launched Daybreak, an AI-powered cybersecurity platform that uses large language models (AI systems trained on vast amounts of text data) and agentic capabilities (the ability for AI to take independent actions toward goals) to help organizations find and fix software vulnerabilities faster. The platform competes with Anthropic's Claude Mythos and works through three stages: prioritizing threats, generating and testing patches in enterprise systems, and documenting results for verification. Daybreak is being rolled out across three versions of GPT-5.5, from general-purpose use to specialized cybersecurity workflows.