OpenAI's GPT-5.5 with Trusted Access for Cyber represents an identity and trust-based approach designed to ensure that advanced cyber capabilities are utilized appropriately. This model enhances the utility of GPT-5.5 for verified defenders engaged in sanctioned defensive operations, while still imposing limitations to prevent actions that could lead to real-world harm. For the majority of teams, this iteration of GPT-5.5 stands out as OpenAI's most robust model for genuine defensive applications, featuring improved safeguards for essential tasks like secure code review, vulnerability assessment and triage, malware analysis, binary reverse engineering, detection engineering, and patch validation. Approved defenders benefit from a reduced rate of classifier-based refusals when conducting authorized cybersecurity tasks, yet the system maintains its protective measures against harmful activities, including credential theft, stealth, persistence, malware deployment, and exploitation of external systems. Consequently, this model not only enhances operational efficiency for cybersecurity professionals but also prioritizes the security and integrity of the overall cyber environment.