OpenAI Publishes GPT-5.6 Preview System Card — 'Most Robust Safety Stack to Date' Plus Eval Data

OpenAI·medium signal

OpenAI released a GPT-5.6 Preview System Card (June 26, 2026) detailing its strongest safety stack yet, with hardened protections for high-risk cyber and bio requests and repeated-misuse handling. It contains the eval data behind the launch claims (Terminal-Bench 2.1, GeneBench, ExploitBench), making it the primary artifact for anyone independently assessing GPT-5.6's real capability and safety posture rather than relying on the marketing summary.