News Summary

• GPT-5.5-Cyber is built to spot flaws before anyone else abuses them.
• The UK's AI Security Institute said it is "one of the strongest models we have tested" Anthropic rolled out its own cyber-focused model, Claude Mythos, to roughly 50 organizations under tight controls, saying it would never be made publicly available.
• Now OpenAI is, if not building the same shelter, at least checking IDs at the door.
• It may be pitched as protection, but when the tools can both break and fix systems, the difference often comes down to who gets there first.