What is Claude Mythos? The AI Changing Cybersecurity
Update: Claude Mythos 5.1 Is Out (September 1, 2026) The Mythos line was updated with Claude Mythos 5.1 on September 1, 2026. It is the identical model to Claude Fable 5.1, released the same day, with only the level of safeguards differing. It scores 60.9% on Terminal-Bench 4.0 against the Fable build’s 55.8%, and access stays limited to verified organizations under Project Glasswing. For benchmarks, pricing and API changes, read Claude Fable 5.1 . There is a new development every single day in the artificial intelligence world, but this time, the news is truly different. Anthropic announced a brand new model called Claude Mythos Preview on April 7, 2026. Moreover, they brought along a massive cyber defense initiative called Project Glasswing. ...