Anthropic releases new ‘Mythos-class’ model to general public with guardrails

June 9, 2026

Wall Street Journal: Called Claude Fable 5, the large language model will mostly let users query Mythos, which the company previously deemed was too dangerous for general release. However, if users ask Fable about sensitive issues such as a bioweapon or exploiting a software bug, it will kick them back to the older Opus 4.8 version of the Claude chatbot…