Claude Fable 5.1 changes behaviour without a code change. The jobs I hand it, the three I keep, and two harness fixes from the release notes.

In June, Anthropic first released Fable 5, its Mythos-class AI model for Claude. Three months later, Anthropic is enhancing Claude...

Claude Fable 5.1 is officially available in the Model Garden on Agent Platform. Built for...