AI NewsAnthropic Claude Fable 5.1, Claude Mythos 5.1 Models Announced for Advanced Coding, Scientific Research

Anthropic Claude Fable 5.1, Claude Mythos 5.1 Models Announced for Advanced Coding, Scientific Research

1:54 PM IST · September 3, 2026

Anthropic has introduced Claude Fable 5.1 and Claude Mythos 5.1 as its latest models designed for advanced coding and knowledge work. Fable 5.1 is confirmed to be generally available, while Mythos 5.1 is accessible through trusted programmes. The two models work on the same system, but have different safety safeguards. As per Anthropic's benchmarks, Claude Fable 5.1 surpassed Fable 5 and Opus 5 in science and agentic coding tasks by scoring 52.6 percent on Terminal-Bench-Science and 73.4 percent on CursorBench.