Anthropic released two advanced AI models, Claude Fable 5.1 and Claude Mythos 5.1, to lead in coding and knowledge work. Claude Fable 5.1 is now generally available. This model costs 25-45% less for typical workloads than its predecessor. Anthropic claims the update sets new standards for software engineering and complex problem-solving.
Both releases share the same underlying architecture but feature different safeguard levels. Mythos 5.1 contains fewer restrictions and remains exclusive to trusted partners. This version supports specialized research in life sciences and cybersecurity.
The dual-release strategy allows Anthropic to test performance boundaries in sensitive fields while providing a safer public version. This move intensifies competition with industry rivals Google and OpenAI.