Mythos · Anthropic · Claude · TechCrunch AI
Anthropic’s new Fable release is cheaper, less restrictive
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On Tuesday, Anthropic released Fable and Mythos 5.1, twinned versions of the company’s most advanced AI model.
Key facts
- Mythos 5.1 is a slight regression on overall misaligned behavior compared to Opus 5, and an improvement over Mythos 5 and Claude Sonnet 5,” the system card reads
- On Tuesday, Anthropic released Fable and Mythos 5.1, twinned versions of the company’s most advanced AI model
- As is common for an Anthropic release, the new models set records in a range of benchmarks, including Terminal-Bench 4.0 (for CLI-based coding) and Humanity’s Last Exam (for general reasoning)
- As with the previous Mythos model, Mythos 5.1 will only be available to registered Anthropic partners engaged in either cybersecurity or life sciences research
Summary
As with the previous Mythos model, Mythos 5.1 will only be available to registered Anthropic partners engaged in either cybersecurity or life sciences research. One of the most significant changes is Anthropic’s previously reported embrace of zero data retention, allowing clients to run Anthropic models on their own infrastructure without data outflows. As part of the announcement, Anthropic assured customers that their data had not been inappropriately accessed. As is common for an Anthropic release, the new models set records in a range of benchmarks, including Terminal-Bench 4.0 (for CLI-based coding) and Humanity’s Last Exam (for general reasoning).