Claude Fable 5 is a Large Language Models (LLMs) tool. Claude Fable 5 is a highly capable AI model excelling at software engineering, knowledge work, vision, and scientific research with built-in safeguards. Best for software development.
About Claude Fable 5
Key Features
State-of-the-art performance on AI capability benchmarks across software engineering and knowledge work
Advanced vision capabilities enabling complex visual tasks like rebuilding code from screenshots
Long-context processing across millions of tokens with persistent file-based memory
Autonomous operation for extended periods on complex multi-step tasks
Conservative safeguards designed for safe general availability with less than 5% false positive rate
Pricing at $10 per million input tokens and $50 per million output tokens
Frequently Asked Questions
Fable 5 includes conservative safeguards that route sensitive queries to Claude Opus 4.8. These safeguards trigger in less than 5% of sessions on average, occasionally catching harmless requests as false positives.
Claude Mythos 5 is the same underlying model as Fable 5 but with lifted safeguards for specialized use. It is currently deployed through Project Glasswing for cyberdefenders and infrastructure providers, with plans for broader trusted access.
Fable 5 demonstrates exceptional software engineering capabilities, achieving state-of-the-art scores on FrontierCode evaluation and handling complex codebase migrations in days rather than months.
Fable 5 excels at autonomous scientific work including drug design acceleration, generating novel molecular biology hypotheses preferred by scientists in blind comparisons, and conducting complex genomics research.
