What is Claude Fable 5?

Claude Fable 5 is Anthropic’s first publicly available Mythos-class AI model — the most capable model the company has ever released to the general public. It is state-of-the-art across nearly every benchmark of AI capability, with standout performance in software engineering, knowledge work, vision, and scientific research.

A capability leap

Fable 5 is the first publicly available model to exceed 90% on core analytical benchmarks — roughly 10 percentage points above Claude Opus. In practice that shows up as obvious superiority on the hardest, most demanding professional tasks.

Its headline strengths:

• Software engineering — planning, writing, and refactoring production code across large repositories.
• Knowledge work — reasoning over dense documents with expert-level depth.
• Scientific research — accelerating literature review, hypothesis generation, and analysis.
• Vision & UI design — turning complex visuals into polished, working interfaces.
• Game coding — generating playable game logic end to end.

“Mythos-class,” made safe

Mythos is Anthropic’s tier for its most powerful frontier models. Fable 5 is the first Mythos-class model released broadly, shipped with safeguards that make it safe for general use — including a fallback to Claude Opus 4.8 on a narrow set of high-risk topics.

Where to use it

Fable 5 is available through the Claude API for developers, the Claude mobile apps, GitHub Copilot, and partner products such as Harvey — at $10 per million input tokens and $50 per million output tokens.