Claude Mythos 5 / Fable 5

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Claude Claude Fable 5

Next generation of intelligence for the hardest knowledge work and coding problems.<br>Try ClaudeGet API access

Announcements<br>NewClaude Fable 5<br>Jun 9, 2026

Claude Fable 5 introduces our 5th model generation for your most ambitious work. Tackle days-long, complex, and asynchronous tasks previous models couldn’t sustain.<br>Read more

Availability and pricing<br>For organizations taking on their hardest knowledge and coding work, Claude Fable 5 is available on the consumption-based Enterprise plan.<br>For developers interested in building AI solutions that demand frontier intelligence, Claude Fable 5 is available on the Claude Platform natively, through available marketplaces, and in Amazon Web Services, Google Cloud, and Microsoft Foundry.<br>Claude Fable 5 is priced at $10 per million input tokens and $50 per million output tokens, with the existing 90% input token discount for prompt caching. To learn more, check out our pricing page. To get started, use claude-fable-5 via the Claude API.<br>For workloads that need to run in the US, US-only inference is available at 1.1x pricing for input and output tokens. Learn more.<br>Use cases<br>Claude Fable 5 is a Mythos-level model built for your most ambitious, long-running projects. Try problems you weren’t able to solve with other models. Claude Fable 5 is thorough, proactive, and tests its own work.<br>Agents<br>Run Claude Fable 5 in an agent harness like Claude Code or Claude Managed Agents, and it can work for days at a time: planning across stages, delegating to sub-agents, and checking its own work.<br>Coding<br>Claude Fable 5 is our most capable model for ambitious coding projects, including large migrations, complex implementations, and multi-day autonomous sessions. It can write its own tests to check its work, implement designs with high fidelity, and use vision to check outputs against goals.<br>Enterprise workflows<br>Claude Fable 5 handles complex, multi-stage knowledge work with minimal oversight, from deep research and analysis to deliverables ready for your review. Teams can hand off large projects and review completed work rather than supervising every step.<br>Vision<br>Claude Fable 5 understands diagrams, charts, and tables nested in files and PDFs, improving work across document-heavy work in finance, legal, analytics, and architecture. The model also uses vision to help evaluate its own coding work, checking outputs against the original design or goal.<br>Safeguards<br>Claude Fable 5 includes robust safeguards for cybersecurity and biology. Queries in these domains are automatically routed to Opus 4.8 if flagged by these safeguards. You won't be charged Fable prices for rerouted requests. Learn more about how the fallback experience works.<br>We extensively test and evaluate our models to ensure they meet Anthropic’s standards for safety, security, and reliability. The accompanying system card covers safety results in depth.<br>Data retention<br>Using Fable requires 30-day data retention for safety monitoring. Learn more.<br>Benchmarks<br>Claude Fable 5 is state-of-the-art at coding, knowledge work, vision, and computer use.

Hear from our customers

Claude Fable 5 is the state of the art model on CursorBench. It's opened up a class of long-horizon problems that were out of reach for earlier models.

Claude Fable 5 is a real step forward for the developers GitHub serves. In our early testing, it took on complex, long-horizon coding tasks with a level of autonomy and reliability that exceeded previous benchmarks. But what excites us most is the direction it points: a future where developers can hand increasingly ambitious work to agents and trust the results across the software lifecycle.

These are the strongest results of any Claude model we've had the opportunity to test. Claude Fable 5 is a clear step forward on agentic coding and prototyping.

Claude Fable 5's reasoning is a clear step beyond Opus 4.8. It works at senior research scientist grade — picking directions, allocating resources, killing its incorrect beliefs, and producing novel first-principles outputs.

Claude Fable 5 understands what builders mean, not just what they type. Apps that took a hundred prompts a year ago, it now one-shots. When a customer really hits a wall, it's the model we reach for to get them past it quickly, so they can finish what they set out to build.

Claude Fable 5 feels materially different. In blind review, our lawyers found its redlines matched or beat our current model every time.

At the highest effort, Claude Fable 5 reflects on and validates its own work. For us, that's what makes highly autonomous operations possible — the extra thinking pays for itself.

Claude Fable 5 delivers more capable engineering in fewer turns than prior models—handling the complex multi-agent workflows our employees run daily in Claude Code.

Claude Fable 5 is the strongest finance-first model we've tested, both on general finance and reasoning. It's a notable step up.

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