Claude Fable

Next generation of intelligence for the hardest knowledge work and coding problems.AnnouncementsNewClaude Fable 5Jun 9, 2026Claude Fable 5 introduces our 5th model generation for your most ambitious work. Tackle days-long, complex, and asynchronous tasks previous models couldn’t sustain. Read moreAvailability and pricingFor organizations taking on their hardest knowledge and coding work, Claude Fable 5 is available on the consumption-based Enterprise plan.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.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.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.Use casesClaude 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.AgentsRun 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.CodingClaude 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.Enterprise workflowsClaude 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.VisionClaude 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.SafeguardsClaude 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.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.Data retentionUsing Fable requires 30-day data retention for safety monitoring. Learn more.BenchmarksClaude Fable 5 is state-of-the-art at coding, knowledge work, vision, and computer use.Hear from our customersClaude 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.Claude Fable 5 is the first to break 90% on our core analytics benchmark of complex, long-running analytical tasks — a 10-point jump over Opus. On the hardest questions, it shows strong judgment and attention to nuance.Claude Fable 5 is the strongest model we've tested on frontier physics research while using a third of the reasoning tokens. In 36 hours it got nearly to where GPT-5.5 landed after four days.On ViBench, our end-to-end vibe-coding benchmark, Claude Fable 5 is the highest-performing model we've tested — nearly saturating our base use cases and building apps in less time with fewer tokens.Claude Fable 5 beats Opus 4.8 on our everyday spreadsheet suite at every effort level — and it does it with fewer turns, finishing runs 25–30% faster.01 / 13When should I use Claude Fable 5?We offer Claude models across the spectrum of speed, price, and performance. Claude Fable 5 is our most capable generally available model. It’s best for ambitious, long-running, asynchronous work.Why did you create new safeguards for Claude Fable 5?Making a model as capable as Fable 5 generally available comes with risks. The model’s capabilities in specific areas like cybersecurity, biology, and chemistry are advanced enough that they could be misused to create wide-reaching cyberattacks or build dangerous bioweapons. For that reason, Fable 5 comes with safeguards that block or limit its performance in these areas. Many queries on topics including biology and cybersecurity will instead receive a response from our next-most-capable generally available model, Claude Opus 4.8.When can I get access to Mythos 5 for cybersecurity and biology research?Our goal is to safely open up access to vetted partners to use Mythos 5 for cybersecurity and biology research. To stay up to date on our plans for trusted access programs for Mythos 5, sign up for notifications.

How does the fallback work?For most Claude applications, queries flagged by our cybersecurity and biology safeguards automatically route to Opus 4.8. API customers must configure their settings with our new Fallback API. Learn moreHow much does it cost to use Claude Fable 5?Pricing depends on how you want to use Claude Fable 5. To learn more, check out our pricing page.