A Mythos-class model built for the hardest knowledge work and coding problems. State-of-the-art on nearly all tested benchmarks of AI capability — exceptional in software engineering, knowledge work, vision, and scientific research.
Claude Fable 5 introduces Anthropic's fifth model generation for your most ambitious work. It can work autonomously for longer than any previous Claude model.
Fable 5 compresses months of engineering into days. Stripe reported a codebase-wide migration in a day that would have taken a team over two months by hand. Highest scorer on Cognition's FrontierCode evaluation.
Strongest performance on complex analytical tasks. Highest score on Hebbia's Finance Benchmark for senior-level reasoning with substantial gains in document reasoning, chart interpretation, and problem solving.
New state-of-the-art for vision tasks. Extract precise numbers from scientific figures, rebuild web apps from screenshots, and play games like Pokémon FireRed with a minimal vision-only harness.
Stays focused across millions of tokens. Persistent file-based memory improved performance three times more than for Opus 4.8 in long-running tasks like the deck-building game Slay the Spire.
Fable 5 is thorough, proactive, and tests its own work. Run it in an agent harness like Claude Code and it can work for days at a time: planning across stages, delegating to sub-agents, and checking its own outputs.
Fable 5 breaks complex projects into phases, allocates resources, and prioritizes the work that matters most.
It spins off sub-tasks, monitors progress, and re-allocates effort when it spots a better path forward.
It writes its own tests to check its work, uses vision to compare outputs against designs, and self-corrects.
Teams hand off large projects and review finished deliverables rather than supervising every step.
Try problems you weren't able to solve with other models. Fable 5 is thorough, proactive, and tests its own work.
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.
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.
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.
Fable 5 excels at life sciences research, positing novel hypotheses and accelerating drug design. Using Mythos 5, protein design experts accelerated aspects of the drug design process by around ten times.
Claude Fable 5 is available on the Claude API, consumption-based Enterprise plans, and through Amazon Web Services, Google Cloud, and Microsoft Foundry.
Developers can use claude-fable-5 via the Claude API. Fable 5 is fully available on consumption-based Enterprise plans and the Claude API from today.
Get API AccessFable 5 includes safety classifiers that detect potential misuse across cybersecurity, biology and chemistry, and distillation. Flagged queries are automatically routed to Opus 4.8 — a far better experience than an outright refusal.
Classifiers prevent Fable from providing uplift on offensive cyber tasks. More than 95% of sessions involve no fallback at all.
Dual-use capabilities are protected by broad safeguards. Bioweapons-related queries and advanced biological research queries fall back to Opus 4.8.
Classifiers detect large-scale extraction attempts to prevent proliferation of near-frontier AI capabilities without appropriate safeguards.
Customers with early access ran their own tests on Fable 5. Here's a selection of what they're seeing.
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. It took on complex, long-horizon coding tasks with a level of autonomy and reliability that exceeded previous benchmarks.
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 is the highest-scoring model on FrontierBench, Cognition's frontier coding eval. It excels at long-horizon reasoning and generalizes to unfamiliar tools out of the box.
The fastest answers to the questions people ask first about 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 is best for ambitious, long-running, asynchronous work that previous models could not sustain.
Fable 5 is a Mythos-class model that substantially exceeds Opus 4.8 across nearly all benchmarks — coding, knowledge work, vision, scientific research, and long-context tasks. The longer and more complex the task, the larger Fable 5's lead.
Fable 5 comes with classifiers that detect potential misuse in cybersecurity, biology and chemistry, and distillation. Flagged queries automatically receive a response from Opus 4.8 instead. More than 95% of sessions involve no fallback.
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. US-only inference is available at 1.1x pricing.
Developers can use claude-fable-5 via the Claude API. Fable 5 is available on consumption-based Enterprise plans, and through Amazon Web Services, Google Cloud, and Microsoft Foundry.
Every claim on this page is grounded in official Anthropic documentation and announcements so you can verify the details yourself.
The official product page for Claude Fable 5 covering capabilities, pricing, and availability.
The full launch announcement detailing Fable 5 capabilities, safeguards, and customer testimonials.
Official API documentation for model access, pricing, and integration guidance.