Just like all its launches, Anthropic has quitely launched its most powerful Claude model ever released to the public. The Claude Fable 5 is termed to be a 'Mythos-class' AI model that is said to top charts like 80.3 percent on SWE-Bench Pro for agentic coding and excels at long, complex tasks, outpacing rivals such as Opus 4.8 and GPT-5.5. Claude Fable 5 is available now for Pro and Max subscribers only.
What Is Claude Fable 5?
Claude Fable 5 is coined to be Anthropic's its most powerful AI model ever made available to the general public. Fable 5's capabilities exceed those of any model Anthropic has ever made generally available, with the company describing exceptional performance in software engineering, knowledge work, vision, scientific research, and many other areas. The longer and more complex the task, the larger Fable 5's lead over other Claude models.
Think of it as Anthropic's answer to the arms race in AI, a model designed to tackle the hardest tasks users and developers throw at it, for longer and with fewer errors than anything before it.
What can it actually do?
The real-world results are striking. Stripe, the payments company, reported that Claude Fable 5 compressed months of engineering work into days. In a 50-million-line codebase, the model performed a migration in a single day that would otherwise have taken a whole team over two months to complete by hand.
On Hebbia's Finance Benchmark for senior-level reasoning, Fable 5 scored highest of any model, with notable gains in document-based reasoning, chart interpretation, and problem-solving. Trading firm IMC noted Fable 5 aced their trading-analysis evaluations nearly across the board.
The model also has significantly improved visual understanding. It can extract precise numbers from detailed scientific figures and rebuild a web app's source code from screenshots alone. Earlier Claude models needed a complex helper harness to play the game Pokémon FireRed; Fable 5 completed it using only raw game screenshots, with no maps or navigation aids.
Claude Fable 5: Built with guardrails from day one
Releasing a model this capable comes with risks. Without safeguards, Fable 5's capabilities in areas like cybersecurity could be misused to cause serious damage. Anthropic has therefore launched Fable 5 with safeguards that mean queries on some topics will instead receive a response from Claude Opus 4.8.
In high-risk areas like cybersecurity, biology, chemistry, and distillation, the model blocks responses and falls back to Claude Opus 4.8. Anthropic says the safeguards are tuned conservatively and will sometimes catch harmless requests, but trigger on average in less than 5 percent of sessions.
Anthropic has also launched Claude Mythos 5
Alongside Fable 5, Anthropic is also launching a second, more powerful version. Claude Mythos 5 is the same underlying model as Fable 5 but with safeguards lifted in some areas. It will initially be deployed through Project Glasswing, in collaboration with the US government, and has the strongest cybersecurity capabilities of any model in the world. This version is not available to the general public.
Claude Fable 5: Who gets it and what does it cost?
Fable 5 is available immediately and is included on Pro, Max, Team, and Enterprise plans until June 22. After June 23, usage credits may be required until capacity expands.
For developers using the API, Fable 5 is priced at $10 per million input tokens and $50 per million output tokens, less than half the price of Claude Mythos Preview. The model supports up to 128,000 output tokens. It is available on Claude.ai, the Claude API, Claude Code, AWS Bedrock, Google Cloud, and Microsoft Foundry.
