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Long Story Video Skill
Let Claude Fable 5.2 orchestrate a 10s–10min story, handling scripts, prompts and footage end to end.
Ads Video Skill
Claude Fable 5.2 drafts the script, prompts and footage for a product ad in a single pass.
3D Science Explainer Video Skill
Turn a hard research result into a 3D explainer animation
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Claude Fable 5.2
Claude Fable 5.2 is built for demanding engineering and research work — stronger code, deeper reasoning, sharper vision, and up to 30% faster output.
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Where Claude Fable 5.2 Delivers Real Leverage
Anthropic designed Claude Fable 5.2 for demanding, open-ended engineering and research — from large code migrations to unsolved physics questions.
- Code decisions that hold up in productionMore than 90% of merged changes in Anthropic's core codebase now come from Claude. Fable 5.2 resolved long-standing bugs quickly and migrated a critical service from Python to Rust, cutting startup time by roughly 26x.
- Progress on unsolved science and mathUsing holographic duality, Claude Fable 5.2 closed two open questions in black hole physics and formalized a proof of Fermat's Last Theorem within 30 hours.
- Safety guardrails and verified Mythos accessFable 5.2 and Mythos 5.2 share one base model. Fable includes cyber and biology safeguards for general use, while security and biomedical teams can request Mythos through the Life Sciences and Cyber Verification Programs.
How to Put Claude Fable 5.2 to Work
Align model tier, effort level and mode with the size and difficulty of the task you are running.
Claude Fable 5.2: Measured Performance and Strengths
See how Claude Fable 5.2 scores on FrontierCode, Chartography, WANDR, HLE and BenchCAD, and how it handles long-horizon agents, Mythos 5.2 vulnerability discovery and MHS hardware control.
Merge-quality scores on FrontierCode
With High effort, Claude Fable 5.2 reached 45.3% on FrontierCode 2.0, close to Opus 5.5's best 45.5% at roughly half the cost per task and ahead of GPT-6 Astra's 42.8%. At Xhigh effort it climbed to 49.1%.
Agent orchestration over long horizons
From an empty folder, Fable 5.2 coordinated over 1,000 subagents across eight days to produce a bootable OS with drivers, file storage, windows and an installer, plus a hypervisor supported by more than 3,500 machine-checked proofs.
Finding vulnerabilities with Mythos 5.2
In the internal CVE Rediscovery test across 1,829 CVEs, Claude Mythos 5.2 uncovered 10.2% more vulnerabilities than Opus 5.5 and 14.4% more than Mythos 5.1. One security firm found that one in six confirmed bugs it reported had been missed by every other frontier model tested.
Chart and visual understanding
At Medium effort, Claude Fable 5.2 scored 66.4% on Chartography, outperforming Opus 5.5 at Max effort (64.4%) for less than a tenth of the cost per task. It also reached 83.5 on BenchCAD 2.1 versus 65.3 for Opus 5.5.
Efficient data collection and knowledge reasoning
On WANDR at Medium effort, Fable 5.2 matched Opus 5.5's best score at about 40% of the cost per task. On Humanity's Last Exam at Low effort, it matched the top score for under a tenth of the cost.
MHS control for lab and factory hardware
In the Model Hardware Standard research preview, a standard MHS driver with simple read/write primitives lets agents operate microscopes, liquid handlers and robotic arms in parallel. Integration drops from weeks to hours across programmable devices and agent harnesses via the Model Context Protocol.
Claude Fable 5.2 Questions, Answered
Get clear answers on Claude Fable 5.2 pricing, speed, model selection, safety testing and Mythos access.
How do Fable 5.2 and Mythos 5.2 differ?
They share one underlying model. Fable 5.2 includes cyber and biology safeguards for public availability, while Mythos 5.2 is released to verified security and biomedical teams.
What does Claude Fable 5.2 cost?
Input tokens are $8 per million and output tokens are $40 per million. Optional fast mode raises that to $16 per million input and $80 per million output tokens.
How much faster is Claude Fable 5.2 compared with Fable 5.1?
Output is up to 30% faster than Fable 5.1, and fast mode can increase token generation by up to 2.5x.
When should I choose Fable 5.2 over Opus 5.5?
Fable is built for broad, open-ended challenges. Start most work on Opus 5.5, then move up or down based on scope and complexity.
What safety testing preceded release?
Pre-release testing covered sandbox escapes and other risky behaviors, alignment comparable to recent models, leaner safeguards and stronger anti-distillation defenses.
Can Fable 5.2 be used for cybersecurity or biomedical work?
Fable 5.2 blocks most cybersecurity tasks, so that work requires Mythos through the Cyber Verification Program. Claude Security now includes Mythos 5.2.
Bring Claude Fable 5.2 to Your Toughest Problems
Use Claude Fable 5.2 at $8 per million input and $40 per million output tokens. Add fast mode for extra speed, and request Mythos access through the Cyber and Life Sciences Verification Programs.