Anthropic Releases Claude Fable 5 — The Mythos-Class Model Is Now Live
Anthropic Releases Claude Fable 5 — The Mythos-Class Model Is Now Live
Anthropic has released Claude Fable 5, the Mythos-class model that had been tracked through leaks and checkpoints over the past several weeks. The model is now available as the safe-for-general-use version of the underlying Mythos frontier model, with additional safeguards applied for high-risk areas including cybersecurity.
Fable 5 represents a substantial generational leap over Anthropic's previous models. The same underlying intelligence as Mythos 5 — the raw frontier variant — powers Fable 5, with safety restrictions lifted only for trusted cybersecurity use cases. This makes Fable 5 the most capable generally available model Anthropic has ever shipped.
Pricing and Availability
| Detail | Value |
|---|---|
| Input tokens | $10 per 1 million |
| Output tokens | $50 per 1 million |
| Context window | 1 million tokens |
| Availability | Claude AI paid plans, API |
| Free period | Included at no extra cost until June 22, 2026 |
| After June 22 | Usage-based pricing depending on capacity |
The model is designed for long-horizon reasoning, agentic workflows, extended autonomous operation, memory, tool use, and complex tasks that can run for days. The 1 million token context window is retained from the previous generation.
Benchmark Performance
Fable 5 achieves state-of-the-art results across nearly every major benchmark:
| Benchmark | Fable 5 | Comparison |
|---|---|---|
| SWE-Bench Pro | ~20% improvement | Over GPT-5.5 (previously best model) |
| OS World | 85% | New record |
| GDP Evo | New SOTA | New state-of-the-art score |
| Agentic coding | New records | Across all coding benchmarks |
| Frontier Code Eval | Highest score | Even at medium reasoning effort |
On Cognition's Frontier Code Evaluation — which tests whether models can solve difficult coding tasks while meeting real production codebase standards — Fable 5 scored the highest among all frontier models, even at medium reasoning effort.
Vision Capabilities: Beating Pokemon Fire Red Raw
Fable 5's vision capabilities are strong enough that the model beat Pokemon Fire Red using only raw vision in under 55 minutes — with no map, no memory access, no navigation harness, and no hidden game stats. The model explored the world, battled trainers, navigated menus, solved routes, and finished the game by looking at the screen and figuring out everything autonomously, the same way a human would.
Generated Outputs
Minecraft Clone
A fully functional Minecraft-style clone was generated using max thinking mode within Claude Code. Features include:
- Block breaking and placement
- Torches and mobs (including creepers)
- Full inventory system with crafting
- Cave systems with ores
- Water dynamics (swimming underwater)
- Multiple biomes with infinite terrain generation
- Day and night cycle
macOS Clone
A macOS-style operating system clone was generated with:
- Functional top bar with sound system and dark mode toggle
- Bottom toolbar with application dock
- Finder with document browsing
- Safari browser
- Music app with functional audio playback
- Photos app with generated images
- Notes, Calendar, Paint (functional), and Terminal apps
- Built-in Minecraft-style 2D Terraria-like game
Windows OS Clone
A Windows operating system clone generated within Claude Code included:
- Sign-in screen with PIN authentication
- Full taskbar with notification system
- Brightness control and calendar
- Weather widget and settings page
- Accent color personalization and wallpaper switching
- Light/dark mode toggle
- Microsoft Edge browser
- Terminal, File Explorer (PC), Solitaire, Minesweeper, Notepad
- Right-click context menu with personalization options
Front-End Generation
Fable 5 leads in front-end generation across all models, surpassing the previous leader Opus 4.8. It handles scroll-triggered animations, responsive layouts, and complex typography with high accuracy. One noted stylistic pattern is its consistent use of orange, black, and white themes.
Image-to-code conversion is also strong — the model can take an image and produce a full front-end implementation accurately.
Three.js and 3D
- FPS Game: First-person shooter with enemies, health bar, multiple weapons, inventory system, round system, and notification system
- Physics Simulation: Blocks and spheres dropped from height with accurate collision and physics handling
- Real-Time WebGL Ray Marching: Toggleable soft shadows, ambient occlusion, reflections, atmospheric fog, and animations
- Isometric Room: Fireplace toggle, pet-able cat, day/night switching with high detail
- Solar System Simulation: Accurate planetary orbits, asteroid belt, planet descriptions, orbital speed control, label and asteroid toggles
- 3D World Building: Full browser-based 3D environment with shadow paths, camera movements, and interactive object system — no Unity or Unreal Engine, pure Three.js
SVG Generation
- Lava Lamp Simulation: Realistic gooey lava effect with color customization, interactive theme settings, and atmospheric lighting
- Butterfly: Well-structured SVG butterfly (noted as potentially expensive to generate compared to open-source alternatives)
Summary
Claude Fable 5 is Anthropic's most capable generally available model. It sets new records across coding, vision, agentic tasks, and 3D generation benchmarks. It is available now through Anthropic's API and chatbot, included in paid plans at no extra cost until June 22, 2026.