Claude Fable 5
Anthropic's most capable generally available Claude model for ambitious, long-running knowledge work and coding projects
Claude Fable 5
Anthropic • June 2026
Training Data
Not disclosed
Claude Fable 5
June 2026
Parameters
Not disclosed
Training Method
Advanced Constitutional AI with safety classifiers and fallback routing
Context Window
1,000,000 tokens
Knowledge Cutoff
January 2026
Key Features
Mythos-class Capabilities • Days-long Agentic Work • 1M Context Window
Capabilities
Agentic: Outstanding
Reasoning: Outstanding
Coding: Outstanding
Vision: Outstanding
What's New in This Version
Exceeds Opus 4.8 on long-horizon coding, complex knowledge work, vision, and autonomous multi-stage tasks while adding safeguards for cyber, biology, chemistry, and distillation-risk queries
Anthropic's most capable generally available Claude model for ambitious, long-running knowledge work and coding projects
What's New in This Version
Exceeds Opus 4.8 on long-horizon coding, complex knowledge work, vision, and autonomous multi-stage tasks while adding safeguards for cyber, biology, chemistry, and distillation-risk queries
Technical Specifications
Key Features
Capabilities
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