Anthropic Releases Claude Fable 5.2 and Mythos 5.2 Models
Anthropic has launched Claude Fable 5.2 and Claude Mythos 5.2, claiming gains in coding, reasoning and vision for tackling demanding technical work. Fable 5.2 is now live in Arena's Agent Arena and Code Arena, where it can use web search, filesystem and terminal tools on long-horizon agentic tasks, with leaderboard scores to follow.
Full Report
Arena.ai (@arena) · 2026-11-09 19
Claude Fable 5.2 by @AnthropicAI is now in the Arena. Head to Agent Arena to test it out, scores coming soon!
In Agent Arena, we measure models on millions of real-world, long-horizon agentic tasks from a global community of users. Models can access web search, filesystem, and terminal tools to complete complex workflows. The leaderboard measures model performance on outcomes relative to the average model using a causal tracing methodology.
Fable 5.2 is also available in Code Arena: WebDev, Text, Vision, Search and Document.
↳ 引用 @claudeai (Claude): Introducing Claude Fable 5.2 and Claude Mythos 5.2, designed to tackle the most daunting technical challenges.
They’re capable collaborators on ambitious projects in many fields, and show improvements in areas like coding, reasoning, and vision.
