Claude Mythos 5.1
AnthropicClaudeProprietary
Description
Claude Mythos 5.1 is Anthropic's trusted-access deployment of the Claude Fable 5.1 weights (cataloged publicly as Fable 5.1). It is targeted for demanding reasoning and long-horizon agentic work with text and image input, tool use, multilingual support, and a 1M-token context window. Benchmarks below are sourced from Anthropic's official Claude Fable/Mythos 5.1 scorecard. It is not generally available via the public Claude API as a cataloged model id.
Release Date
2026-09-01
Parameters
—
Context Length
—
Modalities
image, text
Capability Radar
60
general
60
coding
60
reasoning
51
scienceest.
60
agents
70
multimodal
Science is estimated from LLM Stats science scores or reasoning when no dedicated science benchmarks are available.
Rankings
No ranking data available
Benchmark Scores (LLM Stats)
(LLM Stats (zeroeval))Reasoning
Terminal-Bench 4.0
60.9%SR
AA Evaluation Indices
(Artificial Analysis)No AA evaluation data available
LLM Stats Category Scores
(LLM Stats (zeroeval))Reasoning60
General60
Agents60
Code60
Tool Calling60
Pricing
No pricing data available
Speed
No speed data available
Provider Price Ranking
No provider data available