Claude Mythos 5.1: API Pricing, Context Window & Benchmarks
Claude Mythos 5.1 is a language model from Anthropic, released in September 2026, with multimodal input.
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,
Claude Mythos 5.1 benchmarks
Capability tiers
Standing within each category, adjusted for leaderboard depth.
Real tasks performance
High-confidence performance for Claude Mythos 5.1 across real-world prompt categories. Only 95% intervals at most 4 points wide are shown.
Performance by conversation depth
How Claude Mythos 5.1 holds up as conversations get longer.
Quality Tracker
Claude Mythos 5.1 Performance Across Datasets
Scores sourced from the model's scorecard, paper, or official blog posts
llm-stats.com - Tue Sep 08 2026Claude Mythos 5.1 pricing
Providers
Claude Mythos 5.1 starts at $10.00 per million input tokens and $50.00 per million output tokens via Anthropic. Reused prompt prefixes cost $0.250 per million cached input tokens.
| Provider | Input $/M | Cached input $/M | Output $/M | Context in / out | TTFT p95 s | Output p5 c/s | Modalities in / out |
|---|---|---|---|---|---|---|---|
 Anthropic | $10.00 | $0.250 | $50.00 | 1.0M/128.0K | — | — | / |
Cached input is the discounted price for prompt tokens served from a provider cache. TTFT is time to first token. Output is characters per second; p5 is the sustained floor exceeded by 95% of observed requests.
Claude Mythos 5.1 context window
Input and output token limits for Claude Mythos 5.1, plus how it ranks on long-context understanding.
Claude Mythos 5.1 latency
Claude Mythos 5.1 time to first token, sustained output throughput, and failed-request rate from live API traffic over the trailing 7 days.
Claude Mythos 5.1 examples
Recent arena outputs from Claude Mythos 5.1, picked from the highest-ranked matchups.
Claude Mythos 5.1 license
Claude Mythos 5.1 is a proprietary model available under its provider's product and API terms.
- License
- Proprietary
- Hosted access
Proprietary license - usage restrictions apply
Claude Mythos 5.1 resources
Official sources for Claude Mythos 5.1: paper or system card, official launch post.
Claude Mythos 5.1 vs other models
The most-compared alternatives to Claude Mythos 5.1 are GPT-6 Astra, Claude Fable 5.1. Open any pair side-by-side for benchmarks, pricing, context, and latency.
Models like Claude Mythos 5.1
Models ranked just above and below Claude Mythos 5.1 by LLM Stats score.
FAQ
Common questions about Claude Mythos 5.1.