Anthropic
Anthropic Claude model for long-running agentic coding and knowledge work.
1M ctxUSD 4 / 1M input tok; USD 20 / 1M output tok
Introducing Claude Mythos 5.1AnthropicReleased September 1, 2026
Claude Mythos 5.1
The most capable autonomous intelligence system engineered by Anthropic, restricted to Project Glasswing participants.
reasoning-llmProprietary API$10.00 / 1M tok (Glasswing Exclusive)Context: 1M (1,000,000 tokens)Arena ELO: 1575
Technical Specifications
Architecture Type
Frontier Autonomous Intelligence Architecture
Total Parameters
Frontier Autonomous Scale
Context Window
1M (1,000,000 tokens)
Max Output Tokens
128K (128,000 tokens)
Knowledge Cutoff
June 2026
Supported Modalities
text, code, vision, reasoning
License & Access
Anthropic Limited Commercial Terms
Benchmark Evaluations
Math500
99.5
Mmlu Pro
93.8
Gpqa Diamond
89.2
Swe Bench Verified
88.4
Chatbot Arena ELO
1575
Deep Architectural Overview
Claude Mythos 5.1 delivers Anthropic’s highest tier of reasoning and autonomous execution. Incorporating 0.025x cache reads and 1M context, it handles complex multidisciplinary problems, cyberdefense analytics, and frontier AI research under strict containment.
Strengths & Considerations
Core Strengths
- Highest benchmark performance across Anthropic history (93.8% MMLU-Pro, 88.4% SWE-bench)
- 1M context window and 128k output buffer
- Ultra-low $0.25/MTok cache hit pricing
Known Limitations
- Limited availability exclusively for Project Glasswing participants
Token & API Pricing
Input Tokens (1M)$10.00
Output Tokens (1M)$50.00
Cached Input (1M)$0.2500
Batch API Discount50% Off Standard
Pricing is verified directly against Anthropic's developer documentation and API rate sheets.
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