Fable 5.1 Max
#123 in Frontier LLMsUnknown · v5.1 · max · 2× · last seen Sep 24, 2026
17
Momentum
Claude Fable 5.1 is a "Myth-class" Frontier language model from Anthropic, released on September 1, 2026, and succeeds Claude Fable 5. It is specialized for long-running, complex agentic coding and knowledge work, featuring a 1-million Token context window and up to 128,000 output Token. The proprietary, commercial model is available via the Claude API, Claude Apps (Pro/Max/Team/Enterprise), as well as AWS, Google Cloud, and Microsoft Foundry, and costs $10 per million input Token or $50 per million output Token.
Momentum trend
29.06.27.09.
Features
| Key Benchmark (%) | 73.4% on CursorBench 3.2 (max effort); 55.8% on Terminal-Bench 4.0 |
| Context Window (Tokens) | 1,000,000 tokens (default and maximum), up to 128,000 output tokens |
| License | Proprietary (commercial API model by Anthropic) |
| Multimodality | Text and image input, text output (incl. document/chart understanding) |
| Platform | Claude API, Claude apps (Pro/Max/Team/Enterprise), AWS, Google Cloud, Microsoft Foundry |
| Price per 1M Tokens | $10 input / $50 output per 1M tokens; cache reads $0.25 |
| Release Date | September 1, 2026 |