Claude Fable 5 vs GPT-5.1
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Fable 5 and GPT-5.1.
Claude Fable 5
Claude Fable 5 is a Mythos-class model from Anthropic, built for autonomous knowledge work and coding. It supports text, image, and file inputs with text output, with reasoning support and...
GPT-5.1
GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5. It uses adaptive reasoning...
Technical Specifications
| Specification | Claude Fable 5 | GPT-5.1 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 1,000,000 tokens | 400,000 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2026-06-09 | 2025-11-13 |
API Pricing Comparison
Input Price per Million Tokens
Claude Fable 5
$10.00
GPT-5.1
$1.25
Output Price per Million Tokens
Claude Fable 5
$50.00
GPT-5.1
$10.00
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Claude Fable 5 Quirks & Gotchas
No developer gotchas reported.
GPT-5.1 Quirks & Gotchas
No developer gotchas reported.