Hardest reasoning tasks
Choose Claude Fable 5.1
Claude Fable 5.1 scores 53.4 on the Artificial Analysis Intelligence Index, against 48.1 for Muse Spark 1.3.
Claude Fable 5.1 vs Muse Spark 1.3: price, context and capabilities
Choose Claude Fable 5.1 for the hardest reasoning tasks, reasoning over long documents and images as input; on the other points the two are level or the data is missing.
In short
- A price comparison is not possible: one of them has no comparable published price.
- Muse Spark 1.3 reads more per request: 1.05M tokens against 1M.
- Only Claude Fable 5.1 offers vision, structured output, prompt caching, batch api.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reasoning over long documents
Choose Claude Fable 5.1
Claude Fable 5.1 scores 85.3% on Long-context reasoning (AA-LCR), against 83% for Muse Spark 1.3.
Images as input
Choose Claude Fable 5.1
Claude Fable 5.1 accepts images as input; Muse Spark 1.3 does not.
Specifications side by side
| Claude Fable 5.1 | Muse Spark 1.3 | |
|---|---|---|
| Provider | Anthropic | Meta |
| Category | Language models | Language models |
| Status | Generally available | Generally available |
| Headline price | $20.00 / 1M tokens | No data |
| Input | $10.00 / 1M tokens | No data |
| Output | $50.00 / 1M tokens | No data |
| Cached input | $0.25 / 1M tokens | No data |
| Context window | 1M | 1.05M |
| Max output | 128k | No data |
| Released | September 2026 | Sep 2, 2026 |
| Knowledge cutoff | June 2026 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Reasoning, Tool calling |
| API model id | claude-fable-5-1 | muse-spark-1.3 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Fable 5.1 | Muse Spark 1.3 |
|---|---|---|
| Intelligence Index | 53.4 | 48.1 |
| SciCode | 63.1% | 58.8% |
| GPQA Diamond | 93.7% | 93.5% |
| Humanity's Last Exam | 59.1% | 48.7% |
| Long-context reasoning (AA-LCR) | 85.3% | 83% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Fable 5.1 or Muse Spark 1.3?
Choose Claude Fable 5.1 for the hardest reasoning tasks, reasoning over long documents and images as input; on the other points the two are level or the data is missing.
Which is cheaper, Claude Fable 5.1 or Muse Spark 1.3?
A price comparison is not possible: one of them has no comparable published price.
Which has the larger context window, Claude Fable 5.1 or Muse Spark 1.3?
Muse Spark 1.3 reads more per request: 1.05M tokens against 1M.
What is the difference between Claude Fable 5.1 and Muse Spark 1.3?
Claude Fable 5.1 is made by Anthropic and Muse Spark 1.3 by Meta. A price comparison is not possible: one of them has no comparable published price. Muse Spark 1.3 reads more per request: 1.05M tokens against 1M. Only Claude Fable 5.1 offers vision, structured output, prompt caching, batch api.