Claude Fable 5.5 (Leaked Checkpoint) vs Muse Spark 1.3 (xhigh)
A direct, empirical evaluation of Claude Fable 5.5 (Leaked Checkpoint) (Anthropic) against Muse Spark 1.3 (xhigh) (Meta AI).
Claude Fable 5.5 (Leaked Checkpoint)
Developed by Anthropic · Proprietary Frontier Dynamic Reasoner parameters
Terminal-Bench 4.0 autonomous shell execution (78.5% target), recursive self-critique, and 1.5M-token repository refactoring.
Muse Spark 1.3 (xhigh)
Developed by Meta AI · Proprietary Multimodal parameters
Autonomous codebase refactoring, terminal execution, million-token long context retrieval, and agentic workflows.
| Metric | Claude Fable 5.5 (Leaked Checkpoint) | Muse Spark 1.3 (xhigh) |
|---|---|---|
| SWE-bench Verified | 84.2% | 75.4% |
| MMLU-Pro | 94.6% | 88.4% |
| MATH-500 | 98.4% | 94.8% |
| Context Window | 1,500,000 tokens | 1,000,000 tokens |
| Input Pricing (per 1M) | $3.50 | $1.25 |
| Output Pricing (per 1M) | $17.50 | $5.00 |