Claude Fable 5.1 vs Space Bunny Alpha (Stealth)
A direct, empirical evaluation of Claude Fable 5.1 (Anthropic) against Space Bunny Alpha (Stealth) (MiniMax (Unannounced Stealth Release via OpenRouter)).
Claude Fable 5.1
Developed by Anthropic · Proprietary Frontier parameters
Full-repository software refactoring, agentic tool workflows, formal verification, and 1.5M-token needle retrieval.
Space Bunny Alpha (Stealth)
Developed by MiniMax (Unannounced Stealth Release via OpenRouter) · Proprietary Omni-Modal Frontier Architecture parameters
Massive 512K output codebases, single-shot 3D voxel world generation, native audio/video multimodal debugging, and high-context software synthesis.
| Metric | Claude Fable 5.1 | Space Bunny Alpha (Stealth) |
|---|---|---|
| SWE-bench Verified | 82.8% | 65.4% |
| MMLU-Pro | 92.4% | 86.2% |
| MATH-500 | 97.9% | 92.8% |
| Context Window | 1,500,000 tokens | 1,000,000 tokens |
| Input Pricing (per 1M) | $12.00 | $0.00 |
| Output Pricing (per 1M) | $60.00 | $0.00 |