Claude Fable 5.5 (Leaked Checkpoint) vs Space Bunny Alpha (Stealth)
A direct, empirical evaluation of Claude Fable 5.5 (Leaked Checkpoint) (Anthropic) against Space Bunny Alpha (Stealth) (MiniMax (Unannounced Stealth Release via OpenRouter)).
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.
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 5.5 (Leaked Checkpoint) | Space Bunny Alpha (Stealth) |
|---|---|---|
| SWE-bench Verified | 84.2% | 65.4% |
| MMLU-Pro | 94.6% | 86.2% |
| MATH-500 | 98.4% | 92.8% |
| Context Window | 1,500,000 tokens | 1,000,000 tokens |
| Input Pricing (per 1M) | $3.50 | $0.00 |
| Output Pricing (per 1M) | $17.50 | $0.00 |