Claude Opus 5.5 (Canary Checkpoint) vs Union Alpha (Stealth)
A direct, empirical evaluation of Claude Opus 5.5 (Canary Checkpoint) (Anthropic) against Union Alpha (Stealth) (OpenRouter & OpenCode).
Claude Opus 5.5 (Canary Checkpoint)
Developed by Anthropic · Frontier Mixture-of-Experts Architecture parameters
Autonomous repository issue resolution (81.4% SWE-bench Verified), native 3D glTF/OBJ mesh synthesis, and sub-300ms time-to-first-token.
Union Alpha (Stealth)
Developed by OpenRouter & OpenCode · Multi-Model Ensemble Mixture parameters
Terminal coding agents, pull-request synthesis, multi-model consensus verification, and zero-cost autonomous refactoring.
| Metric | Claude Opus 5.5 (Canary Checkpoint) | Union Alpha (Stealth) |
|---|---|---|
| SWE-bench Verified | 81.4% | 74.2% |
| MMLU-Pro | 94.2% | 89.8% |
| MATH-500 | 97.9% | 95.4% |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Input Pricing (per 1M) | $5.00 | $0.00 |
| Output Pricing (per 1M) | $25.00 | $0.00 |