GPT-6.1 Sol vs Union Alpha (Stealth)
A direct, empirical evaluation of GPT-6.1 Sol (OpenAI) against Union Alpha (Stealth) (OpenRouter & OpenCode).
GPT-6.1 Sol
Developed by OpenAI · Proprietary Frontier Workhorse Engine parameters
Near-Astra reasoning at 1/5th price ($1.25/$5.00), SWE-bench Verified 74.8%, OSWorld 2.0 desktop agent automation, and sub-80ms Ultrafast Mode.
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 | GPT-6.1 Sol | Union Alpha (Stealth) |
|---|---|---|
| SWE-bench Verified | 74.8% | 74.2% |
| MMLU-Pro | 92.4% | 89.8% |
| MATH-500 | 96.2% | 95.4% |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Input Pricing (per 1M) | $1.25 | $0.00 |
| Output Pricing (per 1M) | $5.00 | $0.00 |