Union Alpha (Stealth) vs GPT-6 Astra
A direct, empirical evaluation of Union Alpha (Stealth) (OpenRouter & OpenCode) against GPT-6 Astra (OpenAI).
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.
GPT-6 Astra
Developed by OpenAI · Proprietary Frontier parameters
Complex multi-step engineering, formal math proofs, autonomous computer/browser navigation, and CAD synthesis.
| Metric | Union Alpha (Stealth) | GPT-6 Astra |
|---|---|---|
| SWE-bench Verified | 74.2% | 79.4% |
| MMLU-Pro | 89.8% | 91.2% |
| MATH-500 | 95.4% | 98.6% |
| Context Window | 256,000 tokens | 1,050,000 tokens |
| Input Pricing (per 1M) | $0.00 | $10.00 |
| Output Pricing (per 1M) | $0.00 | $50.00 |