Union Alpha turned out to be Pareto 26.9 by Circuit & Chisel, a hosted system that coordinates existing models such as GPT-6 Astra.
By Stealth Models.
Compare it with GPT-6 Astra, one of the models inside it
Facts as text
| Fact | Value |
|---|---|
| First seen | 16 Sep 2026 |
| Revealed | 18 Sep 2026 |
| Developer | Circuit & Chisel / Unbiased |
| Context | 262,144 tokens |
| Input | Text, image |
| Tool calls | Yes |
| Speed in our tests | about 26 tok/s |
| Access | Paid API; the free preview has ended |
Run it
Pareto 26.9 is a paid hosted service, so there are no weights to download.
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Text and images: CC BY 4.0, stealthmodels.com.
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