Model Guide
Union Alpha with Hermes Agent: What Is Confirmed, and How to Route It
Union Alpha arrived in September 2026 as an unattributed stealth model with a very large context window, and searches for it spiked before anyone knew whose model it was. It has since been revealed as Pareto from Unbiased. This guide separates what is confirmed from what is not, and shows the exact routing config for Hermes Agent and OpenClaw.
unbiased/pareto: $2.50 per million input tokens, $0.25 per million cached input tokens, $7.50 per million output tokens, served by Unbiased. The union-alpha codename is not in the public catalog. Prices and availability change, so verify against the live catalog before you configure anything.What a stealth launch actually is
A stealth model is published under a codename with the provider deliberately withheld. The point is to collect reactions that are not anchored to a brand, and to watch how the model behaves under real load before a named launch. It is a marketing and load-testing exercise, not a technical category, and it has one practical consequence for you: the slug is temporary by design.
Union Alpha followed that pattern closely. It appeared in mid-September 2026 with no parameter count, no architecture note, and no downloadable weights. The free preview window was announced as roughly a week and, according to the account behind the model, was cut short after about a day because demand exceeded what the preview could serve.
What is confirmed, and what is not
| Claim | Standing |
|---|---|
| Positioned for agentic coding, research, and long-context work | Stated at launch |
| 262,144-token context window | Stated at launch |
| Image input and tool calling; 131,072-token max output | Listed on the live OpenRouter entry |
| Free during the preview, not trained on user data | Stated for the preview; the free period has ended |
| Provider is Unbiased; model named Pareto | Confirmed by OpenRouter at the reveal |
| A composite model rather than a single set of weights | Stated by the provider |
| Parameter count, weights | Never published |
| Benchmark parity with frontier models | Third-party claims; treat as unverified |
| Paid pricing: $2.50 in / $7.50 out per million tokens | Listed on OpenRouter as of 22 September 2026 |
The row to hold loosely is the benchmark one. The identity question is settled, because OpenRouter itself announced the reveal. How well a composite model performs on your workload is not settled by anyone’s leaderboard.
Check availability before you configure
Do this first. A model guide that tells you to paste a slug without checking whether it resolves is how an agent ends up silently failing over on every turn.
curl -s https://openrouter.ai/api/v1/models \
| grep -oiE '"id":"(unbiased/pareto|[^"]*union-alpha[^"]*)"'On 22 September 2026 this printed unbiased/pareto. No output means the slug is not currently routable through that aggregator, and no amount of config will change that. Use the id field exactly as printed — that string, not the display name, is what both frameworks need.
Route it in Hermes Agent
The reliable path is the CLI, which writes the config for you and avoids the shape mistakes below:
hermes modelIf you are editing ~/.hermes/config.yaml directly, Hermes keeps the provider in its own key and does not fold it into the model string:
model:
default: unbiased/pareto
provider: openrouterThrough an aggregator, the default carries that aggregator’s own slug while provider names the aggregator. Editing the model key on a running gateway takes effect on the next message; a change to API keys or tool config needs a gateway reload:
hermes gateway restartNote that is hermes gateway restart, not hermes restart.
Route it in OpenClaw
OpenClaw takes a single provider/model string, which is the shape difference people get wrong when copying between the two frameworks:
{
"agents": {
"defaults": {
"model": {
"primary": "openrouter/unbiased/pareto"
}
}
},
"models": {
"providers": {
"openrouter": { "apiKey": "<your-key>" }
}
}
}Do not translate the Hermes form into OpenClaw by analogy or the reverse. Hermes uses the aggregator’s slug in model.default with provider alongside it; OpenClaw prefixes the aggregator onto the model string. Each is correct only in its own file.
Configure a fallback before you rely on it
This is the part that matters more than the routing. A stealth slug can be withdrawn between one turn and the next, and Union Alpha’s preview ending a day into a week-long window is exactly that scenario: any agent pinned to the codename stopped working when the slug changed to unbiased/pareto. A newly named model with a single serving provider carries a smaller version of the same risk. For an agent that runs unattended — scheduled jobs, a messaging bot, anything you are not watching — configure a stable fallback model so a withdrawn preview degrades instead of failing.
A reasonable pattern: keep a known-good production model as the default, and switch to a preview slug only for sessions where you are present to see the results. See BYOK setup for keeping your own aggregator key, and fallback models for the stable options.
Is it worth testing?
A very large context window and tool calling are a genuinely useful combination for agent work, and it is now available under a name you can buy. At $7.50 per million output tokens it is not a budget model, so price a realistic session before switching an agent that runs all day. Test retrieval on your own documents rather than on a published benchmark, keep your current model as the fallback, and then decide.
OpenClaw Launch hosts the agent runtime; the model route and its terms remain between you and the provider you connect.
Union Alpha FAQ
What is Union Alpha?
Union Alpha was the codename of a stealth model that appeared on OpenRouter in mid-September 2026 without a named provider. OpenRouter then revealed it as Pareto from Unbiased, which calls it a composite model built for research, coding, and agentic work. No parameter count or downloadable weights have been published.
Can I use Union Alpha in Hermes Agent right now?
Yes, under its real name. The free stealth preview has ended, and the model is now listed on OpenRouter as unbiased/pareto at $2.50 per million input tokens and $7.50 per million output tokens (checked 22 September 2026). The old union-alpha codename is not in the public catalog, so configure the new slug.
Why does a stealth model need a different setup?
It does not need a different mechanism, but it does need a different habit. A stealth slug can be withdrawn without notice, so configure a fallback model and avoid pinning an unattended agent to a preview slug as its only route.
Does this work on OpenClaw as well as Hermes Agent?
Yes. Both frameworks route models through an aggregator, but the config shape differs: OpenClaw takes a single provider/model string, while Hermes keeps the provider in its own key. Both forms are shown below.
Is a long context window the same as long-context accuracy?
No. A 262,144-token window states what the model will accept, not how reliably it retrieves from the middle of that window. Benchmark on your own documents before moving a production workload onto any long-context claim.