Union Alpha with Hermes Agent: What Is Confirmed, and How to Route It

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

The middle row is the one to hold loosely. Attribution of a stealth model comes from reporting and inference rather than from the listing itself, and it is worth confirming on the provider’s own site before you make a procurement decision on it.

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 -i union-alpha

No output means the slug is not currently routable through that aggregator, and no amount of config will change that. If it returns a record, 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 model

If 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: <slug-as-listed>
  provider: openrouter

Through 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 restart

Note 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/<slug-as-listed>"
      }
    }
  },
  "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. 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, so it is worth a trial when it is available under a name you can buy. What it is not worth is rebuilding a working agent around a codename. Wait for the named release, price it, test retrieval on your own documents rather than on a published benchmark, 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

Related model guides

• Hermes Agent + OpenRouter
• Hermes Agent BYOK
• Hermes Agent + Jev
• Best Models for Hermes Agent