How to Use Union Alpha Free on OpenRouter

Need a free model to point your coding agent at? Union Alpha is up on OpenRouter for free while it is in preview, and it reads text and images in the same request.

That gets you a 262K context window, output of up to 131K tokens, and tool calling, with nothing to pay during the preview period.

Tutorial

1. Open OpenRouter in your browser.
2. Log in to your account, or create one if you do not have it yet.
3. Create an API key.
4. Use the model ID stealth/union-alpha. The model is built for coding, research, and AI agent work, and it handles images as well as text.
5. Set the base URL to https://openrouter.ai/api/v1
6. Paste the API key, the model ID, and the base URL into your coding agent.

Wrapping Up

You now have Union Alpha running through your own agent, on OpenRouter's free preview. Union Alpha is also on OpenCode Go as a free model for a limited time, if you would rather go that route. Keep in mind the free status and model availability can change at any time, so try it while the preview lasts.