UNION ALPHA Try the model
Stealth model Latest information about Union Alpha

UnionAlpha.

Intelligence, under cover - latest updates.

Multiple AI models. One API for coding, research, and creative work. Estimated paid pricing: $0.50 input / $1.50 output per 1M tokens. Free during preview.

Try Union AlphaOpen the playground
76.1LiveBench overallIndependent performance. See the scores.
Union Alpha’s metallic silver and graphite ribbon logo, with a red accent
stealth/union-alpha
262K context. Image input. Tool calling.
262K
Context window · 262,144 tokens
131K
Max. output · 131,072 tokens
Text+ image
Multimodal input · text output
$0.50/ $1.50
Estimated per 1M tokens · input / output
Model capabilitiesstealth/union-alpha · OpenRouter & OpenCode
Demodokos FoundryLocal AI audio

Union Alpha wrote it.
Demodokos performed it.

Expressive voices. Original music. Produced on a local PC.

Meet the studio

Scene 01 · Local AI performance

01 / General benchmarks

The scores.

02 / Custom SVG benchmarks

SVG in action.

03 THE TECHNOLOGY

Strong results.
A smaller bill.

Multiple LLMs work in parallel. Union Alpha synthesizes their strengths into one answer, delivering ensemble performance through a single, low-cost API.

Model ensembling & generative fusionRead the research
Demodokos Foundry
MUSIC · VOICE · VIDEO

A complete scene.
On your own PC.

Turn dialogue, audio, or video into a finished scene with original AI music, expressive voices, translation, and subtitles.

Local generationPrivate by designState-of-the-art AI

Scene 02 · Local AI performance

Create with DemodokosWindows · Your GPU
YOUR LOCAL WORKSPACE ON DEVICE
Demodokos Foundry running locally, with dialogue, music, and waveforms arranged in its production workspace.
Music, voices, and subtitles. One production workspace.
Direct the performanceEmotion, delivery & timing
Compose the soundtrackHigh-quality local AI music
Take it across languagesTranslation, dubbing & subtitles
Finish every detailMix, synchronize & export
04 COMPARE THE MODELS

The cost advantage.

Estimated paid rates: $0.50 input / $1.50 output per million tokens. Currently free in preview.

Specifications & token costs

Full OpenRouter comparison
Model specifications and expected Union Alpha token pricing, 16 September 2026.
SpecificationUnion AlphaClaude Opus 5
Context window262,144 tokens1,000,000 tokens
Maximum output131,072 tokens128,000 tokens
Input modalitiesText, imagesText, images, files / PDFs
Output modalityTextText
Input / 1M tokens$0.50 Expected price · preview currently free$5.00 Listed price
Output / 1M tokens$1.50 Expected price · preview currently free$25.00 Listed price
Tool callingListedListed
Response-format parameterListedListed
Structured-output metadataNot listedListed · provider-dependentConfirm schema enforcement with your provider
Reasoning controlsNot listedListed

Specifications and Opus 5 rates: OpenRouter public model catalog · Union Alpha paid rates are projected.

05 TRY UNION ALPHA

Try Union Alpha.

Run a prompt here or copy the request in cURL, Python, or JavaScript. You can also chat directly on OpenRouter.

NO API KEY TO COPY

Try it in OpenRouter Chat

Sign in to OpenRouter and select Union Alpha from the model picker.

Open hosted chat
REQUEST / UNION ALPHATEXT PLAYGROUND

Prompts go directly to OpenRouter. Credentials stay in this tab and are not saved to browser storage. Manage OpenRouter keys ↗

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "stealth/union-alpha",
    "messages": [{"role": "user", "content": "Hello, Union Alpha."}],
    "max_tokens": 1024
  }'
API key read from your environmentAPI docs
MODEL RESPONSEReady
Enter a prompt and connect OpenRouter to start.
OpenRouter model & chatIntegration quickstartAlso available on OpenCode Zen
06 A FEW ANSWERS

Before your
first request.

What does “stealth” mean?

The developer’s identity is undisclosed. On OpenRouter, the model ID is stealth/union-alpha.

Is Union Alpha free to use?

Yes during the current preview. OpenRouter and OpenCode list $0 input and output pricing as of 16 September 2026. The benchmark implies a likely eventual rate near $0.50 input / $1.50 output per million tokens, but no paid price has been announced. Check the current pricing and availability before a large workload.

How does Union Alpha compare with Claude Opus 5?

Union Alpha has a 262,144-token context window and allows up to 131,072 output tokens. Opus 5 has a 1,000,000-token context window and a 128,000-token output limit. Both accept images and support tool calling. Union Alpha is currently free; its modeled paid rate is ~$0.50 input / ~$1.50 output per million, versus Opus 5 at $5 / $25. Use the comparison and cost calculator for your workload.

Does Union Alpha support images and tool calling?

Yes. The API accepts text and images, supports tools and tool_choice, and offers a response_format parameter. The playground on this page sends text only; use the API for image inputs and tool integrations.

How does Union Alpha perform on Terminal-Bench v4?

OpenCode's chart places Union Alpha at around 51%, near Fable 5.1 Max and Opus 5 Max and just below Astra (high), with an anticipated cost of roughly $1.50 per task.

Can I run Union Alpha locally?

Union Alpha is available through hosted inference on OpenRouter and OpenCode Zen. Downloadable model weights are not listed.

Can I try Union Alpha without an API key?

Yes. Sign in to OpenRouter Chat and select Union Alpha. To use the playground here, connect your OpenRouter account and enter its one-time authorization code. You do not need to create or copy an API key manually.

What happens to my prompt and credentials?

Prompts are sent directly to OpenRouter under its privacy policy. Credentials stay in this tab’s memory. Pasted keys are cleared after each request; connected keys are cleared when you disconnect or leave. Disconnecting here does not revoke the key on OpenRouter. You can revoke it in OpenRouter key settings.

Try Union Alpha.

Available through OpenRouter and OpenCode Zen.

Explore Union Alpha