Union Alpha✓ Catalog verified
Union Alpha is a multimodal model built for research, coding, and agentic workflows, while delivering frontier-level performance across a broad range of general-purpose tasks. Union Alpha is a stealth model....
Overview
Union Alpha is a multimodal model built for research, coding, and agentic workflows, while delivering frontier-level performance across a broad range of general-purpose tasks. Union Alpha is a stealth model....
Access: available through the official Stealth API. Context window: 262K.
Specifications
| API identifier | stealth/union-alpha |
| Provider | Stealth |
| Model type | Multimodal LLM |
| Context window | 262K catalog |
| Input modalities | text · image |
| Output modalities | text |
| Released | Sep 16, 2026 |
| Moderated | No |
| Architecture modality | text+image->text |
| Scheduled expiry | 2098-12-31 |
Pricing
Live pricing components for stealth/union-alpha as published in the catalog.
| Pricing component | Raw unit price | Normalized | Unit |
|---|---|---|---|
| Prompt tokens | $0 | $0.00 / 1M | Per input token |
| Completion tokens | $0 | $0.00 / 1M | Per output token |
| Request fee | N/A | N/A | Per request |
| Image fee | N/A | N/A | Per image unit |
| Web search fee | N/A | N/A | Per search request |
Cost calculator
Estimate monthly spend from your own token volumes.
Estimated Total Cost
$0Calculated from current list pricing in the ModelsAtlas catalog.Capabilities
| Capability | Status | What it means |
|---|---|---|
| Visual Understanding | ✓ Supported | Image and document analysis support |
| Audio Processing | Not advertised | Speech and voice aligned flows |
| Tool Calling | ✓ Supported | Supports tools / function calling |
| Self-Hosting | Not advertised | Deploy outside managed APIs |
Capability signals
Directional signals derived from model metadata and capability tags — not official benchmark submissions.
Quick start
Call Union Alpha through an OpenAI-compatible client.
from openai import OpenAI
client = OpenAI(
base_url="https://openrouter.ai/api/v1",
api_key="YOUR_API_KEY"
)
response = client.chat.completions.create(
model="stealth/union-alpha",
messages=[{"role": "user", "content": "Explain quantum physics."}]
)
print(response.choices[0].message.content)Alternatives
Closest models by context window from a different provider.
| Model | Provider | Context | Input /1M | Actions |
|---|---|---|---|---|
| Arcee AI: Trinity Large Thinking | Arcee Ai | 262K | $0.25 | View → |
| ByteDance Seed: Seed 1.6 | Bytedance Seed | 262K | $0.25 | View → |
Sources & attribution
Pricing and metadata are maintained in the ModelsAtlas catalog.
Frequently asked questions
How much does Union Alpha cost?
$0.00 per 1M input tokens and $0.00 per 1M output tokens on the official Stealth API.
What is the context window of Union Alpha?
Union Alpha supports up to 262K tokens of context.
Does Union Alpha support tool / function calling?
Yes, Union Alpha supports tool / function calling — you can register tools and the model will emit structured tool calls.
How do I access Union Alpha?
Use the official Stealth API with the model id `stealth/union-alpha`. See the Quick start section above for code examples.