Stealth models are AI models that appear on OpenRouter under an anonymous “Stealth” provider, usually with a codename ending in Alpha, free pricing, and no developer name. They are pre-release previews: the lab behind the model collects real-world usage for a short window, then reveals the model under its official name. The current one is Ox Alpha, listed August 20, 2026.
This page tracks two things: which stealth models are live on OpenRouter right now (refreshed automatically from OpenRouter’s public model list), and the complete history of past stealth codenames and what they turned out to be.
Live: stealth models on OpenRouter right now
| Model | Listed since | Context | Price (in / out) | Input | Status |
|---|---|---|---|---|---|
Ox Alphastealth/ox-alpha |
Aug 20, 2026 | 1,048,576 | $0 / $0 | text, image, video | Free preview |
Stealth reveal history
| Stealth codename(s) | Revealed as | When |
|---|---|---|
| Quasar Alpha, Optimus Alpha | GPT-4.1 | April 2025 |
| Sonoma Sky Alpha, Sonoma Dusk Alpha | Grok 4 Fast | September 2025 |
| Pony Alpha | GLM-5 | February 2026 |
| Hunter Alpha, Healer Alpha | Xiaomi MiMo-V2 | March 2026 |
| Elephant Alpha | Ling-2.6-flash | April 2026 |
| Owl Alpha | LongCat-2.0 | June 2026 |
| Ox Alpha | Not yet revealed | August 2026 — listed Aug 20, 2026; reveal pending |
How stealth previews work
- Anonymous listing. The model is published by OpenRouter’s “Stealth” provider. OpenRouter only routes requests; it did not build the model.
- Free for a limited time. Stealth previews have been listed at $0 per token. The preview period is not announced in advance; the current Ox Alpha window is expected to end around August 27, 2026, but that date is an expectation, not a guarantee.
- Data terms. Stealth models run under OpenRouter’s Stealth Program terms. Prompts may be retained by the provider; the Ox Alpha listing states they are not used for training. Do not send personal or confidential information.
- The reveal. Every previous stealth model has eventually been announced under its official name. The history table above records each one.
Who is behind Ox Alpha?
Officially, nobody has claimed it. Independent fingerprinting analyses published by testers point toward the GLM family, with a minority view suggesting Xiaomi’s MiMo line — both are unconfirmed speculation until the developer reveals itself. We cover the evidence in Who made Ox Alpha? and will update this page the moment there is an official announcement.
Want to try the current stealth model? Chat with Ox Alpha for free with your own OpenRouter key, or read how to use Ox Alpha for free.