Ox Alpha: OpenRouter's New Stealth Model, Explained
An anonymous model appeared in OpenRouter's catalog overnight with a million-token context window, mandatory reasoning, and a zero-dollar price tag. Here is the useful signal — and the speculation we are deliberately leaving out.
Input
$0 / 1M
Output
$0 / 1M
Context
1,048,576
Max output
131,072
What actually launched?
OpenRouter's official model API lists Ox Alpha under the provider namespace stealth with the model ID stealth/ox-alpha. The record says it is designed for coding, sustained agentic work, long-horizon software engineering, complex reasoning, and production workloads. A third-party release tracker places it among the models surfaced on August 20, 2026.
That is enough to call it a real catalog release, but not enough to identify its maker. There is no public developer attribution, parameter count, training cutoff, benchmark score, or open-weight checkpoint in the record we verified.
The important capabilities
Long context, not a promise of long-context quality
The published context limit is 1,048,576 tokens, with up to 131,072 completion tokens. That makes large repositories, long agent traces, and document-heavy workflows plausible test cases. It does not, by itself, prove reliable retrieval across a million-token prompt.
Reasoning is mandatory
OpenRouter marks reasoning as mandatory and exposes low, high, and max effort levels. Expect the model to spend part of its completion budget on internal reasoning before the visible answer; compare workloads by total tokens and latency, not visible output alone.
Built for tools and multimodal input
The API record lists text, image, and video input, plus tools, structured response controls, and reasoning parameters. That points toward coding agents and visual software workflows, although no independent tool-call or vision evaluation is published yet.
Treat the free tier as a test window
The current price is $0 for both input and output, but the model is explicitly a stealth/preview release. Provider identity, availability, rate limits, pricing, and data handling can change without the stability guarantees of a named GA model. Do not send secrets, customer data, or regulated information until you have verified the active provider's policy.
Where to use Ox Alpha free right now
OpenRouter
Open ↗Direct model page
Use the model directly with the OpenRouter chat UI or the OpenAI-compatible API. The model ID is `stealth/ox-alpha` and the current input/output price is $0.
OpenCode
Open ↗Free coding agent
Install OpenCode, then check `/models` for the free `x-preview-f-free` entry. OpenCode's live Zen catalog exposes that alias, but its public docs have not yet labeled it Ox Alpha, so verify the mapping before starting a long run.
Command Code
Open ↗Free model on paid harness
Command Code's official Ox Alpha page lists `stealth/ox-alpha` at $0 input, output, and cache-read cost while the preview lasts. The Command Code harness currently requires Go or a higher plan.
Free availability is temporary and capacity-limited. Check each linked model page or live model picker before sending work.
How to evaluate Ox Alpha this week
- Start with disposable workloads. Use synthetic repositories, public documents, and non-sensitive agent tasks.
- Measure total economics. Log input, visible output, reasoning tokens, latency, tool-call errors, and retry rates.
- Test the failure modes. Long-context recall, structured output, tool selection, code repair, and multi-step task completion matter more than a single chat demo.
- Keep a fallback. Route production traffic to a named model if Ox Alpha disappears, changes behavior, or hits a free-tier limit.
Bottom line
Ox Alpha is worth watching because its published shape matches where the market is moving: reasoning-heavy, tool-capable models with very large context windows and aggressive introductory pricing. The strongest claim we can make today is narrower: it is a real, free, anonymous OpenRouter preview with serious infrastructure-level specifications. Its quality, origin, retention policy, and staying power remain open questions.
Sources: OpenRouter model API,OpenCode live model list,Command Code Ox Alpha page, andPrice Per Token's release tracker. Catalog facts last checked 21 Aug 2026.