What is Space Bunny Alpha?
Space Bunny Alpha is a stealth large language model on OpenRouter with a 1,000,000-token context window, native multimodal input, adjustable reasoning, and standout coding performance — and it is free during the preview. Here is what the Space Bunny model actually is, who might be behind it, and how to try it in minutes.
The short version
Space Bunny Alpha (model id stealth/space-bunny-alpha) is an anonymous-provider LLM that appeared on OpenRouter on 2026-09-23. It is a reasoning model: it produces hidden reasoning tokens before the visible answer, and you can dial the reasoning effort up or down. It accepts text, images, audio, and video as input and returns text. It has a million-token context window, is very fast, and is especially strong at coding. During the OpenRouter preview it is free to use.
The stealth preview — and who might have made it
"Stealth" on OpenRouter means the real provider is hidden while a model is in preview. Labs use stealth launches to gather usage and feedback before attaching their brand. That is the case here: nobody has officially claimed Space Bunny Alpha yet.
Community sleuths have reverse-engineered the tokenizer and probed its behavior, and the leading guess is that Space Bunny is a build of MiniMax M3. Treat that as an educated hypothesis, not a fact — the identity is unconfirmed until the provider says so. This site is independent and is not the official provider; we just make the model easy to try.
A 1,000,000-token context window
The headline capability is context. Space Bunny Alpha can hold up to 1,000,000 input tokens and emit up to 524,288 output tokens in a single call. That changes what you can do in one request:
- Load an entire repository and ask for a cross-file refactor or review.
- Feed a book-length document, contract, or spec and query it directly — no chunking or RAG plumbing.
- Keep long agent sessions coherent without aggressively summarizing history.
- Generate very large outputs — full files, long reports, big data transforms — in one shot.
Multimodal input, reasoning, and coding
Native multimodal
Send text, images, audio, and video in the same prompt. It reasons over all of them and returns text.
Adjustable reasoning
It thinks before it answers, producing hidden reasoning tokens. Turn effort up for hard problems or down for speed.
Strong at code
Fast inference plus a huge context make it a good fit for whole-repo coding agents and long refactors.
Is Space Bunny Alpha free?
Yes — it is free while it is in the OpenRouter stealth preview. Preview models can be rate-limited, changed, or withdrawn without notice, so treat free access as temporary and build with a fallback in mind.
How to try the Space Bunny model
There are three easy ways to get your hands on it:
- Free playground — run it in your browser with no signup on our playground.
- In your coding agent — wire it into a tool like OpenCode and let it work across your codebase.
- Hosted API — call our OpenAI-compatible endpoint at
https://spacebunnymodel.com/api/v1with a key likesb_live_.... Get an API key or read the usage guide.
curl https://spacebunnymodel.com/api/v1/chat/completions \
-H "Authorization: Bearer sb_live_..." \
-H "Content-Type: application/json" \
-d '{
"model": "stealth/space-bunny-alpha",
"messages": [{ "role": "user", "content": "Explain this repo." }]
}'Space Bunny Alpha specs
- Model id:
stealth/space-bunny-alpha - Availability: OpenRouter, stealth preview since 2026-09-23
- Context window: 1,000,000 tokens
- Max output: 524,288 tokens
- Input modalities: text, image, audio, video
- Output: text
- Type: reasoning model, adjustable reasoning effort
- Strengths: coding, very fast inference
- Provider: anonymous (community guess: MiniMax M3, unconfirmed)
- Price: free during the preview