# Muse Spark Open

Muse Spark Open is a model from Meta with open weights, released on 15 Oct 2026. The context window is 1,048,576 tokens.

- Developer: Meta
- Id: muse-spark-open
- Released: 2026-10-15T00:00:00.000Z
- Sighting: 2026-10-15T16:55:52.839Z
  - [evidence link](https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B)
- Status: Released
- Open weights: 2026-10-15
  - [evidence link](https://research.meta.ai/blog/muse-spark-open)
- API availability: 2026-10-15
  - [evidence link](https://research.meta.ai/blog/muse-spark-open)
- Canonical: https://alexgetman.com/models/meta/muse-spark-open/

## Questions

### What is the context window of Muse Spark Open?

The context window is 1,048,576 tokens.

### Are the weights of Muse Spark Open publicly available?

Yes. Meta publishes the weights.

### When was Muse Spark Open released?

On 15 Oct 2026.

## Timeline

**Confirmed use**
- 2026-11-11T09:25:58.367Z · [Meta · Research articles · Introducing Muse Spark Open, The Most Capable US Open‑Weight Model to Date](https://research.meta.ai/blog/muse-spark-open)

## Evidence links

- [Artificial Analysis · benchmarks](https://artificialanalysis.ai/models)
- [Command Code · models](https://commandcode.ai/docs/reference/cli/models)
- [Vertex AI · Model Garden](https://console.cloud.google.com/vertex-ai/publishers/meta/model-garden/muse-spark-open)
- [review](https://dev.meta.ai/docs/muse-spark-open)
- [review](https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B)
- [huggingface:meta-models](https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B-NVFP4)
- [models.dev · catalogue](https://models.dev/#Muse-Spark-Open-816B-A42B)
- [models.dev · catalogue](https://models.dev/#muse-spark-open)
- [OpenCode · discovery](https://opencode.ai/data/meta/muse-spark-open)
- [OpenRouter](https://openrouter.ai/meta/muse-spark-open)
- [review](https://research.meta.ai/blog/muse-spark-open)
- [Vercel AI Gateway](https://vercel.com/ai-gateway)
- [DesignArena · website](https://www.designarena.ai/leaderboard/website)

## Signals

- [Muse Spark Open: Open weights](https://alexgetman.com/signals/2026/10/15/muse-spark-open-3/)