# Muse Spark Open

Muse Spark Open is an AI model released by Meta on Oct 15 2026. It has 816B parameters, a 1M context window and open weight. Tracked results include 89.2% on MCP Atlas, 60% on DeepSWE 1.1 and 76.4% on Terminal-Bench 2.1.

## Facts

| Field | Value |
| --- | --- |
| Model | Muse Spark Open |
| Developer | Meta |
| Release date | Thursday, Oct 15 2026 |
| Licensing | Open Weight |
| Parameters | 816B |
| Context window | 1M |

## Tracked benchmark scores

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| DeepSWE 1.1 | 60% | Lab | Artificial Analysis' independent test of deep, agentic software-engineering work — the AI has to plan and carry out substantial coding tasks end to end. (Version 1.1 of the test.) Higher is better. |
| Terminal-Bench 2.1 | 76.4% | Lab | Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better. |
| MCP Atlas | 89.2% | Lab | Can the AI chain together many tools and steps to complete one bigger task, rather than doing just a single thing? Higher is better. |
| JobBench | 61.8% | Lab | Tests the AI on professional workplace tasks that require using real work tools — the kind of multi-step jobs an office worker handles. Higher is better. |
| GDPval-AA v2 | 1401 | Lab | economically valuable knowledge work (v2, re-based Elo) |

## About Muse Spark Open

Muse Spark Open, released October 15, 2026, brought downloadable weights to Meta's Muse Spark line after its closed releases earlier that year. Meta positioned the natively multimodal model for coding, long-running agent tasks and multi-step reasoning, with 816B total parameters, 42B active and a 1M-token context window. The weights were released under the Muse Model License with limited commercial terms. Meta also announced hosted inference partners and support for inference engines including vLLM, SGLang and MLX, and demonstrated local agent workflows on two Apple M5 Ultra Mac Studios.

Meta's launch scorecard reported results at xhigh reasoning: 61.8% on JobBench, 89.2% on MCP Atlas, a GDPval-AA v2 Elo of 1401, 76.4% on Terminal-Bench 2.1 using Terminus 2, and 60% on DeepSWE 1.1 using Muse Code. The evaluation report identified the benchmark providers and harnesses behind the results; the launch table also included HLE-Diamond and tool-assisted visual tests, which use different question sets or tool conditions from the standard HLE and unaided BabyVision rows tracked here.

## Questions and answers

### When was Muse Spark Open released?

Muse Spark Open was released by Meta on Thursday, Oct 15 2026.

### Who made Muse Spark Open?

Muse Spark Open was built by Meta. Develops the open-weight Llama series of models. Committed to open-source AI research.

### What benchmark scores did Muse Spark Open get?

Muse Spark Open reports 5 tracked benchmark scores — DeepSWE 1.1: 60%; Terminal-Bench 2.1: 76.4%; MCP Atlas: 89.2%; JobBench: 61.8%; GDPval-AA v2: 1401. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data. It holds the best score among all models tracked here on MCP Atlas.

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

Muse Spark Open has a context window of 1M. That is the maximum amount of input plus output the model can hold in a single request.

### How many parameters does Muse Spark Open have?

Muse Spark Open is reported at 816B parameters.

### Is Muse Spark Open open source?

Partly. Muse Spark Open is an open-weight model: the trained weights are free to download and run locally or on your own infrastructure, but the training data and code are not fully released and the license may restrict some commercial uses. It is not open source in the strict sense.

### What came before and after Muse Spark Open?

Meta's previous tracked release was Muse Wonder Full on Oct 12 2026, 3 days earlier. It is the most recent Meta model tracked on AI Release Tracker.


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Canonical page: https://aireleasetracker.com/model/meta/muse-spark-open
Site index: https://aireleasetracker.com/llms.txt
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.