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SwapMuse Spark Open
Meta's Muse Spark Open is a text model for writing and answering questions that is free to download under restricted use terms.
Release page →The basics
Released
What it does
Knowledge cutoff
The latest events it learned about
Download
Price and limits, for developers
Input
Per million tokens
Output
Per million tokens
Cached input
Per million tokens
Context window
How much it takes in at once
Longest answer
How they score
Combined test score
Epoch Capabilities Index · Epoch AI
GPT-5.6 Sol scores 8 points higher.
Chat answers, by people's votes
LMArena text, adjusted for style · LMArena
Only GPT-5.6 Sol is in this ranking, which lists the most-voted models.
Building apps, by people's votes
LMArena WebDev · LMArena
In blind votes, people pick GPT-5.6 Sol over Muse Spark Open about 62% of the time.
Green marks the better of the two on each row, red the other. Rows where one side isn't listed, or where the gap is too close to call, stay plain.
Popular comparisons
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MAI-Image-2.6Not sure where to start? Which AI should I use? gives a pick for what you want to do. How to read AI rankings explains the numbers.
Rankings from LMArena and Epoch AI, both CC BY 4.0, updated . Developer prices, context windows and knowledge cutoffs from the labs' own listings on models.dev and from OpenRouter. The app links go to each maker's own app when no source says exactly where the model is available.