Muse Spark 1.2

Muse Spark 1.2 is a new AI model from Meta. If you think of it in car terms, it isn't the visible body of the car but the engine that generates the power underneath. What people actually interact with is Muse Code, a tool that writes code for you in the terminal, but the real brain behind it—the part that understands language and produces the code—is this model.

Meta describes this model as being used to plan, execute, and verify complex development work that requires multiple steps to complete, meaning changes that span an entire project rather than a single file. However, specific details such as the model's size, the data used to train it, and benchmark scores that would indicate its performance have not yet been disclosed.

Around the same time, Meta also released another model, Muse Glimmer, making its internal weights fully available for anyone to download and use. Muse Spark 1.2, by contrast, has no confirmed release scope or terms of use.

In articles, it appears in phrasing like "Muse Code is powered by Muse Spark 1.2, a new model Meta released alongside it." A common misunderstanding here is assuming that Muse Spark 1.2 was released openly for anyone to download, just like Muse Glimmer. In reality, its parameter size, release scope, and access conditions remain unconfirmed, so there's no basis for treating the two models as having the same nature.