Meta releases Muse Spark Open, a new ‘open-weight’ AI model

Meta has released Muse Spark Open, positioning it as a US-built open-weight option for developers who need stronger multi-step reasoning and software engineering capabilities. Meta AI chief Alexandr Wang called it "the most capable US open-weight model to date," and the company says it can match or outperform comparable models from leading Chinese developers. The release gives builders another model whose weights can be accessed and adapted, though "open-weight" does not necessarily mean fully open source. Meta has not provided pricing, licensing terms, availability details, or benchmark scores in the announcement described here, so its performance claims still need independent testing. The launch also signals Meta's effort to regain ground as Chinese labs increasingly set the pace for openly available models.