Meta has released Muse Spark 1.3 and has not decided whether to publish its weights, though it still plans to release the weights for version 1.2. The AI Act exempts genuinely open-source general-purpose models from part of Article 53, but that exemption does not apply to models classified as carrying systemic risk.
Meta has released Muse Spark 1.3, its most capable model so far. Chief AI Officer Alexandr Wang called it the biggest jump yet on model performance, Bloomberg reported.
Wang put it level with the field. He called it competitive with Anthropic’s Claude Fable 5.1, better than OpenAI’s GPT-5.6 Sol at coding, and ahead of any current Chinese model.
The weights are the open question. Meta has not decided whether to publish 1.3’s, still plans to publish 1.2’s, and the first Muse Spark arrived in April closed source.
Those comparisons are hard to check. Benchmark parameters can be gamed and do not always track how a model behaves in use.
