Meta open-sources Muse Spark Open, its top model stays closed

Meta has released Muse Spark Open, an open-weight AI model it calls the most capable US open-weight model ever. However, the company says it performs below Muse Wonder, its newest frontier model, which remains closed source.

Meta's Chief AI Officer Alexandr Wang said the company usually doesn't open-source its top models over safety concerns. Still, Meta plans to keep releasing strong open models. This is the second open release in the Muse series, after the 30-billion-parameter model Glimmer.

The move stands in contrast to what Meta founder Mark Zuckerberg said five weeks ago. On a podcast, he called it "extremely dangerous" for rivals to train better models without sharing them.