Sam Witteveen · 2026-10-19 · notable
Sam Witteveen — 'Meta's New Models & Agent'
Sam Witteveen tests Meta's open 816B Muse Spark Open against Muse Wonder and Reflection's Beam, and covers the Muse license, the closed Wonder models, pricing, LM Arena results and who should use Spark Open.
Sam Witteveen sorts out what Meta made open with Muse Spark Open, and what it kept closed.
What is it?
'Meta's New Models & Agent' went up on Sam Witteveen's channel on 19 October 2026. The video looks at Muse Spark Open, Meta's 816B open-weights model, and asks which parts of the Muse release are open and which stayed proprietary.
How does it work?
The chapters cover Spark Open's specs and its rank in the open field, a benchmark comparison with Reflection's Beam, and the size and license gap between Beam and the Muse license. The video then turns to the closed Muse Wonder and Wonder Full, pricing and access, LM Arena results, Alexandr Wang's account of how Meta built Muse, an eval-spreadsheet method and a side-by-side demo against Muse Wonder.
Why does it matter?
Two large open-weight models landed in the same week, under different licenses. A test that puts Spark Open next to Beam and Meta's own closed models helps builders decide which one to self-host before they download hundreds of gigabytes of weights.
Who is it for?
developers choosing an open-weight model