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Lumma-Fev-v2 released 4B and 27B decision models that answer with a probability per option in one forward pass, and the authors report 87.3 percent average accuracy against Jev's 81.2

AspireAI community · Hugging Face blog (FrontiersMind)
A decision model takes a state plus typed questions and returns a probability for every option in a single forward pass, so there is no generated sentence to parse and every answer carries a usable confidence. Lumma-Fev-v2 is that family across sizes, and this release ships the 4B and 27B versions with 0.1B and 0.6B to come; the 27B is fine-tuned from Qwen3.8-27B and the 4B from Qwen3.5-4B. The authors report 87.3 percent average accuracy for the 27B and 82.4 percent for the 4B across eight public benchmarks, against 81.2 percent for TypeSafe Jev 1.13.0, trained on about 300K samples with 8,192 tokens of context and bidirectional attention in the full-attention layers. Both checkpoints are public under Apache 2.0 on the Hub. These are the authors' own numbers against a Jev baseline they chose, and they say plainly where Jev still leads.
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