The vLLM Semantic Router team's Decision 2.0 is a set of six open decision models, from 0.6B to 27B parameters, each answering several typed questions about one message at once.
The team says each size beats the same-size open models it compared on JevArena, though its 27B and 4B models only draw level with AutoJev-27B and Decider 4B. Its Decision Index numbers come from its own run of version 0.2.1, not the 0.3 named in the launch post. The weights are Apache-2.0, and loading any of them runs code that ships with the weights.
How you can use it
Use it when one message needs several answers at once. For a complaint about a damaged order, it can say which team should handle it, whether the customer has a receipt and how urgent it is, all in one go. The smallest model is the quickest; the largest is slower but can read much longer messages.