Baseten Open-Sources joey-1: A 2B Decision Model for Zero-Token Routing
Baseten has open-sourced joey-1, a 2B-parameter decision model that outputs calibrated probabilities via a single prefill pass without generating any text tokens. Scoring 63.30 on the Jev Decision Index, it ranks as the top model under 4B parameters with a P50 latency of just 20ms, offering a highly efficient solution for agent routing and classification tasks.
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▲ Marktechpost AI · 2026-10-29 21
▲ Baseten just open-sourced joey-1, a 2B decision model that answers routing and classification questions without generating a single token.
The key idea is simple. You send a state plus typed questions (choice, yes/no, score). joey-1 reads everything in 1 shared prefill and returns a calibrated probability for every option. No text to parse, no generation cost.
The numbers (self-reported): 63.30 on the Jev Decision Index 0.4 public split, #37 of 230 and the top model under 4B. That is ahead of Perplexity Decider Flash v1.2 (60.06) at the same $0.01 price. It is a trade-off though: it trails its 9B sibling elephant-1 by 8.94 points (63.30 vs 72.24), in every area.
Baseten reports 20 ms P50 for a 2,000-token request, about 2.5x faster than elephant-1. $0.01 per 1M input tokens, MIT weights on Hugging Face, self-hosts on 1 CUDA GPU......
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