Harvey just published a study showing a hybrid setup, open source GLM 5.1 as primary worker, routing to Opus 4.7 only when needed beats pure…

Harvey just published a study showing a hybrid setup, open source GLM 5.1 as primary worker, routing to Opus 4.7 only when needed beats pure Opus 4.7 on quality and costs less. This is the multi-model routing thesis proved in production on one of the hardest benchmarks in enterprise AI. The insight isn’t that open source beat frontier. It’s that smart routing beat brute force. Using the most expensive model for every task is not a quality strategy. It’s a laziness tax. The teams building routing layers that send each task to the right model at the right cost are now demonstrably ahead on both dimensions simultaneously. Inference optimization just became a first-class competitive advantage. Legal proved it first because the stakes forced the discipline. We partnered with @FireworksAI_HQ to train open-source models for legal. Here's what we found: 1) Hybrid legal agents can beat frontier models on quality and cost by routing selectively to a frontier advisor. We tested a hybrid setup where GLM 5.1 served as the primary worker, ro…

Source: Clem Delangue (X) | 2026-06-03