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, routing tasks to Opus 4.7 as an advisor when needed.
GLM invoked Opus sparingly, just 0.83 times per task on average.
The hybrid setup beat Opus on both quality and cost: 18% all-pass vs 14%, at $368 vs $954 across the same 100 tasks.
2) Post-training can push open models to frontier-level legal performance.
On a 100-task slice of our Legal Agent Benchmark (LAB), SFT moved Kimi 2.6's all-pass rate from 11% to 15%, beating Opus' 14%.
But the cost gap was even more striking: $84 vs $954 across the same 100 tasks, or ~11x cheaper.
We're excited to continue working with @FireworksAI_HQ on the next generation of open-source legal agents.
