Google benchmarks cheap classifiers to route Gemini models by cost per task

Google ran a 50-question auto-graded coding-agent benchmark testing whether a lightweight classifier, TypeSafe's Jev, can route each task to the cheapest Gemini configuration that still answers correctly. A frozen regex and prompt-length heuristic scored 93.8% on the 16 development questions but dropped 23.2 points to 70.6% on 34 held-out tasks, while Jev reached 96.0% across the full suite. The strongest no-router setup, Gemini 3.8 Flash on low thinking, solved all 50 tasks, and a Jev router sending tasks to Flash-Lite first and escalating flagged ones also solved all 50 while reducing cost and response time; capping maxOutputTokens at 300 saved nothing on easy tasks and broke 7 of 25 hard ones.