arXiv Computation and Language
Oct 28

A Unified Approach to Routing and Cascading for LLMs

The paper introduces a unified framework called cascade routing that combines routing and cascading strategies for selecting large language models (LLMs) in agentic systems. It derives an optimal cascading strategy, proves the optimality of an existing routing strategy, and demonstrates that integrating both leads to a theoretically optimal approach. Experiments show cascade routing consistently outperforms the individual methods, and the study identifies high‑quality estimators as crucial for effective model selection.

By Jasper Dekoninck, Maximilian Baader, Martin Vechev
arXiv Computation and Language
Aug 27

VDAR-Router: Adaptive LLMs Routing via Verbalized Query Difficulty Analysis Retrieval

The paper introduces VDAR-Router, a routing framework for large language models that uses verbalized query difficulty analysis to guide model selection. It first generates an explicit difficulty profile for each query, retrieves historical examples with similar profiles, and then estimates model suitability to choose a model based on a reward function balancing performance and cost. Experiments on three datasets show that VDAR-Router consistently outperforms existing baselines in cost‑performance trade‑offs, and case studies confirm that explicit difficulty analysis improves example relevance and routing reliability.

By Yu-Chien Tang, Jun-Chen Hung, Wen-Chih Peng, An-Zi Yen