arXiv Machine Learning

Response-Informed Value Estimation for Cost-Aware Multi-Turn LLM Routing

The paper introduces RIVET, a method for multi‑turn large language model routing that uses post‑call responses to train two value estimators: a deployable Routing Value Estimator that operates on pre‑call information, and a training‑only Response‑Informed Value Estimator that also observes the actual response. By conditioning on the response, RIVET turns response‑induced return variation into an observable covariate, reducing asymptotic estimation error. Experiments on the MINT benchmark show that RIVET solves more held‑out tasks than the strongest baseline while cutting total call cost by 74.7%.

arXiv AI
Sep 30

TwinRouterBench: Fast Static and Live Dynamic Evaluation for Realistic Agentic LLM Routing

arXiv:2605.18859v3 Announce Type: replace-cross Abstract: LLM routing matters most in long-horizon applications such as coding agents, deep research systems, and computer-use agents, where a single u...

By Pei Yang, Wanyi Chen, Tongyun Yang, Pengbin Feng, Jiarong Xing, Wentao Guo, Yuhang Yao, Yuhang Han, Hanchen Li, Xu Wang, Zeyu Wang, Jie Xiao, Anjie Yang, Liang Tian, Lynn Ai, Eric Yang, Tianyu Shi
arXiv Machine Learning
Sep 30

RAISE: Diagnosing Acquisition Collapse in Costly LLM Signals

The paper introduces RAISE, a diagnostic framework that tests whether a costly large language model (LLM) signal provides enough pre-call information to justify selective use. It identifies the failure mode of acquisition collapse, where an LLM appears useful overall but lacks actionable evidence for individual decisions. The authors demonstrate RAISE with Structured Hypothesis Embeddings (SHE) and evaluate it across multiple study designs, showing that predictable incremental benefit, rather than average lift, indicates recoverable selective value.

By Ying Yuan, Yu Wang, Yize Cheng, Xuyang Wu
arXiv AI
Jul 24

Routing Without Training: Controllable-Ratio LLM Offloading via Reliability Gating

arXiv:2607. 20481v1 Announce Type: new Abstract: Local-cloud collaboration is a practical way to deploy large language models under resource constraints, but existing methods often rely on trained routers or collaboration-aware finetuning that tie routing behavior to a particular operating regime.

By Evan Chen, Shiqiang Wang, Kevin S Chan, Su Wang, Christopher Brinton
arXiv AI
Oct 1

FlexRouter: Learning Complementary Model Sets for Flexible LLM Routing

FlexRouter is a routing framework for large language models that explicitly models model complementarity to maximize answer coverage. It formulates routing as a coverage-oriented subset selection problem and uses Determinantal Point Processes to capture both competence and redundancy. During inference, a greedy strategy based on marginal log-determinant gains allows the router to adaptively determine subset sizes without a fixed budget, achieving higher coverage with lower redundancy on the RouterEval benchmark.

By Wang Wei, Harry Yang, Tiankai Yang, Samyadeep Basu, Hongjie Chen, Andy Zhao, Franck Dernoncourt, Ryan A. Rossi, Hoda Eldardiry
arXiv Machine Learning
Oct 9

Amortized Off-Policy Evaluation for LLMs

The paper introduces PFN‑OPE, a prior‑data fitted network that performs amortized off‑policy evaluation (OPE) for large language models (LLMs). Unlike traditional OPE methods that must be retrained for each new logged dataset or reward definition, PFN‑OPE is pretrained once on a diverse set of contextual‑bandit tasks and can estimate value for any new logged dataset and target response in a single forward pass. Experiments on HelpSteer2 and UltraFeedback with Qwen, Llama, and Gemma policies show that PFN‑OPE reduces error by 2.0 to 9.3 times compared to the best baselines in reward‑shifted settings.

By Younwoo Choi, Leo Feng, Vincent Liu, Haanvid Lee