English

MAVIS: Multi-Objective Alignment via Inference-Time Value-Guided Selection

Machine Learning 2026-02-17 v3

Abstract

Large Language Models (LLMs) are increasingly deployed across diverse applications that demand balancing multiple, often conflicting, objectives -- such as helpfulness, harmlessness, or humor. Many traditional methods for aligning outputs to user-specific preferences require fine-tuning models for each objective or for specific preference configurations, which is computationally expensive and inflexible. We introduce \textbf{MAVIS} -- \textit{Multi-Objective Alignment via Inference-Time Value-Guided Selection} -- a lightweight inference-time alignment framework that enables dynamic control over LLM behavior without modifying the base model's weights. MAVIS trains a set of small value models, each corresponding to a distinct objective. At inference time, these value models are combined using user-specified weights to produce a tilting function that adjusts the base model's output distribution toward desired trade-offs. The value models are trained using a simple iterative algorithm that enables monotonic improvement of the KL-regularized policy. We show empirically that MAVIS achieves a superior pareto front compared to baselines which fine-tune per-objective models and combine them post hoc or train a single preference-conditioned value model for guidance. Our code is available at https://github.com/5-Jeremy/MAVIS/tree/main.

Keywords

Cite

@article{arxiv.2508.13415,
  title  = {MAVIS: Multi-Objective Alignment via Inference-Time Value-Guided Selection},
  author = {Jeremy Carleton and Debajoy Mukherjee and Srinivas Shakkottai and Dileep Kalathil},
  journal= {arXiv preprint arXiv:2508.13415},
  year   = {2026}
}

Comments

32 pages, 7 figures

R2 v1 2026-07-01T04:55:47.836Z