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

Fuente: arXiv
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Main Authors: Carleton, Jeremy, Mukherjee, Debajoy, Shakkottai, Srinivas, Kalathil, Dileep
Format: Preprint
Published: 2025
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author Carleton, Jeremy
Mukherjee, Debajoy
Shakkottai, Srinivas
Kalathil, Dileep
author_facet Carleton, Jeremy
Mukherjee, Debajoy
Shakkottai, Srinivas
Kalathil, Dileep
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2508_13415
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle MAVIS: Multi-Objective Alignment via Inference-Time Value-Guided Selection
Carleton, Jeremy
Mukherjee, Debajoy
Shakkottai, Srinivas
Kalathil, Dileep
Machine Learning
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.
title MAVIS: Multi-Objective Alignment via Inference-Time Value-Guided Selection
topic Machine Learning
url https://arxiv.org/abs/2508.13415