Generalist Graph Anomaly Detection via Prototype-Based Distillation

Fuente: arXiv
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Auteurs principaux: Xu, Yiming, Chen, Zihan, Peng, Zhen, Wang, Song, Shi, Bin, Dong, Bo, Shen, Chao
Format: Preprint
Publié: 2026
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author Xu, Yiming
Chen, Zihan
Peng, Zhen
Wang, Song
Shi, Bin
Dong, Bo
Shen, Chao
author_facet Xu, Yiming
Chen, Zihan
Peng, Zhen
Wang, Song
Shi, Bin
Dong, Bo
Shen, Chao
contents Driven by the pressing demand for graph anomaly detection (GAD) in high-stakes domains, the generalist GAD paradigm, which trains a single detector transferable across new graphs, has recently gained growing attention. However, existing methods often rely on scarce and costly annotations for training and sometimes even require few-shot support at inference, which limits their robustness to diverse and unseen anomaly patterns. To address this limitation, we introduce ProMoS, the first unsupervised generalist GAD framework, which detects anomalies by modeling the abundant normality in unlabeled data. ProMoS adopts a knowledge-distillation paradigm to distill normality priors from a frozen self-supervised graph neural network (GNN) teacher to a mixture-of-students model with shared global and lightweight personalized branches, enabling efficient and expressive normality modeling without learning from scratch. We further propose prototype-guided soft-label distillation to align teacher and student in a shared prototype space, enhancing cross-graph generalizability. During inference, ProMoS performs zero-shot anomaly detection on unseen graphs via distillation bias and prototype geometric deviation. Extensive experiments show the effectiveness and efficiency of ProMoS, charting a practical path toward label-free, zero-shot generalist GAD.
format Preprint
id arxiv_https___arxiv_org_abs_2605_26857
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Generalist Graph Anomaly Detection via Prototype-Based Distillation
Xu, Yiming
Chen, Zihan
Peng, Zhen
Wang, Song
Shi, Bin
Dong, Bo
Shen, Chao
Machine Learning
Driven by the pressing demand for graph anomaly detection (GAD) in high-stakes domains, the generalist GAD paradigm, which trains a single detector transferable across new graphs, has recently gained growing attention. However, existing methods often rely on scarce and costly annotations for training and sometimes even require few-shot support at inference, which limits their robustness to diverse and unseen anomaly patterns. To address this limitation, we introduce ProMoS, the first unsupervised generalist GAD framework, which detects anomalies by modeling the abundant normality in unlabeled data. ProMoS adopts a knowledge-distillation paradigm to distill normality priors from a frozen self-supervised graph neural network (GNN) teacher to a mixture-of-students model with shared global and lightweight personalized branches, enabling efficient and expressive normality modeling without learning from scratch. We further propose prototype-guided soft-label distillation to align teacher and student in a shared prototype space, enhancing cross-graph generalizability. During inference, ProMoS performs zero-shot anomaly detection on unseen graphs via distillation bias and prototype geometric deviation. Extensive experiments show the effectiveness and efficiency of ProMoS, charting a practical path toward label-free, zero-shot generalist GAD.
title Generalist Graph Anomaly Detection via Prototype-Based Distillation
topic Machine Learning
url https://arxiv.org/abs/2605.26857