SubmissionNumber#=%=#24 FinalPaperTitle#=%=#SPADE: Structured Prompting Augmentation for Dialogue Enhancement in Machine-Generated Text Detection ShortPaperTitle#=%=# NumberOfPages#=%=#26 CopyrightSigned#=%=#haoyi li JobTitle#==# Organization#==# Abstract#==#The increasing capability of large language models (LLMs) to generate synthetic content has heightened concerns about their misuse, driving the development of Machine-Generated Text (MGT) detection models. However, these detectors face significant challenges due to the lack of high-quality synthetic datasets for training. To address this issue, we propose SPADE, a structured framework for detecting synthetic dialogues using prompt-based adversarial samples. Our proposed methods yield 14 new dialogue datasets, which we benchmark against eight MGT detection models. The results demonstrate improved generalization performance when utilizing a mixed dataset produced by proposed augmentation frameworks, offering a practical approach to enhancing LLM application security. Considering that real-world agents lack knowledge of future opponent utterances, we simulate online dialogue detection and examine the relationship between chat history length and detection accuracy. Our open-source datasets can be downloaded. Author{1}{Firstname}#=%=#Haoyi Author{1}{Lastname}#=%=#Li Author{1}{Username}#=%=#haoyili Author{1}{Email}#=%=#haoyil4@student.unimelb.edu.au Author{1}{Affiliation}#=%=#The University of Melbourne Author{2}{Firstname}#=%=#Angela Yifei Author{2}{Lastname}#=%=#Yuan Author{2}{Email}#=%=#yuanay@student.unimelb.edu.au Author{2}{Affiliation}#=%=#The University of Melbourne Author{3}{Firstname}#=%=#Soyeon Caren Author{3}{Lastname}#=%=#Han Author{3}{Email}#=%=#caren.han@unimelb.edu.au Author{3}{Affiliation}#=%=#The University of Melbourne Author{4}{Firstname}#=%=#Chirstopher Author{4}{Lastname}#=%=#Leckie Author{4}{Email}#=%=#caleckie@unimelb.edu.au Author{4}{Affiliation}#=%=#The University of Melbourne ========== èéáğö