AI agents can autonomously perform tasks and, often without explicit user consent, collect or disclose users' sensitive local data, which raises serious privacy concerns. Although AI agents' privacy policies describe their intended data practices, there remains limited transparency and accountability about whether runtime behavior matches those policies. To close this gap, we introduce AudAgent, a visual tool that continuously monitors AI agents' data practices in real time and guards compliance with stated privacy policies. AudAgent consists of four components for automated privacy auditing of AI agents. (i) Policy formalization: a novel cross-LLM voting mechanism to guarantee confidence of the parsed privacy policy model. (ii) Runtime annotation: a lightweight Presidio-based analyzer detects sensitive data and annotates data practices based on the AI agent's context and the privacy policy model. (iii) Compliance auditing: ontology graphs and automata-based checking connect the privacy policy model with runtime annotations, enabling on-the-fly compliance checking. (iv) User interface: an infrastructure-independent implementation visualizes the real-time execution trace of AI agents along with potential privacy policy violations, providing user-friendly transparency and accountability. We evaluate AudAgent with AI agents built using mainstream frameworks, demonstrating its effectiveness in detecting and visualizing privacy policy violations in real time. Using AudAgent, we also find that most privacy policies omit explicit safeguards for highly sensitive data such as SSNs, whose misuse violates legal requirements, and that many agents do not refuse handling such data via third-party tools, including those controlled by Claude, Gemini, and DeepSeek. AudAgent proactively blocks operations on such data, overriding the agents' original privacy policy and behavior.

翻译：AI智能体能够自主执行任务，且常常在未经用户明确同意的情况下收集或披露用户的敏感本地数据，这引发了严重的隐私担忧。尽管AI智能体的隐私政策描述了其预期的数据处理行为，但关于运行时行为是否与这些政策相符，仍缺乏足够的透明度和问责机制。为弥补这一差距，我们提出了AudAgent，一种可视化工具，能够持续实时监控AI智能体的数据处理行为，并确保其与声明的隐私政策保持一致。AudAgent包含四个组件，用于对AI智能体进行自动化隐私审计。（i）政策形式化：采用一种新颖的跨大语言模型投票机制，以确保解析出的隐私政策模型具有高置信度。（ii）运行时标注：一个基于Presidio的轻量级分析器，根据AI智能体的上下文和隐私政策模型检测敏感数据并标注数据处理行为。（iii）合规性审计：基于本体图和自动机的检查机制，将隐私政策模型与运行时标注关联起来，实现即时合规性检查。（iv）用户界面：一个与基础设施无关的实现，可视化AI智能体的实时执行轨迹以及潜在的隐私政策违规行为，提供用户友好的透明度和问责机制。我们使用主流框架构建的AI智能体对AudAgent进行了评估，证明了其在实时检测和可视化隐私政策违规方面的有效性。通过使用AudAgent，我们还发现大多数隐私政策未对高度敏感数据（如社会安全号码）提供明确的保护措施，而滥用此类数据违反了法律要求；并且许多智能体未拒绝通过第三方工具（包括由Claude、Gemini和DeepSeek控制的工具）处理此类数据。AudAgent会主动阻止对此类数据的操作，覆盖智能体原有的隐私政策与行为。