DiLLS: Interactive Diagnosis of LLM-based Multi-agent Systems via Layered Summary of Agent Behaviors
Rui Sheng, Yukun Yang, Chuhan Shi, Yanna Lin, Zixin Chen, Huamin Qu, Furui Cheng
TL;DR
Diagnosing failures in LLM-based multi-agent systems is hard due to unstructured logs and complex inter-agent coordination. The authors propose DiLLS, a layered, Activity Theory–inspired framework that summarizes agent behaviors at activity, action, and operation levels and an interactive visualization with Activity, Action, and Operation views to support diagnosis. A formative study informs design, and a 12-participant user study demonstrates that DiLLS improves failure identification, increases developer confidence, and reduces cognitive load compared with a baseline log-based interface. This work offers a practical, scalable approach to interpretable MAS debugging and provides a foundation for theory-informed analysis of multi-agent behaviors.
Abstract
Large language model (LLM)-based multi-agent systems have demonstrated impressive capabilities in handling complex tasks. However, the complexity of agentic behaviors makes these systems difficult to understand. When failures occur, developers often struggle to identify root causes and to determine actionable paths for improvement. Traditional methods that rely on inspecting raw log records are inefficient, given both the large volume and complexity of data. To address this challenge, we propose a framework and an interactive system, DiLLS, designed to reveal and structure the behaviors of multi-agent systems. The key idea is to organize information across three levels of query completion: activities, actions, and operations. By probing the multi-agent system through natural language, DiLLS derives and organizes information about planning and execution into a structured, multi-layered summary. Through a user study, we show that DiLLS significantly improves developers' effectiveness and efficiency in identifying, diagnosing, and understanding failures in LLM-based multi-agent systems.
