Causal Attribution Meets Impact-aware Verification: Debugging LLM-based Multi-Agent Systems via Static–Dynamic Synergy

Yawen Wang, Wenjie wu, Junjie Wang, Qing Wang


Abstract
Large Language Model (LLM)-based Multi-Agent Systems (MASs) are vulnerable to stochastic reasoning and coordination failures, yielding verbose, unstructured trajectories that are difficult to debug. Existing debuggers typically rely on either post-hoc static analysis, which suffers from ambiguous causal attribution, or dynamic verification, which incurs prohibitive computational costs and execution instability. To bridge this gap, we propose SynDebug, a static–dynamic synergistic debugging framework. Statically, SynDebug reconstructs execution topologies from flat logs via a Hierarchical Causal Graph and prioritizes root-cause candidates using synthesized Virtual Oracles.Dynamically, it performs targeted interventions on prioritized candidates to progressively recalibrate suspiciousness rankings based on execution impact. Evaluated across three MAS frameworks and four benchmarks, SynDebug outperforms six baselines, improving the repair success rate by 5.59%–81.81% while maintaining competitive efficiency.
Anthology ID:
2026.findings-emnlp.1310
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
27703–27720
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URL:
https://aclanthology.org/2026.findings-emnlp.1310/
DOI:
Bibkey:
Cite (ACL):
Yawen Wang, Wenjie wu, Junjie Wang, and Qing Wang. 2026. Causal Attribution Meets Impact-aware Verification: Debugging LLM-based Multi-Agent Systems via Static–Dynamic Synergy. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 27703–27720, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Causal Attribution Meets Impact-aware Verification: Debugging LLM-based Multi-Agent Systems via Static–Dynamic Synergy (Wang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1310.pdf