Superficial Success vs. Internal Breakdown: An Empirical Study of Generalization in Adaptive Multi-Agent Systems
Paper · 2026 · Namyeong So, Seokgyu Jang and Taeuk Kim
Summary
The paper examines whether adaptive multi-agent systems (MAS) can serve as general-purpose tools. In these systems, LLM agent roles and communication links are learned from a small task-specific training set. The authors test two representative optimizers on GPT-oss-20B, with Qwen3-30B-A3B in the appendix. AFlow builds topologies bottom-up, and AgentDropout prunes a fully connected graph top-down. Topologies are trained on one of six datasets covering legal, detective, multi-hop, science, math and commonsense reasoning, then applied unchanged to the other five.
Two problems emerge. The first is topological overfitting: accuracy often falls on unseen domains. The second is illusory coordination: some transfers look accurate, but agents abandon their roles or ignore each other's messages, so the answer comes from individual LLM strength rather than collaboration. To measure this, the authors introduce two metrics, Role Alignment (R) and Connection Significance (O), alongside a MAST-based failure analysis. The work matters because final-answer accuracy alone can hide broken internal collaboration. This motivates evaluation protocols that inspect agent interactions and design choices aimed at generalization, such as multi-domain training.
Key points
- Datasets: CaseHOLD, COM², MuSiQue, SciBench, TheoremQA and StrategyQA. Training was capped at 100 examples for AFlow and 60 for AgentDropout, with AgentInit used to set AgentDropout's roles.
- Out-of-domain drop: AgentDropout trained on CaseHOLD falls from 63.5% in-domain to about 55.8% average OOD. StrategyQA-trained (true/false) topologies collapse on numerical and multiple-choice formats. Mixing all six domains in training gives more stable results.
- Failure analysis: Using MAST, a GPT-oss-120B judge labeled 100 execution logs. Role- and connection-related failures make up roughly 60% of breakdowns, with disobeying the role specification the largest single category (about 15%).
- Accuracy vs. collaboration: CaseHOLD→SciBench appears to transfer well, yet R drops to 22% of its in-domain value. Pearson correlations between accuracy and R or O are close to zero.
- Ablation: Replacing roles with OOD ones costs about 13.0 pp on average, versus about 1.24 pp for replacing connections. MuSiQue is the exception, losing 5.36 pp when connections are swapped.
Institutions
Fields, topics and concepts
📚 Shelves 2The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 works
Cite
Cite as Namyeong So, Seokgyu Jang and Taeuk Kim. 2026. Superficial Success vs. Internal Breakdown: An Empirical Study of Generalization in Adaptive Multi-Agent Systems. Findings of the Association for Computational Linguistics: ACL 2026.
@inproceedings{so2026superficial,
title = {{Superficial Success vs. Internal Breakdown: An Empirical Study of Generalization in Adaptive Multi-Agent Systems}},
author = {Namyeong So, Seokgyu Jang and Taeuk Kim},
booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-acl.753},
url = {https://doi.org/10.18653/v1/2026.findings-acl.753}
}References
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