RouterKGQA: Specialized–General Model Routing for Constraint-Aware Knowledge Graph Question Answering

Bo Yuan, Hexuan Deng, Long Bang, Xuebo Liu, Zheng Shuai, Zhou Mingzhen, Min Zhang


Abstract
Knowledge graph question answering (KGQA) is a promising approach for mitigating LLM hallucination by grounding reasoning in structured and verifiable knowledge graphs. Existing approaches fall into two paradigms: retrieval-based methods utilize small specialized models, which are efficient but often produce unreachable paths and miss implicit constraints, while agent-based methods utilize large general models, which achieve stronger structural grounding at substantially higher cost. We propose RouterKGQA, a framework for specialized–general model collaboration, in which a specialized model generates reasoning paths and a general model performs KG-guided repair only when needed, improving performance at minimal cost. We further equip the specialized model with constraint-aware answer filtering, which reduces redundant answers. In addition, we design a more efficient general agent workflow, further lowering inference cost. Experimental results show that RouterKGQA outperforms the previous best by 3.57 points in F1 and 0.49 points in Hits@1 on average across benchmarks, while requiring only 1.15 LLM calls per question on WebQSP (1.23 on CWQ). Code and models are available at https://github.com/Oldcircle/RouterKGQA.
Anthology ID:
2026.aacl-long.87
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1903–1924
Language:
URL:
https://aclanthology.org/2026.aacl-long.87/
DOI:
Bibkey:
Cite (ACL):
Bo Yuan, Hexuan Deng, Long Bang, Xuebo Liu, Zheng Shuai, Zhou Mingzhen, and Min Zhang. 2026. RouterKGQA: Specialized–General Model Routing for Constraint-Aware Knowledge Graph Question Answering. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 1903–1924, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
RouterKGQA: Specialized–General Model Routing for Constraint-Aware Knowledge Graph Question Answering (Yuan et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-long.87.pdf