HALT: Evaluator-Guided Clause-Level Pruning and Early Halting for Lower-Cost Multi-Agent Systems

Zongwei Tang, Yewen Li, Bo Liu, Zezong Zhang, Cai Yiqing, Yiwei Guo, Houjie Qiu, Xingkong Ma


Abstract
Multi-agent systems enhance complex reasoning but face a critical cost and effectiveness dilemma: API costs grow exponentially while performance degrades due to context degradation and error propagation. This paper proposes an evaluator-guided clause-level pruning and early halting method for lower-cost multi-agent systems named HALT, which implements a macro-to-micro intervention. At the macro-level, a difficulty aware router classifies query complexity, bypassing redundant multi-agent systems overhead for simple tasks. At the micro-level, a lightweight hindsight evaluator monitors generation in real time for complex reasoning, driving a dual-axis intervention policy: spatial pruning removes erroneous clauses, while temporal halting terminates multi-agent interaction early upon reaching a purified consensus. The extensive experiments across three different datasets demonstrate the outperformance of HALT over the baselines, achieving the 97.98%, 90.82%, 87.14% in GSM8K, MMLU, MMLU-Pro in accuracy while drastically mitigating computational overhead, with a maximum reduction of 94.3% in prompt tokens and an unprecedented reduction of 98.9% in completion tokens, which validate the effectiveness of HALT. Code is available at URL.
Anthology ID:
2026.emnlp-main.1012
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
23283–23307
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1012/
DOI:
Bibkey:
Cite (ACL):
Zongwei Tang, Yewen Li, Bo Liu, Zezong Zhang, Cai Yiqing, Yiwei Guo, Houjie Qiu, and Xingkong Ma. 2026. HALT: Evaluator-Guided Clause-Level Pruning and Early Halting for Lower-Cost Multi-Agent Systems. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 23283–23307, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
HALT: Evaluator-Guided Clause-Level Pruning and Early Halting for Lower-Cost Multi-Agent Systems (Tang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1012.pdf