Cost-Efficient Intent Classification via Semantic-Candidate Adaptation and Selective Capability Routing

Jiawei Sun, Yongsheng Sang


Abstract
Intent classification deployments trade accuracy against retraining effort and inference cost. We study frozen generative reranking and budgeted large-model escalation, introducing Semantic-Candidate Adaptation (SCA): BGE top-5 retrieval followed by joint reranking with one representative training example per candidate. On CLINC150, aligned examples raise Qwen2.5-3B-Instruct from 68.18% label-only accuracy to 76.13% and Gemma-2-2B-it from 66.02% to 76.15%, without LLM parameter updates. CLINC150 wrong-example controls support the role of correct alignment, while BANKING77 and HWU64 provide transfer evidence. Broader comparisons clarify the deployment regimes: direct centroid retrieval reaches 80.71%, while a task-trained MPNet Energy baseline reaches 90.05%; always-on SCA is therefore not a universal replacement for direct or trained classifiers. A validation-selected low-margin SCA fallback provides only a marginal gain at an 8.62% realized test call rate. For real Qwen3.7-Max escalation on CLINC150, routing the lowest BGE top-1 retrieval scores reaches 82.11–82.89% accuracy at a 10% budget and 87.33–88.07% at 20%, with OOS F1 of 70.00–70.13% and 87.47–87.70%, respectively. Learned and token-confidence routing remain alternatives, but no policy dominates every evaluated point.
Anthology ID:
2026.emnlp-industry.257
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
4338–4348
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.257/
DOI:
Bibkey:
Cite (ACL):
Jiawei Sun and Yongsheng Sang. 2026. Cost-Efficient Intent Classification via Semantic-Candidate Adaptation and Selective Capability Routing. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 4338–4348, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Cost-Efficient Intent Classification via Semantic-Candidate Adaptation and Selective Capability Routing (Sun & Sang, EMNLP 2026)
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https://aclanthology.org/2026.emnlp-industry.257.pdf