Simple Beats Spend: Cost-Performance Trade-Offs for Multi-Agent Machine Translation of Financial Long Documents

Arturo Oncevay, Zhijin Guo, Elena Kochkina, Damiano Fassina, Simerjot Kaur, Charese Smiley, Xiaomo Liu, Manuela Veloso


Abstract
Agentic MT frameworks often adopt human-inspired roles, layered post-editing, and complex workflows. To stress-test these designs, we examine cost–performance trade-offs across five multi-agent MT workflows on specialized long documents. Using six language pairs from two financial test sets and LLMs spanning lower to higher capacity and cost tiers, we evaluate translation quality and terminology accuracy relative to token-level cost. We find: (i) lean pipelines match the quality of more complex systems at lower cost; (ii) terminology accuracy depends more on model capacity than on workflow complexity; (iii) document-length resilience is not universal, as some simple and some complex workflows maintain quality on longer documents; and (iv) post-editing agents offer a better return on model capacity than base translation. Edited-span analysis further suggests that many post-edits are stylistic or lexical alternatives rather than consistently preferred improvements.
Anthology ID:
2026.findings-emnlp.1767
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:
37804–37818
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1767/
DOI:
Bibkey:
Cite (ACL):
Arturo Oncevay, Zhijin Guo, Elena Kochkina, Damiano Fassina, Simerjot Kaur, Charese Smiley, Xiaomo Liu, and Manuela Veloso. 2026. Simple Beats Spend: Cost-Performance Trade-Offs for Multi-Agent Machine Translation of Financial Long Documents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 37804–37818, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Simple Beats Spend: Cost-Performance Trade-Offs for Multi-Agent Machine Translation of Financial Long Documents (Oncevay et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1767.pdf