Local Prompt Optimization

Yash Jain, Vishal Chowdhary


Abstract
In recent years, the use of prompts to guide the output of Large Language Models have increased dramatically. However, even the best of experts struggle to choose the correct words to stitch up a prompt for the desired task. To solve this, LLM driven prompt optimization emerged as an important problem. Existing prompt optimization methods optimize a prompt globally, where in all the prompt tokens have to be optimized over a large vocabulary while solving a complex task. The large optimization space (tokens) leads to insufficient guidance for a better prompt. In this work, we introduce Local Prompt Optimization (LPO) that integrates with any general automatic prompt engineering method. We identify the optimization tokens in a prompt and nudge the LLM to focus only on those tokens in its optimization step. We observe remarkable performance improvements on Math Reasoning (GSM8k and MultiArith) and BIG-bench Hard benchmarks across various automatic prompt engineering methods. Further, we show that LPO converges to the optimal prompt faster than global methods.
Anthology ID:
2025.naacl-short.7
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
75–81
Language:
URL:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-short.7/
DOI:
Bibkey:
Cite (ACL):
Yash Jain and Vishal Chowdhary. 2025. Local Prompt Optimization. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers), pages 75–81, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Local Prompt Optimization (Jain & Chowdhary, NAACL 2025)
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https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-short.7.pdf