EvoFormat: Discovering Effective Graph-to-Text Formats via Rule-Based Evolutionary Search

Kazuya Kakizaki, Taiki Miyagawa, Hideyuki Oiso, Ryo Furukawa


Abstract
Encoding graphs as text prompts enables LLM-based graph reasoning. However, effective graph-to-text encodings depend on the downstream task, graph structure, and target LLM, making manual format design time-consuming and brittle. We propose EvoFormat, a black-box evolutionary search framework that automatically discovers interpretable graph-to-text formats represented as human-readable formatting rules over node naming, relation expression, and global arrangement. Using only task-level feedback from LLM outputs, EvoFormat iteratively mutates and selects rules without gradients or internal model access. Across synthetic GraphQA and IMDB-MULTI-derived structural QA tasks over unattributed graphs, EvoFormat outperforms strong hand-crafted encodings in most settings.
Anthology ID:
2026.findings-emnlp.1845
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:
39404–39415
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1845/
DOI:
10.18653/2026.findings-emnlp.1845
Bibkey:
Cite (ACL):
Kazuya Kakizaki, Taiki Miyagawa, Hideyuki Oiso, and Ryo Furukawa. 2026. EvoFormat: Discovering Effective Graph-to-Text Formats via Rule-Based Evolutionary Search. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 39404–39415, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
EvoFormat: Discovering Effective Graph-to-Text Formats via Rule-Based Evolutionary Search (Kakizaki et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1845.pdf