Unifying Inference-Time Planning Language Generation

Prabhu Prakash Kagitha, Bo Sun, Ishan Desai, Andrew Zhu, Cassie Huang, Manling Li, Ziyang Li, Li Zhang


Abstract
A line of work in planning uses LLM not to generate a plan, but to generate a formal representation in some planning language, which can be input into a symbolic solver to deterministically find a plan. While showing improved trust and promising performance, dozens of recent publications have proposed scattered methods on a variety of benchmarks under different experimental settings. We attempt to unify the inference-time LLM-as-formalizer methodology for classical planning by proposing a unifying organizational framework based on intermediate representations. We thus systematically evaluate more than a dozen pipelines that subsume most existing work, while proposing novel ones that involve syntactically similar but high-resource intermediate languages (such as a Python wrapper of PDDL). We provide recipes for planning language generation pipelines, draw a series of conclusions showing the efficacy of their various components, and evidence their robustness against problem complexity.
Anthology ID:
2026.findings-acl.415
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
8531–8574
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.415/
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Bibkey:
Cite (ACL):
Prabhu Prakash Kagitha, Bo Sun, Ishan Desai, Andrew Zhu, Cassie Huang, Manling Li, Ziyang Li, and Li Zhang. 2026. Unifying Inference-Time Planning Language Generation. In Findings of the Association for Computational Linguistics: ACL 2026, pages 8531–8574, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Unifying Inference-Time Planning Language Generation (Kagitha et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.415.pdf
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