Large Language Models Can Solve Real-World Planning Rigorously with Formal Verification Tools

Yilun Hao, Yongchao Chen, Yang Zhang, Chuchu Fan


Abstract
Large Language Models (LLMs) struggle to directly generate correct plans for complex multi-constraint planning problems, even with self-verification and self-critique. For example, a U.S. domestic travel planning benchmark TravelPlanner was proposed in Xie et al. (2024), where the best LLM OpenAI o1-preview can only find viable travel plans with a 10% success rate given all needed information. In this work, we tackle this by proposing an LLM-based planning framework that formalizes and solves complex multi-constraint planning problems as constrained satisfiability problems, which are further consumed by sound and complete satisfiability solvers. We start with TravelPlanner as the primary use case and show that our framework achieves a success rate of 93.9% and is effective with diverse paraphrased prompts. More importantly, our framework has strong zero-shot generalizability, successfully handling unseen constraints in our newly created unseen international travel dataset and generalizing well to new fundamentally different domains. Moreover, when user input queries are infeasible, our framework can identify the unsatisfiable core, provide failure reasons, and offers personalized modification suggestions. We show that our framework can modify and solve for an average of 81.6% and 91.7% unsatisfiable queries from two datasets and prove with ablations that all key components of our framework are effective and necessary.
Anthology ID:
2025.naacl-long.176
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long 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:
3434–3483
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.176/
DOI:
Bibkey:
Cite (ACL):
Yilun Hao, Yongchao Chen, Yang Zhang, and Chuchu Fan. 2025. Large Language Models Can Solve Real-World Planning Rigorously with Formal Verification Tools. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 3434–3483, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Large Language Models Can Solve Real-World Planning Rigorously with Formal Verification Tools (Hao et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-long.176.pdf