Towards Trustworthy Smart Contract Synthesis: A Multi-Agent Framework with Lean-Based Verification

Bowei Zhang, Hanbing Liu, Qixin Tian, Siyu Chen, Ziyuan Wang, Qi Qi


Abstract
Smart Contracts are the foundation of Decentralized Finance (DeFi), executing financial logic without trusted intermediaries. Recent advances in large language models (LLMs) have substantially lowered the barrier to smart contract development by enabling code generation from natural language. However, because smart contracts are immutable and directly manage financial assets, this accessibility introduces a critical trust gap: generated contracts are easy to produce but hard to trust. To bridge this gap, we present LeVer, the first trustworthy smart contract synthesis framework that integrates LLM-based generation with Lean-based auto-formalization and Verification. LeVer employs a closed-loop multi-agent architecture to iteratively generate, verify, attack, and repair contracts, providing both formal guarantees and empirical robustness. To facilitate the adoption of automated formal verification in smart contract generation and audition, we open-source our framework and datasets at: https://github.com/gl-bowei/LeVer
Anthology ID:
2026.acl-long.1836
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
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Pages:
39548–39582
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1836/
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Cite (ACL):
Bowei Zhang, Hanbing Liu, Qixin Tian, Siyu Chen, Ziyuan Wang, and Qi Qi. 2026. Towards Trustworthy Smart Contract Synthesis: A Multi-Agent Framework with Lean-Based Verification. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 39548–39582, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Towards Trustworthy Smart Contract Synthesis: A Multi-Agent Framework with Lean-Based Verification (Zhang et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.1836.pdf
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