RCBSF: A Multi-Agent Framework for Automated Contract Revision via Stackelberg Game

arXiv cs.CL / 4/14/2026

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Key Points

  • The paper argues that current LLM-based legal contract revision is limited by safety hallucinations and insufficient behavioral constraints, motivating a more rigorously controlled approach.
  • It introduces the Risk-Constrained Bilevel Stackelberg Framework (RCBSF), modeling contract revision as a hierarchical non-cooperative Stackelberg game with a Global Prescriptive Agent (GPA) setting risk budgets for follower agents (CRA and LVA).
  • RCBSF iteratively optimizes revisions under risk constraints and includes theoretical convergence guarantees to an equilibrium with provably better utility than unguided baselines.
  • Experiments on a unified benchmark show state-of-the-art results, including an average Risk Resolution Rate (RRR) of 84.21% and improved token efficiency compared with iterative baselines.
  • The authors release accompanying code on GitHub to support replication and further development of the framework.

Abstract

Despite the widespread adoption of Large Language Models (LLMs) in Legal AI, their utility for automated contract revision remains impeded by hallucinated safety and a lack of rigorous behavioral constraints. To address these limitations, we propose the Risk-Constrained Bilevel Stackelberg Framework (RCBSF), which formulates revision as a non-cooperative Stackelberg game. RCBSF establishes a hierarchical Leader Follower structure where a Global Prescriptive Agent (GPA) imposes risk budgets upon a follower system constituted by a Constrained Revision Agent (CRA) and a Local Verification Agent (LVA) to iteratively optimize output. We provide theoretical guarantees that this bilevel formulation converges to an equilibrium yielding strictly superior utility over unguided configurations. Empirical validation on a unified benchmark demonstrates that RCBSF achieves state-of-the-art performance, surpassing iterative baselines with an average Risk Resolution Rate (RRR) of 84.21\% while enhancing token efficiency. Our code is available at https://github.com/xjiacs/RCBSF .