LegalWorld: A Life-Cycle Interactive Environment for Legal Agents

Songhan Zuo, Shengbin Yue, Tao Chiang, Guanying LI, Yun Song, Xuanjing Huang, Zhongyu Wei


Abstract
Civil litigation is inherently a life-cycle process: what a lawyer drafts on day one constrains what unfolds at trial months later. Yet existing legal benchmarks evaluate isolated subtasks, and prior legal-agent simulators reinitialize each scenario from shared ground truth, leaving cross-stage causal dependencies unmodeled. We present LegalWorld, a life-cycle interactive environment that models Chinese civil litigation as a causally connected state chain of five stages (seven sub-scenarios), grounded in 75,309 paired Chinese civil judgments. We pair it with reusable infrastructure (local memory, global case memory, a Skill/Tool library) and Reflective Legal Skill (RLS), which distills completed trajectories into reusable procedural skills. Building on this environment, we construct LongJud-Bench to evaluate agent capability across all five connected stages. 18,992 ratings from 217 legal-background evaluators confirm that LegalWorld trajectories are procedurally faithful and role-consistent; cross-model evaluation reveals stage-level divergences invisible to aggregate scores (backbones within 4 overall points can differ by up to 15 normalized points on individual stages), and RLS yields consistent gains on both reflected and held-out cases. Detailed resources will be provided upon acceptance.
Anthology ID:
2026.emnlp-main.390
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
8942–8976
Language:
URL:
https://aclanthology.org/2026.emnlp-main.390/
DOI:
Bibkey:
Cite (ACL):
Songhan Zuo, Shengbin Yue, Tao Chiang, Guanying LI, Yun Song, Xuanjing Huang, and Zhongyu Wei. 2026. LegalWorld: A Life-Cycle Interactive Environment for Legal Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 8942–8976, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LegalWorld: A Life-Cycle Interactive Environment for Legal Agents (Zuo et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.390.pdf