SOCIA-EVO: Automated Simulator Construction via Dual-Anchored Bi-Level Optimization

Yuncheng Hua, Sion Weatherhead, Mehdi Jafari, Hao Xue, Flora D. Salim


Abstract
Automated simulator construction requires distributional fidelity, distinguishing it from generic code generation. We identify two failure modes in long-horizon LLM agents: contextual drift and optimization instability arising from conflating structural and parametric errors. We propose SOCIA-EVO, a dual-anchored evolutionary framework. SOCIA-EVO introduces: (1) a static blueprint to enforce empirical constraints; (2) a bi-level optimization to decouple structural refinement from parameter calibration; and (3) a self-curating Strategy Playbook that manages remedial hypotheses via Bayesian-weighted retrieval. By falsifying ineffective strategies through execution feedback, SOCIA-EVO achieves robust convergence, generating simulators that are statistically consistent with observational data. SOCIA-EVO’s code and data are available here: https://github.com/cruiseresearchgroup/SOCIA/tree/evo.
Anthology ID:
2026.acl-long.1274
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
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ACL
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Publisher:
Association for Computational Linguistics
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Pages:
27596–27634
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1274/
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Cite (ACL):
Yuncheng Hua, Sion Weatherhead, Mehdi Jafari, Hao Xue, and Flora D. Salim. 2026. SOCIA-EVO: Automated Simulator Construction via Dual-Anchored Bi-Level Optimization. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 27596–27634, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
SOCIA-EVO: Automated Simulator Construction via Dual-Anchored Bi-Level Optimization (Hua et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.1274.pdf
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