Agentic Time Machine as an Infrastructure for Future-Event Forecasting

Jingyi Chai, Bingyang Zheng, Xiangrui Liu, Hao Lu, Zihang Zhou, Tianchen Wang, Kemeng Zhang, Siheng Chen


Abstract
Forecasting future events is a critical challenge for large language model (LLM) agents, spanning domains from elections and monetary policy to financial markets. However, evaluating progress on this task presents a fundamental trade-off between efficiency and environment fidelity. While live evaluation benchmarks suffer from an inherently slow feedback loop, existing retrospective replays typically restrict agents to static, pre-frozen databases that sacrifice the environmental realism of actual deployments. To tackle this issue, we introduce Agentic Time Machine (TM), an infrastructure that approximates the pre-cutoff web state at any chosen past time by filtering post-cutoff content. Leveraging this evaluation infrastructure, we further propose a planner-solver-aggregator multi-agent framework that breaks each question into diverse analytical angles, gathers evidence in parallel, and combines the results into a single forecast. Experiments show that offline scores under TM correlate strongly with live FutureX scores, validating that TM offers a fast and reliable sandbox for forecasting-agent evaluation. On FutureX-Past and Polymarket evaluated under TM, our framework achieves the highest score among strong closed-book, tool-augmented, and self-consistency baselines. On the live FutureX leaderboard, our system achieves the best average rank over four consecutive weeks, ranking 1st in May Week 1.
Anthology ID:
2026.emnlp-main.2020
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:
46016–46035
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2020/
DOI:
Bibkey:
Cite (ACL):
Jingyi Chai, Bingyang Zheng, Xiangrui Liu, Hao Lu, Zihang Zhou, Tianchen Wang, Kemeng Zhang, and Siheng Chen. 2026. Agentic Time Machine as an Infrastructure for Future-Event Forecasting. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 46016–46035, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Agentic Time Machine as an Infrastructure for Future-Event Forecasting (Chai et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2020.pdf