DeepSearch-World: Self-Distillation for Deep Search Agents in a Verifiable Environment

Xinyu Geng, Xuanhua He, Sixiang Chen, Yanjing Xiao, Fan Zhang, Shijue Huang, Haitao Mi, Zhenwen Liang, Tianqing Fang, Yi R. Fung


Abstract
Training tool-use agents to improve from their own experience remains challenging, as supervised fine-tuning relies on fixed teacher-distilled trajectories, while sparse-reward reinforcement learning provides weak supervision for long-horizon interactions. We present DeepSearch-Evolve, a self-distillation framework for web agents built on DeepSearch-World, a deterministic and verifiable environment with reproducible search and page-reading tools. DeepSearch-World contains 420K multi-hop QA tasks constructed from entity-level random walks and supports key agentic cognitive behaviors useful for self-evolving, including progress verification, grounded reflection, and failure recovery. DeepSearch-Evolve iteratively performs trajectory generation, filtering, data mixing, and fine-tuning to train stronger agents. Without distillation from more capable models, DeepSearch-World-9B achieves competitive performance compared with open-source agents, reaching 31.2% on BrowseComp, 61.5% on GAIA, and 93.4% on HotpotQA, showing that verifiable environments enable scalable self-evolution for long-horizon web agents. We will release the environment, 420K training pool, validation set, model, and code to facilitate future research on self-improving deep search agents.
Anthology ID:
2026.emnlp-main.1117
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:
25576–25601
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1117/
DOI:
Bibkey:
Cite (ACL):
Xinyu Geng, Xuanhua He, Sixiang Chen, Yanjing Xiao, Fan Zhang, Shijue Huang, Haitao Mi, Zhenwen Liang, Tianqing Fang, and Yi R. Fung. 2026. DeepSearch-World: Self-Distillation for Deep Search Agents in a Verifiable Environment. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 25576–25601, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DeepSearch-World: Self-Distillation for Deep Search Agents in a Verifiable Environment (Geng et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1117.pdf