LiteResearcher: A Scalable Agentic RL Training Framework for Deep Research Agent

[Submitted on 20 Apr 2026 (v1), last revised 1 Jul 2026 (this version, v4)]

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Abstract:Reinforcement Learning (RL) has emerged as a powerful training paradigm for LLM-based agents. However, scaling agentic RL for deep research remains constrained by two coupled challenges: hand-crafted synthetic data fails to elicit genuine real-world search capabilities, and real-world search dependency during RL training introduces instability and prohibitive cost, which limits the scalability of Agentic RL. LiteResearcher is a training framework that makes Agentic RL scalable: by constructing a lite virtual world that mirrors real-world search dynamics, we enable a continuously improving training recipe that empowers a tiny search agent to outperform large-scale open-source and commercial models (e.g., Tongyi DeepResearch and Claude-4.5 Sonnet). Specifically, on common benchmarks such as GAIA and Xbench, our LiteResearcher-4B achieves open-source state-of-the-art results of 71.3% and 78.0% respectively, demonstrating that scalable RL training is a key enabler for Deep Research Agents.

Submission history

From: Wanli Li [view email]
[v1] Mon, 20 Apr 2026 08:11:09 UTC (1,922 KB)
[v2] Wed, 22 Apr 2026 09:13:22 UTC (1,930 KB)
[v3] Tue, 30 Jun 2026 17:17:12 UTC (2,194 KB)
[v4] Wed, 1 Jul 2026 16:44:57 UTC (2,209 KB)