This paper highlights recent advances in LLM-based agents that integrate external tools to handle complex, knowledge-intensive tasks. In particular, we emphasize the importance of search tools and aim to improve the search capabilities of open-source agents. ASearcher is an open-source project for large-scale reinforcement learning (RL) training that addresses scalability, efficiency, and data quality challenges. ASearcher uses a prompt-based LLM agent to generate high-quality, challenging questions and answers (QAs) to build a large-scale QA dataset. Through RL training, the QwQ-32B agent achieves an Avg@4 improvement of 78.0% on xBench and 34.3% on GAIA. It also demonstrates long-term search capabilities, logging over 100 tool calls and over 400,000 output tokens. ASearcher-Web-QwQ achieves an Avg@4 score of 51.1 on xBench and 58.7 on GAIA, outperforming existing open-source 32B agents. We demonstrate that commercial system-level performance can be achieved through zero-shot transition and test-time search methods.