To address the challenges of smart contract vulnerability discovery, this paper proposes an agent system, A1, based on a large-scale language model (LLM). Leveraging LLM, A1 autonomously discovers vulnerabilities in smart contracts and generates exploits by testing them on real blockchains. Evaluation results on 36 real-world vulnerable smart contracts demonstrate a 63% success rate on the VERITE benchmark, with a potential profit of up to $8.59 million for a successful attack. Furthermore, the paper highlights the importance of rapid vulnerability discovery and the economic imbalance between attackers and defenders.