How do ordinary people in China obtain adequate information to safely petition the government? And how does the government acquire information to monitor petitioners? This article argues that petition brokers are the go-betweens who provide information to both parties. During normal times, petition brokers are the agents of petitioners, helping them to seek redress. During politically sensitive times, petition brokers are "bought off" by the government—i.e. they provide the government with information on petitioners and also assist in monitoring petitioners. The brokers' role has therefore created a principal–agent problem. However, findings in this article have shown that the said activities of petition brokers may be conducive to the maintenance of social stability and political control in China.