Cyber-attacks can be mitigated by automatically coordinating responses from cyber-security tools. For example, a cyber-security engine can include software modules created by multiple sources, each of the software modules being for integrating a respective cyber-security tool with the cyber-security engine. The cyber-security engine can use the software modules to communicate with the cyber-security tools in order to detect one or more events indicative of a cyber-attack against a computing environment. The cyber-security engine can then determine a coordinated-response strategy involving cooperation among the cyber-security tools to mitigate the cyber-attack. The cyber-security engine can transmit commands to the cyber-security tools to cause the cyber-security tools to implement the coordinated-response strategy.