Agent/Connect is a Jenkins permission that lets a user or system establish a connection from an agent to the controller. In practice, it controls who can bring a remote build node into the Jenkins trust boundary and participate in job execution. Because agents run code on behalf of the CI/CD system, this permission is more sensitive than a simple login right.
It matters because the controller usually holds credentials, pipeline definitions, and orchestration power. If an attacker gains Agent/Connect access, or compromises an agent account, they may be able to join a malicious node, intercept build activity, or abuse remoting paths to reach higher-privilege functions. Defenders should treat this permission as tightly scoped, combine it with strong agent authentication, and limit which systems can initiate agent connections. In secure Jenkins setups, Agent/Connect is a boundary control, not a convenience setting.