Hi,

Took me a while to understand why tools were not installed on running agent even if the labels were set on the node.

I happen that the https://github.com/jenkinsci/jenkins/blob/master/core/src/main/java/hudson/tools/ToolInstaller.java#L87 doesn't consider assigned labels (Typically the ones created by LabelFinder extensions). Like https://github.com/jenkinsci/platformlabeler-plugin/blob/master/src/main/java/org/jvnet/hudson/plugins/platformlabeler/PlatformLabeler.java#L40

It's specially true of ephemeral agent and tool directive installation. Dynamic labels are assigned "too late" on the build.

I propose to change it to (not tested)

public boolean appliesTo(Node node) {
   Label l = Jenkins.get().getLabel(label);
   return l == null || node.getAssignedLabels().contains(l);
}

Any thought ?