Jar exclude not working

My first gradle build and have made progress but stuck at excluding some classes from a jar. Here is what I am using. But I see the final jar file still has the folders I want to exclude.

task agentJar(type: Jar) {
   from sourceSets.main.output 
    exclude "**/common/**"
    archiveBaseName = agentJarName;
    includeEmptyDirs = false
}