When overriding UserIdCause.getShortDescription, you need to override print as well.

Noticed via failure in BuildCommandTest.testConsoleOutput.
https://github.com/jenkinsci/jenkins/pull/522

core/src/main/java/hudson/cli/BuildCommand.java

@@ -32,7 +32,9 @@ import hudson.model.ParametersDefinitionProperty;
 import hudson.model.ParameterDefinition;
 import hudson.Extension;
 import hudson.AbortException;
+import hudson.console.ModelHyperlinkNote;
 import hudson.model.Item;
+import hudson.model.TaskListener;
 import hudson.model.queue.QueueTaskFuture;
 import hudson.scm.PollingResult.Change;
 import hudson.util.EditDistance;
@@ -158,6 +160,12 @@ public class BuildCommand extends CLICommand {
             return "Started by command line by " + startedBy;
         }
 
+        @Override
+        public void print(TaskListener listener) {
+            listener.getLogger().println("Started by command line by " +
+                    ModelHyperlinkNote.encodeTo("/user/"+getUserId(), getUserName()));
+        }
+
         @Override
         public boolean equals(Object o) {
             return o instanceof CLICause;

test/src/test/groovy/hudson/cli/BuildCommandTest.groovy

@@ -105,7 +105,7 @@ public class BuildCommandTest extends HudsonTestCase {
             def o = new ByteArrayOutputStream()
             cli.execute(["build","-s","-v",p.name],System.in,new TeeOutputStream(System.out,o),System.err)
             assertBuildStatusSuccess(p.getBuildByNumber(1))
-            assertTrue(o.toString().contains("Started by command line by anonymous"))
+            assertTrue(o.toString(), o.toString().contains("Started by command line by anonymous"))
             assertTrue(o.toString().contains("Finished: SUCCESS"))
         } finally {
             cli.close()