diff --git a/BUCK b/BUCK
index f47a479..0160c15 100644
--- a/BUCK
+++ b/BUCK
@@ -14,7 +14,7 @@
     'Gerrit-SshModule: com.googlesource.gerrit.plugins.cookbook.SshModule',
     'Implementation-Title: Cookbook plugin',
     'Implementation-URL: https://gerrit-review.googlesource.com/#/admin/projects/plugins/cookbook-plugin',
-  ]
+  ],
 )
 
 java_test(
diff --git a/lib/gerrit/BUCK b/lib/gerrit/BUCK
index 968cdb1..1d742dc 100644
--- a/lib/gerrit/BUCK
+++ b/lib/gerrit/BUCK
@@ -1,6 +1,6 @@
 include_defs('//bucklets/maven_jar.bucklet')
 
-VER = '2.12-SNAPSHOT'
+VER = '2.13-SNAPSHOT'
 REPO = MAVEN_LOCAL
 
 maven_jar(
diff --git a/src/main/java/com/googlesource/gerrit/plugins/cookbook/ConsoleMetricReporter.java b/src/main/java/com/googlesource/gerrit/plugins/cookbook/ConsoleMetricReporter.java
new file mode 100644
index 0000000..f2a3eb6
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/cookbook/ConsoleMetricReporter.java
@@ -0,0 +1,80 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.googlesource.gerrit.plugins.cookbook;
+
+import com.google.gerrit.extensions.annotations.Listen;
+import com.google.gerrit.extensions.annotations.PluginName;
+import com.google.gerrit.extensions.events.LifecycleListener;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import com.codahale.metrics.ConsoleReporter;
+import com.codahale.metrics.MetricRegistry;
+
+import org.eclipse.jgit.lib.Config;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Demonstration of how to add a new Dropwizard  Metrics Reporter using
+ * Gerrit's plug-in API.
+ *
+ * @see <a href="https://dropwizard.github.io/metrics/3.1.0/getting-started/#reporting-via-jmx">here</a>
+ * @see <a href="https://dropwizard.github.io/metrics/3.1.0/getting-started/#reporting-via-http">here</a>
+ * @see <a href="https://dropwizard.github.io/metrics/3.1.0/getting-started/#other-reporting">here</a>
+ *
+ * Also shows how to fetch plug-in specific configuration values.
+ * <@see com.google.gerrit.server.config.PluginConfigFactory>
+ *
+ * Enable by adding the file etc/cookbook.config:
+ *
+ *  [console-metrics]
+ *      enabled = true
+ *
+ */
+@Listen
+@Singleton
+public class ConsoleMetricReporter implements LifecycleListener {
+  private ConsoleReporter consoleReporter;
+  private boolean enabled;
+
+  @Inject
+  public ConsoleMetricReporter(MetricRegistry registry,
+      PluginConfigFactory configFactory,
+      @PluginName String pluginName) {
+    Config config = configFactory.getGlobalPluginConfig(pluginName);
+    enabled = config.getBoolean("console-metrics", "enabled", false);
+    if (!enabled) {
+      return;
+    }
+    this.consoleReporter =
+        ConsoleReporter.forRegistry(registry).convertRatesTo(TimeUnit.SECONDS)
+            .convertDurationsTo(TimeUnit.MILLISECONDS).build();
+  }
+
+  @Override
+  public void start() {
+    if (enabled) {
+      consoleReporter.start(1, TimeUnit.MINUTES);
+    }
+  }
+
+  @Override
+  public void stop() {
+    if (enabled) {
+      consoleReporter.stop();
+    }
+  }
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/cookbook/MergeUserValidator.java b/src/main/java/com/googlesource/gerrit/plugins/cookbook/MergeUserValidator.java
index 0147839..ca48312 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/cookbook/MergeUserValidator.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/cookbook/MergeUserValidator.java
@@ -18,7 +18,6 @@
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.git.CodeReviewCommit;
-import com.google.gerrit.server.git.CommitMergeStatus;
 import com.google.gerrit.server.git.validators.MergeValidationException;
 import com.google.gerrit.server.git.validators.MergeValidationListener;
 import com.google.gerrit.server.project.ProjectState;
@@ -43,7 +42,8 @@
       PatchSet.Id patchSetId, IdentifiedUser caller)
           throws MergeValidationException {
     if (!caller.getCapabilities().canAdministrateServer()) {
-      throw new MergeValidationException(CommitMergeStatus.MISSING_DEPENDENCY);
+      throw new MergeValidationException("Submitter " + caller.getNameEmail()
+          + " is not a site administrator");
     }
   }
 }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/cookbook/Module.java b/src/main/java/com/googlesource/gerrit/plugins/cookbook/Module.java
index b182159..61f6375 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/cookbook/Module.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/cookbook/Module.java
@@ -20,6 +20,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.extensions.annotations.Exports;
 import com.google.gerrit.extensions.client.InheritableBoolean;
+import com.google.gerrit.extensions.events.LifecycleListener;
 import com.google.gerrit.extensions.events.NewProjectCreatedListener;
 import com.google.gerrit.extensions.events.UsageDataPublishedListener;
 import com.google.gerrit.extensions.registration.DynamicSet;
@@ -34,6 +35,7 @@
 import com.google.gerrit.server.git.validators.MergeValidationListener;
 import com.google.gerrit.server.git.validators.UploadValidationListener;
 import com.google.gerrit.server.plugins.ServerPluginProvider;
+import com.google.gerrit.server.query.change.ChangeQueryBuilder.ChangeOperatorFactory;
 import com.google.gerrit.server.validators.HashtagValidationListener;
 import com.google.inject.AbstractModule;
 
@@ -52,7 +54,7 @@
     DynamicSet.bind(binder(), ServerPluginProvider.class).to(
         HelloSshPluginProvider.class);
     DynamicSet.bind(binder(), UsageDataPublishedListener.class).to(UsageDataLogger.class);
-
+    DynamicSet.bind(binder(), LifecycleListener.class).to(ConsoleMetricReporter.class);
     install(new RestApiModule() {
       @Override
       protected void configure() {
@@ -74,6 +76,10 @@
     DynamicSet.bind(binder(), CommitValidationListener.class)
         .to(CommitValidator.class);
     configurePluginParameters();
+
+    bind(ChangeOperatorFactory.class)
+        .annotatedWith(Exports.named("sample"))
+        .to(SampleOperator.class);
   }
 
   private void configurePluginParameters() {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/cookbook/SampleOperator.java b/src/main/java/com/googlesource/gerrit/plugins/cookbook/SampleOperator.java
new file mode 100644
index 0000000..908a934
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/cookbook/SampleOperator.java
@@ -0,0 +1,52 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.cookbook;
+
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.query.OperatorPredicate;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryParseException;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangeQueryBuilder;
+import com.google.inject.Singleton;
+
+@Singleton
+public class SampleOperator
+    implements ChangeQueryBuilder.ChangeOperatorFactory {
+  public static class MyPredicate extends OperatorPredicate<ChangeData> {
+    private final Change.Id id;
+
+    MyPredicate(Change.Id id) {
+      super("sample", id.toString());
+      this.id = id;
+    }
+
+    @Override
+    public boolean match(ChangeData object) {
+      return id.equals(object.getId());
+    }
+
+    @Override
+    public int getCost() {
+      return 1;
+    }
+  }
+
+  @Override
+  public Predicate<ChangeData> create(ChangeQueryBuilder builder, String value)
+      throws QueryParseException {
+    return new MyPredicate(Change.Id.parse(value));
+  }
+}
diff --git a/src/main/resources/Documentation/change-search-operators.md b/src/main/resources/Documentation/change-search-operators.md
new file mode 100644
index 0000000..78d7bf3
--- /dev/null
+++ b/src/main/resources/Documentation/change-search-operators.md
@@ -0,0 +1,12 @@
+Search Operators
+================
+
+Sample Operator
+---------------
+
+The @PLUGIN@ plugin provides a new `sample_@PLUGIN@` change search operator
+which can search for one specific change by change number.
+
+*sample_@PLUGIN@:number*
+
+Returns changes which match the change number `number`.
diff --git a/src/test/java/com/googlesource/gerrit/plugins/cookbook/CookbookIT.java b/src/test/java/com/googlesource/gerrit/plugins/cookbook/CookbookIT.java
index 4c5bf0e..0d985c5 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/cookbook/CookbookIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/cookbook/CookbookIT.java
@@ -16,12 +16,11 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import com.google.gerrit.acceptance.NoHttpd;
 import com.google.gerrit.acceptance.PluginDaemonTest;
+import com.google.gerrit.acceptance.RestResponse;
 
 import org.junit.Test;
 
-@NoHttpd
 public class CookbookIT extends PluginDaemonTest {
 
   @Test
@@ -29,4 +28,13 @@
     assertThat(sshSession.exec("cookbook print")).isEqualTo("Hello world!\n");
     assertThat(sshSession.hasError()).isFalse();
   }
+
+  @Test
+  public void revisionTest() throws Exception {
+    createChange();
+    RestResponse response =
+        adminSession.post("/changes/1/revisions/1/cookbook~hello-revision");
+    assertThat(response.getEntityContent())
+        .contains("Hello admin from change 1, patch set 1!");
+  }
 }