diff --git a/Documentation/config-robot-comments.txt b/Documentation/config-robot-comments.txt
new file mode 100644
index 0000000..cf5de10
--- /dev/null
+++ b/Documentation/config-robot-comments.txt
@@ -0,0 +1,49 @@
+= Gerrit Code Review - Robot Comments
+
+Gerrit has special support for inline comments that are generated by
+automated third-party systems, so called "robot comments". For example
+robot comments can be used to represent the results of code analyzers.
+
+In contrast to regular inline comments which are free-text comments,
+robot comments are more structured and can contain additional data,
+such as a robot ID, a robot run ID and a URL, see
+link:rest-api-changes.html#robot-comment-info[RobotCommentInfo] for
+details.
+
+It is planned to visualize robot comments differently in the web UI so
+that they can be easily distinguished from human comments. Users should
+also be able to use filtering on robot comments, so that only part of
+the robot comments or no robot comments are shown. In addition it is
+planned that robot comments can contain fixes, that users can apply by
+a single click.
+
+== REST endpoints
+
+* Posting robot comments is done by the
+  link:rest-api-changes.html[Set Review] REST endpoint. The
+  link:rest-api-changes.html#review-input[input] for this REST endpoint
+  can contain robot comments in its `robot_comments` field.
+* link:rest-api-changes.html#list-robot-comments[List Robot Comments]
+* link:rest-api-changes.html#get-robot-comment[Get Robot Comment]
+
+== Storage
+
+Robot comments are stored per change in a
+`refs/changes/XX/YYYY/robot-comments` ref, where `XX/YYYY` is the
+sharded change ID.
+
+Robot comments can be dropped by deleting this ref.
+
+== Limitations
+
+* Robot comments are only supported with NoteDb, but not with ReviewDb.
+* Robot comments are not displayed in the web UI yet.
+* There is no support for draft robot comments, but robot comments are
+  always published and visible to everyone who can see the change.
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------
diff --git a/Documentation/index.txt b/Documentation/index.txt
index f53463c..06a416d 100644
--- a/Documentation/index.txt
+++ b/Documentation/index.txt
@@ -45,6 +45,7 @@
 . link:config-hooks.html[Hooks]
 . link:config-mail.html[Mail Templates]
 . link:config-cla.html[Contributor Agreements]
+. link:config-robot-comments.html[Robot Comments]
 
 == Server Administration
 . link:install.html[Installation Guide]
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index 95fa1c9..88c1765 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -3904,6 +3904,102 @@
   }
 ----
 
+[[list-comments]]
+=== List Robot Comments
+--
+'GET /changes/link:#change-id[\{change-id\}]/revisions/link:#revision-id[\{revision-id\}]/robotcomments/'
+--
+
+Lists the link:config-robot-comments.html[robot comments] of a
+revision.
+
+As result a map is returned that maps the file path to a list of
+link:#robot-comment-info[RobotCommentInfo] entries. The entries in the
+map are sorted by file path.
+
+.Request
+----
+  GET /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/revisions/674ac754f91e64a0efb8087e59a176484bd534d1/robotcomments/ HTTP/1.0
+----
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json; charset=UTF-8
+
+  )]}'
+  {
+    "gerrit-server/src/main/java/com/google/gerrit/server/project/RefControl.java": [
+      {
+        "id": "TvcXrmjM",
+        "line": 23,
+        "message": "unused import",
+        "updated": "2016-02-26 15:40:43.986000000",
+        "author": {
+          "_account_id": 1000110,
+          "name": "Code Analyzer",
+          "email": "code.analyzer@example.com"
+        },
+        "robotId": "importChecker",
+        "robotRunId": "76b1375aa8626ea7149792831fe2ed85e80d9e04"
+      },
+      {
+        "id": "TveXwFiA",
+        "line": 49,
+        "message": "wrong indention",
+        "updated": "2016-02-26 15:40:45.328000000",
+        "author": {
+          "_account_id": 1000110,
+          "name": "Code Analyzer",
+          "email": "code.analyzer@example.com"
+        },
+        "robotId": "styleChecker",
+        "robotRunId": "5c606c425dd45184484f9d0a2ffd725a7607839b"
+      }
+    ]
+  }
+----
+
+[[get-robot-comment]]
+=== Get Robot Comment
+--
+'GET /changes/link:#change-id[\{change-id\}]/revisions/link:#revision-id[\{revision-id\}]/robotcomments/link:#comment-id[\{comment-id\}]'
+--
+
+Retrieves a link:config-robot-comments.html[robot comment] of a
+revision.
+
+.Request
+----
+  GET /changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/revisions/674ac754f91e64a0efb8087e59a176484bd534d1/robotcomments/TvcXrmjM HTTP/1.0
+----
+
+As response a link:#robot-comment-info[RobotCommentInfo] entity is
+returned that describes the robot comment.
+
+.Response
+----
+  HTTP/1.1 200 OK
+  Content-Disposition: attachment
+  Content-Type: application/json; charset=UTF-8
+
+  )]}'
+  {
+    "id": "TvcXrmjM",
+    "line": 23,
+    "message": "unused import",
+    "updated": "2016-02-26 15:40:43.986000000",
+    "author": {
+      "_account_id": 1000110,
+      "name": "Code Analyzer",
+      "email": "code.analyzer@example.com"
+    },
+    "robotId": "importChecker",
+    "robotRunId": "76b1375aa8626ea7149792831fe2ed85e80d9e04"
+  }
+----
+
 [[list-files]]
 === List Files
 --
@@ -5465,6 +5561,9 @@
 |`comments`               |optional|
 The comments that should be added as a map that maps a file path to a
 list of link:#comment-input[CommentInput] entities.
+|`robot_comments`         |optional|
+The robot comments that should be added as a map that maps a file path
+to a list of link:#robot-comment-input[RobotCommentInput] entities.
 |`strict_labels`          |`true` if not set|
 Whether all labels are required to be within the user's permitted ranges
 based on access controls. +
@@ -5591,6 +5690,29 @@
 certificate was provided, it is set to an empty object.
 |===========================
 
+[[robot-comment-info]]
+=== RobotCommentInfo
+The `RobotCommentInfo` entity contains information about a robot inline
+comment.
+
+`RobotCommentInfo` has the same fields as link:#[CommentInfo].
+In addition `RobotCommentInfo` has the following fields:
+
+[options="header",cols="1,^1,5"]
+|===========================
+|Field Name     ||Description
+|`robot_id`     ||The ID of the robot that generated this comment.
+|`robot_run_id` ||An ID of the run of the robot.
+|`url`          |optional|URL to more information.
+|===========================
+
+[[robot-comment-input]]
+=== RobotCommentInput
+The `RobotCommentInput` entity contains information for creating an inline
+robot comment.
+
+`RobotCommentInput` has the same fields as link:#[RobotCommentInfo].
+
 [[rule-input]]
 === RuleInput
 The `RuleInput` entity contains information to test a Prolog rule.
diff --git a/ReleaseNotes/ReleaseNotes-2.13.2.txt b/ReleaseNotes/ReleaseNotes-2.13.2.txt
new file mode 100644
index 0000000..87e902c
--- /dev/null
+++ b/ReleaseNotes/ReleaseNotes-2.13.2.txt
@@ -0,0 +1,34 @@
+= Release notes for Gerrit 2.13.2
+
+Gerrit 2.13.2 is now available:
+
+link:https://gerrit-releases.storage.googleapis.com/gerrit-2.13.2.war[
+https://gerrit-releases.storage.googleapis.com/gerrit-2.13.2.war]
+
+== Schema Upgrade
+
+There are no schema changes from link:ReleaseNotes-2.13.1.html[2.13.1].
+
+== Bug Fixes
+
+* link:https://bugs.chromium.org/p/gerrit/issues/detail?id=4630[Issue 4630]:
+Fix server error when navigating up to change while 'Working' is displayed.
+
+* link:https://bugs.chromium.org/p/gerrit/issues/detail?id=4631[Issue 4631]:
+Read project watches from database.
++
+Project watches were being read from the git backend by default, but the
+migration to git is not yet completed.
+
+* Hooks plugin: Fix incorrect value passed to `--change-url` parameter.
++
+The URL was being generated using the change's Change-Id rather than the
+change number.
+
+* Check for CLA when creating project config changes from the web UI.
++
+If contributor agreements were enabled and required for a project, and
+the user had not signed a CLA, it was still possible to upload changes
+for review on `refs/meta/config` by making changes in the project access
+editor and pressing 'Save for Review'.
+
diff --git a/ReleaseNotes/index.txt b/ReleaseNotes/index.txt
index 2938c1c6..945f09f 100644
--- a/ReleaseNotes/index.txt
+++ b/ReleaseNotes/index.txt
@@ -2,6 +2,7 @@
 
 [[s2_13]]
 == Version 2.13.x
+* link:ReleaseNotes-2.13.2.html[2.13.2]
 * link:ReleaseNotes-2.13.1.html[2.13.1]
 * link:ReleaseNotes-2.13.html[2.13]
 
diff --git a/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java b/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java
new file mode 100644
index 0000000..064b206
--- /dev/null
+++ b/gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/revision/RobotCommentsIT.java
@@ -0,0 +1,130 @@
+// Copyright (C) 2016 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.google.gerrit.acceptance.api.revision;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.TruthJUnit.assume;
+import static com.google.gerrit.acceptance.PushOneCommit.FILE_NAME;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.extensions.api.changes.ReviewInput;
+import com.google.gerrit.extensions.api.changes.ReviewInput.RobotCommentInput;
+import com.google.gerrit.extensions.common.RobotCommentInfo;
+import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
+
+import org.junit.Test;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class RobotCommentsIT extends AbstractDaemonTest {
+  @Test
+  public void comments() throws Exception {
+    assume().that(notesMigration.enabled()).isTrue();
+
+    PushOneCommit.Result r = createChange();
+    RobotCommentInput in = createRobotCommentInput();
+    ReviewInput reviewInput = new ReviewInput();
+    Map<String, List<RobotCommentInput>> robotComments = new HashMap<>();
+    robotComments.put(in.path, Collections.singletonList(in));
+    reviewInput.robotComments = robotComments;
+    reviewInput.message = "comment test";
+    gApi.changes()
+       .id(r.getChangeId())
+       .current()
+       .review(reviewInput);
+
+    Map<String, List<RobotCommentInfo>> out = gApi.changes()
+        .id(r.getChangeId())
+        .revision(r.getCommit().name())
+        .robotComments();
+    assertThat(out).hasSize(1);
+    RobotCommentInfo comment = Iterables.getOnlyElement(out.get(in.path));
+    assertRobotComment(comment, in, false);
+
+    List<RobotCommentInfo> list = gApi.changes()
+        .id(r.getChangeId())
+        .revision(r.getCommit().name())
+        .robotCommentsAsList();
+    assertThat(list).hasSize(1);
+
+    RobotCommentInfo comment2 = list.get(0);
+    assertRobotComment(comment2, in);
+
+    RobotCommentInfo comment3 = gApi.changes()
+        .id(r.getChangeId())
+        .revision(r.getCommit().name())
+        .robotComment(comment.id)
+        .get();
+    assertRobotComment(comment3, in);
+  }
+
+  @Test
+  public void robotCommentsNotSupported() throws Exception {
+    assume().that(notesMigration.enabled()).isFalse();
+
+    PushOneCommit.Result r = createChange();
+    RobotCommentInput in = createRobotCommentInput();
+    ReviewInput reviewInput = new ReviewInput();
+    Map<String, List<RobotCommentInput>> robotComments = new HashMap<>();
+    robotComments.put(FILE_NAME, Collections.singletonList(in));
+    reviewInput.robotComments = robotComments;
+    reviewInput.message = "comment test";
+
+    exception.expect(MethodNotAllowedException.class);
+    exception.expectMessage("robot comments not supported");
+    gApi.changes()
+       .id(r.getChangeId())
+       .current()
+       .review(reviewInput);
+  }
+
+  private RobotCommentInput createRobotCommentInput() {
+    RobotCommentInput in = new RobotCommentInput();
+    in.robotId = "happyRobot";
+    in.robotRunId = "1";
+    in.url = "http://www.happy-robot.com";
+    in.line = 1;
+    in.message = "nit: trailing whitespace";
+    in.path = FILE_NAME;
+    return in;
+  }
+
+  private void assertRobotComment(RobotCommentInfo c,
+      RobotCommentInput expected) {
+    assertRobotComment(c, expected, true);
+  }
+
+  private void assertRobotComment(RobotCommentInfo c,
+      RobotCommentInput expected, boolean expectPath) {
+    assertThat(c.robotId).isEqualTo(expected.robotId);
+    assertThat(c.robotRunId).isEqualTo(expected.robotRunId);
+    assertThat(c.url).isEqualTo(expected.url);
+    assertThat(c.line).isEqualTo(expected.line);
+    assertThat(c.message).isEqualTo(expected.message);
+
+    assertThat(c.author.email).isEqualTo(admin.email);
+
+    if (expectPath) {
+      assertThat(c.path).isEqualTo(expected.path);
+    } else {
+      assertThat(c.path).isNull();
+    }
+  }
+}
diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/ReviewInput.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/ReviewInput.java
index cbe16ed..8f1e283 100644
--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/ReviewInput.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/ReviewInput.java
@@ -34,6 +34,7 @@
 
   public Map<String, Short> labels;
   public Map<String, List<CommentInput>> comments;
+  public Map<String, List<RobotCommentInput>> robotComments;
 
   /**
    * If true require all labels to be within the user's permitted ranges based
@@ -94,6 +95,12 @@
   public static class CommentInput extends Comment {
   }
 
+  public static class RobotCommentInput extends CommentInput {
+    public String robotId;
+    public String robotRunId;
+    public String url;
+  }
+
   public ReviewInput message(String msg) {
     message = msg != null && !msg.isEmpty() ? msg : null;
     return this;
diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RevisionApi.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
index d6897b1..29bf00b 100644
--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RevisionApi.java
@@ -20,6 +20,7 @@
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.common.MergeableInfo;
+import com.google.gerrit.extensions.common.RobotCommentInfo;
 import com.google.gerrit.extensions.common.TestSubmitRuleInput;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.NotImplementedException;
@@ -54,15 +55,18 @@
   MergeableInfo mergeableOtherBranches() throws RestApiException;
 
   Map<String, List<CommentInfo>> comments() throws RestApiException;
+  Map<String, List<RobotCommentInfo>> robotComments() throws RestApiException;
   Map<String, List<CommentInfo>> drafts() throws RestApiException;
 
   List<CommentInfo> commentsAsList() throws RestApiException;
   List<CommentInfo> draftsAsList() throws RestApiException;
+  List<RobotCommentInfo> robotCommentsAsList() throws RestApiException;
 
   DraftApi createDraft(DraftInput in) throws RestApiException;
   DraftApi draft(String id) throws RestApiException;
 
   CommentApi comment(String id) throws RestApiException;
+  RobotCommentApi robotComment(String id) throws RestApiException;
 
   /**
    * Returns patch of revision.
@@ -197,6 +201,12 @@
     }
 
     @Override
+    public Map<String, List<RobotCommentInfo>> robotComments()
+        throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
     public List<CommentInfo> commentsAsList() throws RestApiException {
       throw new NotImplementedException();
     }
@@ -207,6 +217,12 @@
     }
 
     @Override
+    public List<RobotCommentInfo> robotCommentsAsList()
+        throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
     public Map<String, List<CommentInfo>> drafts() throws RestApiException {
       throw new NotImplementedException();
     }
@@ -227,6 +243,11 @@
     }
 
     @Override
+    public RobotCommentApi robotComment(String id) throws RestApiException {
+      throw new NotImplementedException();
+    }
+
+    @Override
     public BinaryResult patch() throws RestApiException {
       throw new NotImplementedException();
     }
diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RobotCommentApi.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RobotCommentApi.java
new file mode 100644
index 0000000..e1ed107
--- /dev/null
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/changes/RobotCommentApi.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2016 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.google.gerrit.extensions.api.changes;
+
+import com.google.gerrit.extensions.common.RobotCommentInfo;
+import com.google.gerrit.extensions.restapi.NotImplementedException;
+import com.google.gerrit.extensions.restapi.RestApiException;
+
+public interface RobotCommentApi {
+  RobotCommentInfo get() throws RestApiException;
+
+  /**
+   * A default implementation which allows source compatibility
+   * when adding new methods to the interface.
+   **/
+  class NotImplemented implements RobotCommentApi {
+    @Override
+    public RobotCommentInfo get() throws RestApiException {
+      throw new NotImplementedException();
+    }
+  }
+}
diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/RobotCommentInfo.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/RobotCommentInfo.java
new file mode 100644
index 0000000..a6b7593
--- /dev/null
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/RobotCommentInfo.java
@@ -0,0 +1,21 @@
+// Copyright (C) 2016 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.google.gerrit.extensions.common;
+
+public class RobotCommentInfo extends CommentInfo {
+  public String robotId;
+  public String robotRunId;
+  public String url;
+}
diff --git a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
index 4a01128..111dfc9 100644
--- a/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
+++ b/gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/project/ProjectAccessHandler.java
@@ -18,11 +18,13 @@
 
 import com.google.common.base.MoreObjects;
 import com.google.gerrit.common.data.AccessSection;
+import com.google.gerrit.common.data.Capable;
 import com.google.gerrit.common.data.GroupReference;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.common.data.PermissionRule;
 import com.google.gerrit.common.errors.InvalidNameException;
 import com.google.gerrit.common.errors.NoSuchGroupException;
+import com.google.gerrit.common.errors.PermissionDeniedException;
 import com.google.gerrit.common.errors.UpdateParentFailedException;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
@@ -89,10 +91,15 @@
   @Override
   public final T call() throws NoSuchProjectException, IOException,
       ConfigInvalidException, InvalidNameException, NoSuchGroupException,
-      OrmException, UpdateParentFailedException {
+      OrmException, UpdateParentFailedException, PermissionDeniedException {
     final ProjectControl projectControl =
         projectControlFactory.controlFor(projectName);
 
+    Capable r = projectControl.canPushToAtLeastOneRef();
+    if (r != Capable.OK) {
+      throw new PermissionDeniedException(r.getMessage());
+    }
+
     try (MetaDataUpdate md = metaDataUpdateFactory.create(projectName)) {
       ProjectConfig config = ProjectConfig.read(md, base);
       Set<String> toDelete = scanSectionNames(config);
diff --git a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
index f3a68a1..0f3d45c 100644
--- a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
+++ b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
@@ -149,6 +149,7 @@
       }
       int ce = nextNonDigit(ref, cs);
       if (ref.substring(ce).equals(RefNames.META_SUFFIX)
+          || ref.substring(ce).equals(RefNames.ROBOT_COMMENTS_SUFFIX)
           || PatchSet.Id.fromRef(ref, ce) >= 0) {
         return new Change.Id(Integer.parseInt(ref.substring(cs, ce)));
       }
diff --git a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java
index b2bd818..7629705 100644
--- a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java
+++ b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java
@@ -68,6 +68,9 @@
   /** Suffix of a meta ref in the NoteDb. */
   public static final String META_SUFFIX = "/meta";
 
+  /** Suffix of a ref that stores robot comments in the NoteDb. */
+  public static final String ROBOT_COMMENTS_SUFFIX = "/robot-comments";
+
   public static final String EDIT_PREFIX = "edit-";
 
   public static String fullName(String ref) {
@@ -92,6 +95,14 @@
     return r.toString();
   }
 
+  public static String robotCommentsRef(Change.Id id) {
+    StringBuilder r = new StringBuilder();
+    r.append(REFS_CHANGES);
+    r.append(shard(id.get()));
+    r.append(ROBOT_COMMENTS_SUFFIX);
+    return r.toString();
+  }
+
   public static String refsUsers(Account.Id accountId) {
     StringBuilder r = new StringBuilder();
     r.append(REFS_USERS);
diff --git a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RobotComment.java b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RobotComment.java
new file mode 100644
index 0000000..da9584d
--- /dev/null
+++ b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RobotComment.java
@@ -0,0 +1,54 @@
+// Copyright (C) 2016 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.google.gerrit.reviewdb.client;
+
+import java.sql.Timestamp;
+import java.util.Objects;
+
+public class RobotComment extends Comment {
+  public String robotId;
+  public String robotRunId;
+  public String url;
+
+  public RobotComment(Key key, Account.Id author, Timestamp writtenOn,
+      short side, String message, String serverId, String robotId,
+      String robotRunId) {
+    super(key, author, writtenOn, side, message, serverId);
+    this.robotId = robotId;
+    this.robotRunId = robotRunId;
+  }
+
+  @Override
+  public String toString() {
+    return new StringBuilder()
+        .append("RobotComment{")
+        .append("key=").append(key).append(',')
+        .append("robotId=").append(robotId).append(',')
+        .append("robotRunId=").append(robotRunId).append(',')
+        .append("lineNbr=").append(lineNbr).append(',')
+        .append("author=").append(author.getId().get()).append(',')
+        .append("writtenOn=").append(writtenOn.toString()).append(',')
+        .append("side=").append(side).append(',')
+        .append("message=").append(Objects.toString(message, "")).append(',')
+        .append("parentUuid=")
+            .append(Objects.toString(parentUuid, "")).append(',')
+        .append("range=").append(Objects.toString(range, "")).append(',')
+        .append("revId=").append(revId != null ? revId : "").append(',')
+        .append("tag=").append(Objects.toString(tag, "")).append(',')
+        .append("url=").append(url)
+        .append('}')
+        .toString();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/CommentsUtil.java b/gerrit-server/src/main/java/com/google/gerrit/server/CommentsUtil.java
index f15ff66..8197689 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/CommentsUtil.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/CommentsUtil.java
@@ -21,6 +21,7 @@
 import com.google.common.base.Optional;
 import com.google.common.collect.ComparisonChain;
 import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Ordering;
@@ -34,6 +35,7 @@
 import com.google.gerrit.reviewdb.client.PatchLineComment.Status;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.GerritServerId;
@@ -156,9 +158,17 @@
     }
 
     notes.load();
-    List<Comment> comments = new ArrayList<>();
-    comments.addAll(notes.getComments().values());
-    return sort(comments);
+    return sort(Lists.newArrayList(notes.getComments().values()));
+  }
+
+  public List<RobotComment> robotCommentsByChange(ChangeNotes notes)
+      throws OrmException {
+    if (!migration.readChanges()) {
+      return ImmutableList.of();
+    }
+
+    notes.load();
+    return sort(Lists.newArrayList(notes.getRobotComments().values()));
   }
 
   public List<Comment> draftByChange(ReviewDb db, ChangeNotes notes)
@@ -221,6 +231,14 @@
         commentsOnPatchSet(notes.load().getComments().values(), psId));
   }
 
+  public List<RobotComment> robotCommentsByPatchSet(ChangeNotes notes,
+      PatchSet.Id psId) throws OrmException {
+    if (!migration.readChanges()) {
+      return ImmutableList.of();
+    }
+    return commentsOnPatchSet(notes.load().getRobotComments().values(), psId);
+  }
+
   /**
    * For the commit message the A side in a diff view is always empty when a
    * comparison against an ancestor is done, so there can't be any comments on
@@ -309,6 +327,13 @@
         .upsert(toPatchLineComments(update.getId(), status, comments));
   }
 
+  public void putRobotComments(ChangeUpdate update,
+      Iterable<RobotComment> comments) {
+    for (RobotComment c : comments) {
+      update.putRobotComment(c);
+    }
+  }
+
   public void deleteComments(ReviewDb db, ChangeUpdate update,
       Iterable<Comment> comments) throws OrmException {
     for (Comment c : comments) {
@@ -352,11 +377,11 @@
     return sort(result);
   }
 
-  private static List<Comment> commentsOnPatchSet(
-      Collection<Comment> allComments,
+  private static <T extends Comment> List<T> commentsOnPatchSet(
+      Collection<T> allComments,
       PatchSet.Id psId) {
-    List<Comment> result = new ArrayList<>(allComments.size());
-    for (Comment c : allComments) {
+    List<T> result = new ArrayList<>(allComments.size());
+    for (T c : allComments) {
       if (c.key.patchSetId == psId.get()) {
         result.add(c);
       }
@@ -400,7 +425,7 @@
         RefNames.refsDraftCommentsPrefix(changeId)).values();
   }
 
-  private static List<Comment> sort(List<Comment> comments) {
+  private static <T extends Comment> List<T> sort(List<T> comments) {
     Collections.sort(comments, COMMENT_ORDER);
     return comments;
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountCacheImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountCacheImpl.java
index 63d2ddb..149931d 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountCacheImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountCacheImpl.java
@@ -174,7 +174,7 @@
       this.loader = loader;
       this.byName = byUsername;
       this.readFromGit =
-          cfg.getBoolean("user", null, "readProjectWatchesFromGit", true);
+          cfg.getBoolean("user", null, "readProjectWatchesFromGit", false);
       this.watchConfig = watchConfig;
     }
 
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/GetWatchedProjects.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/GetWatchedProjects.java
index 7cda472..3748e17 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/GetWatchedProjects.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/GetWatchedProjects.java
@@ -60,7 +60,7 @@
     this.dbProvider = dbProvider;
     this.self = self;
     this.readFromGit =
-        cfg.getBoolean("user", null, "readProjectWatchesFromGit", true);
+        cfg.getBoolean("user", null, "readProjectWatchesFromGit", false);
     this.watchConfig = watchConfig;
   }
 
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
index 871b1cd..aa32d27 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/VersionedAuthorizedKeys.java
@@ -101,7 +101,7 @@
       return read(accountId).getKey(seq);
     }
 
-    public AccountSshKey addKey(Account.Id accountId, String pub)
+    public synchronized AccountSshKey addKey(Account.Id accountId, String pub)
         throws IOException, ConfigInvalidException, InvalidSshKeyException {
       VersionedAuthorizedKeys authorizedKeys = read(accountId);
       AccountSshKey key = authorizedKeys.addKey(pub);
@@ -109,7 +109,7 @@
       return key;
     }
 
-    public void deleteKey(Account.Id accountId, int seq)
+    public synchronized void deleteKey(Account.Id accountId, int seq)
         throws IOException, ConfigInvalidException {
       VersionedAuthorizedKeys authorizedKeys = read(accountId);
       if (authorizedKeys.deleteKey(seq)) {
@@ -117,7 +117,7 @@
       }
     }
 
-    public void markKeyInvalid(Account.Id accountId, int seq)
+    public synchronized void markKeyInvalid(Account.Id accountId, int seq)
         throws IOException, ConfigInvalidException {
       VersionedAuthorizedKeys authorizedKeys = read(accountId);
       if (authorizedKeys.markKeyInvalid(seq)) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/WatchConfig.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/WatchConfig.java
index c3d28ca..a3cd0c9 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/WatchConfig.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/WatchConfig.java
@@ -121,7 +121,7 @@
       }
     }
 
-    public void upsertProjectWatches(Account.Id accountId,
+    public synchronized void upsertProjectWatches(Account.Id accountId,
         Map<ProjectWatchKey, Set<NotifyType>> newProjectWatches)
         throws IOException, ConfigInvalidException {
       WatchConfig watchConfig = read(accountId);
@@ -131,7 +131,7 @@
       commit(watchConfig);
     }
 
-    public void deleteProjectWatches(Account.Id accountId,
+    public synchronized void deleteProjectWatches(Account.Id accountId,
         Collection<ProjectWatchKey> projectWatchKeys)
             throws IOException, ConfigInvalidException {
       WatchConfig watchConfig = read(accountId);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/Module.java b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/Module.java
index 228dad6..bc38df2 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/Module.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/Module.java
@@ -24,6 +24,7 @@
 
     factory(ChangeApiImpl.Factory.class);
     factory(CommentApiImpl.Factory.class);
+    factory(RobotCommentApiImpl.Factory.class);
     factory(DraftApiImpl.Factory.class);
     factory(RevisionApiImpl.Factory.class);
     factory(FileApiImpl.Factory.class);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
index fed792b..4e847a1 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RevisionApiImpl.java
@@ -26,6 +26,7 @@
 import com.google.gerrit.extensions.api.changes.RebaseInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.RevisionApi;
+import com.google.gerrit.extensions.api.changes.RobotCommentApi;
 import com.google.gerrit.extensions.api.changes.SubmitInput;
 import com.google.gerrit.extensions.client.SubmitType;
 import com.google.gerrit.extensions.common.ActionInfo;
@@ -33,6 +34,7 @@
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.extensions.common.FileInfo;
 import com.google.gerrit.extensions.common.MergeableInfo;
+import com.google.gerrit.extensions.common.RobotCommentInfo;
 import com.google.gerrit.extensions.common.TestSubmitRuleInput;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.IdString;
@@ -50,6 +52,7 @@
 import com.google.gerrit.server.change.GetRevisionActions;
 import com.google.gerrit.server.change.ListRevisionComments;
 import com.google.gerrit.server.change.ListRevisionDrafts;
+import com.google.gerrit.server.change.ListRobotComments;
 import com.google.gerrit.server.change.Mergeable;
 import com.google.gerrit.server.change.PostReview;
 import com.google.gerrit.server.change.PreviewSubmit;
@@ -58,6 +61,7 @@
 import com.google.gerrit.server.change.RebaseUtil;
 import com.google.gerrit.server.change.Reviewed;
 import com.google.gerrit.server.change.RevisionResource;
+import com.google.gerrit.server.change.RobotComments;
 import com.google.gerrit.server.change.Submit;
 import com.google.gerrit.server.change.TestSubmitType;
 import com.google.gerrit.server.git.GitRepositoryManager;
@@ -101,12 +105,15 @@
   private final Mergeable mergeable;
   private final FileApiImpl.Factory fileApi;
   private final ListRevisionComments listComments;
+  private final ListRobotComments listRobotComments;
   private final ListRevisionDrafts listDrafts;
   private final CreateDraftComment createDraft;
   private final DraftComments drafts;
   private final DraftApiImpl.Factory draftFactory;
   private final Comments comments;
   private final CommentApiImpl.Factory commentFactory;
+  private final RobotComments robotComments;
+  private final RobotCommentApiImpl.Factory robotCommentFactory;
   private final GetRevisionActions revisionActions;
   private final TestSubmitType testSubmitType;
   private final TestSubmitType.Get getSubmitType;
@@ -131,12 +138,15 @@
       Mergeable mergeable,
       FileApiImpl.Factory fileApi,
       ListRevisionComments listComments,
+      ListRobotComments listRobotComments,
       ListRevisionDrafts listDrafts,
       CreateDraftComment createDraft,
       DraftComments drafts,
       DraftApiImpl.Factory draftFactory,
       Comments comments,
       CommentApiImpl.Factory commentFactory,
+      RobotComments robotComments,
+      RobotCommentApiImpl.Factory robotCommentFactory,
       GetRevisionActions revisionActions,
       TestSubmitType testSubmitType,
       TestSubmitType.Get getSubmitType,
@@ -160,12 +170,15 @@
     this.mergeable = mergeable;
     this.fileApi = fileApi;
     this.listComments = listComments;
+    this.robotComments = robotComments;
+    this.listRobotComments = listRobotComments;
     this.listDrafts = listDrafts;
     this.createDraft = createDraft;
     this.drafts = drafts;
     this.draftFactory = draftFactory;
     this.comments = comments;
     this.commentFactory = commentFactory;
+    this.robotCommentFactory = robotCommentFactory;
     this.revisionActions = revisionActions;
     this.testSubmitType = testSubmitType;
     this.getSubmitType = getSubmitType;
@@ -353,6 +366,15 @@
   }
 
   @Override
+  public Map<String, List<RobotCommentInfo>> robotComments() throws RestApiException {
+    try {
+      return listRobotComments.apply(revision);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot retrieve robot comments", e);
+    }
+  }
+
+  @Override
   public List<CommentInfo> commentsAsList() throws RestApiException {
     try {
       return listComments.getComments(revision);
@@ -371,6 +393,15 @@
   }
 
   @Override
+  public List<RobotCommentInfo> robotCommentsAsList() throws RestApiException {
+    try {
+      return listRobotComments.getComments(revision);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot retrieve robot comments", e);
+    }
+  }
+
+  @Override
   public List<CommentInfo> draftsAsList() throws RestApiException {
     try {
       return listDrafts.getComments(revision);
@@ -413,6 +444,16 @@
   }
 
   @Override
+  public RobotCommentApi robotComment(String id) throws RestApiException {
+    try {
+      return robotCommentFactory
+          .create(robotComments.parse(revision, IdString.fromDecoded(id)));
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot retrieve robot comment", e);
+    }
+  }
+
+  @Override
   public BinaryResult patch() throws RestApiException {
     try {
       return getPatch.apply(revision);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RobotCommentApiImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RobotCommentApiImpl.java
new file mode 100644
index 0000000..9169a4f
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/api/changes/RobotCommentApiImpl.java
@@ -0,0 +1,49 @@
+// Copyright (C) 2016 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.google.gerrit.server.api.changes;
+
+import com.google.gerrit.extensions.api.changes.RobotCommentApi;
+import com.google.gerrit.extensions.common.RobotCommentInfo;
+import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.server.change.GetRobotComment;
+import com.google.gerrit.server.change.RobotCommentResource;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+
+public class RobotCommentApiImpl implements RobotCommentApi {
+  interface Factory {
+    RobotCommentApiImpl create(RobotCommentResource c);
+  }
+
+  private final GetRobotComment getComment;
+  private final RobotCommentResource comment;
+
+  @Inject
+  RobotCommentApiImpl(GetRobotComment getComment,
+      @Assisted RobotCommentResource comment) {
+    this.getComment = getComment;
+    this.comment = comment;
+  }
+
+  @Override
+  public RobotCommentInfo get() throws RestApiException {
+    try {
+      return getComment.apply(comment);
+    } catch (OrmException e) {
+      throw new RestApiException("Cannot retrieve robot comment", e);
+    }
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java
index 1e48717..be019fb 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/CommentJson.java
@@ -21,8 +21,10 @@
 import com.google.gerrit.extensions.client.Comment.Range;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.common.CommentInfo;
+import com.google.gerrit.extensions.common.RobotCommentInfo;
 import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.reviewdb.client.Comment;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.server.account.AccountLoader;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -55,100 +57,134 @@
     return this;
   }
 
-  CommentInfo format(Comment c) throws OrmException {
-    AccountLoader loader = null;
-    if (fillAccounts) {
-      loader = accountLoaderFactory.create(true);
-    }
-    CommentInfo commentInfo = toCommentInfo(c, loader);
-    if (fillAccounts) {
-      loader.fill();
-    }
-    return commentInfo;
+  public CommentFormatter newCommentFormatter() {
+    return new CommentFormatter();
   }
 
-  Map<String, List<CommentInfo>> format(Iterable<Comment> l)
-      throws OrmException {
-    Map<String, List<CommentInfo>> out = new TreeMap<>();
-    AccountLoader accountLoader = fillAccounts
-        ? accountLoaderFactory.create(true)
-        : null;
+  public RobotCommentFormatter newRobotCommentFormatter() {
+    return new RobotCommentFormatter();
+  }
 
-    for (Comment c : l) {
-      CommentInfo o = toCommentInfo(c, accountLoader);
-      List<CommentInfo> list = out.get(o.path);
-      if (list == null) {
-        list = new ArrayList<>();
-        out.put(o.path, list);
+  private abstract class BaseCommentFormatter<F extends Comment,
+      T extends CommentInfo> {
+    public T format(F comment) throws OrmException {
+      AccountLoader loader =
+          fillAccounts ? accountLoaderFactory.create(true) : null;
+      T info = toInfo(comment, loader);
+      if (loader != null) {
+        loader.fill();
       }
-      o.path = null;
-      list.add(o);
+      return info;
     }
 
-    for (List<CommentInfo> list : out.values()) {
-      Collections.sort(list, COMMENT_INFO_ORDER);
+    public Map<String, List<T>> format(Iterable<F> comments)
+        throws OrmException {
+      AccountLoader loader =
+          fillAccounts ? accountLoaderFactory.create(true) : null;
+
+      Map<String, List<T>> out = new TreeMap<>();
+
+      for (F c : comments) {
+        T o = toInfo(c, loader);
+        List<T> list = out.get(o.path);
+        if (list == null) {
+          list = new ArrayList<>();
+          out.put(o.path, list);
+        }
+        o.path = null;
+        list.add(o);
+      }
+
+      for (List<T> list : out.values()) {
+        Collections.sort(list, COMMENT_INFO_ORDER);
+      }
+
+      if (loader != null) {
+        loader.fill();
+      }
+      return out;
     }
 
-    if (accountLoader != null) {
-      accountLoader.fill();
+    public List<T> formatAsList(Iterable<F> comments) throws OrmException {
+      AccountLoader loader =
+          fillAccounts ? accountLoaderFactory.create(true) : null;
+
+      List<T> out = FluentIterable.from(comments)
+          .transform(c -> toInfo(c, loader))
+          .toSortedList(COMMENT_INFO_ORDER);
+
+      if (loader != null) {
+        loader.fill();
+      }
+      return out;
     }
 
-    return out;
-  }
+    protected abstract T toInfo(F comment, AccountLoader loader);
 
-  List<CommentInfo> formatAsList(Iterable<Comment> l)
-      throws OrmException {
-    AccountLoader accountLoader = fillAccounts
-        ? accountLoaderFactory.create(true)
-        : null;
-    List<CommentInfo> out = FluentIterable
-        .from(l)
-        .transform(c -> toCommentInfo(c, accountLoader))
-        .toSortedList(COMMENT_INFO_ORDER);
-
-    if (accountLoader != null) {
-      accountLoader.fill();
-    }
-
-    return out;
-  }
-
-  private CommentInfo toCommentInfo(Comment c, AccountLoader loader) {
-    CommentInfo r = new CommentInfo();
-    if (fillPatchSet) {
-      r.patchSet = c.key.patchSetId;
-    }
-    r.id = Url.encode(c.key.uuid);
-    r.path = c.key.filename;
-    if (c.side <= 0) {
-      r.side = Side.PARENT;
-      if (c.side < 0) {
-        r.parent = -c.side;
+    protected void fillCommentInfo(Comment c, CommentInfo r,
+        AccountLoader loader) {
+      if (fillPatchSet) {
+        r.patchSet = c.key.patchSetId;
+      }
+      r.id = Url.encode(c.key.uuid);
+      r.path = c.key.filename;
+      if (c.side <= 0) {
+        r.side = Side.PARENT;
+        if (c.side < 0) {
+          r.parent = -c.side;
+        }
+      }
+      if (c.lineNbr > 0) {
+        r.line = c.lineNbr;
+      }
+      r.inReplyTo = Url.encode(c.parentUuid);
+      r.message = Strings.emptyToNull(c.message);
+      r.updated = c.writtenOn;
+      r.range = toRange(c.range);
+      r.tag = c.tag;
+      if (loader != null) {
+        r.author = loader.get(c.author.getId());
       }
     }
-    if (c.lineNbr > 0) {
-      r.line = c.lineNbr;
+
+    private Range toRange(Comment.Range commentRange) {
+      Range range = null;
+      if (commentRange != null) {
+        range = new Range();
+        range.startLine = commentRange.startLine;
+        range.startCharacter = commentRange.startChar;
+        range.endLine = commentRange.endLine;
+        range.endCharacter = commentRange.endChar;
+      }
+      return range;
     }
-    r.inReplyTo = Url.encode(c.parentUuid);
-    r.message = Strings.emptyToNull(c.message);
-    r.updated = c.writtenOn;
-    r.range = toRange(c.range);
-    r.tag = c.tag;
-    if (loader != null) {
-      r.author = loader.get(c.author.getId());
-    }
-    return r;
   }
 
-  private Range toRange(Comment.Range commentRange) {
-    Range range = null;
-    if (commentRange != null) {
-      range = new Range();
-      range.startLine = commentRange.startLine;
-      range.startCharacter = commentRange.startChar;
-      range.endLine = commentRange.endLine;
-      range.endCharacter = commentRange.endChar;
+  class CommentFormatter extends BaseCommentFormatter<Comment, CommentInfo> {
+    @Override
+    protected CommentInfo toInfo(Comment c, AccountLoader loader) {
+      CommentInfo ci = new CommentInfo();
+      fillCommentInfo(c, ci, loader);
+      return ci;
     }
-    return range;
+
+    private CommentFormatter() {
+    }
+  }
+
+  class RobotCommentFormatter
+      extends BaseCommentFormatter<RobotComment, RobotCommentInfo> {
+    @Override
+    protected RobotCommentInfo toInfo(RobotComment c, AccountLoader loader) {
+      RobotCommentInfo rci = new RobotCommentInfo();
+      rci.robotId = c.robotId;
+      rci.robotRunId = c.robotRunId;
+      rci.url = c.url;
+      fillCommentInfo(c, rci, loader);
+      return rci;
+    }
+
+    private RobotCommentFormatter() {
+    }
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/CreateDraftComment.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/CreateDraftComment.java
index 37af37f..7ca8478 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/CreateDraftComment.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/CreateDraftComment.java
@@ -90,8 +90,8 @@
       Op op = new Op(rsrc.getPatchSet().getId(), in);
       bu.addOp(rsrc.getChange().getId(), op);
       bu.execute();
-      return Response.created(
-          commentJson.get().setFillAccounts(false).format(op.comment));
+      return Response.created(commentJson.get().setFillAccounts(false)
+          .newCommentFormatter().format(op.comment));
     }
   }
 
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetComment.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetComment.java
index d87c7eb..d601737 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetComment.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetComment.java
@@ -33,6 +33,6 @@
 
   @Override
   public CommentInfo apply(CommentResource rsrc) throws OrmException {
-    return commentJson.get().format(rsrc.getComment());
+    return commentJson.get().newCommentFormatter().format(rsrc.getComment());
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetDraftComment.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetDraftComment.java
index 22f90c9..a380ce3 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetDraftComment.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetDraftComment.java
@@ -33,6 +33,6 @@
 
   @Override
   public CommentInfo apply(DraftCommentResource rsrc) throws OrmException {
-    return commentJson.get().format(rsrc.getComment());
+    return commentJson.get().newCommentFormatter().format(rsrc.getComment());
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/GetRobotComment.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetRobotComment.java
new file mode 100644
index 0000000..c10cd2e
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/GetRobotComment.java
@@ -0,0 +1,39 @@
+// Copyright (C) 2016 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.google.gerrit.server.change;
+
+import com.google.gerrit.extensions.common.RobotCommentInfo;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+@Singleton
+public class GetRobotComment implements RestReadView<RobotCommentResource> {
+
+  private final Provider<CommentJson> commentJson;
+
+  @Inject
+  GetRobotComment(Provider<CommentJson> commentJson) {
+    this.commentJson = commentJson;
+  }
+
+  @Override
+  public RobotCommentInfo apply(RobotCommentResource rsrc) throws OrmException {
+    return commentJson.get().newRobotCommentFormatter()
+        .format(rsrc.getComment());
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeComments.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeComments.java
index 40fa7c8..32b5ae8 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeComments.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeComments.java
@@ -53,6 +53,7 @@
     return commentJson.get()
         .setFillAccounts(true)
         .setFillPatchSet(true)
+        .newCommentFormatter()
         .format(commentsUtil.publishedByChange(db.get(), cd.notes()));
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeDrafts.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeDrafts.java
index dbbd35d..6a3e237 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeDrafts.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListChangeDrafts.java
@@ -59,6 +59,6 @@
     return commentJson.get()
         .setFillAccounts(false)
         .setFillPatchSet(true)
-        .format(drafts);
+        .newCommentFormatter().format(drafts);
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRevisionDrafts.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRevisionDrafts.java
index 2c45219..21d427c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRevisionDrafts.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRevisionDrafts.java
@@ -57,13 +57,13 @@
       throws OrmException {
     return commentJson.get()
         .setFillAccounts(includeAuthorInfo())
-        .format(listComments(rsrc));
+        .newCommentFormatter().format(listComments(rsrc));
   }
 
   public List<CommentInfo> getComments(RevisionResource rsrc)
       throws OrmException {
     return commentJson.get()
         .setFillAccounts(includeAuthorInfo())
-        .formatAsList(listComments(rsrc));
+        .newCommentFormatter().formatAsList(listComments(rsrc));
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRobotComments.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRobotComments.java
new file mode 100644
index 0000000..01ad9ee
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/ListRobotComments.java
@@ -0,0 +1,67 @@
+// Copyright (C) 2016 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.google.gerrit.server.change;
+
+import com.google.gerrit.extensions.common.RobotCommentInfo;
+import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.reviewdb.client.RobotComment;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.CommentsUtil;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+import java.util.List;
+import java.util.Map;
+
+@Singleton
+public class ListRobotComments implements RestReadView<RevisionResource> {
+  protected final Provider<ReviewDb> db;
+  protected final Provider<CommentJson> commentJson;
+  protected final CommentsUtil commentsUtil;
+
+  @Inject
+  ListRobotComments(Provider<ReviewDb> db,
+      Provider<CommentJson> commentJson,
+      CommentsUtil commentsUtil) {
+    this.db = db;
+    this.commentJson = commentJson;
+    this.commentsUtil = commentsUtil;
+  }
+
+  @Override
+  public Map<String, List<RobotCommentInfo>> apply(RevisionResource rsrc)
+      throws OrmException {
+    return commentJson.get()
+        .setFillAccounts(true)
+        .newRobotCommentFormatter()
+        .format(listComments(rsrc));
+  }
+
+  public List<RobotCommentInfo> getComments(RevisionResource rsrc)
+      throws OrmException {
+    return commentJson.get()
+        .setFillAccounts(true)
+        .newRobotCommentFormatter()
+        .formatAsList(listComments(rsrc));
+  }
+
+  private Iterable<RobotComment> listComments(RevisionResource rsrc)
+      throws OrmException {
+    return commentsUtil.robotCommentsByPatchSet(
+        rsrc.getNotes(), rsrc.getPatchSet().getId());
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java
index 9b284fa..a52920a 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/Module.java
@@ -21,6 +21,7 @@
 import static com.google.gerrit.server.change.FileResource.FILE_KIND;
 import static com.google.gerrit.server.change.ReviewerResource.REVIEWER_KIND;
 import static com.google.gerrit.server.change.RevisionResource.REVISION_KIND;
+import static com.google.gerrit.server.change.RobotCommentResource.ROBOT_COMMENT_KIND;
 import static com.google.gerrit.server.change.VoteResource.VOTE_KIND;
 
 import com.google.gerrit.extensions.registration.DynamicMap;
@@ -37,11 +38,13 @@
     bind(Reviewers.class);
     bind(DraftComments.class);
     bind(Comments.class);
+    bind(RobotComments.class);
     bind(Files.class);
     bind(Votes.class);
 
     DynamicMap.mapOf(binder(), CHANGE_KIND);
     DynamicMap.mapOf(binder(), COMMENT_KIND);
+    DynamicMap.mapOf(binder(), ROBOT_COMMENT_KIND);
     DynamicMap.mapOf(binder(), DRAFT_COMMENT_KIND);
     DynamicMap.mapOf(binder(), FILE_KIND);
     DynamicMap.mapOf(binder(), REVIEWER_KIND);
@@ -116,6 +119,9 @@
     child(REVISION_KIND, "comments").to(Comments.class);
     get(COMMENT_KIND).to(GetComment.class);
 
+    child(REVISION_KIND, "robotcomments").to(RobotComments.class);
+    get(ROBOT_COMMENT_KIND).to(GetRobotComment.class);
+
     child(REVISION_KIND, "files").to(Files.class);
     put(FILE_KIND, "reviewed").to(PutReviewed.class);
     delete(FILE_KIND, "reviewed").to(DeleteReviewed.class);
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReview.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReview.java
index 1ac9e11..7ccda0d 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReview.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/PostReview.java
@@ -19,6 +19,7 @@
 import static com.google.gerrit.server.CommentsUtil.setCommentRevId;
 import static com.google.gerrit.server.notedb.ReviewerStateInternal.REVIEWER;
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.stream.Collectors.toSet;
 import static javax.servlet.http.HttpServletResponse.SC_BAD_REQUEST;
 
 import com.google.auto.value.AutoValue;
@@ -43,10 +44,12 @@
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput.CommentInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput.DraftHandling;
+import com.google.gerrit.extensions.api.changes.ReviewInput.RobotCommentInput;
 import com.google.gerrit.extensions.api.changes.ReviewResult;
 import com.google.gerrit.extensions.client.Side;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.BadRequestException;
+import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
 import com.google.gerrit.extensions.restapi.ResourceConflictException;
 import com.google.gerrit.extensions.restapi.Response;
 import com.google.gerrit.extensions.restapi.RestApiException;
@@ -59,6 +62,7 @@
 import com.google.gerrit.reviewdb.client.PatchLineComment.Status;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetApproval;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.ChangeMessagesUtil;
@@ -76,6 +80,7 @@
 import com.google.gerrit.server.git.UpdateException;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.notedb.NotesMigration;
 import com.google.gerrit.server.patch.PatchListCache;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.query.change.ChangeData;
@@ -94,7 +99,6 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -118,6 +122,7 @@
   private final CommentAdded commentAdded;
   private final PostReviewers postReviewers;
   private final String serverId;
+  private final NotesMigration migration;
 
   @Inject
   PostReview(Provider<ReviewDb> db,
@@ -133,7 +138,8 @@
       EmailReviewComments.Factory email,
       CommentAdded commentAdded,
       PostReviewers postReviewers,
-      @GerritServerId String serverId) {
+      @GerritServerId String serverId,
+      NotesMigration migration) {
     this.db = db;
     this.batchUpdateFactory = batchUpdateFactory;
     this.changes = changes;
@@ -148,6 +154,7 @@
     this.commentAdded = commentAdded;
     this.postReviewers = postReviewers;
     this.serverId = serverId;
+    this.migration = migration;
   }
 
   @Override
@@ -173,6 +180,12 @@
     if (input.comments != null) {
       checkComments(revision, input.comments);
     }
+    if (input.robotComments != null) {
+      if (!migration.readChanges()) {
+        throw new MethodNotAllowedException("robot comments not supported");
+      }
+      checkRobotComments(revision, input.robotComments);
+    }
     if (input.notify == null) {
       log.warn("notify = null; assuming notify = NONE");
       input.notify = NotifyHandling.NONE;
@@ -316,16 +329,16 @@
     }
   }
 
-  private void checkComments(RevisionResource revision, Map<String, List<CommentInput>> in)
-      throws BadRequestException, OrmException {
-    Iterator<Map.Entry<String, List<CommentInput>>> mapItr =
-        in.entrySet().iterator();
+  private <T extends CommentInput> void checkComments(RevisionResource revision,
+      Map<String, List<T>> in) throws BadRequestException, OrmException {
+    Iterator<? extends Map.Entry<String, List<T>>> mapItr =
+            in.entrySet().iterator();
     Set<String> filePaths =
         Sets.newHashSet(changeDataFactory.create(
             db.get(), revision.getControl()).filePaths(
                 revision.getPatchSet()));
     while (mapItr.hasNext()) {
-      Map.Entry<String, List<CommentInput>> ent = mapItr.next();
+      Map.Entry<String, List<T>> ent = mapItr.next();
       String path = ent.getKey();
       if (!filePaths.contains(path) && !Patch.isMagic(path)) {
         throw new BadRequestException(String.format(
@@ -333,7 +346,7 @@
             path, revision.getChange().currentPatchSetId()));
       }
       if (Patch.isMagic(path)) {
-        for (CommentInput comment : ent.getValue()) {
+        for (T comment : ent.getValue()) {
           if (comment.side == Side.PARENT && comment.parent == null) {
             throw new BadRequestException(
                 String.format("cannot comment on %s on auto-merge", path));
@@ -341,15 +354,15 @@
         }
       }
 
-      List<CommentInput> list = ent.getValue();
+      List<T> list = ent.getValue();
       if (list == null) {
         mapItr.remove();
         continue;
       }
 
-      Iterator<CommentInput> listItr = list.iterator();
+      Iterator<T> listItr = list.iterator();
       while (listItr.hasNext()) {
-        CommentInput c = listItr.next();
+        T c = listItr.next();
         if (c == null) {
           listItr.remove();
           continue;
@@ -370,6 +383,25 @@
     }
   }
 
+  private void checkRobotComments(RevisionResource revision,
+      Map<String, List<RobotCommentInput>> in)
+          throws BadRequestException, OrmException {
+    for (Map.Entry<String, List<RobotCommentInput>> e : in.entrySet()) {
+      String path = e.getKey();
+      for (RobotCommentInput c : e.getValue()) {
+        if (c.robotId == null) {
+          throw new BadRequestException(String
+              .format("robotId is missing for robot comment on %s", path));
+        }
+        if (c.robotRunId == null) {
+          throw new BadRequestException(String
+              .format("robotRunId is missing for robot comment on %s", path));
+        }
+      }
+    }
+    checkComments(revision, in);
+  }
+
   /**
    * Used to compare Comments with CommentInput comments.
    */
@@ -427,6 +459,7 @@
       ps = psUtil.get(ctx.getDb(), ctx.getNotes(), psId);
       boolean dirty = false;
       dirty |= insertComments(ctx);
+      dirty |= insertRobotComments(ctx);
       dirty |= updateLabels(ctx);
       dirty |= insertMessage(ctx);
       return dirty;
@@ -471,7 +504,7 @@
 
       Set<CommentSetEntry> existingIds = in.omitDuplicateComments
           ? readExistingComments(ctx)
-          : Collections.<CommentSetEntry>emptySet();
+          : Collections.emptySet();
 
       for (Map.Entry<String, List<CommentInput>> ent : map.entrySet()) {
         String path = ent.getKey();
@@ -530,14 +563,53 @@
       return !toDel.isEmpty() || !toPublish.isEmpty();
     }
 
+    private boolean insertRobotComments(ChangeContext ctx) throws OrmException {
+      if (in.robotComments == null) {
+        return false;
+      }
+
+      List<RobotComment> toAdd = new ArrayList<>(in.robotComments.size());
+
+      Set<CommentSetEntry> existingIds = in.omitDuplicateComments
+          ? readExistingRobotComments(ctx)
+          : Collections.emptySet();
+
+      for (Map.Entry<String, List<RobotCommentInput>> ent : in.robotComments.entrySet()) {
+        String path = ent.getKey();
+        for (RobotCommentInput c : ent.getValue()) {
+          RobotComment e = new RobotComment(
+              new Comment.Key(ChangeUtil.messageUUID(ctx.getDb()), path,
+                  psId.get()),
+              user.getAccountId(), ctx.getWhen(), c.side(), c.message, serverId,
+              c.robotId, c.robotRunId);
+          e.parentUuid = Url.decode(c.inReplyTo);
+          e.url = c.url;
+          e.setLineNbrAndRange(c.line, c.range);
+          e.tag = in.tag;
+          setCommentRevId(e, patchListCache, ctx.getChange(), ps);
+
+          if (existingIds.contains(CommentSetEntry.create(e))) {
+            continue;
+          }
+          toAdd.add(e);
+        }
+      }
+
+      commentsUtil.putRobotComments(ctx.getUpdate(psId), toAdd);
+      comments.addAll(toAdd);
+      return !toAdd.isEmpty();
+    }
+
     private Set<CommentSetEntry> readExistingComments(ChangeContext ctx)
         throws OrmException {
-      Set<CommentSetEntry> r = new HashSet<>();
-      for (Comment c : commentsUtil.publishedByChange(ctx.getDb(),
-            ctx.getNotes())) {
-        r.add(CommentSetEntry.create(c));
-      }
-      return r;
+      return commentsUtil.publishedByChange(ctx.getDb(), ctx.getNotes())
+          .stream().map(CommentSetEntry::create).collect(toSet());
+    }
+
+    private Set<CommentSetEntry> readExistingRobotComments(ChangeContext ctx)
+        throws OrmException {
+      return commentsUtil.robotCommentsByChange(ctx.getNotes())
+          .stream().map(CommentSetEntry::create).collect(toSet());
     }
 
     private Map<String, Comment> changeDrafts(ChangeContext ctx)
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/PutDraftComment.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/PutDraftComment.java
index feb17b3..0808f95 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/change/PutDraftComment.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/PutDraftComment.java
@@ -92,8 +92,9 @@
       Op op = new Op(rsrc.getComment().key, in);
       bu.addOp(rsrc.getChange().getId(), op);
       bu.execute();
-      return Response.ok(
-          commentJson.get().setFillAccounts(false).format(op.comment));
+      return Response.ok(commentJson.get()
+          .setFillAccounts(false)
+          .newCommentFormatter().format(op.comment));
     }
   }
 
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotCommentResource.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotCommentResource.java
new file mode 100644
index 0000000..856c777
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotCommentResource.java
@@ -0,0 +1,51 @@
+// Copyright (C) 2016 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.google.gerrit.server.change;
+
+import com.google.gerrit.extensions.restapi.RestResource;
+import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.reviewdb.client.RobotComment;
+import com.google.inject.TypeLiteral;
+
+public class RobotCommentResource implements RestResource {
+  public static final TypeLiteral<RestView<RobotCommentResource>> ROBOT_COMMENT_KIND =
+      new TypeLiteral<RestView<RobotCommentResource>>() {};
+
+  private final RevisionResource rev;
+  private final RobotComment comment;
+
+  public RobotCommentResource(RevisionResource rev, RobotComment c) {
+    this.rev = rev;
+    this.comment = c;
+  }
+
+  public PatchSet getPatchSet() {
+    return rev.getPatchSet();
+  }
+
+  RobotComment getComment() {
+    return comment;
+  }
+
+  String getId() {
+    return comment.key.uuid;
+  }
+
+  Account.Id getAuthorId() {
+    return comment.author.getId();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotComments.java b/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotComments.java
new file mode 100644
index 0000000..886af1d
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/change/RobotComments.java
@@ -0,0 +1,69 @@
+// Copyright (C) 2016 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.google.gerrit.server.change;
+
+import com.google.gerrit.extensions.registration.DynamicMap;
+import com.google.gerrit.extensions.restapi.ChildCollection;
+import com.google.gerrit.extensions.restapi.IdString;
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.extensions.restapi.RestView;
+import com.google.gerrit.reviewdb.client.RobotComment;
+import com.google.gerrit.server.CommentsUtil;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+@Singleton
+public class RobotComments
+    implements ChildCollection<RevisionResource, RobotCommentResource> {
+  private final DynamicMap<RestView<RobotCommentResource>> views;
+  private final ListRobotComments list;
+  private final CommentsUtil commentsUtil;
+
+  @Inject
+  RobotComments(DynamicMap<RestView<RobotCommentResource>> views,
+      ListRobotComments list,
+      CommentsUtil commentsUtil) {
+    this.views = views;
+    this.list = list;
+    this.commentsUtil = commentsUtil;
+  }
+
+  @Override
+  public DynamicMap<RestView<RobotCommentResource>> views() {
+    return views;
+  }
+
+  @Override
+  public ListRobotComments list() {
+    return list;
+  }
+
+  @Override
+  public RobotCommentResource parse(RevisionResource rev, IdString id)
+      throws ResourceNotFoundException, OrmException {
+    String uuid = id.get();
+    ChangeNotes notes = rev.getNotes();
+
+    for (RobotComment c : commentsUtil.robotCommentsByPatchSet(
+        notes, rev.getPatchSet().getId())) {
+      if (uuid.equals(c.key.uuid)) {
+        return new RobotCommentResource(rev, c);
+      }
+    }
+    throw new ResourceNotFoundException(id);
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/mail/CommentSender.java b/gerrit-server/src/main/java/com/google/gerrit/server/mail/CommentSender.java
index 93f820d..bce114f 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/mail/CommentSender.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/mail/CommentSender.java
@@ -24,6 +24,7 @@
 import com.google.gerrit.reviewdb.client.Comment;
 import com.google.gerrit.reviewdb.client.Patch;
 import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.server.CommentsUtil;
 import com.google.gerrit.server.patch.PatchFile;
 import com.google.gerrit.server.patch.PatchList;
@@ -165,6 +166,14 @@
 
   private void appendComment(StringBuilder out, int contextLines,
       PatchFile currentFileData, Comment comment) {
+    if (comment instanceof RobotComment) {
+      RobotComment robotComment = (RobotComment) comment;
+      out.append("Robot Comment from ")
+         .append(robotComment.robotId)
+         .append(" (run ID ")
+         .append(robotComment.robotRunId)
+         .append("):\n");
+    }
     short side = comment.side;
     Comment.Range range = comment.range;
     if (range != null) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeDraftUpdate.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeDraftUpdate.java
index 6d546cd..b4ab290 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeDraftUpdate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeDraftUpdate.java
@@ -138,7 +138,7 @@
   private CommitBuilder storeCommentsInNotes(RevWalk rw, ObjectInserter ins,
       ObjectId curr, CommitBuilder cb)
       throws ConfigInvalidException, OrmException, IOException {
-    RevisionNoteMap rnm = getRevisionNoteMap(rw, curr);
+    RevisionNoteMap<ChangeRevisionNote> rnm = getRevisionNoteMap(rw, curr);
     Set<RevId> updatedRevs =
         Sets.newHashSetWithExpectedSize(rnm.revisionNotes.size());
     RevisionNoteBuilder.Cache cache = new RevisionNoteBuilder.Cache(rnm);
@@ -158,7 +158,7 @@
     for (Map.Entry<RevId, RevisionNoteBuilder> e : builders.entrySet()) {
       updatedRevs.add(e.getKey());
       ObjectId id = ObjectId.fromString(e.getKey().get());
-      byte[] data = e.getValue().build(noteUtil);
+      byte[] data = e.getValue().build(noteUtil, noteUtil.getWriteJson());
       if (!Arrays.equals(data, e.getValue().baseRaw)) {
         touchedAnyRevs = true;
       }
@@ -189,8 +189,8 @@
     return cb;
   }
 
-  private RevisionNoteMap getRevisionNoteMap(RevWalk rw, ObjectId curr)
-      throws ConfigInvalidException, OrmException, IOException {
+  private RevisionNoteMap<ChangeRevisionNote> getRevisionNoteMap(RevWalk rw,
+      ObjectId curr) throws ConfigInvalidException, OrmException, IOException {
     if (migration.readChanges()) {
       // If reading from changes is enabled, then the old DraftCommentNotes
       // already parsed the revision notes. We can reuse them as long as the ref
@@ -202,7 +202,8 @@
         if (draftNotes != null) {
           ObjectId idFromNotes =
               firstNonNull(draftNotes.getRevision(), ObjectId.zeroId());
-          RevisionNoteMap rnm = draftNotes.getRevisionNoteMap();
+          RevisionNoteMap<ChangeRevisionNote> rnm =
+              draftNotes.getRevisionNoteMap();
           if (idFromNotes.equals(curr) && rnm != null) {
             return rnm;
           }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java
index 313d8b7..360785f 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotes.java
@@ -45,6 +45,7 @@
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.client.RevId;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.reviewdb.server.ReviewDbUtil;
 import com.google.gerrit.server.ReviewerSet;
@@ -339,10 +340,11 @@
 
   // Parsed note map state, used by ChangeUpdate to make in-place editing of
   // notes easier.
-  RevisionNoteMap revisionNoteMap;
+  RevisionNoteMap<ChangeRevisionNote> revisionNoteMap;
 
   private NoteDbUpdateManager.Result rebuildResult;
   private DraftCommentNotes draftCommentNotes;
+  private RobotCommentNotes robotCommentNotes;
 
   @VisibleForTesting
   public ChangeNotes(Args args, Change change) {
@@ -448,6 +450,12 @@
         filtered);
   }
 
+  public ImmutableListMultimap<RevId, RobotComment> getRobotComments()
+      throws OrmException {
+    loadRobotComments();
+    return robotCommentNotes.getComments();
+  }
+
   /**
    * If draft comments have already been loaded for this author, then they will
    * not be reloaded. However, this method will load the comments if no draft
@@ -464,11 +472,22 @@
     }
   }
 
+  private void loadRobotComments() throws OrmException {
+    if (robotCommentNotes == null) {
+      robotCommentNotes = new RobotCommentNotes(args, change);
+      robotCommentNotes.load();
+    }
+  }
+
   @VisibleForTesting
   DraftCommentNotes getDraftCommentNotes() {
     return draftCommentNotes;
   }
 
+  RobotCommentNotes getRobotCommentNotes() {
+    return robotCommentNotes;
+  }
+
   public boolean containsComment(Comment c) throws OrmException {
     if (containsCommentPublished(c)) {
       return true;
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesCache.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
index a8f85a4..85df4b7 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesCache.java
@@ -73,14 +73,14 @@
      * used as an optimization; {@link ChangeNotes} is capable of lazily loading
      * it as necessary.
      */
-    @Nullable abstract RevisionNoteMap revisionNoteMap();
+    @Nullable abstract RevisionNoteMap<ChangeRevisionNote> revisionNoteMap();
   }
 
   private class Loader implements Callable<ChangeNotesState> {
     private final Key key;
     private final ChangeNotesRevWalk rw;
 
-    private RevisionNoteMap revisionNoteMap;
+    private RevisionNoteMap<ChangeRevisionNote> revisionNoteMap;
 
     private Loader(Key key, ChangeNotesRevWalk rw) {
       this.key = key;
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesParser.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
index a0e7f305..de37b72 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeNotesParser.java
@@ -149,7 +149,7 @@
   private String submissionId;
   private String tag;
   private PatchSet.Id currentPatchSetId;
-  private RevisionNoteMap revisionNoteMap;
+  private RevisionNoteMap<ChangeRevisionNote> revisionNoteMap;
 
   ChangeNotesParser(Change.Id changeId, ObjectId tip, ChangeNotesRevWalk walk,
       ChangeNoteUtil noteUtil, NoteDbMetrics metrics) {
@@ -195,7 +195,7 @@
     return buildState();
   }
 
-  RevisionNoteMap getRevisionNoteMap() {
+  RevisionNoteMap<ChangeRevisionNote> getRevisionNoteMap() {
     return revisionNoteMap;
   }
 
@@ -630,18 +630,18 @@
     revisionNoteMap = RevisionNoteMap.parse(
         noteUtil, id, reader, NoteMap.read(reader, tipCommit),
         PatchLineComment.Status.PUBLISHED);
-    Map<RevId, RevisionNote> rns = revisionNoteMap.revisionNotes;
+    Map<RevId, ChangeRevisionNote> rns = revisionNoteMap.revisionNotes;
 
-    for (Map.Entry<RevId, RevisionNote> e : rns.entrySet()) {
-      for (Comment c : e.getValue().comments) {
+    for (Map.Entry<RevId, ChangeRevisionNote> e : rns.entrySet()) {
+      for (Comment c : e.getValue().getComments()) {
         comments.put(e.getKey(), c);
       }
     }
 
     for (PatchSet ps : patchSets.values()) {
-      RevisionNote rn = rns.get(ps.getRevision());
-      if (rn != null && rn.pushCert != null) {
-        ps.setPushCertificate(rn.pushCert);
+      ChangeRevisionNote rn = rns.get(ps.getRevision());
+      if (rn != null && rn.getPushCert() != null) {
+        ps.setPushCertificate(rn.getPushCert());
       }
     }
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeRevisionNote.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeRevisionNote.java
new file mode 100644
index 0000000..b95c92a
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeRevisionNote.java
@@ -0,0 +1,114 @@
+// Copyright (C) 2016 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.google.gerrit.server.notedb;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.primitives.Bytes;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Comment;
+import com.google.gerrit.reviewdb.client.PatchLineComment;
+
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.util.MutableInteger;
+import org.eclipse.jgit.util.RawParseUtils;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.List;
+
+class ChangeRevisionNote extends RevisionNote<Comment> {
+  private static final byte[] CERT_HEADER =
+      "certificate version ".getBytes(UTF_8);
+  // See org.eclipse.jgit.transport.PushCertificateParser.END_SIGNATURE
+  private static final byte[] END_SIGNATURE =
+      "-----END PGP SIGNATURE-----\n".getBytes(UTF_8);
+
+  private final ChangeNoteUtil noteUtil;
+  private final Change.Id changeId;
+  private final PatchLineComment.Status status;
+  private String pushCert = null;
+
+  ChangeRevisionNote(ChangeNoteUtil noteUtil, Change.Id changeId,
+      ObjectReader reader, ObjectId noteId, PatchLineComment.Status status) {
+    super(reader, noteId);
+    this.noteUtil = noteUtil;
+    this.changeId = changeId;
+    this.status = status;
+  }
+
+  public String getPushCert() {
+    checkParsed();
+    return pushCert;
+  }
+
+  @Override
+  protected List<Comment> parse(byte[] raw, int offset)
+      throws IOException, ConfigInvalidException {
+    MutableInteger p = new MutableInteger();
+    p.value = offset;
+
+    if (isJson(raw, p.value)) {
+      RevisionNoteData data = parseJson(noteUtil, raw, p.value);
+      if (status == PatchLineComment.Status.PUBLISHED) {
+        pushCert = data.pushCert;
+      } else {
+        pushCert = null;
+      }
+      return data.comments;
+    }
+
+    if (status == PatchLineComment.Status.PUBLISHED) {
+      pushCert = parsePushCert(changeId, raw, p);
+      trimLeadingEmptyLines(raw, p);
+    } else {
+      pushCert = null;
+    }
+    return noteUtil.parseNote(raw, p, changeId);
+  }
+
+  private static boolean isJson(byte[] raw, int offset) {
+    return raw[offset] == '{' || raw[offset] == '[';
+  }
+
+  private RevisionNoteData parseJson(ChangeNoteUtil noteUtil, byte[] raw,
+      int offset) throws IOException {
+    try (InputStream is = new ByteArrayInputStream(
+        raw, offset, raw.length - offset);
+        Reader r = new InputStreamReader(is)) {
+      return noteUtil.getGson().fromJson(r, RevisionNoteData.class);
+    }
+  }
+
+  private static String parsePushCert(Change.Id changeId, byte[] bytes,
+      MutableInteger p) throws ConfigInvalidException {
+    if (RawParseUtils.match(bytes, p.value, CERT_HEADER) < 0) {
+      return null;
+    }
+    int end = Bytes.indexOf(bytes, END_SIGNATURE);
+    if (end < 0) {
+      throw ChangeNotes.parseException(
+          changeId, "invalid push certificate in note");
+    }
+    int start = p.value;
+    p.value = end + END_SIGNATURE.length;
+    return new String(bytes, start, p.value);
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
index 263edab..96cd4c6 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/ChangeUpdate.java
@@ -51,6 +51,7 @@
 import com.google.gerrit.reviewdb.client.PatchLineComment;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RevId;
+import com.google.gerrit.reviewdb.client.RobotComment;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.config.AnonymousCowardName;
@@ -110,6 +111,7 @@
 
   private final AccountCache accountCache;
   private final ChangeDraftUpdate.Factory draftUpdateFactory;
+  private final RobotCommentUpdate.Factory robotCommentUpdateFactory;
   private final NoteDbUpdateManager.Factory updateManagerFactory;
 
   private final Table<String, Account.Id, Optional<Short>> approvals;
@@ -135,6 +137,7 @@
   private boolean isAllowWriteToNewtRef;
 
   private ChangeDraftUpdate draftUpdate;
+  private RobotCommentUpdate robotCommentUpdate;
 
   @AssistedInject
   private ChangeUpdate(
@@ -144,11 +147,12 @@
       AccountCache accountCache,
       NoteDbUpdateManager.Factory updateManagerFactory,
       ChangeDraftUpdate.Factory draftUpdateFactory,
+      RobotCommentUpdate.Factory robotCommentUpdateFactory,
       ProjectCache projectCache,
       @Assisted ChangeControl ctl,
       ChangeNoteUtil noteUtil) {
     this(serverIdent, anonymousCowardName, migration, accountCache,
-        updateManagerFactory, draftUpdateFactory,
+        updateManagerFactory, draftUpdateFactory, robotCommentUpdateFactory,
         projectCache, ctl, serverIdent.getWhen(), noteUtil);
   }
 
@@ -160,13 +164,14 @@
       AccountCache accountCache,
       NoteDbUpdateManager.Factory updateManagerFactory,
       ChangeDraftUpdate.Factory draftUpdateFactory,
+      RobotCommentUpdate.Factory robotCommentUpdateFactory,
       ProjectCache projectCache,
       @Assisted ChangeControl ctl,
       @Assisted Date when,
       ChangeNoteUtil noteUtil) {
     this(serverIdent, anonymousCowardName, migration, accountCache,
-        updateManagerFactory, draftUpdateFactory, ctl,
-        when,
+        updateManagerFactory, draftUpdateFactory, robotCommentUpdateFactory,
+        ctl, when,
         projectCache.get(getProjectName(ctl)).getLabelTypes().nameComparator(),
         noteUtil);
   }
@@ -188,6 +193,7 @@
       AccountCache accountCache,
       NoteDbUpdateManager.Factory updateManagerFactory,
       ChangeDraftUpdate.Factory draftUpdateFactory,
+      RobotCommentUpdate.Factory robotCommentUpdateFactory,
       @Assisted ChangeControl ctl,
       @Assisted Date when,
       @Assisted Comparator<String> labelNameComparator,
@@ -196,6 +202,7 @@
         anonymousCowardName, noteUtil, when);
     this.accountCache = accountCache;
     this.draftUpdateFactory = draftUpdateFactory;
+    this.robotCommentUpdateFactory = robotCommentUpdateFactory;
     this.updateManagerFactory = updateManagerFactory;
     this.approvals = approvals(labelNameComparator);
   }
@@ -208,6 +215,7 @@
       AccountCache accountCache,
       NoteDbUpdateManager.Factory updateManagerFactory,
       ChangeDraftUpdate.Factory draftUpdateFactory,
+      RobotCommentUpdate.Factory robotCommentUpdateFactory,
       ChangeNoteUtil noteUtil,
       @Assisted Change change,
       @Assisted @Nullable Account.Id accountId,
@@ -218,6 +226,7 @@
         accountId, authorIdent, when);
     this.accountCache = accountCache;
     this.draftUpdateFactory = draftUpdateFactory;
+    this.robotCommentUpdateFactory = robotCommentUpdateFactory;
     this.updateManagerFactory = updateManagerFactory;
     this.approvals = approvals(labelNameComparator);
   }
@@ -320,6 +329,12 @@
     }
   }
 
+  public void putRobotComment(RobotComment c) {
+    verifyComment(c);
+    createRobotCommentUpdateIfNull();
+    robotCommentUpdate.putComment(c);
+  }
+
   public void deleteComment(Comment c) {
     verifyComment(c);
     createDraftUpdateIfNull().deleteComment(c);
@@ -340,6 +355,21 @@
     return draftUpdate;
   }
 
+  @VisibleForTesting
+  RobotCommentUpdate createRobotCommentUpdateIfNull() {
+    if (robotCommentUpdate == null) {
+      ChangeNotes notes = getNotes();
+      if (notes != null) {
+        robotCommentUpdate =
+            robotCommentUpdateFactory.create(notes, accountId, authorIdent, when);
+      } else {
+        robotCommentUpdate = robotCommentUpdateFactory.create(
+            getChange(), accountId, authorIdent, when);
+      }
+    }
+    return robotCommentUpdate;
+  }
+
   private void verifyComment(Comment c) {
     checkArgument(c.revId != null, "RevId required for comment: %s", c);
     checkArgument(c.author.getId().equals(getAccountId()),
@@ -415,7 +445,7 @@
     if (comments.isEmpty() && pushCert == null) {
       return null;
     }
-    RevisionNoteMap rnm = getRevisionNoteMap(rw, curr);
+    RevisionNoteMap<ChangeRevisionNote> rnm = getRevisionNoteMap(rw, curr);
 
     RevisionNoteBuilder.Cache cache = new RevisionNoteBuilder.Cache(rnm);
     for (Comment c : comments) {
@@ -431,15 +461,15 @@
 
     for (Map.Entry<RevId, RevisionNoteBuilder> e : builders.entrySet()) {
       ObjectId data = inserter.insert(
-          OBJ_BLOB, e.getValue().build(noteUtil));
+          OBJ_BLOB, e.getValue().build(noteUtil, noteUtil.getWriteJson()));
       rnm.noteMap.set(ObjectId.fromString(e.getKey().get()), data);
     }
 
     return rnm.noteMap.writeTree(inserter);
   }
 
-  private RevisionNoteMap getRevisionNoteMap(RevWalk rw, ObjectId curr)
-      throws ConfigInvalidException, OrmException, IOException {
+  private RevisionNoteMap<ChangeRevisionNote> getRevisionNoteMap(RevWalk rw,
+      ObjectId curr) throws ConfigInvalidException, OrmException, IOException {
     if (curr.equals(ObjectId.zeroId())) {
       return RevisionNoteMap.emptyMap();
     }
@@ -467,12 +497,12 @@
         PatchLineComment.Status.PUBLISHED);
   }
 
-  private void checkComments(Map<RevId, RevisionNote> existingNotes,
+  private void checkComments(Map<RevId, ChangeRevisionNote> existingNotes,
       Map<RevId, RevisionNoteBuilder> toUpdate) throws OrmException {
     // Prohibit various kinds of illegal operations on comments.
     Set<Comment.Key> existing = new HashSet<>();
-    for (RevisionNote rn : existingNotes.values()) {
-      for (Comment c : rn.comments) {
+    for (ChangeRevisionNote rn : existingNotes.values()) {
+      for (Comment c : rn.getComments()) {
         existing.add(c.key);
         if (draftUpdate != null) {
           // Take advantage of an existing update on All-Users to prune any
@@ -677,6 +707,10 @@
     return draftUpdate;
   }
 
+  RobotCommentUpdate getRobotCommentUpdate() {
+    return robotCommentUpdate;
+  }
+
   public void setAllowWriteToNewRef(boolean allow) {
     isAllowWriteToNewtRef = allow;
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/DraftCommentNotes.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/DraftCommentNotes.java
index 34da36d..661112e 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/DraftCommentNotes.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/DraftCommentNotes.java
@@ -70,7 +70,7 @@
   private final NoteDbUpdateManager.Result rebuildResult;
 
   private ImmutableListMultimap<RevId, Comment> comments;
-  private RevisionNoteMap revisionNoteMap;
+  private RevisionNoteMap<ChangeRevisionNote> revisionNoteMap;
 
   @AssistedInject
   DraftCommentNotes(
@@ -103,7 +103,7 @@
     this.rebuildResult = rebuildResult;
   }
 
-  RevisionNoteMap getRevisionNoteMap() {
+  RevisionNoteMap<ChangeRevisionNote> getRevisionNoteMap() {
     return revisionNoteMap;
   }
 
@@ -144,8 +144,8 @@
         args.noteUtil, getChangeId(), reader, NoteMap.read(reader, tipCommit),
         PatchLineComment.Status.DRAFT);
     Multimap<RevId, Comment> cs = ArrayListMultimap.create();
-    for (RevisionNote rn : revisionNoteMap.revisionNotes.values()) {
-      for (Comment c : rn.comments) {
+    for (ChangeRevisionNote rn : revisionNoteMap.revisionNotes.values()) {
+      for (Comment c : rn.getComments()) {
         cs.put(new RevId(c.revId), c);
       }
     }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbModule.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbModule.java
index 876f47f..72a1f1b 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbModule.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbModule.java
@@ -53,6 +53,8 @@
     factory(ChangeUpdate.Factory.class);
     factory(ChangeDraftUpdate.Factory.class);
     factory(DraftCommentNotes.Factory.class);
+    factory(RobotCommentUpdate.Factory.class);
+    factory(RobotCommentNotes.Factory.class);
     factory(NoteDbUpdateManager.Factory.class);
     if (!useTestBindings) {
       install(ChangeNotesCache.module());
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbUpdateManager.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbUpdateManager.java
index 7f6eb5c..300f753 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbUpdateManager.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/NoteDbUpdateManager.java
@@ -179,6 +179,7 @@
   private final Project.NameKey projectName;
   private final ListMultimap<String, ChangeUpdate> changeUpdates;
   private final ListMultimap<String, ChangeDraftUpdate> draftUpdates;
+  private final ListMultimap<String, RobotCommentUpdate> robotCommentUpdates;
   private final Set<Change.Id> toDelete;
 
   private OpenRepo changeRepo;
@@ -199,6 +200,7 @@
     this.projectName = projectName;
     changeUpdates = ArrayListMultimap.create();
     draftUpdates = ArrayListMultimap.create();
+    robotCommentUpdates = ArrayListMultimap.create();
     toDelete = new HashSet<>();
   }
 
@@ -273,6 +275,7 @@
     }
     return changeUpdates.isEmpty()
         && draftUpdates.isEmpty()
+        && robotCommentUpdates.isEmpty()
         && toDelete.isEmpty();
   }
 
@@ -294,6 +297,10 @@
     if (du != null) {
       draftUpdates.put(du.getRefName(), du);
     }
+    RobotCommentUpdate rcu = update.getRobotCommentUpdate();
+    if (rcu != null) {
+      robotCommentUpdates.put(rcu.getRefName(), rcu);
+    }
   }
 
   public void add(ChangeDraftUpdate draftUpdate) {
@@ -453,6 +460,9 @@
     if (!draftUpdates.isEmpty()) {
       addUpdates(draftUpdates, allUsersRepo);
     }
+    if (!robotCommentUpdates.isEmpty()) {
+      addUpdates(robotCommentUpdates, changeRepo);
+    }
     for (Change.Id id : toDelete) {
       doDelete(id);
     }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNote.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNote.java
index 7d44ffb..46e6dc5 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNote.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNote.java
@@ -14,106 +14,66 @@
 
 package com.google.gerrit.server.notedb;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
+import static com.google.common.base.Preconditions.checkState;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 
 import com.google.common.collect.ImmutableList;
-import com.google.common.primitives.Bytes;
-import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Comment;
-import com.google.gerrit.reviewdb.client.PatchLineComment;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectReader;
 import org.eclipse.jgit.util.MutableInteger;
-import org.eclipse.jgit.util.RawParseUtils;
 
-import java.io.ByteArrayInputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.Reader;
+import java.util.List;
 
-class RevisionNote {
+abstract class RevisionNote<T extends Comment> {
   static final int MAX_NOTE_SZ = 25 << 20;
 
-  private static final byte[] CERT_HEADER =
-      "certificate version ".getBytes(UTF_8);
-  // See org.eclipse.jgit.transport.PushCertificateParser.END_SIGNATURE
-  private static final byte[] END_SIGNATURE =
-      "-----END PGP SIGNATURE-----\n".getBytes(UTF_8);
-
-  private static void trimLeadingEmptyLines(byte[] bytes, MutableInteger p) {
+  protected static void trimLeadingEmptyLines(byte[] bytes, MutableInteger p) {
     while (p.value < bytes.length && bytes[p.value] == '\n') {
       p.value++;
     }
   }
 
-  private static String parsePushCert(Change.Id changeId, byte[] bytes,
-      MutableInteger p) throws ConfigInvalidException {
-    if (RawParseUtils.match(bytes, p.value, CERT_HEADER) < 0) {
-      return null;
-    }
-    int end = Bytes.indexOf(bytes, END_SIGNATURE);
-    if (end < 0) {
-      throw ChangeNotes.parseException(
-          changeId, "invalid push certificate in note");
-    }
-    int start = p.value;
-    p.value = end + END_SIGNATURE.length;
-    return new String(bytes, start, p.value);
+  private final ObjectReader reader;
+  private final ObjectId noteId;
+
+  private byte[] raw;
+  private ImmutableList<T> comments;
+
+  RevisionNote(ObjectReader reader, ObjectId noteId) {
+    this.reader = reader;
+    this.noteId = noteId;
   }
 
-  final byte[] raw;
-  final ImmutableList<Comment> comments;
-  final String pushCert;
+  public byte[] getRaw() {
+    checkParsed();
+    return raw;
+  }
 
-  RevisionNote(ChangeNoteUtil noteUtil, Change.Id changeId,
-      ObjectReader reader, ObjectId noteId, PatchLineComment.Status status)
-      throws ConfigInvalidException, IOException {
+  public ImmutableList<T> getComments() {
+    checkParsed();
+    return comments;
+  }
 
+  public void parse() throws IOException, ConfigInvalidException {
     raw = reader.open(noteId, OBJ_BLOB).getCachedBytes(MAX_NOTE_SZ);
     MutableInteger p = new MutableInteger();
     trimLeadingEmptyLines(raw, p);
     if (p.value >= raw.length) {
       comments = null;
-      pushCert = null;
       return;
     }
 
-    if (isJson(raw, p.value)) {
-      RevisionNoteData data = parseJson(noteUtil, p.value);
-      comments = ImmutableList.copyOf(data.comments);
-      if (status == PatchLineComment.Status.PUBLISHED) {
-        pushCert = data.pushCert;
-      } else {
-        pushCert = null;
-      }
-      return;
-    }
-
-    if (status == PatchLineComment.Status.PUBLISHED) {
-      pushCert = parsePushCert(changeId, raw, p);
-      trimLeadingEmptyLines(raw, p);
-    } else {
-      pushCert = null;
-    }
-    comments = ImmutableList.copyOf(noteUtil.parseNote(raw, p, changeId));
+    comments = ImmutableList.copyOf(parse(raw, p.value));
   }
 
-  private static boolean isJson(byte[] raw, int offset) {
-    return raw[offset] == '{' || raw[offset] == '[';
-  }
+  protected abstract List<T> parse(byte[] raw, int offset)
+      throws IOException, ConfigInvalidException;
 
-  private RevisionNoteData parseJson(ChangeNoteUtil noteUtil, int offset)
-      throws IOException{
-    RevisionNoteData data;
-    try (InputStream is = new ByteArrayInputStream(
-        raw, offset, raw.length - offset);
-        Reader r = new InputStreamReader(is)) {
-      data = noteUtil.getGson().fromJson(r, RevisionNoteData.class);
-    }
-    return data;
+  protected void checkParsed() {
+    checkState(raw != null, "revision note not parsed yet");
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteBuilder.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteBuilder.java
index 266a891..8eacb1c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteBuilder.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteBuilder.java
@@ -37,10 +37,12 @@
 
 class RevisionNoteBuilder {
   static class Cache {
-    private final RevisionNoteMap revisionNoteMap;
+    private final RevisionNoteMap<?
+        extends RevisionNote<? extends Comment>> revisionNoteMap;
     private final Map<RevId, RevisionNoteBuilder> builders;
 
-    Cache(RevisionNoteMap revisionNoteMap) {
+    Cache(RevisionNoteMap<?
+        extends RevisionNote<? extends Comment>> revisionNoteMap) {
       this.revisionNoteMap = revisionNoteMap;
       this.builders = new HashMap<>();
     }
@@ -61,18 +63,20 @@
   }
 
   final byte[] baseRaw;
-  final List<Comment> baseComments;
+  final List<? extends Comment> baseComments;
   final Map<Comment.Key, Comment> put;
   final Set<Comment.Key> delete;
 
   private String pushCert;
 
-  RevisionNoteBuilder(RevisionNote base) {
+  RevisionNoteBuilder(RevisionNote<? extends Comment> base) {
     if (base != null) {
-      baseRaw = base.raw;
-      baseComments = base.comments;
-      put = Maps.newHashMapWithExpectedSize(base.comments.size());
-      pushCert = base.pushCert;
+      baseRaw = base.getRaw();
+      baseComments = base.getComments();
+      put = Maps.newHashMapWithExpectedSize(baseComments.size());
+      if (base instanceof ChangeRevisionNote) {
+        pushCert = ((ChangeRevisionNote) base).getPushCert();
+      }
     } else {
       baseRaw = new byte[0];
       baseComments = Collections.emptyList();
@@ -82,9 +86,10 @@
     delete = new HashSet<>();
   }
 
-  public byte[] build(ChangeNoteUtil noteUtil) throws IOException {
+  public byte[] build(ChangeNoteUtil noteUtil, boolean writeJson)
+      throws IOException {
     ByteArrayOutputStream out = new ByteArrayOutputStream();
-    if (noteUtil.getWriteJson()) {
+    if (writeJson) {
       buildNoteJson(noteUtil, out);
     } else {
       buildNoteLegacy(noteUtil, out);
@@ -123,7 +128,7 @@
     return all;
   }
 
-  private void buildNoteJson(final ChangeNoteUtil noteUtil, OutputStream out)
+  private void buildNoteJson(ChangeNoteUtil noteUtil, OutputStream out)
       throws IOException {
     Multimap<Integer, Comment> comments = buildCommentMap();
     if (comments.isEmpty() && pushCert == null) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteMap.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteMap.java
index 1783c1a..8a9f711 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteMap.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RevisionNoteMap.java
@@ -16,6 +16,7 @@
 
 import com.google.common.collect.ImmutableMap;
 import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Comment;
 import com.google.gerrit.reviewdb.client.PatchLineComment;
 import com.google.gerrit.reviewdb.client.RevId;
 
@@ -28,30 +29,45 @@
 import java.util.HashMap;
 import java.util.Map;
 
-class RevisionNoteMap {
+class RevisionNoteMap<T extends RevisionNote<? extends Comment>> {
   final NoteMap noteMap;
-  final ImmutableMap<RevId, RevisionNote> revisionNotes;
+  final ImmutableMap<RevId, T> revisionNotes;
 
-  static RevisionNoteMap parse(ChangeNoteUtil noteUtil,
+  static RevisionNoteMap<ChangeRevisionNote> parse(ChangeNoteUtil noteUtil,
       Change.Id changeId, ObjectReader reader, NoteMap noteMap,
       PatchLineComment.Status status)
-      throws ConfigInvalidException, IOException {
-    Map<RevId, RevisionNote> result = new HashMap<>();
+          throws ConfigInvalidException, IOException {
+    Map<RevId, ChangeRevisionNote> result = new HashMap<>();
     for (Note note : noteMap) {
-      RevisionNote rn = new RevisionNote(
+      ChangeRevisionNote rn = new ChangeRevisionNote(
           noteUtil, changeId, reader, note.getData(), status);
+      rn.parse();
       result.put(new RevId(note.name()), rn);
     }
-    return new RevisionNoteMap(noteMap, ImmutableMap.copyOf(result));
+    return new RevisionNoteMap<>(noteMap, ImmutableMap.copyOf(result));
   }
 
-  static RevisionNoteMap emptyMap() {
-    return new RevisionNoteMap(NoteMap.newEmptyMap(),
-        ImmutableMap.<RevId, RevisionNote> of());
+  static RevisionNoteMap<RobotCommentsRevisionNote> parseRobotComments(
+      ChangeNoteUtil noteUtil, ObjectReader reader, NoteMap noteMap)
+          throws ConfigInvalidException, IOException {
+    Map<RevId, RobotCommentsRevisionNote> result = new HashMap<>();
+    for (Note note : noteMap) {
+      RobotCommentsRevisionNote rn = new RobotCommentsRevisionNote(
+          noteUtil, reader, note.getData());
+      rn.parse();
+      result.put(new RevId(note.name()), rn);
+    }
+    return new RevisionNoteMap<>(noteMap, ImmutableMap.copyOf(result));
+  }
+
+  static <T extends RevisionNote<? extends Comment>> RevisionNoteMap<T>
+      emptyMap() {
+    return new RevisionNoteMap<>(NoteMap.newEmptyMap(),
+        ImmutableMap.<RevId, T> of());
   }
 
   private RevisionNoteMap(NoteMap noteMap,
-      ImmutableMap<RevId, RevisionNote> revisionNotes) {
+      ImmutableMap<RevId, T> revisionNotes) {
     this.noteMap = noteMap;
     this.revisionNotes = revisionNotes;
   }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentNotes.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentNotes.java
new file mode 100644
index 0000000..4a26d7e
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentNotes.java
@@ -0,0 +1,108 @@
+// Copyright (C) 2016 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.google.gerrit.server.notedb;
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.ImmutableListMultimap;
+import com.google.common.collect.Multimap;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.reviewdb.client.RevId;
+import com.google.gerrit.reviewdb.client.RobotComment;
+import com.google.inject.assistedinject.Assisted;
+import com.google.inject.assistedinject.AssistedInject;
+
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.notes.NoteMap;
+import org.eclipse.jgit.revwalk.RevCommit;
+
+import java.io.IOException;
+
+public class RobotCommentNotes extends AbstractChangeNotes<RobotCommentNotes> {
+  public interface Factory {
+    RobotCommentNotes create(Change change);
+  }
+
+  private final Change change;
+
+  private ImmutableListMultimap<RevId, RobotComment> comments;
+  private RevisionNoteMap<RobotCommentsRevisionNote> revisionNoteMap;
+
+  @AssistedInject
+  RobotCommentNotes(
+      Args args,
+      @Assisted Change change) {
+    super(args, change.getId(), false);
+    this.change = change;
+  }
+
+  RevisionNoteMap<RobotCommentsRevisionNote> getRevisionNoteMap() {
+    return revisionNoteMap;
+  }
+
+  public ImmutableListMultimap<RevId, RobotComment> getComments() {
+    return comments;
+  }
+
+  public boolean containsComment(RobotComment c) {
+    for (RobotComment existing : comments.values()) {
+      if (c.key.equals(existing.key)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  @Override
+  protected String getRefName() {
+    return RefNames.robotCommentsRef(getChangeId());
+  }
+
+  @Override
+  protected void onLoad(LoadHandle handle)
+      throws IOException, ConfigInvalidException {
+    ObjectId rev = handle.id();
+    if (rev == null) {
+      loadDefaults();
+      return;
+    }
+
+    RevCommit tipCommit = handle.walk().parseCommit(rev);
+    ObjectReader reader = handle.walk().getObjectReader();
+    revisionNoteMap = RevisionNoteMap.parseRobotComments(args.noteUtil, reader,
+        NoteMap.read(reader, tipCommit));
+    Multimap<RevId, RobotComment> cs = ArrayListMultimap.create();
+    for (RobotCommentsRevisionNote rn :
+        revisionNoteMap.revisionNotes.values()) {
+      for (RobotComment c : rn.getComments()) {
+        cs.put(new RevId(c.revId), c);
+      }
+    }
+    comments = ImmutableListMultimap.copyOf(cs);
+  }
+
+  @Override
+  protected void loadDefaults() {
+    comments = ImmutableListMultimap.of();
+  }
+
+  @Override
+  public Project.NameKey getProjectName() {
+    return change.getProject();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentUpdate.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentUpdate.java
new file mode 100644
index 0000000..fd47d02
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentUpdate.java
@@ -0,0 +1,222 @@
+// Copyright (C) 2016 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.google.gerrit.server.notedb;
+
+import static com.google.common.base.MoreObjects.firstNonNull;
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.gerrit.reviewdb.client.RefNames.robotCommentsRef;
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+
+import com.google.common.collect.Sets;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.client.RevId;
+import com.google.gerrit.reviewdb.client.RobotComment;
+import com.google.gerrit.server.GerritPersonIdent;
+import com.google.gerrit.server.config.AnonymousCowardName;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.assistedinject.Assisted;
+import com.google.inject.assistedinject.AssistedInject;
+
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.CommitBuilder;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.PersonIdent;
+import org.eclipse.jgit.notes.NoteMap;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * A single delta to apply atomically to a change.
+ * <p>
+ * This delta contains only robot comments on a single patch set of a change by
+ * a single author. This delta will become a single commit in the repository.
+ * <p>
+ * This class is not thread safe.
+ */
+public class RobotCommentUpdate extends AbstractChangeUpdate{
+  public interface Factory {
+    RobotCommentUpdate create(ChangeNotes notes, Account.Id accountId,
+        PersonIdent authorIdent, Date when);
+    RobotCommentUpdate create(Change change, Account.Id accountId,
+        PersonIdent authorIdent, Date when);
+  }
+
+  private List<RobotComment> put = new ArrayList<>();
+
+  @AssistedInject
+  private RobotCommentUpdate(
+      @GerritPersonIdent PersonIdent serverIdent,
+      @AnonymousCowardName String anonymousCowardName,
+      NotesMigration migration,
+      ChangeNoteUtil noteUtil,
+      @Assisted ChangeNotes notes,
+      @Assisted Account.Id accountId,
+      @Assisted PersonIdent authorIdent,
+      @Assisted Date when) {
+    super(migration, noteUtil, serverIdent, anonymousCowardName, notes, null,
+        accountId, authorIdent, when);
+  }
+
+  @AssistedInject
+  private RobotCommentUpdate(
+      @GerritPersonIdent PersonIdent serverIdent,
+      @AnonymousCowardName String anonymousCowardName,
+      NotesMigration migration,
+      ChangeNoteUtil noteUtil,
+      @Assisted Change change,
+      @Assisted Account.Id accountId,
+      @Assisted PersonIdent authorIdent,
+      @Assisted Date when) {
+    super(migration, noteUtil, serverIdent, anonymousCowardName, null, change,
+        accountId, authorIdent, when);
+  }
+
+  public void putComment(RobotComment c) {
+    verifyComment(c);
+    put.add(c);
+  }
+
+  private void verifyComment(RobotComment comment) {
+    checkArgument(comment.author.getId().equals(accountId),
+        "The author for the following comment does not match the author of"
+        + " this RobotCommentUpdate (%s): %s", accountId, comment);
+  }
+
+  private CommitBuilder storeCommentsInNotes(RevWalk rw, ObjectInserter ins,
+      ObjectId curr, CommitBuilder cb)
+      throws ConfigInvalidException, OrmException, IOException {
+    RevisionNoteMap<RobotCommentsRevisionNote> rnm =
+        getRevisionNoteMap(rw, curr);
+    Set<RevId> updatedRevs =
+        Sets.newHashSetWithExpectedSize(rnm.revisionNotes.size());
+    RevisionNoteBuilder.Cache cache = new RevisionNoteBuilder.Cache(rnm);
+
+    for (RobotComment c : put) {
+      cache.get(new RevId(c.revId)).putComment(c);
+    }
+
+    Map<RevId, RevisionNoteBuilder> builders = cache.getBuilders();
+    boolean touchedAnyRevs = false;
+    boolean hasComments = false;
+    for (Map.Entry<RevId, RevisionNoteBuilder> e : builders.entrySet()) {
+      updatedRevs.add(e.getKey());
+      ObjectId id = ObjectId.fromString(e.getKey().get());
+      byte[] data = e.getValue().build(noteUtil, true);
+      if (!Arrays.equals(data, e.getValue().baseRaw)) {
+        touchedAnyRevs = true;
+      }
+      if (data.length == 0) {
+        rnm.noteMap.remove(id);
+      } else {
+        hasComments = true;
+        ObjectId dataBlob = ins.insert(OBJ_BLOB, data);
+        rnm.noteMap.set(id, dataBlob);
+      }
+    }
+
+    // If we didn't touch any notes, tell the caller this was a no-op update. We
+    // couldn't have done this in isEmpty() below because we hadn't read the old
+    // data yet.
+    if (!touchedAnyRevs) {
+      return NO_OP_UPDATE;
+    }
+
+    // If we touched every revision and there are no comments left, tell the
+    // caller to delete the entire ref.
+    boolean touchedAllRevs = updatedRevs.equals(rnm.revisionNotes.keySet());
+    if (touchedAllRevs && !hasComments) {
+      return null;
+    }
+
+    cb.setTreeId(rnm.noteMap.writeTree(ins));
+    return cb;
+  }
+
+  private RevisionNoteMap<RobotCommentsRevisionNote> getRevisionNoteMap(
+      RevWalk rw, ObjectId curr)
+          throws ConfigInvalidException, OrmException, IOException {
+    if (curr.equals(ObjectId.zeroId())) {
+      return RevisionNoteMap.emptyMap();
+    }
+    if (migration.readChanges()) {
+      // If reading from changes is enabled, then the old RobotCommentNotes
+      // already parsed the revision notes. We can reuse them as long as the ref
+      // hasn't advanced.
+      ChangeNotes changeNotes = getNotes();
+      if (changeNotes != null) {
+        RobotCommentNotes robotCommentNotes =
+            changeNotes.load().getRobotCommentNotes();
+        if (robotCommentNotes != null) {
+          ObjectId idFromNotes =
+              firstNonNull(robotCommentNotes.getRevision(), ObjectId.zeroId());
+          RevisionNoteMap<RobotCommentsRevisionNote> rnm =
+              robotCommentNotes.getRevisionNoteMap();
+          if (idFromNotes.equals(curr) && rnm != null) {
+            return rnm;
+          }
+        }
+      }
+    }
+    NoteMap noteMap;
+    if (!curr.equals(ObjectId.zeroId())) {
+      noteMap = NoteMap.read(rw.getObjectReader(), rw.parseCommit(curr));
+    } else {
+      noteMap = NoteMap.newEmptyMap();
+    }
+    // Even though reading from changes might not be enabled, we need to
+    // parse any existing revision notes so we can merge them.
+    return RevisionNoteMap.parseRobotComments(
+        noteUtil,
+        rw.getObjectReader(),
+        noteMap);
+  }
+
+  @Override
+  protected CommitBuilder applyImpl(RevWalk rw, ObjectInserter ins,
+      ObjectId curr) throws OrmException, IOException {
+    CommitBuilder cb = new CommitBuilder();
+    cb.setMessage("Update robot comments");
+    try {
+      return storeCommentsInNotes(rw, ins, curr, cb);
+    } catch (ConfigInvalidException e) {
+      throw new OrmException(e);
+    }
+  }
+
+  @Override
+  protected Project.NameKey getProjectName() {
+    return getNotes().getProjectName();
+  }
+
+  @Override
+  protected String getRefName() {
+    return robotCommentsRef(getId());
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return put.isEmpty();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNote.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNote.java
new file mode 100644
index 0000000..e007ff3
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNote.java
@@ -0,0 +1,48 @@
+// Copyright (C) 2016 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.google.gerrit.server.notedb;
+
+import com.google.gerrit.reviewdb.client.RobotComment;
+
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.util.List;
+
+public class RobotCommentsRevisionNote extends RevisionNote<RobotComment> {
+  private final ChangeNoteUtil noteUtil;
+
+  RobotCommentsRevisionNote(ChangeNoteUtil noteUtil, ObjectReader reader,
+      ObjectId noteId) {
+    super(reader, noteId);
+    this.noteUtil = noteUtil;
+  }
+
+  @Override
+  protected List<RobotComment> parse(byte[] raw, int offset)
+      throws IOException {
+    try (InputStream is = new ByteArrayInputStream(
+        raw, offset, raw.length - offset);
+        Reader r = new InputStreamReader(is)) {
+      return noteUtil.getGson().fromJson(r,
+          RobotCommentsRevisionNoteData.class).comments;
+    }
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNoteData.java b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNoteData.java
new file mode 100644
index 0000000..ea3a149
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/notedb/RobotCommentsRevisionNoteData.java
@@ -0,0 +1,23 @@
+// Copyright (C) 2016 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.google.gerrit.server.notedb;
+
+import com.google.gerrit.reviewdb.client.RobotComment;
+
+import java.util.List;
+
+public class RobotCommentsRevisionNoteData {
+  List<RobotComment> comments;
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
index 9573f99..3a0c699 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
@@ -176,7 +176,11 @@
       }
       stmt.executeBatch();
     } catch (SQLException e) {
-      throw convertError("insert", e);
+      OrmException ormException = convertError("insert", e);
+      if (ormException instanceof OrmDuplicateKeyException) {
+        return;
+      }
+      throw ormException;
     }
   }
 
diff --git a/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java b/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
index df0284a..9dba629 100644
--- a/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
+++ b/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
@@ -19,8 +19,8 @@
 
 import com.google.common.base.Splitter;
 import com.google.gerrit.common.EventBroker;
-import com.google.gerrit.extensions.client.AuthType;
 import com.google.gerrit.elasticsearch.ElasticIndexModule;
+import com.google.gerrit.extensions.client.AuthType;
 import com.google.gerrit.gpg.GpgModule;
 import com.google.gerrit.httpd.auth.oauth.OAuthModule;
 import com.google.gerrit.httpd.auth.openid.OpenIdModule;
diff --git a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
index a7d99a7..f58f762 100644
--- a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
+++ b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
@@ -15,6 +15,7 @@
 -->
 
 <link rel="import" href="../../../bower_components/polymer/polymer.html">
+<link rel="import" href="../../shared/gr-linked-text/gr-linked-text.html">
 
 <dom-module id="gr-comment-list">
   <template>
@@ -39,8 +40,6 @@
       }
       .message {
         flex: 1;
-        white-space: pre-wrap;
-        word-wrap: break-word;
       }
     </style>
     <template is="dom-repeat" items="[[_computeFilesFromComments(comments)]]" as="file">
@@ -60,7 +59,10 @@
                File comment:
              </span>
           </a>
-          <div class="message">[[comment.message]]</div>
+          <gr-linked-text class="message"
+              pre
+              content="[[comment.message]]"
+              config="[[projectConfig.commentlinks]]"></gr-linked-text>
         </div>
       </template>
     </template>
diff --git a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
index eaafc447..0362089 100644
--- a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
+++ b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
@@ -21,6 +21,7 @@
       changeNum: Number,
       comments: Object,
       patchNum: Number,
+      projectConfig: Object,
     },
 
     _computeFilesFromComments: function(comments) {
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.html b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
index c0773d3..287e9e4 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
@@ -121,7 +121,8 @@
             <gr-comment-list
                 comments="[[comments]]"
                 change-num="[[changeNum]]"
-                patch-num="[[message._revision_number]]"></gr-comment-list>
+                patch-num="[[message._revision_number]]"
+                project-config="[[projectConfig]]"></gr-comment-list>
           </div>
           <a class="date" href$="[[_computeMessageHash(message)]]" on-tap="_handleLinkTap">
             <gr-date-formatter date-str="[[message.date]]"></gr-date-formatter>
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
index efe8684..6c73e08 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.js
@@ -174,6 +174,10 @@
           this._patchRange.patchNum, this._path, reviewed);
     },
 
+    _checkForModifiers: function(e) {
+      return e.altKey || e.ctrlKey || e.metaKey || e.shiftKey || false;
+    },
+
     _handleKey: function(e) {
       if (this.shouldSupressKeyboardShortcut(e)) { return; }
 
@@ -201,6 +205,7 @@
           this.$.cursor.moveUp();
           break;
         case 67: // 'c'
+          if (this._checkForModifiers(e)) { return; }
           if (!this.$.diff.isRangeSelected()) {
             e.preventDefault();
             var line = this.$.cursor.getTargetLineElement();
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
index 14fd2b7..1eb3f95 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.html
@@ -509,5 +509,13 @@
       assert.equal(element.$.cursor.initialLineNumber, 345);
       assert.equal(element.$.cursor.side, 'left');
     });
+
+    test('_checkForModifiers', function() {
+      assert.isTrue(element._checkForModifiers({altKey: true}));
+      assert.isTrue(element._checkForModifiers({ctrlKey: true}));
+      assert.isTrue(element._checkForModifiers({metaKey: true}));
+      assert.isTrue(element._checkForModifiers({shiftKey: true}));
+      assert.isFalse(element._checkForModifiers({}));
+    });
   });
 </script>
diff --git a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
index d565a12..fbd1ef3 100644
--- a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
+++ b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box.js
@@ -74,9 +74,14 @@
       return rect;
     },
 
+    _checkForModifiers: function(e) {
+      return e.altKey || e.ctrlKey || e.metaKey || e.shiftKey || false;
+    },
+
     _handleKey: function(e) {
       if (this.shouldSupressKeyboardShortcut(e)) { return; }
       if (e.keyCode === 67) { // 'c'
+        if (this._checkForModifiers(e)) { return; }
         e.preventDefault();
         this._fireCreateComment();
       }
diff --git a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
index adc8532..c12966d 100644
--- a/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-selection-action-box/gr-selection-action-box_test.html
@@ -117,5 +117,13 @@
         document.createRange.restore();
       });
     });
+
+    test('_checkForModifiers', function() {
+      assert.isTrue(element._checkForModifiers({altKey: true}));
+      assert.isTrue(element._checkForModifiers({ctrlKey: true}));
+      assert.isTrue(element._checkForModifiers({metaKey: true}));
+      assert.isTrue(element._checkForModifiers({shiftKey: true}));
+      assert.isFalse(element._checkForModifiers({}));
+    });
   });
 </script>