diff --git a/recipe_modules/gerrit_comment/api.py b/recipe_modules/gerrit_comment/api.py
index 5dc3d60..f1e4c5a 100644
--- a/recipe_modules/gerrit_comment/api.py
+++ b/recipe_modules/gerrit_comment/api.py
@@ -86,4 +86,5 @@
                     self.m.buildbucket.build.id,
                 ),
                 notify="OWNER",
+                tag="autogenerated:pigweed:gerrit_comment",
             )
diff --git a/recipe_modules/gerrit_comment/tests/full.expected/try-build.json b/recipe_modules/gerrit_comment/tests/full.expected/try-build.json
index dd3e482..f311767 100644
--- a/recipe_modules/gerrit_comment/tests/full.expected/try-build.json
+++ b/recipe_modules/gerrit_comment/tests/full.expected/try-build.json
@@ -144,7 +144,7 @@
       "-host",
       "https://pigweed-review.googlesource.com",
       "-input",
-      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\"}, \"revision_id\": \"current\"}",
+      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\", \"tag\": \"autogenerated:pigweed:gerrit_comment\"}, \"revision_id\": \"current\"}",
       "-output",
       "/path/to/tmp/json"
     ],
@@ -172,7 +172,8 @@
       "@@@STEP_LOG_LINE@json.input@  \"change_id\": \"123456\",@@@",
       "@@@STEP_LOG_LINE@json.input@  \"input\": {@@@",
       "@@@STEP_LOG_LINE@json.input@    \"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\",@@@",
-      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\"@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\",@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"tag\": \"autogenerated:pigweed:gerrit_comment\"@@@",
       "@@@STEP_LOG_LINE@json.input@  },@@@",
       "@@@STEP_LOG_LINE@json.input@  \"revision_id\": \"current\"@@@",
       "@@@STEP_LOG_LINE@json.input@}@@@",
@@ -194,7 +195,7 @@
       "-host",
       "https://pigweed-review.googlesource.com",
       "-input",
-      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status Bad stuff: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\"}, \"revision_id\": \"current\"}",
+      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status Bad stuff: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\", \"tag\": \"autogenerated:pigweed:gerrit_comment\"}, \"revision_id\": \"current\"}",
       "-output",
       "/path/to/tmp/json"
     ],
@@ -222,7 +223,8 @@
       "@@@STEP_LOG_LINE@json.input@  \"change_id\": \"123456\",@@@",
       "@@@STEP_LOG_LINE@json.input@  \"input\": {@@@",
       "@@@STEP_LOG_LINE@json.input@    \"message\": \"builder completed with status Bad stuff: http://go/bbid/8945511751514863184\",@@@",
-      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\"@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\",@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"tag\": \"autogenerated:pigweed:gerrit_comment\"@@@",
       "@@@STEP_LOG_LINE@json.input@  },@@@",
       "@@@STEP_LOG_LINE@json.input@  \"revision_id\": \"current\"@@@",
       "@@@STEP_LOG_LINE@json.input@}@@@",
diff --git a/recipe_modules/pw_presubmit/tests/full.expected/comment-always.json b/recipe_modules/pw_presubmit/tests/full.expected/comment-always.json
index f37ce35..6a14d3d 100644
--- a/recipe_modules/pw_presubmit/tests/full.expected/comment-always.json
+++ b/recipe_modules/pw_presubmit/tests/full.expected/comment-always.json
@@ -1882,7 +1882,7 @@
       "-host",
       "https://pigweed-review.googlesource.com",
       "-input",
-      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\"}, \"revision_id\": \"current\"}",
+      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\", \"tag\": \"autogenerated:pigweed:gerrit_comment\"}, \"revision_id\": \"current\"}",
       "-output",
       "/path/to/tmp/json"
     ],
@@ -1910,7 +1910,8 @@
       "@@@STEP_LOG_LINE@json.input@  \"change_id\": \"123456\",@@@",
       "@@@STEP_LOG_LINE@json.input@  \"input\": {@@@",
       "@@@STEP_LOG_LINE@json.input@    \"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\",@@@",
-      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\"@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\",@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"tag\": \"autogenerated:pigweed:gerrit_comment\"@@@",
       "@@@STEP_LOG_LINE@json.input@  },@@@",
       "@@@STEP_LOG_LINE@json.input@  \"revision_id\": \"current\"@@@",
       "@@@STEP_LOG_LINE@json.input@}@@@",
@@ -3363,7 +3364,7 @@
       "-host",
       "https://pigweed-review.googlesource.com",
       "-input",
-      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\"}, \"revision_id\": \"current\"}",
+      "{\"change_id\": \"123456\", \"input\": {\"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\", \"notify\": \"OWNER\", \"tag\": \"autogenerated:pigweed:gerrit_comment\"}, \"revision_id\": \"current\"}",
       "-output",
       "/path/to/tmp/json"
     ],
@@ -3391,7 +3392,8 @@
       "@@@STEP_LOG_LINE@json.input@  \"change_id\": \"123456\",@@@",
       "@@@STEP_LOG_LINE@json.input@  \"input\": {@@@",
       "@@@STEP_LOG_LINE@json.input@    \"message\": \"builder completed with status OK: http://go/bbid/8945511751514863184\",@@@",
-      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\"@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"notify\": \"OWNER\",@@@",
+      "@@@STEP_LOG_LINE@json.input@    \"tag\": \"autogenerated:pigweed:gerrit_comment\"@@@",
       "@@@STEP_LOG_LINE@json.input@  },@@@",
       "@@@STEP_LOG_LINE@json.input@  \"revision_id\": \"current\"@@@",
       "@@@STEP_LOG_LINE@json.input@}@@@",