diff --git a/tests/bin/action_runner_test.py b/tests/bin/action_runner_test.py
index 1ecc206e6..1aa102396 100644
--- a/tests/bin/action_runner_test.py
+++ b/tests/bin/action_runner_test.py
@@ -152,38 +152,38 @@ class TestBuildLabels:
     def test_build_labels(self):
         labels = action_runner.build_labels("MASTER.foo.10.bar")
 
-        assert labels == dict(
-            TRON_RUN_NUM="10",
-        )
+        assert labels == {
+            "tron.yelp.com/run_num": "10",
+        }
 
     def test_build_labels_with_merging(self):
         current_labels = {"LABEL1": "value_1"}
         labels = action_runner.build_labels("MASTER.foo.10.bar", current_labels)
 
-        assert labels == dict(
-            TRON_RUN_NUM="10",
-            LABEL1="value_1",
-        )
+        assert labels == {
+            "tron.yelp.com/run_num": "10",
+            "LABEL1": "value_1",
+        }
 
     def test_build_labels_with_merging_on_unknown(self):
         current_labels = {"LABEL1": "value_1"}
         labels = action_runner.build_labels("asdf", current_labels)
 
-        assert labels == dict(
-            TRON_RUN_NUM="UNKNOWN",
-            LABEL1="value_1",
-        )
+        assert labels == {
+            "tron.yelp.com/run_num": "UNKNOWN",
+            "LABEL1": "value_1",
+        }
 
     def test_build_labels_invalid_run_id(self):
         labels = action_runner.build_labels("asdf")
 
-        assert labels == dict(
-            TRON_RUN_NUM="UNKNOWN",
-        )
+        assert labels == {
+            "tron.yelp.com/run_num": "UNKNOWN",
+        }
 
     def test_build_labels_too_long_run_id(self):
         labels = action_runner.build_labels("MASTER.foo.10.bar.baz")
 
-        assert labels == dict(
-            TRON_RUN_NUM="10",
-        )
+        assert labels == {
+            "tron.yelp.com/run_num": "10",
+        }
diff --git a/tests/core/actionrun_test.py b/tests/core/actionrun_test.py
index 99786bb98..63170f85d 100644
--- a/tests/core/actionrun_test.py
+++ b/tests/core/actionrun_test.py
@@ -1803,7 +1803,7 @@ def mock_k8s_action_run(self):
                 "TRON_ACTION": "mock_action_name",
             },
             labels={
-                "TRON_RUN_NUM": "42",
+                "tron.yelp.com/run_num": "42",
             },
         )
 
diff --git a/tron/bin/action_runner.py b/tron/bin/action_runner.py
index 177f356d9..939c5a76c 100755
--- a/tron/bin/action_runner.py
+++ b/tron/bin/action_runner.py
@@ -108,7 +108,7 @@ def build_labels(run_id: str, original_labels: Optional[Dict[str, str]] = None)
         run_num = "UNKNOWN"
 
     new_labels = dict(original_labels)
-    new_labels["TRON_RUN_NUM"] = run_num
+    new_labels["tron.yelp.com/run_num"] = run_num
 
     return new_labels