--- a/taskcluster/taskgraph/actions/registry.py
+++ b/taskcluster/taskgraph/actions/registry.py
@@ -182,17 +182,22 @@ def register_callback_action(name, title
             match = re.match(r'https://(hg.mozilla.org)/(.*?)/?$', parameters[repo_param])
             if not match:
                 raise Exception('Unrecognized {}'.format(repo_param))
             repo_scope = 'assume:repo:{}/{}:branch:default'.format(
                 match.group(1), match.group(2))
 
             task_group_id = os.environ.get('TASK_ID', slugid())
 
-            template = os.path.join(GECKO, '.taskcluster.yml')
+            # FIXME: https://bugzilla.mozilla.org/show_bug.cgi?id=1454034
+            # trust-domain works, but isn't semantically correct here.
+            if graph_config['trust-domain'] == 'comm':
+                template = os.path.join(GECKO, 'comm', '.taskcluster.yml')
+            else:
+                template = os.path.join(GECKO, '.taskcluster.yml')
 
             with open(template, 'r') as f:
                 taskcluster_yml = yaml.safe_load(f)
                 if taskcluster_yml['version'] != 1:
                     raise Exception('actions.json must be updated to work with .taskcluster.yml')
                 if not isinstance(taskcluster_yml['tasks'], list):
                     raise Exception('.taskcluster.yml "tasks" must be a list for action tasks')