--- a/taskcluster/taskgraph/transforms/l10n.py
+++ b/taskcluster/taskgraph/transforms/l10n.py
@@ -52,16 +52,17 @@ l10n_description_schema = Schema({
     # max run time of the task
     Required('run-time'): _by_platform(int),
 
     # Locales not to repack for
     Required('ignore-locales'): _by_platform([basestring]),
 
     # All l10n jobs use mozharness
     Required('mozharness'): {
+        Required('comm-checkout', default=False): bool, 
         # Script to invoke for mozharness
         Required('script'): _by_platform(basestring),
 
         # Config files passed to the mozharness script
         Required('config'): _by_platform([basestring]),
 
         # Options to pass to the mozharness script
         Required('options'): _by_platform([basestring]),