--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -99,17 +99,17 @@ tasks:
           - -cx
           - >
               cd /home/worker/checkouts/gecko &&
               ln -s /home/worker/artifacts artifacts &&
               ./mach --log-no-times taskgraph decision
               --pushlog-id='{{pushlog_id}}'
               --pushdate='{{pushdate}}'
               --project='{{project}}'
-              --message='{{comment}}'
+              --message='{{#shellquote}}{{{comment}}}{{/shellquote}}'
               --owner='{{owner}}'
               --level='{{level}}'
               --base-repository='https://hg.mozilla.org/mozilla-central'
               --head-repository='{{{url}}}'
               --head-ref='{{revision}}'
               --head-rev='{{revision}}'
               --revision-hash='{{revision_hash}}'