diff --git a/services/jsonnet/buildbucket.libsonnet b/services/jsonnet/buildbucket.libsonnet
index 2930ae0..7497b7b 100644
--- a/services/jsonnet/buildbucket.libsonnet
+++ b/services/jsonnet/buildbucket.libsonnet
@@ -14,7 +14,7 @@
 local builderTmpl = {
   execution_timeout_secs: 60 * 60,
   dimensions: ['pool:luci.fuchsia.ci'],
-  swarming_tags+: [
+  swarming_tags: [
     'allow_milo:1',
     'vpython:native-python-wrapper',
   ],