diff --git a/.github/workflows/size.yml b/.github/workflows/size.yml
index bb1e153d8..591920b8f 100644
--- a/.github/workflows/size.yml
+++ b/.github/workflows/size.yml
@@ -2,7 +2,8 @@ name: size
 on:
   # this action will error unless run in a pr context
   pull_request:
-  pull_request_target:
+    branches:
+      - main
 
 jobs:
   # Build current and upload stats.json