diff --git a/.github/workflows/auto-label.yml b/.github/workflows/auto-label.yml
index 0575e2f96..36ad92179 100644
--- a/.github/workflows/auto-label.yml
+++ b/.github/workflows/auto-label.yml
@@ -14,6 +14,7 @@
 
 name: Auto Label
 on:
+  # Do not use pull_request_target with actions/cache or actions/checkout.
   pull_request_target:
     types: [ opened, reopened, synchronize, edited ]