diff --git a/.github/workflows/diagnose_cache_size.yaml b/.github/workflows/diagnose_cache_size.yaml
index dcbeb652..480a4cc2 100644
--- a/.github/workflows/diagnose_cache_size.yaml
+++ b/.github/workflows/diagnose_cache_size.yaml
@@ -2,6 +2,7 @@
 name: Diagnose Cache Size
 on:
   push:
+  pull_request:
 jobs:
   diagnose-cache-size:
     runs-on: ubuntu-latest