diff --git a/.github/workflows/cleanup-cache-postpr.yml b/.github/workflows/cleanup-cache-postpr.yml
index 9a2ffb0f61a..e24369a7b39 100644
--- a/.github/workflows/cleanup-cache-postpr.yml
+++ b/.github/workflows/cleanup-cache-postpr.yml
@@ -23,8 +23,8 @@ jobs:
 
           REPO=${{ github.repository }}
 
-          gh run download ${{ github.event.workflow_run.id }} -n pr_number
-          pr_number=`cat pr_number.txt`
+          pr_number=$(jq --raw-output .workflow_run.pull_requests[0].number < ${GITHUB_EVENT_PATH})
+          echo "Clean up cache for PR ${pr_number}."
           BRANCH=refs/pull/${pr_number}/merge
 
           # Setting this to not fail the workflow while deleting cache keys.
diff --git a/.github/workflows/post-pr.yml b/.github/workflows/post-pr.yml
index 2768ef376cc..6fa886e4abb 100644
--- a/.github/workflows/post-pr.yml
+++ b/.github/workflows/post-pr.yml
@@ -4,17 +4,13 @@ on:
     types:
       - closed
 
+# Because this workflow is run in the context of a pull_request event, it
+# does not have the permission to remove caches. We use this workflow to
+# trigger CleanUpCachePostPR to remove caches.
+
 jobs:
   cleanup:
     runs-on: ubuntu-latest
     steps:
-      - name: Save PR number
-        env:
-          PR_NUMBER: ${{ github.event.number }}
-        run: |
-          echo $PR_NUMBER > pr_number.txt
-      - uses: actions/upload-artifact@v4
-        with:
-          name: pr_number
-          path: pr_number.txt
-          retention-days: 1
+      - name: Do nothing
+        run: echo "This workflow will trigger CleanUpCachePostPR."