diff --git a/.github/workflows/cache-report.yml b/.github/workflows/cache-report.yml
index b3fc11c19..201cbd346 100644
--- a/.github/workflows/cache-report.yml
+++ b/.github/workflows/cache-report.yml
@@ -1,4 +1,4 @@
-# Reports total GitHub Actions cache usage for BuildKit blob caches (used by docker-release).
+# Reports GitHub Actions cache usage grouped by key prefix (e.g. buildkit, ccache, vcpkg).
 # Run locally: .ci/gh_buildkit_cache_usage.sh
 
 name: Cache usage report
@@ -10,7 +10,7 @@ on:
 jobs:
   report:
     name: GHA cache usage
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     permissions:
       actions: read
       contents: read