diff --git a/apps/registry/retention-script.yaml b/apps/registry/retention-script.yaml
index 63ecedb..fba33a7 100644
--- a/apps/registry/retention-script.yaml
+++ b/apps/registry/retention-script.yaml
@@ -87,8 +87,8 @@ data:
       rows.sort(key=lambda x: x[0], reverse=True)
       KEEP_N=2   # keep last 2 SHA builds (current + 1 previous)
       keep_set=set(t for _, t, _ in rows[:KEEP_N])
-      # preserve any -latest aliases regardless of age
-      keep_set.update(t for t in tags if t.endswith('-latest'))
+      # preserve buildcache for performance
+      keep_set.update(t for t in tags if t == 'buildcache')
       keep_list=sorted(keep_set)
       print(f'[{repo}] sha_total={len(rows)} keep={keep_list} remove={max(0, len(rows)-len(keep_set))}')
       for _, t, d in rows: