diff --git a/bundles/left4me/metadata.py b/bundles/left4me/metadata.py
index d589ced..2655dda 100644
--- a/bundles/left4me/metadata.py
+++ b/bundles/left4me/metadata.py
@@ -1,3 +1,11 @@
+assert node.has_bundle('nftables'), (
+    f'{node.name}: bundle left4me requires bundle nftables (uses nftables/output for srcds DSCP marking)'
+)
+assert node.has_bundle('systemd'), (
+    f'{node.name}: bundle left4me requires bundle systemd (declares units via systemd/units metadata)'
+)
+
+
 defaults = {
     'left4me': {
         'gunicorn_workers': 1,