diff --git a/app.sh b/app.sh
index 0a774a3..b153c72 100644
--- a/app.sh
+++ b/app.sh
@@ -1,7 +1,15 @@
 #!/bin/sh
 
+set -eu
+
 echo "Munin-bitcoin starting..."
 
+if [ -n "${MUNIN_FULCRUM_URL:-}" ]; then
+    echo "Fulcrum endpoint configured: ${MUNIN_FULCRUM_URL}"
+else
+    echo "Warning: MUNIN_FULCRUM_URL is not configured"
+fi
+
 echo "Starting status API..."
 
 node /app/server/status.js &