diff --git a/tools/monitoring_setup.py b/tools/monitoring_setup.py
index 65f43d20..b9d3b052 100644
--- a/tools/monitoring_setup.py
+++ b/tools/monitoring_setup.py
@@ -78,7 +78,7 @@
     },
     {
         "name": "HighMemoryUsage",
-        "expr": "process_resident_memory_bytes / process_resident_memory_bytes > 0.9",
+        "expr": "process_resident_memory_bytes / machine_memory_bytes > 0.9",
         "duration": "10m",
         "severity": "warning",
         "summary": "High memory usage on {{$labels.instance}}",
diff --git a/tools/test_monitoring.py b/tools/test_monitoring.py
new file mode 100644
index 00000000..46dcadae
--- /dev/null
+++ b/tools/test_monitoring.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""Validation test for monitoring alert expressions."""
+
+import sys
+sys.path.insert(0, '/home/pista/zeroeye-fix/tools')
+from monitoring_setup import RECOMMENDED_ALERT_RULES
+
+
+def test_no_self_dividing_expressions():
+    """Alert expressions must not divide a metric by itself."""
+    for alert in RECOMMENDED_ALERT_RULES:
+        expr = alert.get("expr", "")
+        # Check for self-dividing pattern: metric / metric
+        parts = expr.split("/")
+        if len(parts) == 2:
+            left = parts[0].strip().split("{")[0].strip()
+            right = parts[1].strip().split("{")[0].strip()
+            # Remove comparison operators
+            left = left.replace(">0.9", "").replace("<0.1", "").replace(">0.05", "").replace(">0.8", "").replace(">2", "").replace("==0", "").strip()
+            right = right.replace(">0.9", "").replace("<0.1", "").replace(">0.05", "").replace(">0.8", "").replace(">2", "").replace("==0", "").strip()
+            if left == right and left:
+                print(f"FAIL: {alert['name']} has self-dividing expression: {expr}")
+                return False
+    print("PASS: No self-dividing expressions found")
+    return True
+
+
+if __name__ == "__main__":
+    success = test_no_self_dividing_expressions()
+    sys.exit(0 if success else 1)