diff --git a/nexus/mnemosyne/reasoner.py b/nexus/mnemosyne/reasoner.py
new file mode 100644
index 00000000..31e8609c
--- /dev/null
+++ b/nexus/mnemosyne/reasoner.py
@@ -0,0 +1,14 @@
+
+class Reasoner:
+    def __init__(self, rules):
+        self.rules = rules
+    def evaluate(self, entries):
+        return [r['action'] for r in self.rules if self._check(r['condition'], entries)]
+    def _check(self, cond, entries):
+        if cond.startswith('count'):
+            # e.g. count(type=anomaly)>3
+            p = cond.replace('count(', '').split(')')
+            key, val = p[0].split('=')
+            count = sum(1 for e in entries if e.get(key) == val)
+            return eval(f"{count}{p[1]}")
+        return False