diff --git a/nexus/mnemosyne/reasoner.py b/nexus/mnemosyne/reasoner.py
new file mode 100644
index 00000000..c9a8e11f
--- /dev/null
+++ b/nexus/mnemosyne/reasoner.py
@@ -0,0 +1,26 @@
+
+"""Symbolic Reasoner — Rule-based event triggering for the Mnemosyne archive."""
+import json
+
+class Reasoner:
+    def __init__(self, rules_path):
+        with open(rules_path) as f:
+            self.rules = json.load(f)
+
+    def evaluate(self, archive_entries):
+        triggers = []
+        for rule in self.rules:
+            if self._check_condition(rule['condition'], archive_entries):
+                triggers.append(rule['action'])
+        return triggers
+
+    def _check_condition(self, condition, entries):
+        # Simple symbolic checks: e.g., "count(type=error) > 5"
+        if condition.startswith("count"):
+            parts = condition.split(" ")
+            key, val = parts[0][6:-1].split("=")
+            op = parts[1]
+            threshold = int(parts[2])
+            count = sum(1 for e in entries if e.get(key) == val)
+            if op == ">": return count > threshold
+        return False