diff --git a/agents-flex-core/src/main/java/com/agentsflex/core/store/condition/Key.java b/agents-flex-core/src/main/java/com/agentsflex/core/store/condition/Key.java
new file mode 100644
index 0000000..591898d
--- /dev/null
+++ b/agents-flex-core/src/main/java/com/agentsflex/core/store/condition/Key.java
@@ -0,0 +1,38 @@
+/*
+ *  Copyright (c) 2023-2025, Agents-Flex (fuhai999@gmail.com).
+ *  <p>
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *  <p>
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *  <p>
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package com.agentsflex.core.store.condition;
+
+public class Key implements Operand {
+
+    private Object key;
+
+    public Key(Object key) {
+        this.key = key;
+    }
+
+    public Object getKey() {
+        return key;
+    }
+
+    public void setKey(Object key) {
+        this.key = key;
+    }
+
+    @Override
+    public String toExpression(ExpressionAdaptor adaptor) {
+        return key != null ? key.toString() : "";
+    }
+}