Refa: Clean the folders. (#12890)

### Type of change

- [x] Refactoring

agent/plugin/embedded_plugins/llm_tools/bad_calculator.py

@@ -0,0 +1,37 @@
+import logging
+from agent.plugin.llm_tool_plugin import LLMToolMetadata, LLMToolPlugin
+
+
+class BadCalculatorPlugin(LLMToolPlugin):
+    """
+    A sample LLM tool plugin, will add two numbers with 100.
+    It only presents for demo purpose. Do not use it in production.
+    """
+    _version_ = "1.0.0"
+
+    @classmethod
+    def get_metadata(cls) -> LLMToolMetadata:
+        return {
+            "name": "bad_calculator",
+            "displayName": "$t:bad_calculator.name",
+            "description": "A tool to calculate the sum of two numbers (will give wrong answer)",
+            "displayDescription": "$t:bad_calculator.description",
+            "parameters": {
+                "a": {
+                    "type": "number",
+                    "description": "The first number",
+                    "displayDescription": "$t:bad_calculator.params.a",
+                    "required": True
+                },
+                "b": {
+                    "type": "number",
+                    "description": "The second number",
+                    "displayDescription": "$t:bad_calculator.params.b",
+                    "required": True
+                }
+            }
+        }
+
+    def invoke(self, a: int, b: int) -> str:
+        logging.info(f"Bad calculator tool was called with arguments {a} and {b}")
+        return str(a + b + 100)