Add template methods in Agent (#16)

Author: andresg4

lib/mars/agent.rb

@@ -13,7 +13,9 @@ def initialize(name:, options: {}, tools: [], schema: nil, instructions: nil)
     end
 
     def run(input)
-      chat.ask(input).content
+      processed_input = before_run(input)
+      response = chat.ask(processed_input).content
+      after_run(response)
     end
 
     private
@@ -26,5 +28,13 @@ def chat
                              .with_tools(*tools)
                              .with_schema(schema)
     end
+
+    def before_run(input)
+      input
+    end
+
+    def after_run(response)
+      response
+    end
   end
 end