diff --git a/core/src/command/CommandFactory.ts b/core/src/command/CommandFactory.ts
index af367b276..7f39d3b02 100644
--- a/core/src/command/CommandFactory.ts
+++ b/core/src/command/CommandFactory.ts
@@ -2,13 +2,14 @@ import { Command } from './Command';
 import { BaseCommand } from './BaseCommand';
 import { getLogger } from 'log4js';
 import { LOG4JS_BASE_CATEGORY_NAME } from '../config/const';
+import { ICommandConstructor } from './CommandTypes';
 
 const createLogger = (method: string) =>
   getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.command.CommandFactory.${method}`)
 
 export class CommandFactory {
   private static instance: CommandFactory;
-  private commands: Map<string, new (params: any) => Command> = new Map();
+  private commands: Map<string, ICommandConstructor> = new Map();
 
   private constructor() {}
 
@@ -19,10 +20,10 @@ export class CommandFactory {
     return CommandFactory.instance;
   }
 
-  registerCommand(name: string, commandClass: new (params: any) => Command): void {
+  registerCommand<T>(name: string, commandClass: ICommandConstructor<T>): void {
     const methodLogger = createLogger(`registerCommand`)
     if (methodLogger.isDebugEnabled()) {
-      methodLogger.debug(`registerCommand() name=${name}`)
+      methodLogger.debug(`registerCommand() name=${name}, commandClass=${commandClass.name}`)
     }
     this.commands.set(name, commandClass);
     if (methodLogger.isDebugEnabled()) {
@@ -36,6 +37,9 @@ export class CommandFactory {
       methodLogger.debug(`createCommand() name=${name} params=${JSON.stringify(params)}`)
     }
     const CommandClass = this.commands.get(name);
+    if (methodLogger.isDebugEnabled()) {
+      methodLogger.debug(`createCommand() name=${name} commandClass=${CommandClass ? CommandClass.name : 'null'}`)
+    }
     if (!CommandClass) {
       const errmsg = `Command ${name} not found`;
       methodLogger.error(errmsg);
diff --git a/core/src/command/CommandTypes.ts b/core/src/command/CommandTypes.ts
new file mode 100644
index 000000000..70fc16515
--- /dev/null
+++ b/core/src/command/CommandTypes.ts
@@ -0,0 +1,5 @@
+import { Command } from "./Command";
+
+export interface ICommandConstructor<T = any> {
+  new (params: any): Command<T>;
+}
diff --git a/core/src/command/commands/SendEmailCommand.ts b/core/src/command/commands/SendEmailCommand.ts
index 2caf51b76..78db629bc 100644
--- a/core/src/command/commands/SendEmailCommand.ts
+++ b/core/src/command/commands/SendEmailCommand.ts
@@ -7,19 +7,20 @@ import { getLogger } from 'log4js';
 const createLogger = (method: string) =>
   getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.command.CommandExecutor.${method}`)
 
+export interface SendEmailCommandParams {
+  mailType: string;
+  senderComUuid: string;
+  senderGradidoId: string;
+  receiverComUuid: string;
+  receiverGradidoId: string;
+  memo?: string;
+  amount?: number;
+}
 export class SendEmailCommand extends BaseCommand<{ success: boolean }> {
   static readonly SEND_MAIL_COMMAND = 'SEND_MAIL_COMMAND';
   protected requiredFields: string[] = ['mailType', 'senderComUuid', 'senderGradidoId', 'receiverComUuid', 'receiverGradidoId'];
 
-  constructor(params: { 
-    mailType: string,
-    senderComUuid: string,
-    senderGradidoId: string,
-    receiverComUuid: string,
-    receiverGradidoId: string,
-    memo?: string,
-    amount?: number,
-  }) {
+  constructor(params: SendEmailCommandParams) {
     super(params);
   }
 
@@ -28,6 +29,8 @@ export class SendEmailCommand extends BaseCommand<{ success: boolean }> {
     if (!baseValid) {
       return false;
     }
+    // Additional validations
+
     return true;
   }