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MCP Send Email - Helidon MCP Server Example

Description

This is an example MCP (Model Context Protocol) Server project built with the Helidon framework.

The project implements a basic MCP server that provides a simple tool for simulating email sending, demonstrating how to create MCP servers using Java and Helidon.

Purpose

This project is part of a series of examples with increasing complexity developed for studying Java in conjunction with LLM (Large Language Models). The goal is to provide a practical foundation for understanding how to build MCP servers that can be used by AI agents and LLM-based assistants.

Technologies

• Java (JDK 17+)
• Helidon 4.3.1 (Helidon SE)
• MCP (Model Context Protocol)
• Maven (dependency management and build)

Project Structure

The project contains:

• McpServer.java: MCP server implementation with:

  • sendEmail: Tool for simulated email sending
  • sendEmailPrompt: Example prompt for LLM interaction

• Main.java: Main class that initializes the server

Features

Tool: Send Email

Tool that simulates sending an email with the following parameters:

• from: Sender's email address
• to: Recipient's email address(es)
• subject: Email subject
• body: Email body

Prompt: Send Email Prompt

Example prompt demonstrating how to structure an email sending request for use by an LLM.

How to Run

Prerequisites

• Java JDK 17 or higher
• Maven 3.8+

Build

mvn clean package

Run

mvn exec:java -Dexec.mainClass="com.r13a.mcp.sendemail.Main"

Or run the generated JAR:

java -jar target/mcp-send-email.jar

The server will start on port 8080 (configurable in application.yaml).

Configuration

Server configuration can be adjusted in the src/main/resources/application.yaml file:

server:
  port: 8080
  host: 0.0.0.0

Next Steps

This is the initial project in the series. Subsequent projects will include:

• Integration with real email sending APIs
• Authentication and authorization
• Data persistence
• More complex MCP tools
• Integration with multiple services

Resources

• Helidon Documentation
• Model Context Protocol
• MCP Specification

License

This is a sample project for educational purposes.

Author

Developed as part of a series of studies on Java and LLM.