Inventory MCP Server Demo

This project is a Spring Boot 3 application that exposes a legacy inventory service as an MCP (Model Context Protocol) server using Spring AI.

Prerequisites

• Java 17 or higher
• Maven 3.8+

How to Run

1. Build the project:

   mvn clean install

2. Run the application:

   mvn spring-boot:run

3. Access the MCP Server:

   • The server will be running on http://localhost:8080.
   • The MCP SSE endpoint is available at http://localhost:8080/mcp.

Exposed Tools and Resources

Tools

• getStockLevel: Retrieve current stock level for a product.
• updateLeadTime: Update supplier lead time for a purchase order.

Resources

• inventory://warehouse/{warehouseCode}: Get a JSON snapshot of a warehouse's inventory.

Understanding Tools vs. Resources

In MCP, choosing between a Tool and a Resource depends on the intent of the interaction.

Feature	Tools	Resources
Nature	Active (Action-oriented)	Passive (Data-oriented)
Interaction	LLM calls the tool to perform a task.	LLM reads the resource to gain context.
Side Effects	Can change system state (Write/Update).	Read-only (Idempotent).
Example	updateLeadTime(orderId, days)	inventory://warehouse/WH001

When to use a Tool

Use a Tool when the LLM needs to do something or perform a calculation that requires specific parameters.

• Example: getStockLevel is a tool because the LLM needs to provide a productCode to get a specific answer. It's a "query" action.
• Example: updateLeadTime is a tool because it changes data in the system.

When to use a Resource

Use a Resource when you want to provide a "document" or a "snapshot" of data that the LLM can use as background knowledge.

• Example: inventory://warehouse/{warehouseCode} is a resource because it provides a complete snapshot of everything in a warehouse. The LLM can then look through this data to answer multiple questions without making further tool calls.

Testing with MCP Inspector

You can test this server using the MCP Inspector: