A simple Model Context Protocol (MCP) server built using the Python MCP SDK to demonstrate the three core MCP Primitives:

• 🛠️ Tools – Generate a secure password.
• 📄 Resources – Expose a password policy.
• 💡 Prompts – Provide a reusable prompt template for generating secure passwords.

This project accompanies my Medium article on MCP Inspector and MCP Primitives, providing a hands-on example to help you understand how these concepts work together.

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Project Structure

MCP-INSPECTOR/
│
├── prompts/
│   ├── __init__.py
│   └── password_prompt.py
│
├── resources/
│   ├── __init__.py
│   └── password_resource.py
│
├── tools/
│   ├── __init__.py
│   └── password_tool.py
│
├── .gitignore
├── .python-version
├── app.py
├── pyproject.toml
├── README.md
├── server.py
└── uv.lock

Project Overview

• app.py – Creates the FastMCP server instance.
• server.py – Entry point that registers all MCP primitives and starts the server.
• tools/password_tool.py – Implements the Password Generator Tool.
• resources/password_resource.py – Exposes the Password Policy Resource.
• prompts/password_prompt.py – Defines the reusable Prompt template.
• pyproject.toml – Project configuration and project dependencies.
• uv.lock – Lock file generated by UV.
• README.md – Project documentation.

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Clone the Repository

Clone the repository to your local machine.

git clone <YOUR_GITHUB_REPOSITORY_LINK>

Navigate to the project directory.

cd MCP-INSPECTOR

Synchronize and install all project dependencies.

uv sync

Activate the virtual environment.

Windows

.venv\Scripts\activate

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Running the MCP Server with MCP Inspector

Start the MCP server using:

mcp dev server.py

This command starts the MCP server and automatically launches MCP Inspector in your browser.

Using MCP Inspector you can:

• View all registered MCP primitives.
• Execute Tools.
• Read Resources.
• Test Prompt templates.
• Validate your MCP server before integrating it with an MCP client.

Screenshot: MCP Inspector Home Page

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Testing the Tool

Open the Tools section inside MCP Inspector.

Select generate_password and provide the required inputs such as:

• Password Length
• Include Special Characters

Execute the Tool to generate a secure password.

Screenshot: Password Generator Tool

Screenshot: Generated Password Output

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Testing the Resource

Open the Resources section.

Select the password://policy resource.

The server returns the password policy and security recommendations exposed by the MCP server.

Screenshot: Password Policy Resource

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Testing the Prompt

Navigate to the Prompts section.

Select create_secure_password_prompt.

Provide an account type such as:

• Banking
• Email
• Social Media

The Prompt generates a reusable instruction template for creating a secure password.

Screenshot: Prompt Execution

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Installing the MCP Server in Claude Desktop

Open a new terminal and run:

mcp install server.py

Once the installation is complete, restart Claude Desktop if it is already running.

Claude Desktop will automatically discover the MCP server and its registered primitives.

You can now interact with the server using natural language.

For example:

Generate a strong password for my email.

or

Show me the password policy.

Claude Desktop Detecting the MCP Server

Claude Desktop Invoking the Password Generator Tool

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Creating an MCP Project from Scratch

If you'd like to build your own MCP server from scratch, follow these steps.

1. Initialize a UV Project

uv init

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2. Create a Virtual Environment

uv venv

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3. Activate the Virtual Environment

Windows

.venv\Scripts\activate

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4. Install the MCP SDK

uv add "mcp[cli]"

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5. Start MCP Inspector

mcp dev server.py

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6. Install the MCP Server in Claude Desktop

Open a new terminal and run:

mcp install server.py

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MCP Primitives Included

🛠️ Tool

generate_password()

Generates a secure password with configurable length and optional special characters.

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📄 Resource

password://policy

Returns the password generation policy and recommended password security practices.

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💡 Prompt

create_secure_password_prompt()

Creates a reusable prompt template for generating a secure password for a specified account type.

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Medium Article

If you're new to MCP and would like a detailed explanation of MCP Inspector and MCP Primitives, check out my accompanying Medium article.

Medium: https://medium.com/@n.raki2331/understanding-mcp-inspector-and-the-three-core-mcp-primitives-tools-resources-prompts-e6069f1ca75d?sharedUserId=n.raki2331

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