Lexiguard HR — Local MySQL MCP Server for Cursor

A small Model Context Protocol (MCP) demo that lets Cursor query a local MySQL HR database in natural language—without pasting credentials or schema into every chat.

Cursor (AI)  ←── MCP (stdio) ──→  server.py  ←── SQL ──→  MySQL (lexiguard)

What it does

MCP tool	Description
get_db_schema	Lists tables, columns, types, and keys so the AI knows what exists
query_hr_db	Runs read-only SQL (SELECT, SHOW, DESCRIBE, EXPLAIN, WITH) and returns formatted text

Example questions in Cursor chat:

• “Use get_db_schema to show all tables.”
• “Who works in Engineering?”
• “List employees with their department names.”
• “Average salary by department.”

Tech stack

• Python 3.10+
• MCP Python SDK (mcp, FastMCP)
• mysql-connector-python
• Cursor with project MCP config (.cursor/mcp.json)

Prerequisites

• MySQL running locally
• Cursor IDE
• Python 3.10+

Quick start

1. Create database and sample data

In MySQL Workbench or the CLI:

CREATE DATABASE IF NOT EXISTS lexiguard;
USE lexiguard;

CREATE TABLE IF NOT EXISTS departments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    location VARCHAR(100)
);

CREATE TABLE IF NOT EXISTS employees (
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(50) NOT NULL,
    last_name VARCHAR(50) NOT NULL,
    email VARCHAR(100) UNIQUE,
    department_id INT,
    hire_date DATE,
    salary DECIMAL(10, 2),
    FOREIGN KEY (department_id) REFERENCES departments(id)
);

INSERT INTO departments (name, location) VALUES
('Engineering', 'London'),
('HR', 'Manchester'),
('Finance', 'Birmingham');

INSERT INTO employees (first_name, last_name, email, department_id, hire_date, salary) VALUES
('Alice', 'Smith', 'alice.smith@lexiguard.com', 1, '2022-03-15', 65000.00),
('Bob', 'Jones', 'bob.jones@lexiguard.com', 1, '2021-07-01', 72000.00),
('Carol', 'Brown', 'carol.brown@lexiguard.com', 2, '2020-11-20', 48000.00),
('David', 'Taylor', 'david.taylor@lexiguard.com', 3, '2023-01-10', 55000.00);

2. Install Python dependencies

Windows (PowerShell):

cd db-mcp-server
python -m venv .venv
.\.venv\Scripts\pip install -r requirements.txt

macOS / Linux:

cd db-mcp-server
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

3. Configure environment

cp .env.example .env

Edit .env with your MySQL settings (especially MYSQL_PASSWORD if root has a password).

4. Connect Cursor

This repo includes project-level MCP config at .cursor/mcp.json.

1. Open this folder as a Cursor workspace.
2. Go to Cursor Settings → Models → MCP.
3. Enable lexiguard-hr (should show 2 tools).
4. Restart Cursor if the server does not appear.

macOS / Linux: Update .cursor/mcp.json so command points to your venv Python, for example:

"command": "${workspaceFolder}/.venv/bin/python"

Windows (default in this repo):

"command": "${workspaceFolder}/.venv/Scripts/python.exe"

Credentials are loaded from .env via envFile—do not commit .env (it is in .gitignore).

5. Try it

Open chat (Ctrl+L / Cmd+L), use Agent mode, and allow MCP tool runs when prompted.

Project layout

db-mcp-server/
├── .cursor/
│   └── mcp.json          # Cursor MCP launch config
├── server.py             # MCP server (FastMCP + MySQL)
├── requirements.txt
├── .env.example          # Copy to .env locally
├── .gitignore
├── README.md             # This file (demo / setup)
└── MCP-HOW-IT-WORKS.md   # Short technical notes on MCP

Security notes

• Read-only queries only in query_hr_db (no INSERT / UPDATE / DELETE).
• Keep .env local; use .env.example as a template for collaborators.
• Intended for local development demos, not production exposure of a database.

Troubleshooting

Issue	What to check
MCP server red / disconnected	MySQL running; .env password correct; re-run pip install
“Connection refused”	Start MySQL service; confirm MYSQL_HOST / MYSQL_PORT
Tools not listed	Reopen project folder; toggle MCP server; restart Cursor
GitKraken MCP error	Unrelated third-party config in global ~/.cursor/mcp.json

Learn more

See MCP-HOW-IT-WORKS.md for a concise technical explanation of MCP and how this repo implements it.

License

Use and adapt freely for learning and demos.