mcp-mysql-explorer

MCP MySQL Server

A Model Context Protocol (MCP) server that connects AI agents (Cursor, Claude Desktop, etc.) to MySQL databases, enabling schema exploration, data querying, and SQL execution through natural language.

Chinese docs: README.zh.md

Features

Tool	Description
list_tables	List all tables in the database
describe_table	View table schema with column types and comments
query	Execute read-only queries (SELECT / SHOW / DESCRIBE / EXPLAIN)
execute_sql	Execute write operations (INSERT / UPDATE / DELETE / DDL), disabled in read-only mode
get_table_indexes	Show all indexes of a table
get_create_table	Get the CREATE TABLE statement
get_database_info	Get database overview (version, size, table count)

Installation

pip install mcp-mysql-explorer

Usage in Cursor

Open Cursor Settings -> MCP, add a new server. Three ways to configure the database connection. SSH tunneling through a bastion/jump host is also supported.

Option 1: Command-line arguments (recommended)

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer",
      "args": [
        "--host", "your-mysql-host",
        "--port", "3306",
        "--user", "your-user",
        "--password", "your-password",
        "--database", "your-database"
      ]
    }
  }
}

Enable write mode explicitly:

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer",
      "args": [
        "--host", "your-mysql-host",
        "--database", "your-database",
        "--allow-write"
      ]
    }
  }
}

If the database is only reachable through an SSH bastion, add --ssh-* arguments:

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer",
      "args": [
        "--host", "mysql.internal",
        "--port", "3306",
        "--user", "your-db-user",
        "--password", "your-db-password",
        "--database", "your-database",
        "--ssh-host", "bastion.example.com",
        "--ssh-port", "22",
        "--ssh-user", "your-ssh-user",
        "--ssh-private-key", "/Users/you/.ssh/id_rsa"
      ]
    }
  }
}

In SSH mode, --host / MYSQL_HOST is the MySQL address as seen from the SSH server. SSH tunneling is enabled automatically when --ssh-host or MYSQL_SSH_HOST is set. You can explicitly disable it with --ssh-enabled false.

Option 2: Environment variables

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer",
      "env": {
        "MYSQL_HOST": "your-mysql-host",
        "MYSQL_PORT": "3306",
        "MYSQL_USER": "your-user",
        "MYSQL_PASSWORD": "your-password",
        "MYSQL_DATABASE": "your-database",
        "MYSQL_READ_ONLY": "true",
        "MYSQL_SSH_HOST": "bastion.example.com",
        "MYSQL_SSH_PORT": "22",
        "MYSQL_SSH_USER": "your-ssh-user",
        "MYSQL_SSH_PRIVATE_KEY": "/Users/you/.ssh/id_rsa"
      }
    }
  }
}

SSH environment variables:

Environment variable	Description
MYSQL_SSH_ENABLED	Enable SSH tunneling (true/false). Defaults to enabled when MYSQL_SSH_HOST is set
MYSQL_SSH_HOST	SSH bastion/jump host
MYSQL_SSH_PORT	SSH port, defaults to 22
MYSQL_SSH_USER	SSH username
MYSQL_SSH_PASSWORD	SSH password
MYSQL_SSH_PRIVATE_KEY	Path to SSH private key
MYSQL_SSH_PRIVATE_KEY_PASSWORD	SSH private key passphrase
MYSQL_SSH_LOCAL_HOST	Local forwarding bind host, defaults to 127.0.0.1
MYSQL_SSH_LOCAL_PORT	Local forwarding bind port, defaults to 0 for automatic assignment

Option 3: .env file

Create a .env file in the working directory:

MYSQL_HOST=your-mysql-host
MYSQL_PORT=3306
MYSQL_USER=your-user
MYSQL_PASSWORD=your-password
MYSQL_DATABASE=your-database
MYSQL_READ_ONLY=true
MYSQL_SSH_HOST=bastion.example.com
MYSQL_SSH_USER=your-ssh-user
MYSQL_SSH_PRIVATE_KEY=/Users/you/.ssh/id_rsa

Then simply:

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer"
    }
  }
}

Priority: command-line args > environment variables > .env file

Usage in Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "mysql": {
      "command": "mcp-mysql-explorer",
      "args": [
        "--host", "your-mysql-host",
        "--user", "your-user",
        "--password", "your-password",
        "--database", "your-database"
      ]
    }
  }
}

Run Manually

# With command-line arguments
mcp-mysql-explorer --host localhost --user root --password secret --database mydb

# Explicitly allow write operations
mcp-mysql-explorer --host localhost --user root --password secret --database mydb --allow-write

# Through an SSH bastion
mcp-mysql-explorer --host mysql.internal --user root --password secret --database mydb \
  --ssh-host bastion.example.com --ssh-user deploy --ssh-private-key ~/.ssh/id_rsa

# With .env file
mcp-mysql-explorer

# As a Python module
python -m mcp_mysql_explorer --host localhost --database mydb

Testing

# Run unit tests (no real database needed)
python scripts/run_tests.py

# Optional manual smoke check (reads credentials from env only)
# Required env: MYSQL_HOST, MYSQL_PORT, MYSQL_USER, MYSQL_PASSWORD, MYSQL_DATABASE
python scripts/manual_smoke_check.py --mode both

Security Notes

• The query tool only allows SELECT / SHOW / DESCRIBE / EXPLAIN statements.
• Read-only mode is enabled by default (MYSQL_READ_ONLY=true).
• To enable writes, set MYSQL_READ_ONLY=false or pass --allow-write.
• The execute_sql tool can run write operations only when read-only mode is disabled.
• Query results are capped at 1000 rows by default.
• Table/column identifiers are backtick-wrapped to prevent SQL injection.

License

MIT