Custom MySQL MCP

A Model Context Protocol server that lets AI agents (Cursor, Claude Desktop, etc.) interact with a MySQL database — query data, inspect schemas, and optionally execute write operations.

Tools

| Tool | Description | |---|---| | list_tables | List all tables in the connected database | | describe_table | Get the schema of a table (columns, types, keys, defaults) | | execute_query | Execute a read-only SELECT query and return results | | execute_write | Execute a write statement (INSERT, UPDATE, DELETE, ALTER…) — requires MYSQL_MCP_ALLOW_WRITE=true |

Configuration in Cursor

Add the following to your Cursor MCP configuration file (~/.cursor/mcp.json or your project's .cursor/mcp.json):

Via NPX (recommended)

{
  "mcpServers": {
    "custom-mysql-mcp": {
      "command": "npx",
      "args": ["-y", "custom-mysql-mcp"],
      "env": {
        "MYSQL_MCP_HOST": "127.0.0.1",
        "MYSQL_MCP_PORT": "3306",
        "MYSQL_MCP_DATABASE": "my_database",
        "MYSQL_MCP_USERNAME": "my_user",
        "MYSQL_MCP_PASSWORD": "my_password",
        "MYSQL_MCP_ALLOW_WRITE": "false"
      }
    }
  }
}

Via local install

{
  "mcpServers": {
    "custom-mysql-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/custom-mysql-mcp/dist/index.js"],
      "env": {
        "MYSQL_MCP_HOST": "127.0.0.1",
        "MYSQL_MCP_PORT": "3306",
        "MYSQL_MCP_DATABASE": "my_database",
        "MYSQL_MCP_USERNAME": "my_user",
        "MYSQL_MCP_PASSWORD": "my_password",
        "MYSQL_MCP_ALLOW_WRITE": "false"
      }
    }
  }
}

Environment Variables

| Variable | Required | Description | |---|---|---| | MYSQL_MCP_HOST | Yes | MySQL server hostname or IP address | | MYSQL_MCP_PORT | Yes | MySQL server port (usually 3306) | | MYSQL_MCP_DATABASE | Yes | Name of the database to connect to | | MYSQL_MCP_USERNAME | Yes | MySQL username | | MYSQL_MCP_PASSWORD | Yes | MySQL password | | MYSQL_MCP_ALLOW_WRITE | No | Set to true to enable write operations. Defaults to read-only if absent or any other value. |

Security note: Write operations are disabled by default. You must explicitly set MYSQL_MCP_ALLOW_WRITE=true to allow INSERT, UPDATE, DELETE, and other write statements. If the variable is missing or set to anything other than true, the execute_write tool will immediately return an error.

Development

# Install dependencies
npm install

# Run in development mode (no build required)
npm run dev

# Build for production
npm run build

# Start the compiled server
npm start

License

ISC