MCP Rand

A Model Context Protocol (MCP) server providing various random generation utilities, including UUID, numbers, strings, passwords, Gaussian distribution, dice rolling, and card drawing.

Installation

npm install mcp-rand

Or install globally:

npm install -g mcp-rand

Features

UUID Generator

Generates RFC 4122 version 4 UUIDs
Uses Node's native crypto module for secure random generation
No parameters required

Random Number Generator

Generates random numbers within a specified range
Configurable minimum and maximum values (inclusive)
Defaults to range 0-100 if no parameters provided

Gaussian Random Generator

Generates random numbers following a Gaussian (normal) distribution
Normalized to range 0-1
No parameters required

Random String Generator

Generates random strings with configurable length and character sets
Supports multiple character sets:
- alphanumeric (default): A-Z, a-z, 0-9
- numeric: 0-9
- lowercase: a-z
- uppercase: A-Z
- special: !@#$%^&*()_+-=[]{};'"\|,.<>/?
Configurable string length (defaults to 10)

Password Generator

Generates strong passwords with a mix of character types
Ensures at least one character from each type (uppercase, lowercase, numbers, special)
Configurable length (minimum 8, default 16)
WARNING: While passwords are generated locally, it's recommended to use a dedicated password manager

Dice Roller

Roll multiple dice using standard dice notation
Supports notation like "2d6" (two six-sided dice), "1d20" (one twenty-sided die)
Returns individual rolls and total for each set of dice
Can roll multiple different dice sets at once (e.g., "2d6", "1d20", "4d4")

Card Drawer

Draw cards from a standard 52-card deck
Maintains deck state between draws using base64 encoding
Returns drawn cards and remaining deck state
Supports drawing any number of cards up to the deck size
Properly shuffles available cards before each draw

Usage

As a CLI Tool

npx mcp-rand

Integration with MCP Clients

Add to your MCP client configuration:

{
  "mcpServers": {
    "mcp-rand": {
      "command": "node",
      "args": ["path/to/mcp-rand/build/index.js"],
      "disabled": false,
      "alwaysAllow": []
    }
  }
}

Example Usage

// Generate UUID
const uuid = await client.callTool('generate_uuid', {});
console.log(uuid); // e.g., "550e8400-e29b-41d4-a716-446655440000"

// Generate random number
const number = await client.callTool('generate_random_number', {
  min: 1,
  max: 100
});
console.log(number); // e.g., 42

// Generate Gaussian random number
const gaussian = await client.callTool('generate_gaussian', {});
console.log(gaussian); // e.g., 0.6827

// Generate random string
const string = await client.callTool('generate_string', {
  length: 15,
  charset: 'alphanumeric'
});
console.log(string); // e.g., "aB9cD8eF7gH6iJ5"

// Generate password
const password = await client.callTool('generate_password', {
  length: 20
});
console.log(password); // e.g., "aB9#cD8$eF7@gH6*iJ5"

// Roll dice
const rolls = await client.callTool('roll_dice', {
  dice: ['2d6', '1d20', '4d4']
});
console.log(rolls);
/* Output example:
[
  {
    "dice": "2d6",
    "rolls": [3, 1],
    "total": 4
  },
  {
    "dice": "1d20",
    "rolls": [4],
    "total": 4
  },
  {
    "dice": "4d4",
    "rolls": [2, 3, 2, 3],
    "total": 10
  }
]
*/

// Draw cards
const draw1 = await client.callTool('draw_cards', {
  count: 5
});
console.log(draw1);
/* Output example:
{
  "drawnCards": [
    { "suit": "hearts", "value": "A" },
    { "suit": "diamonds", "value": "7" },
    { "suit": "clubs", "value": "K" },
    { "suit": "spades", "value": "2" },
    { "suit": "hearts", "value": "10" }
  ],
  "remainingCount": 47,
  "deckState": "t//+///bDw=="
}
*/

// Draw more cards using previous deck state
const draw2 = await client.callTool('draw_cards', {
  count: 3,
  deckState: draw1.deckState
});
console.log(draw2);
/* Output example:
{
  "drawnCards": [
    { "suit": "diamonds", "value": "Q" },
    { "suit": "clubs", "value": "5" },
    { "suit": "spades", "value": "J" }
  ],
  "remainingCount": 44,
  "deckState": "l//+//zbDw=="
}
*/

Contributing

Please see CONTRIBUTING.md for development setup and guidelines.

License

ISC