📌Overview

Purpose: LiteMCP is designed to simplify the process of building Model Context Protocol (MCP) servers using TypeScript.

Overview: LiteMCP provides an elegant framework for developers to create and manage MCP servers efficiently. It supports a variety of features including tools, resources, and logging, ensuring robust server functionalities tailored for integration with Large Language Models (LLMs).

Key Features:

Simple Tool, Resource, Prompt Definition: Easily define interactive tools and resources that clients can invoke, allowing for straightforward integration of complex functionalities.
Full TypeScript Support: Built with TypeScript, ensuring type safety and enhancing the development experience with better IDE support and error checking.
Built-in Logging: Incorporates a robust logging mechanism to track server activities, helping in debugging and monitoring the server's behavior.
Error Handling: Features built-in error handling, ensuring that server failures are managed gracefully without disrupting user experience.
Built-in CLI for Testing and Debugging: Provides a command-line interface (CLI) for rapid testing of the server, facilitating the development workflow.
SSE Transport Support: Allows servers to communicate over Server-Sent Events (SSE), enabling real-time updates to clients in an efficient manner.

LiteMCP

A TypeScript framework for building MCP (Model Context Protocol) servers elegantly.

Features

Simple Tool, Resource, Prompt definition
Full TypeScript support
Built-in logging
Built-in error handling
Built-in CLI for testing and debugging
Built-in support for SSE transport

Installation

npm install litemcp zod

Quickstart

import { LiteMCP } from "litemcp";
import { z } from "zod";

const server = new LiteMCP("demo", "1.0.0");

server.addTool({
  name: "add",
  description: "Add two numbers",
  parameters: z.object({
    a: z.number(),
    b: z.number(),
  }),
  execute: async (args) => {
    return args.a + args.b;
  },
});

server.start();

You can test the server in terminal with:

npx litemcp dev server.js

Core Concepts

Tools

Tools in MCP allow servers to expose executable functions invokable by clients.

server.addTool({
  name: "fetch",
  description: "Fetch the content of a url",
  parameters: z.object({
    url: z.string(),
  }),
  execute: async (args) => {
    const content = await fetchWebpageContent(args.url);
    return content;
  },
});

Resources

Resources represent data that an MCP server makes available to clients, using unique URIs.

server.addResource({
  uri: "file:///logs/app.log",
  name: "Application Logs",
  mimeType: "text/plain",
  async load() {
    return {
      text: await readLogFile(),
    };
  },
});

You can also return binary contents in load.

Prompts

Prompts define reusable templates and workflows for client interactions.

server.addPrompt({
  name: "git-commit",
  description: "Generate a Git commit message",
  arguments: [
    {
      name: "changes",
      description: "Git diff or description of changes",
      required: true,
    },
  ],
  load: async (args) => {
    return `Generate a concise but descriptive commit message for these changes:\n\n${args.changes}`;
  },
});

Logging

Send log messages to the client with server.logger.

server.addTool({
  name: "download",
  description: "Download a file from a url",
  parameters: z.object({
    url: z.string(),
  }),
  execute: async (args) => {
    server.logger.info("Downloading file", { url: args.url });
    // ...
    server.logger.info("Downloaded file", { url: args.url });
    return response;
  },
});

Running Your Server

Debugging with `mcp-cli`

The fastest way to test your server is with mcp-cli:

npx litemcp dev server.js

SSE Transport

You can run the server with SSE mode:

server.start({
  transportType: "sse",
  sse: {
    endpoint: "/sse",
    port: 8080,
  },
});

Showcase

If you've developed a server using LiteMCP, please submit a PR to showcase it here!

Roadmap

Add support for Resource Templates

mcp-cli - A CLI for testing and debugging MCP servers
mcpservers.org - A curated list of MCP servers
FastMCP - A Python library for MCP server development

litemcp