A TypeScript framework for building MCP servers elegantly
A TypeScript framework for building MCP (Model Context Protocol) servers elegantly
npm install litemcp zod
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.addResource({
uri: "file:///logs/app.log",
name: "Application Logs",
mimeType: "text/plain",
async load() {
return {
text: "Example log content",
};
},
});
server.start();
You can test the server in terminal with:
npx litemcp dev server.js
Tools in MCP allow servers to expose executable functions that can be invoked by clients and used by LLMs to perform actions.
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 represent any kind of data that an MCP server wants to make available to clients. This can include:
Each resource is identified by a unique URI and can contain either text or binary data.
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:
async load() {
return {
blob: 'base64-encoded-data'
}
}
Prompts enable servers to define reusable prompt templates and workflows that clients can easily surface to users and LLMs. They provide a powerful way to standardize and share common LLM 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}`;
},
});
You can 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;
},
});
The logger object has the following methods:
debug(message: string, context?: JsonValue)info(message: string, context?: JsonValue)warn(message: string, context?: JsonValue)error(message: string, context?: JsonValue)mcp-cliThe fastest way to test and debug your server is with mcp-cli:
npx litemcp dev server.js
npx litemcp dev server.ts // ts files are also supported
This will run your server with mcp-cli for testing and debugging your MCP server in the terminal.
MCP InspectorAnother way is to use the official MCP Inspector to inspect your server with a Web UI:
npx litemcp inspect server.js
The servers are running with stdio transport by default. You can also run the server with SSE mode:
server.start({
transportType: "sse",
sse: {
endpoint: "/sse",
port: 8080,
},
});
This will start the server and listen for SSE connections on http://localhost:8080/sse.
You can then connect to the server with SSE transport in the client.
If you’ve developed a server using LiteMCP, please submit a PR to showcase it here!
A simple MCP Server for Taskwarrior
The registry mcp server updates your resume while you code
A beginner-friendly guide server that helps users understand MCP concepts, provides interactive examples, and demonstrates best practices for building MCP integrations. Features tools for exploring MCP capabilities, resources for learning core concepts, and prompts for guided tutorials.
