#!/usr/bin/env node
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
CallToolRequestSchema,
ListToolsRequestSchema,
ListResourcesRequestSchema,
ReadResourceRequestSchema,
ListPromptsRequestSchema,
GetPromptRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
/**
* Basic MCP Server Implementation
*
* A clean, minimal implementation of an MCP server
* without any framework dependencies
*/
async function main() {
// Create server instance
const server = new Server(
{
name: "basic-mcp-server",
version: "0.1.0",
},
{
capabilities: {
tools: {},
resources: {},
prompts: {},
},
}
);
// Register tools
server.setRequestHandler(ListToolsRequestSchema, async () => {
return {
tools: [
{
name: "hello",
description: "A simple greeting tool that says hello",
inputSchema: {
type: "object",
properties: {
name: {
type: "string",
description: "The name to greet",
},
},
required: ["name"],
},
},
{
name: "calculate",
description: "Perform basic arithmetic calculations",
inputSchema: {
type: "object",
properties: {
operation: {
type: "string",
enum: ["add", "subtract", "multiply", "divide"],
description: "The arithmetic operation to perform",
},
a: {
type: "number",
description: "First number",
},
b: {
type: "number",
description: "Second number",
},
},
required: ["operation", "a", "b"],
},
},
],
};
});
// Handle tool execution
server.setRequestHandler(CallToolRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
if (name === "hello") {
const userName = (args?.name as string) || "World";
return {
content: [
{
type: "text",
text: `Hello, ${userName}! Welcome to MCP!`,
},
],
};
}
if (name === "calculate") {
const operation = args?.operation as string;
const a = args?.a as number;
const b = args?.b as number;
let result: number;
switch (operation) {
case "add":
result = a + b;
break;
case "subtract":
result = a - b;
break;
case "multiply":
result = a * b;
break;
case "divide":
if (b === 0) {
throw new Error("Division by zero is not allowed");
}
result = a / b;
break;
default:
throw new Error(`Unknown operation: ${operation}`);
}
return {
content: [
{
type: "text",
text: `${a} ${operation} ${b} = ${result}`,
},
],
};
}
throw new Error(`Unknown tool: ${name}`);
});
// Register resources
server.setRequestHandler(ListResourcesRequestSchema, async () => {
return {
resources: [
{
uri: "demo://example",
name: "Example Resource",
description: "A simple example resource",
mimeType: "text/plain",
},
{
uri: "demo://config",
name: "Server Configuration",
description: "Current server configuration",
mimeType: "application/json",
},
],
};
});
// Handle resource reading
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
const { uri } = request.params;
if (uri === "demo://example") {
return {
contents: [
{
uri,
mimeType: "text/plain",
text: "This is an example resource from the MCP server!",
},
],
};
}
if (uri === "demo://config") {
return {
contents: [
{
uri,
mimeType: "application/json",
text: JSON.stringify(
{
serverName: "basic-mcp-server",
version: "0.1.0",
capabilities: ["tools", "resources", "prompts"],
},
null,
2
),
},
],
};
}
throw new Error(`Unknown resource: ${uri}`);
});
// Register prompts
server.setRequestHandler(ListPromptsRequestSchema, async () => {
return {
prompts: [
{
name: "greet_user",
description: "Generate a greeting message",
arguments: [
{
name: "name",
description: "The name of the person to greet",
required: true,
},
],
},
{
name: "explain_mcp",
description: "Get an explanation of what MCP is",
arguments: [],
},
],
};
});
// Handle prompt execution
server.setRequestHandler(GetPromptRequestSchema, async (request) => {
const { name, arguments: args } = request.params;
if (name === "greet_user") {
const userName = (args?.name as string) || "User";
return {
messages: [
{
role: "user",
content: {
type: "text",
text: `Please create a friendly greeting for ${userName}. Make it warm and welcoming!`,
},
},
],
};
}
if (name === "explain_mcp") {
return {
messages: [
{
role: "user",
content: {
type: "text",
text: "What is the Model Context Protocol (MCP)? Explain it in simple terms.",
},
},
],
};
}
throw new Error(`Unknown prompt: ${name}`);
});
// Connect to stdio transport
const transport = new StdioServerTransport();
await server.connect(transport);
console.error("Basic MCP Server running on stdio");
}
main().catch((error) => {
console.error("Fatal error:", error);
process.exit(1);
});
