MCP Builder

MCP Server Builder

Build production-ready MCP servers with tools, resources, prompts, and interactive widgets using mcp-use.

Before You Code

Decompose user requests into tools, widgets, and resources. Decide what needs UI vs text.

Read design-and-architecture.md: when planning what to build, deciding tool vs widget, or designing UX flows.

Implementation

• Tools, resources, prompts → tools-and-resources.md: when writing server-side server.tool(), server.resource(), server.prompt() code
• Visual widgets (React TSX) → widgets.md: when creating interactive UI widgets in resources/ folder
• Response helper API → response-helpers.md: when choosing how to format tool/resource return values
• URI template patterns → resource-templates.md: when defining parameterized resources
• Server proxying & composition → proxy.md: when composing multiple MCP servers into a unified aggregator

Quick Reference

import { MCPServer, text, object, markdown, html, image, widget, error } from "mcp-use/server";
import { z } from "zod";

const server = new MCPServer({ name: "my-server", version: "1.0.0" });

// Tool
server.tool(
  { name: "my-tool", description: "...", schema: z.object({ param: z.string().describe("...") }) },
  async ({ param }) => text("result")
);

// Resource
server.resource(
  { uri: "config://settings", name: "Settings", mimeType: "application/json" },
  async () => object({ key: "value" })
);

// Prompt
server.prompt(
  { name: "my-prompt", description: "...", schema: z.object({ topic: z.string() }) },
  async ({ topic }) => text(`Write about ${topic}`)
);

server.listen();

Response helpers: text(), object(), markdown(), html(), image(), audio(), binary(), error(), mix(), widget()

Server methods:

• server.tool() - Define executable tool
• server.resource() - Define static/dynamic resource
• server.resourceTemplate() - Define parameterized resource
• server.prompt() - Define prompt template
• server.proxy() - Compose/Proxy multiple MCP servers
• server.uiResource() - Define widget resource
• server.listen() - Start server