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

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(), server.resource(), server.resourceTemplate(), server.prompt(), server.listen()