ext-apps/examples/basic-server-react/server.ts
Jonathan Hefner 8b8ecbea64 Restore educational comments in basic-server-* examples
PR #184 accidentally removed/reverted educational comments from
`basic-server-react` and `basic-server-vanillajs` that were established
in PR #182. This restores consistency with the other basic-server
examples (Vue, Svelte, Preact, Solid).

Changes:
- Add back the three-comment pattern explaining two-part registration
- Restore full tool description ("as an ISO 8601 string")
- Change vanillajs to return plain text instead of JSON (matching #182)
- Use local `resourceUri` variable instead of top-level constant

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-12 11:57:46 -06:00

68 lines
2.3 KiB
TypeScript

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import type { CallToolResult, ReadResourceResult } from "@modelcontextprotocol/sdk/types.js";
import fs from "node:fs/promises";
import path from "node:path";
import { registerAppTool, registerAppResource, RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "@modelcontextprotocol/ext-apps/server";
import { startServer } from "./server-utils.js";
const DIST_DIR = path.join(import.meta.dirname, "dist");
/**
* Creates a new MCP server instance with tools and resources registered.
*/
export function createServer(): McpServer {
const server = new McpServer({
name: "Basic MCP App Server (React)",
version: "1.0.0",
});
// Two-part registration: tool + resource, tied together by the resource URI.
const resourceUri = "ui://get-time/mcp-app.html";
// Register a tool with UI metadata. When the host calls this tool, it reads
// `_meta[RESOURCE_URI_META_KEY]` to know which resource to fetch and render
// as an interactive UI.
registerAppTool(server,
"get-time",
{
title: "Get Time",
description: "Returns the current server time as an ISO 8601 string.",
inputSchema: {},
_meta: { [RESOURCE_URI_META_KEY]: resourceUri },
},
async (): Promise<CallToolResult> => {
const time = new Date().toISOString();
return { content: [{ type: "text", text: time }] };
},
);
// Register the resource, which returns the bundled HTML/JavaScript for the UI.
registerAppResource(server,
resourceUri,
resourceUri,
{ mimeType: RESOURCE_MIME_TYPE },
async (): Promise<ReadResourceResult> => {
const html = await fs.readFile(path.join(DIST_DIR, "mcp-app.html"), "utf-8");
return {
contents: [{ uri: resourceUri, mimeType: RESOURCE_MIME_TYPE, text: html }],
};
},
);
return server;
}
async function main() {
if (process.argv.includes("--stdio")) {
await createServer().connect(new StdioServerTransport());
} else {
const port = parseInt(process.env.PORT ?? "3001", 10);
await startServer(createServer, { port, name: "Basic MCP App Server (React)" });
}
}
main().catch((e) => {
console.error(e);
process.exit(1);
});