Simplify basic-server-* examples

- Clarify comments
- Return plain text from `get-time` tool instead of JSON
- Remove simulated cleanup delay from `onteardown`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jonathanhefner

examples/basic-server-react/server.ts

@@ -6,7 +6,6 @@ import { registerAppTool, registerAppResource, RESOURCE_MIME_TYPE, RESOURCE_URI_
 import { startServer } from "./src/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
-const RESOURCE_URI = "ui://get-time/mcp-app.html";
 
 /**
  * Creates a new MCP server instance with tools and resources registered.
@@ -17,37 +16,37 @@ function createServer(): McpServer {
     version: "1.0.0",
   });
 
-  // MCP Apps require two-part registration: a tool (what the LLM calls) and a
-  // resource (the UI it renders). The `_meta` field on the tool links to the
-  // resource URI, telling hosts which UI to display when the tool executes.
+  // 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]: RESOURCE_URI },
+      _meta: { [RESOURCE_URI_META_KEY]: resourceUri },
     },
     async (): Promise<CallToolResult> => {
       const time = new Date().toISOString();
-      return {
-        content: [{ type: "text", text: JSON.stringify({ time }) }],
-      };
+      return { content: [{ type: "text", text: time }] };
     },
   );
 
+  // Register the resource, which returns the bundled HTML/JavaScript for the UI.
   registerAppResource(server,
-    RESOURCE_URI,
-    RESOURCE_URI,
+    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: [
-          // Per the MCP App specification, "text/html;profile=mcp-app" signals
-          // to the Host that this resource is indeed for an MCP App UI.
-          { uri: RESOURCE_URI, mimeType: RESOURCE_MIME_TYPE, text: html },
+          { uri: resourceUri, mimeType: RESOURCE_MIME_TYPE, text: html },
         ],
       };
     },

examples/basic-server-react/src/mcp-app.tsx

@@ -20,12 +20,8 @@ const log = {
 
 
 function extractTime(callToolResult: CallToolResult): string {
-  const text = callToolResult.content!
-    .filter((c): c is { type: "text"; text: string } => c.type === "text")
-    .map((c) => c.text)
-    .join("");
-  const { time } = JSON.parse(text) as { time: string };
-  return time;
+  const { text } = callToolResult.content?.find((c) => c.type === "text")!;
+  return text;
 }
 
 
@@ -37,8 +33,6 @@ function GetTimeApp() {
     onAppCreated: (app) => {
       app.onteardown = async () => {
         log.info("App is being torn down");
-        await new Promise((resolve) => setTimeout(resolve, 500)); // Simulate cleanup work
-        log.info("App teardown complete");
         return {};
       };
       app.ontoolinput = async (input) => {

examples/basic-server-vanillajs/server.ts

@@ -6,7 +6,6 @@ import { registerAppTool, registerAppResource, RESOURCE_MIME_TYPE, RESOURCE_URI_
 import { startServer } from "./src/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
-const RESOURCE_URI = "ui://get-time/mcp-app.html";
 
 /**
  * Creates a new MCP server instance with tools and resources registered.
@@ -17,37 +16,37 @@ function createServer(): McpServer {
     version: "1.0.0",
   });
 
-  // MCP Apps require two-part registration: a tool (what the LLM calls) and a
-  // resource (the UI it renders). The `_meta` field on the tool links to the
-  // resource URI, telling hosts which UI to display when the tool executes.
+  // 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]: RESOURCE_URI },
+      _meta: { [RESOURCE_URI_META_KEY]: resourceUri },
     },
     async (): Promise<CallToolResult> => {
       const time = new Date().toISOString();
-      return {
-        content: [{ type: "text", text: JSON.stringify({ time }) }],
-      };
+      return { content: [{ type: "text", text: time }] };
     },
   );
 
+  // Register the resource, which returns the bundled HTML/JavaScript for the UI.
   registerAppResource(server,
-    RESOURCE_URI,
-    RESOURCE_URI,
+    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: [
-          // Per the MCP App specification, "text/html;profile=mcp-app" signals
-          // to the Host that this resource is indeed for an MCP App UI.
-          { uri: RESOURCE_URI, mimeType: RESOURCE_MIME_TYPE, text: html },
+          { uri: resourceUri, mimeType: RESOURCE_MIME_TYPE, text: html },
         ],
       };
     },

examples/basic-server-vanillajs/src/mcp-app.ts

@@ -15,12 +15,8 @@ const log = {
 
 
 function extractTime(result: CallToolResult): string {
-  const text = result.content!
-    .filter((c): c is { type: "text"; text: string } => c.type === "text")
-    .map((c) => c.text)
-    .join("");
-  const { time } = JSON.parse(text) as { time: string };
-  return time;
+  const { text } = result.content?.find((c) => c.type === "text")!;
+  return text;
 }
 
 
@@ -40,8 +36,6 @@ const app = new App({ name: "Get Time App", version: "1.0.0" });
 
 app.onteardown = async () => {
   log.info("App is being torn down");
-  await new Promise((resolve) => setTimeout(resolve, 500)); // Simulate cleanup work
-  log.info("App teardown complete");
   return {};
 };