Implement MCP 2026-07-28 (#2286)

Co-authored-by: Matt <77928207+mattzcarey@users.noreply.github.com>
Co-authored-by: Konstantin Konstantinov <KKonstantinov@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

examples/prompts/README.md

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+# prompts
+
+Register prompts with `McpServer.registerPrompt`; wrap argument schemas with `completable(...)` for autocompletion. The client lists prompts, completes the `language` argument, and renders one with `getPrompt()`.
+
+```bash
+pnpm tsx examples/prompts/client.ts
+```

examples/prompts/client.ts

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+/**
+ * Drives the prompts example: list, complete an argument, get a prompt.
+ */
+import { check, parseExampleArgs, siblingPath } from '@mcp-examples/shared';
+import { Client, StreamableHTTPClientTransport } from '@modelcontextprotocol/client';
+import { StdioClientTransport } from '@modelcontextprotocol/client/stdio';
+
+const { transport, url, era } = parseExampleArgs();
+
+const client = new Client(
+    { name: 'prompts-example-client', version: '1.0.0' },
+    { versionNegotiation: { mode: era === 'modern' ? 'auto' : 'legacy' } }
+);
+
+await (transport === 'stdio'
+    ? client.connect(new StdioClientTransport({ command: 'npx', args: ['-y', 'tsx', siblingPath(import.meta.url, 'server.ts')] }))
+    : client.connect(new StreamableHTTPClientTransport(new URL(url))));
+
+const list = await client.listPrompts();
+check.ok(list.prompts.some(p => p.name === 'review-code'));
+
+const completion = await client.complete({
+    ref: { type: 'ref/prompt', name: 'review-code' },
+    argument: { name: 'language', value: 'ty' }
+});
+check.ok(completion.completion.values.includes('typescript'));
+
+const got = await client.getPrompt({ name: 'review-code', arguments: { language: 'rust', code: 'fn main() {}' } });
+check.equal(got.messages.length, 1);
+const text = got.messages[0]?.content.type === 'text' ? got.messages[0].content.text : '';
+check.match(text, /Review this rust code/);
+
+await client.close();

examples/prompts/package.json

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+{
+    "name": "@mcp-examples/prompts",
+    "private": true,
+    "type": "module",
+    "scripts": {
+        "server": "tsx server.ts",
+        "client": "tsx client.ts"
+    },
+    "dependencies": {
+        "@mcp-examples/shared": "workspace:*",
+        "@modelcontextprotocol/client": "workspace:*",
+        "@modelcontextprotocol/node": "workspace:*",
+        "@modelcontextprotocol/server": "workspace:*",
+        "zod": "catalog:runtimeShared"
+    },
+    "devDependencies": {
+        "tsx": "catalog:devTools"
+    }
+}

examples/prompts/server.ts

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+/**
+ * Prompts primitive + completion.
+ *
+ * Register prompts with `McpServer.registerPrompt`; wrap an arg schema with
+ * `completable(...)` so the client's `complete()` call returns suggestions.
+ * One binary, either transport.
+ */
+import { createServer } from 'node:http';
+
+import { parseExampleArgs } from '@mcp-examples/shared';
+import { toNodeHandler } from '@modelcontextprotocol/node';
+import { completable, createMcpHandler, McpServer } from '@modelcontextprotocol/server';
+import { serveStdio } from '@modelcontextprotocol/server/stdio';
+import * as z from 'zod/v4';
+
+const LANGUAGES = ['python', 'typescript', 'rust', 'go'];
+
+function buildServer(): McpServer {
+    const server = new McpServer({ name: 'prompts-example', version: '1.0.0' });
+
+    server.registerPrompt(
+        'review-code',
+        {
+            title: 'Code review',
+            description: 'Review code for quality and idioms',
+            argsSchema: z.object({
+                language: completable(z.string().describe('Programming language'), value => LANGUAGES.filter(l => l.startsWith(value))),
+                code: z.string().describe('The code to review')
+            })
+        },
+        async ({ language, code }) => ({
+            messages: [
+                {
+                    role: 'user',
+                    content: { type: 'text', text: `Review this ${language} code for quality and idioms:\n\n${code}` }
+                }
+            ]
+        })
+    );
+
+    return server;
+}
+
+const { transport, port } = parseExampleArgs();
+
+if (transport === 'stdio') {
+    void serveStdio(buildServer);
+    console.error('[server] serving over stdio');
+} else {
+    const handler = createMcpHandler(buildServer);
+    createServer(toNodeHandler(handler)).listen(port, () => {
+        console.error(`[server] listening on http://127.0.0.1:${port}/mcp`);
+    });
+}