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/streaming/client.ts

@@ -0,0 +1,54 @@
+/**
+ * Drives the streaming example: a `countdown` call with `onprogress`
+ * (asserts progress notifications arrived), a logging-notification handler
+ * (asserts log messages arrived), and a cancelled call (asserts the cancel
+ * propagated).
+ */
+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: 'streaming-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))));
+
+let logCount = 0;
+client.setNotificationHandler('notifications/message', () => {
+    logCount++;
+});
+
+// --- progress + logging ---
+let progressCount = 0;
+const result = await client.callTool(
+    { name: 'countdown', arguments: { n: 5, delayMs: 20 } },
+    {
+        onprogress: p => {
+            progressCount++;
+            check.equal(p.total, 5);
+        }
+    }
+);
+check.equal((result.structuredContent as { completed?: number } | undefined)?.completed, 5);
+check.equal((result.structuredContent as { cancelled?: boolean } | undefined)?.cancelled, false);
+check.ok(progressCount >= 4, `expected >=4 progress notifications, got ${progressCount}`);
+check.ok(logCount >= 4, `expected >=4 log notifications, got ${logCount}`);
+
+// --- cancellation propagation ---
+const ac = new AbortController();
+setTimeout(() => ac.abort(), 60);
+let cancelled = false;
+try {
+    await client.callTool({ name: 'countdown', arguments: { n: 50, delayMs: 50 } }, { signal: ac.signal });
+} catch {
+    cancelled = true;
+}
+check.ok(cancelled, 'a client-side abort should reject the in-flight callTool');
+
+await client.close();