diff --git a/src/vs/platform/agentHost/node/agentHostServerMain.ts b/src/vs/platform/agentHost/node/agentHostServerMain.ts
index 7e0c9eb1027..93f0152531e 100644
--- a/src/vs/platform/agentHost/node/agentHostServerMain.ts
+++ b/src/vs/platform/agentHost/node/agentHostServerMain.ts
@@ -252,6 +252,9 @@ async function main(): Promise<void> {
 	const agentService = new AgentService(logService, fileService, sessionDataService, productService, gitService, checkpointService, rootConfigResource, telemetryService, fileMonitorService, undefined, fetchFn);
 	disposables.add(agentService);
 	diServices.set(IAgentService, agentService);
+	const networkDiagnosticsService = instantiationService.createInstance(NetworkDiagnosticsService);
+	diServices.set(INetworkDiagnosticsService, networkDiagnosticsService);
+	agentService.setNetworkDiagnosticsService(networkDiagnosticsService);
 
 	// Register agents
 	let sdkDownloadProgress: Event<IAgentSdkDownloadProgress> | undefined;
@@ -296,9 +299,6 @@ async function main(): Promise<void> {
 		// to satisfy CopilotAgent / CopilotSessionLauncher DI.
 		diServices.set(IByokLmBridgeRegistry, new NullByokLmBridgeRegistry());
 		diServices.set(IByokLmProxyService, new NullByokLmProxyService());
-		const networkDiagnosticsService = instantiationService.createInstance(NetworkDiagnosticsService);
-		diServices.set(INetworkDiagnosticsService, networkDiagnosticsService);
-		agentService.setNetworkDiagnosticsService(networkDiagnosticsService);
 		const copilotAgent = disposables.add(instantiationService.createInstance(CopilotAgent));
 		agentService.registerProvider(copilotAgent);
 		log('CopilotAgent registered');
diff --git a/src/vs/platform/agentHost/test/node/protocol/networkDiagnostics.integrationTest.ts b/src/vs/platform/agentHost/test/node/protocol/networkDiagnostics.integrationTest.ts
new file mode 100644
index 00000000000..26e07474b2c
--- /dev/null
+++ b/src/vs/platform/agentHost/test/node/protocol/networkDiagnostics.integrationTest.ts
@@ -0,0 +1,82 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import assert from 'assert';
+import type * as http from 'http';
+import type { AddressInfo } from 'net';
+import type { IAgentHostNetworkDiagnosticsInfo, IAgentHostNetworkFetchResult } from '../../../common/agentService.js';
+import { PROTOCOL_VERSION } from '../../../common/state/protocol/version/registry.js';
+import { ROOT_STATE_URI } from '../../../common/state/sessionState.js';
+import { IServerHandle, startServer, TestProtocolClient } from './testHelpers.js';
+
+suite('Protocol WebSocket - quiet network diagnostics', function () {
+
+	let server: IServerHandle;
+	let client: TestProtocolClient;
+	let target: http.Server;
+	let targetUrl: string;
+
+	suiteSetup(async function () {
+		this.timeout(15_000);
+		server = await startServer({ quiet: true });
+		const httpModule = await import('http');
+		target = httpModule.createServer((_request, response) => {
+			response.writeHead(200, { 'content-type': 'text/plain' });
+			response.end('pong');
+		});
+		await new Promise<void>((resolve, reject) => {
+			target.once('error', reject);
+			target.listen(0, '127.0.0.1', resolve);
+		});
+		targetUrl = `http://127.0.0.1:${(target.address() as AddressInfo).port}/ping`;
+	});
+
+	suiteTeardown(async function () {
+		server.process.kill();
+		await new Promise<void>(resolve => target.close(() => resolve()));
+	});
+
+	setup(async function () {
+		this.timeout(10_000);
+		client = new TestProtocolClient(server.port);
+		await client.connect();
+		await client.call('initialize', {
+			protocolVersions: [PROTOCOL_VERSION],
+			clientId: 'test-quiet-network-diagnostics',
+			initialSubscriptions: [ROOT_STATE_URI],
+		});
+	});
+
+	teardown(function () {
+		client.close();
+	});
+
+	test('serves host info and freeform fetch without production agents', async function () {
+		this.timeout(10_000);
+
+		const info = await client.call<IAgentHostNetworkDiagnosticsInfo>('getNetworkDiagnosticsInfo');
+		const result = await client.call<IAgentHostNetworkFetchResult>('diagnosticsFetch', { url: targetUrl });
+
+		assert.deepStrictEqual({
+			hasVersion: typeof info.version === 'string',
+			os: info.os,
+			arch: info.arch,
+			endpoints: info.endpoints,
+			url: result.url,
+			statusCode: result.statusCode,
+			body: result.body,
+			error: result.error,
+		}, {
+			hasVersion: true,
+			os: process.platform,
+			arch: process.arch,
+			endpoints: [],
+			url: targetUrl,
+			statusCode: 200,
+			body: 'pong',
+			error: undefined,
+		});
+	});
+});