Fix desktop GoAgentCore endpoint routing

lib/runtime/go_agent_core_desktop_transport.dart

@@ -22,6 +22,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     GoCoreLocator? goCoreLocator,
     GoAgentCoreProcessStarter? processStarter,
   }) : _acpClient = acpClient,
+       _endpointResolver = endpointResolver,
        _goCoreLocator = goCoreLocator ?? GoCoreLocator(),
        _processStarter =
            processStarter ??
@@ -35,6 +36,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
            });
 
   final GatewayAcpClient _acpClient;
+  final Uri? Function(AssistantExecutionTarget target) _endpointResolver;
   final GoCoreLocator _goCoreLocator;
   final GoAgentCoreProcessStarter _processStarter;
 
@@ -62,7 +64,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     required AssistantExecutionTarget target,
     bool forceRefresh = false,
   }) async {
-    final endpoint = await _ensureLocalEndpoint();
+    final endpoint = await _resolveEndpoint(target);
     if (endpoint == null) {
       return const GoAgentCoreCapabilities.empty();
     }
@@ -83,7 +85,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     GoAgentCoreSessionRequest request, {
     required void Function(GoAgentCoreSessionUpdate update) onUpdate,
   }) async {
-    final endpoint = await _ensureLocalEndpoint();
+    final endpoint = await _resolveEndpoint(request.target);
     if (endpoint == null) {
       throw const GatewayAcpException(
         'Missing Go Agent-core endpoint',
@@ -123,7 +125,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     required String sessionId,
     required String threadId,
   }) async {
-    final endpoint = await _ensureLocalEndpoint();
+    final endpoint = await _resolveEndpoint(target);
     if (endpoint == null) {
       return;
     }
@@ -140,7 +142,7 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     required String sessionId,
     required String threadId,
   }) async {
-    final endpoint = await _ensureLocalEndpoint();
+    final endpoint = await _resolveEndpoint(target);
     if (endpoint == null) {
       return;
     }
@@ -166,6 +168,14 @@ class GoAgentCoreDesktopTransport implements GoAgentCoreClient {
     }
   }
 
+  Future<Uri?> _resolveEndpoint(AssistantExecutionTarget target) async {
+    if (target == AssistantExecutionTarget.singleAgent ||
+        target == AssistantExecutionTarget.auto) {
+      return _ensureLocalEndpoint();
+    }
+    return _endpointResolver(target);
+  }
+
   Future<Uri?> _ensureLocalEndpoint() async {
     if (_localEndpoint != null) {
       return _localEndpoint;

test/runtime/go_agent_core_desktop_transport_suite.dart

@@ -0,0 +1,153 @@
+@TestOn('vm')
+library;
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:xworkmate/runtime/gateway_acp_client.dart';
+import 'package:xworkmate/runtime/go_agent_core_client.dart';
+import 'package:xworkmate/runtime/go_agent_core_desktop_transport.dart';
+import 'package:xworkmate/runtime/runtime_models.dart';
+
+void main() {
+  group('GoAgentCoreDesktopTransport', () {
+    test('uses resolved gateway endpoint for local gateway sessions', () async {
+      final server = await _AcpFakeServer.start();
+      addTearDown(server.close);
+
+      final transport = GoAgentCoreDesktopTransport(
+        acpClient: GatewayAcpClient(endpointResolver: () => null),
+        endpointResolver: (target) => switch (target) {
+          AssistantExecutionTarget.local => server.baseHttpUri,
+          _ => null,
+        },
+      );
+
+      final result = await transport.executeSession(
+        const GoAgentCoreSessionRequest(
+          sessionId: 'session-local',
+          threadId: 'thread-local',
+          target: AssistantExecutionTarget.local,
+          prompt: 'ping local gateway',
+          workingDirectory: '/tmp',
+          model: '',
+          thinking: '',
+          selectedSkills: <String>[],
+          inlineAttachments: <GatewayChatAttachmentPayload>[],
+          localAttachments: <CollaborationAttachment>[],
+          aiGatewayBaseUrl: '',
+          aiGatewayApiKey: '',
+          agentId: '',
+          metadata: <String, dynamic>{},
+        ),
+        onUpdate: (_) {},
+      );
+
+      expect(result.success, isTrue);
+      expect(result.message, 'gateway-ok');
+      expect(server.lastHttpRequestPath, '/acp/rpc');
+      expect(server.rpcMethods, contains('session.start'));
+      expect(server.lastSessionMode, 'gateway-chat');
+    });
+
+    test('reports missing endpoint when gateway target cannot resolve', () async {
+      final transport = GoAgentCoreDesktopTransport(
+        acpClient: GatewayAcpClient(endpointResolver: () => null),
+        endpointResolver: (_) => null,
+      );
+
+      await expectLater(
+        () => transport.executeSession(
+          const GoAgentCoreSessionRequest(
+            sessionId: 'session-local',
+            threadId: 'thread-local',
+            target: AssistantExecutionTarget.local,
+            prompt: 'ping local gateway',
+            workingDirectory: '/tmp',
+            model: '',
+            thinking: '',
+            selectedSkills: <String>[],
+            inlineAttachments: <GatewayChatAttachmentPayload>[],
+            localAttachments: <CollaborationAttachment>[],
+            aiGatewayBaseUrl: '',
+            aiGatewayApiKey: '',
+            agentId: '',
+            metadata: <String, dynamic>{},
+          ),
+          onUpdate: (_) {},
+        ),
+        throwsA(
+          isA<GatewayAcpException>().having(
+            (error) => error.code,
+            'code',
+            'GO_AGENT_CORE_ENDPOINT_MISSING',
+          ),
+        ),
+      );
+    });
+  });
+}
+
+class _AcpFakeServer {
+  _AcpFakeServer._(this._server);
+
+  final HttpServer _server;
+  final List<String> rpcMethods = <String>[];
+  String? lastHttpRequestPath;
+  String? lastSessionMode;
+
+  Uri get baseHttpUri => Uri.parse('http://127.0.0.1:${_server.port}');
+
+  static Future<_AcpFakeServer> start() async {
+    final server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
+    final fake = _AcpFakeServer._(server);
+    unawaited(fake._listen());
+    return fake;
+  }
+
+  Future<void> close() async {
+    await _server.close(force: true);
+  }
+
+  Future<void> _listen() async {
+    await for (final request in _server) {
+      if (request.uri.path == '/acp/rpc' && request.method == 'POST') {
+        lastHttpRequestPath = request.uri.path;
+        await _handleHttpRpc(request);
+        continue;
+      }
+      request.response.statusCode = HttpStatus.notFound;
+      await request.response.close();
+    }
+  }
+
+  Future<void> _handleHttpRpc(HttpRequest request) async {
+    final body = await utf8.decodeStream(request);
+    final envelope = (jsonDecode(body) as Map).cast<String, dynamic>();
+    final id = envelope['id'];
+    final method = envelope['method']?.toString() ?? '';
+    final params =
+        (envelope['params'] as Map?)?.cast<String, dynamic>() ??
+        const <String, dynamic>{};
+    rpcMethods.add(method);
+
+    request.response.headers.set(
+      HttpHeaders.contentTypeHeader,
+      'text/event-stream; charset=utf-8',
+    );
+    if (method == 'session.start' || method == 'session.message') {
+      lastSessionMode = params['mode']?.toString();
+      request.response.write(
+        'data: ${jsonEncode(<String, dynamic>{'jsonrpc': '2.0', 'id': id, 'result': <String, dynamic>{'success': true, 'message': 'gateway-ok', 'summary': 'gateway-ok', 'turnId': 'turn-1'}})}\n\n',
+      );
+      await request.response.close();
+      return;
+    }
+    request.response.write(
+      'data: ${jsonEncode(<String, dynamic>{'jsonrpc': '2.0', 'id': id, 'result': <String, dynamic>{'singleAgent': true, 'multiAgent': true, 'providers': <String>['codex'], 'capabilities': <String, dynamic>{'single_agent': true, 'multi_agent': true, 'providers': <String>['codex']}}})}\n\n',
+    );
+    await request.response.close();
+  }
+}