connectToApp function

Future<CallToolResult> connectToApp(VmBridge bridge, Map<String, dynamic> args)

Connects the server to a running Flutter app's VM Service.

args may contain vmUri. When omitted — or when the supplied URI fails to connect — the tool falls back to discovering running apps through the Dart Tooling Daemon, so the agent does not have to read flutter run output.

Implementation

Future<CallToolResult> connectToApp(
  VmBridge bridge,
  Map<String, dynamic> args,
) async {
  final uri = args['vmUri'] as String?;
  final failures = <String>[];

  if (uri != null && uri.isNotEmpty) {
    final result = await _tryConnect(bridge, uri);
    // `isError` is nullable: null means success.
    if (result.isError != true) return result;
    failures.add(textOf(result).split('\n').first);
  }

  try {
    final apps = await VmServiceDiscovery.discoverApps(
      workspaceFilter: args['workspaceFilter'] as String?,
    );

    if (apps.isEmpty) {
      return CallToolResult(
        content: [
          TextContent(
            text:
                'Could not connect.\n\n'
                '${failures.isEmpty ? '' : '${failures.join("\n")}\n\n'}'
                'No running apps were found via the Dart Tooling Daemon.\n\n'
                'Make sure the app is running in debug mode with `flutter run`, '
                'then retry. Apps started outside `flutter run` or an IDE are '
                'not discoverable; for those, pass `vmUri` explicitly — take it '
                'from the "linked to the debug service" line, which includes the '
                'auth code that the bare app URL omits.',
          ),
        ],
        isError: true,
      );
    }

    for (final app in apps) {
      final result = await _tryConnect(bridge, app.vmServiceUri);
      if (result.isError != true) {
        final origin = [
          'discovered automatically via DTD',
          if (app.name != null) app.name!,
          if (app.workspaceRoot != null) app.workspaceRoot!,
        ].join(' — ');
        return CallToolResult(
          content: [TextContent(text: '${textOf(result)}\n($origin)')],
        );
      }
      failures.add('${app.name ?? app.vmServiceUri}: connection failed');
    }
  } on Object catch (e) {
    failures.add('DTD discovery error: $e');
  }

  return CallToolResult(
    content: [
      TextContent(
        text: 'Could not connect to any app.\n\n${failures.join("\n")}',
      ),
    ],
    isError: true,
  );
}