One pubspec line.

dependencies:
  agentlib: ^1.1.0

flutter pub get

flutter run -d  --dart-define=ANTHROPIC_API_KEY=sk-ant-...

import 'package:agentlib/agentlib.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';

Future main() async {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const HelloAgentApp());
}

class HelloAgentApp extends StatelessWidget {
  const HelloAgentApp({super.key});
  @override
  Widget build(BuildContext ctx) => const MaterialApp(home: _Screen());
}

class _Screen extends StatefulWidget { const _Screen(); @override State<_Screen> createState() => _State(); }

class _State extends State<_Screen> {
  final _out = StringBuffer();

  Future _run() async {
    final docs = await getApplicationDocumentsDirectory();
    final vfs = Vfs()
      ..mount('/workspace', WorkspaceMount(docs))
      ..mount('/scratch', ScratchMount());

    final agent = AgentSpec(
      name: 'hello',
      instructions: 'You are a helpful mobile assistant.',
      model: AnthropicProvider(
        apiKey: const String.fromEnvironment('ANTHROPIC_API_KEY'),
      ),
    );

    final run = Runner.runStreamed(
      agent.toRunConfig(vfs: vfs, threadId: 'hello'),
      input: 'In one sentence: what is agentlib?',
    );
    await for (final e in run.events) {
      if (e is TextDelta) setState(() => _out.write(e.delta));
    }
  }

  @override
  Widget build(BuildContext ctx) => Scaffold(
    appBar: AppBar(title: const Text('agentlib hello')),
    body: Padding(padding: const EdgeInsets.all(16), child: Text(_out.toString())),
    floatingActionButton: FloatingActionButton(onPressed: _run, child: const Icon(Icons.play_arrow)),
  );
}

flutter run -d ios
# or
flutter run -d android