> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dartantic.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom History Providers

> Build your own LLM provider for the chat widget

The `ChatHistoryProvider` interface connects any LLM to `AgentChatView`:

```dart theme={null}
abstract class ChatHistoryProvider implements Listenable {
  Stream<String> transcribeAudio(XFile audioFile);
  Stream<String> sendMessageStream(String prompt, {Iterable<Part> attachments});
  Iterable<ChatMessage> get history;
  set history(Iterable<ChatMessage> history);
}
```

Built-in providers:

* **DartanticProvider**: Wraps dartantic\_ai for multi-provider support
* **EchoProvider**: Minimal example, useful for testing

## Implementation Guide

To build your own provider:

1. **Configuration**: Allow model creation as a parameter
2. **History**: Manage history, notify listeners, support serialization
3. **Messages**: Map `ChatMessage` and `Part` types to your LLM format
4. **LLM calls**: Implement `sendMessageStream` and `transcribeAudio`

Example structure:

```dart theme={null}
class MyProvider extends ChatHistoryProvider with ChangeNotifier {
  MyProvider({
    required MyLlmModel model,
    Iterable<ChatMessage>? history,
  }) : _model = model,
       _history = history?.toList() ?? [];

  final MyLlmModel _model;
  final List<ChatMessage> _history;

  @override
  Stream<String> sendMessageStream(
    String prompt, {
    Iterable<Part> attachments = const [],
  }) async* {
    final userMessage = ChatMessage.user(prompt);
    _history.add(userMessage);

    // Call your LLM here and stream the response
    final response = await _model.generate(prompt);

    _history.add(ChatMessage.model(response));
    yield response;
    notifyListeners();
  }

  @override
  Iterable<ChatMessage> get history => _history;

  @override
  set history(Iterable<ChatMessage> history) {
    _history.clear();
    _history.addAll(history);
    notifyListeners();
  }

  @override
  Stream<String> transcribeAudio(XFile audioFile) async* {
    // Implement audio transcription
    yield 'Transcribed text';
  }
}
```

See the [EchoProvider
implementation](https://github.com/csells/dartantic/tree/main/packages/dartantic_chat/blob/main/lib/src/providers/implementations/echo_provider.dart)
for a complete example.