Adapters customize runtime behavior. They can be passed as options to useLocalRuntime or useRemoteThreadListRuntime.
Persistence#
By default, useLocalRuntime stores threads and messages in memory only -- they are lost when the app restarts. To persist data, use one of these approaches:
Assistant Cloud#
The simplest way to add persistence. Pass a cloud option to useLocalRuntime:
import { useLocalRuntime } from "@assistant-ui/react-native";
import { AssistantCloud } from "assistant-cloud";
const cloud = new AssistantCloud({
baseUrl: "https://backend.assistant-ui.com",
authToken: () => fetchTokenFromYourBackend(),
});
const runtime = useLocalRuntime(chatModel, { cloud });
This gives you multi-thread support with server-side persistence, cross-device sync, and automatic title generation.
History adapter#
For custom persistence (e.g. saving message history to your own backend), pass a ThreadHistoryAdapter via adapters.history:
import { useLocalRuntime } from "@assistant-ui/react-native";
import type { ThreadHistoryAdapter } from "@assistant-ui/react-native";
const myHistoryAdapter: ThreadHistoryAdapter = {
async load() {
// Load saved messages from your storage
const data = await fetchMessagesFromBackend();
return data; // { headId, messages }
},
async append(item) {
// Persist a new message
await saveMessageToBackend(item);
},
};
const runtime = useLocalRuntime(chatModel, {
adapters: {
history: myHistoryAdapter,
},
});
RemoteThreadListAdapter#
For full backend thread management (thread list, archiving, cross-device sync), use useRemoteThreadListRuntime. See the Custom Backend page for a full example.
RemoteThreadListAdapter#
Title generation is configured via the generateTitle method on RemoteThreadListAdapter. See the Custom Backend page for a full example.
import type { RemoteThreadListAdapter } from "@assistant-ui/react-native";
import { createAssistantStream } from "assistant-stream";
const myAdapter: RemoteThreadListAdapter = {
// ... other methods ...
async generateTitle(remoteId, unstable_messages) {
return createAssistantStream(async (controller) => {
const res = await fetch(`/api/threads/${remoteId}/title`, {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({ messages: unstable_messages }),
});
const { title } = await res.json();
controller.appendText(title);
});
},
};
Which option to choose?#
ChatModelAdapter + useLocalRuntime | RemoteThreadListAdapter + useRemoteThreadListRuntime | |
|---|---|---|
| Thread storage | In-memory (or cloud) | Your backend |
| Message storage | In-memory (can add history adapter) | In-memory (can add history adapter for server-side) |
| Cross-device sync | Only with cloud | Yes |
| Setup complexity | Minimal | Moderate |
| Best for | Single-device apps, prototypes | Production apps with user accounts |