adapters | Dosu

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-ui/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