Assistant UI: Fixing First Message RemoteId Issue

by Alex Johnson 50 views

Experiencing issues with your Assistant UI implementation where the first message in a new conversation is sent without a remoteId? This can be a frustrating problem, but understanding the underlying cause and implementing the right solution can quickly resolve it. This article will guide you through diagnosing and fixing this issue, ensuring your Assistant UI functions smoothly from the very first message.

Understanding the Problem

When integrating the Assistant UI, particularly following architectures like Frontend → Runtime → API backend (FastAPI) → LLM, you might encounter a scenario where the initial message in a conversation is saved without a remoteId. This usually happens when using @assistant-ui/react along with adapters like RemoteThreadListAdapter, ThreadHistoryAdapter, and ChatModelAdapter. The core of the problem lies in the timing of asynchronous operations during thread initialization.

Specifically, the issue occurs because the append() function in ThreadHistoryAdapter is called before the initialize() function in RemoteThreadListAdapter returns the remoteId. This results in the first message being associated with an undefined remoteId, which can cause backend rejections or ignored messages. After this initial hiccup, subsequent messages usually work fine because the thread has been correctly initialized.

To effectively tackle this, it's essential to delve into the sequence of events and pinpoint where the synchronization falters.

Diagnosing the Issue: A Step-by-Step Breakdown

To effectively diagnose this issue, let's break down the sequence of events that occur when a new conversation is initiated in your Assistant UI:

  1. list() in RemoteThreadListAdapter is Called: This function is responsible for fetching all existing threads. It's the starting point for understanding the current state of your conversations.
  2. initialize() in RemoteThreadListAdapter is Triggered: When a new conversation is started, this function creates a new thread on the backend. It's a crucial step in setting up the context for the conversation.
  3. append() in ThreadHistoryAdapter is Called (Prematurely): Here's where the problem begins. The append() function, which persists messages, is called before initialize() has returned the remoteId. This timing issue is the heart of the problem.
  4. ChatModelAdapter Sends the User Message: The user's input is sent to the backend LLM API via the ChatModelAdapter. This step is essential for generating a response, but it relies on the correct thread context.
  5. initialize() Returns the remoteId (Finally): Only after all the above steps does the initialize() function return the remoteId. By this time, the first message has already been processed without the correct identifier.

The result of this sequence is that the first message is saved with remoteId = undefined. This is because append() receives undefined for remoteId, leading to backend rejection or ignoring of the message. Understanding this flow is crucial for implementing the correct fix.

Analyzing the Code Snippets

To further understand the issue, let's examine the provided code snippets for RemoteThreadListAdapter.ts and ChatRuntimeContext.tsx.

RemoteThreadListAdapter.ts

This code defines the MyThreadListAdapter, which handles thread-related operations such as listing, deleting, renaming, fetching, archiving, unarchiving, and initializing threads. The key function here is initialize():

async initialize(localId) {
 console.error('RemoteThreadListAdapter:: initialize a thread');
 const response = await fetch(`${API_BASE_URL}/threads`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({ localId }),
 });
 const result = await response.json();
 console.error('initialize response', result);
 return { remoteId: result.id, externalId: result.external_id };
},

This function makes an asynchronous call to the backend to create a new thread and retrieve its remoteId. The problem arises because the subsequent message processing doesn't wait for this remoteId to be available.

ChatRuntimeContext.tsx

This component sets up the runtime context for the Assistant UI, including the AssistantRuntimeProvider and the adapters. The critical part of this code is the ThreadHistoryAdapter within the RuntimeAdapterProvider:

const history = useMemo<ThreadHistoryAdapter>(
 () => ({
 async load() {
 if (!remoteId) return ExportedMessageRepository.fromArray([]);
 console.error(
 'ThreadHistoryAdapter: load a thread with ID ==>’,
 remoteId
 );
 const res = await fetch(
 `http://localhost:8801/chat/thread?threadId=${remoteId}`
 );
 const data1 = await res.json();

 return ExportedMessageRepository.fromArray(
 data1.messages.map(m => ({
 id: m.id,
 role: m.role,
 content: m.content,
 createdAt: new Date(),
 }))
 );
 },

 async append(message) {
 console.error(
 'ThreadHistoryAdapter:: append is called with remoteid----’,
 message,
 remoteId
 );
 if (!remoteId) return;
 if (!message.parentId) {
 console.warn('Cannot save message - thread not initialized');
 return;
 }
 await fetch(`http://localhost:8801/chat/threads/messages`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 role: message?.message.role,
 content: message?.message?.content,
 threadId: remoteId,
 }),
 }).then(r => r.json());
 },
 }),
 [remoteId]
);

The append() function checks for remoteId before proceeding, but due to the asynchronous nature of initialize(), it often receives undefined for the first message. This is the crux of the issue.

Implementing Solutions: Synchronizing Thread Initialization

To resolve the issue of the first message being sent without a remoteId, you need to ensure that the append() function in ThreadHistoryAdapter waits for the initialize() function in RemoteThreadListAdapter to complete and return the remoteId. Here are a few strategies you can employ:

1. Using useThreadListItemRuntime to Initialize Thread

One effective solution is to use the useThreadListItemRuntime hook to explicitly initialize the thread before sending the first message. This hook provides a way to manage the lifecycle of a thread, including its initialization. You can modify the ChatModelAdapter to use useThreadListItemRuntime to initialize the thread and obtain the remoteId before sending the message.

Here’s how you can modify the ChatModelAdapter:

import {
  AssistantRuntimeProvider,
  useLocalRuntime,
  useAssistantState,
  ThreadHistoryAdapter,
  RuntimeAdapterProvider,
  useAssistantApi,
  useThreadListItem,
  useThreadListItemRuntime,
  unstable_useRemoteThreadListRuntime as useRemoteThreadListRuntime,
  type ChatModelAdapter,
  ExportedMessageRepository,
} from '@assistant-ui/react';

const MyModelAdapter: ChatModelAdapter = {
 async *run({ messages, abortSignal }) {
 const itemRt = useThreadListItemRuntime();
 const { remoteId } = await itemRt.initialize(); // creates only once
 if (!remoteId) throw new Error("Failed to initialize thread");

 console.error('ChatModelAdapter:: send message');
 // Get the last user message
 const lastMessage = messages[messages.length - 1];
 const firstContent = lastMessage.content[0];

 // Type guard to check if it's a text message part
 const userMessage =
 firstContent && 'text' in firstContent ? firstContent.text : '';

 try {
 // Make the fetch call to your streaming API
 // http://localhost:8800/chat/stream
 const response = await fetch('http://localhost:8801/chat/stream', {
 method: 'POST',
 headers: {
 'Content-Type': 'application/json',
 },
 body: JSON.stringify({
 question: userMessage,
 threadId: remoteId // Pass remoteId here
 }),
 signal: abortSignal,
 });

 console.log('Response status:', response.status);

 // Handle SSE streaming response
 const reader = response.body?.getReader();
 if (!reader) {
 throw new Error('No reader available');
 }

 const decoder = new TextDecoder();
 let text = '';
 let buffer = '';

 while (true) {
 const { done, value } = await reader.read();

 if (done) break;

 buffer += decoder.decode(value, { stream: true });

 const lines = buffer.split('\n');
 buffer = lines.pop() || '';

 for (const line of lines) {
 if (line.startsWith('data: ')) {
 const content = line.substring(6);

 if (content && content !== '[DONE]') {
 text += content + ' ';

 yield {
 content: [{ type: 'text', text }],
 };
 }
 }
 }
 }
 } catch (error) {
 console.error('ERROR in run:', error);
 throw error;
 }
 },
};

By initializing the thread using itemRt.initialize() and awaiting the result, you ensure that remoteId is available before sending the message. Additionally, include the remoteId when sending the message to the backend, ensuring the message is correctly associated with the thread.

2. Modifying append Function to Await Initialization

Another approach is to modify the append function in ThreadHistoryAdapter to await the thread initialization if the remoteId is not yet available. This can be achieved by introducing a mechanism to track whether the thread is initialized and awaiting its completion before appending the message.

Here’s how you can modify the ThreadHistoryAdapter:

import {
  AssistantRuntimeProvider,
  useLocalRuntime,
  useAssistantState,
  ThreadHistoryAdapter,
  RuntimeAdapterProvider,
  useAssistantApi,
  useThreadListItem,
  useThreadListItemRuntime,
  unstable_useRemoteThreadListRuntime as useRemoteThreadListRuntime,
  type ChatModelAdapter,
  ExportedMessageRepository,
} from '@assistant-ui/react';

const history = useMemo<ThreadHistoryAdapter>(
 () => {
 let initializing = false;
 let initializationPromise: Promise<any> | null = null;

 return {
 async load() {
 if (!remoteId) return ExportedMessageRepository.fromArray([]);
 console.error(
 'ThreadHistoryAdapter: load a thread with ID ==>’,
 remoteId
 );
 const res = await fetch(
 `http://localhost:8801/chat/thread?threadId=${remoteId}`
 );
 const data1 = await res.json();

 return ExportedMessageRepository.fromArray(
 data1.messages.map(m => ({
 id: m.id,
 role: m.role,
 content: m.content,
 createdAt: new Date(),
 }))
 );
 },

 async append(message) {
 console.error(
 'ThreadHistoryAdapter:: append is called with remoteid----’,
 message,
 remoteId
 );

 // If remoteId is not available, wait for initialization
 if (!remoteId) {
 if (!initializing) {
 initializing = true;
 initializationPromise = new Promise(async (resolve) => {
 // Await the initialize function directly or use a similar mechanism
 const response = await fetch(`${API_BASE_URL}/threads`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({ localId }),
 });
 const result = await response.json();

 // Ensure you have access to set the remoteId
 // This might require a state update or context update
 // setRemoteId(result.id);
 resolve(result.id);
 });
 }

 if (initializationPromise) {
 const newRemoteId = await initializationPromise;
 // Use the newRemoteId for saving the message
 await fetch(`http://localhost:8801/chat/threads/messages`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 role: message?.message.role,
 content: message?.message?.content,
 threadId: newRemoteId,
 }),
 }).then(r => r.json());

 initializing = false;
 initializationPromise = null;
 return;
 }

 return;
 }

 // Proceed with saving if remoteId is available
 if (!message.parentId) {
 console.warn('Cannot save message - thread not initialized');
 return;
 }
 await fetch(`http://localhost:8801/chat/threads/messages`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 role: message?.message.role,
 content: message?.message?.content,
 threadId: remoteId,
 }),
 }).then(r => r.json());
 },
 };
 },
 [remoteId]
);

In this approach, the append function checks if remoteId is available. If not, it initializes the thread and waits for the remoteId before saving the message. This ensures that the message is always saved with the correct remoteId.

3. Using a Promise to Synchronize Initialization

Another robust solution involves using a Promise to synchronize the thread initialization. You can create a Promise that resolves when the remoteId is available and ensure that the append function waits for this Promise to resolve before proceeding.

Here’s how you can implement this solution:

import {
  AssistantRuntimeProvider,
  useLocalRuntime,
  useAssistantState,
  ThreadHistoryAdapter,
  RuntimeAdapterProvider,
  useAssistantApi,
  useThreadListItem,
  useThreadListItemRuntime,
  unstable_useRemoteThreadListRuntime as useRemoteThreadListRuntime,
  type ChatModelAdapter,
  ExportedMessageRepository,
} from '@assistant-ui/react';

const ChatRuntimeContext: React.FC<{ children: React.ReactNode }> = ({
 children,
}) => {
 const [threadInitialization, setThreadInitialization] = React.useState<{ [key: string]: Promise<any> }>({})
 const runtime = useRemoteThreadListRuntime({
 runtimeHook: () => {
 return useLocalRuntime(MyModelAdapter);
 },
 adapter: {
 ...MyThreadListAdapter,
 unstable_Provider: ({ children }) => {
 const threadListItem = useAssistantState(
 ({ threadListItem }) => threadListItem
 );
 const remoteId = threadListItem.remoteId;
 const localId = threadListItem.id;

 const history = useMemo<ThreadHistoryAdapter>(
 () => ({
 async load() {
 if (!remoteId) return ExportedMessageRepository.fromArray([]);
 console.error(
 'ThreadHistoryAdapter: load a thread with ID ==>’,
 remoteId
 );
 const res = await fetch(
 `http://localhost:8801/chat/thread?threadId=${remoteId}`
 );
 const data1 = await res.json();

 return ExportedMessageRepository.fromArray(
 data1.messages.map(m => ({
 id: m.id,
 role: m.role,
 content: m.content,
 createdAt: new Date(),
 }))
 );
 },
 async append(message) {
 console.error(
 'ThreadHistoryAdapter:: append is called with remoteid----’,
 message,
 remoteId
 );

 let initializationPromise = threadInitialization[localId];

 if (!remoteId) {
 if (!initializationPromise) {
 initializationPromise = new Promise(async (resolve) => {
 console.log("Initializing thread for localId:", localId);
 const response = await fetch(`${API_BASE_URL}/threads`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({ localId }),
 });
 const result = await response.json();
 console.log("Thread initialized, result:", result);
 setThreadInitialization(prev => ({
 ...prev,
 [localId]: null // Clear promise after initialization
 }));
 resolve(result.id);
 });
 setThreadInitialization(prev => ({
 ...prev,
 [localId]: initializationPromise
 }));
 } else {
 console.log("Thread initialization promise found for localId:", localId);
 }

 if (initializationPromise) {
 console.log("Awaiting thread initialization for localId:", localId);
 const newRemoteId = await initializationPromise;
 console.log("Thread initialized, newRemoteId:", newRemoteId);
 await fetch(`http://localhost:8801/chat/threads/messages`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 role: message?.message.role,
 content: message?.message?.content,
 threadId: newRemoteId,
 }),
 }).then(r => r.json());
 return;
 }
 return;
 }

 if (!message.parentId) {
 console.warn('Cannot save message - thread not initialized');
 return;
 }
 await fetch(`http://localhost:8801/chat/threads/messages`, {
 method: 'POST',
 headers: { 'Content-Type': 'application/json' },
 body: JSON.stringify({
 role: message?.message.role,
 content: message?.message?.content,
 threadId: remoteId,
 }),
 }).then(r => r.json());
 },
 }),
 [remoteId, threadListItem.id]
 );

 const adapters = useMemo(() => ({ history }), [history]);

 return (
 <RuntimeAdapterProvider adapters={adapters}>
 {children}
 </RuntimeAdapterProvider>
 );
 },
 },
 });

 return (
 <AssistantRuntimeProvider runtime={runtime}>
 {children}
 </AssistantRuntimeProvider>
 );
};

export default ChatRuntimeContext;

In this setup, a threadInitialization state is used to store Promises for each thread's initialization. The append function checks if a Promise exists for the current thread; if not, it creates one and awaits its resolution before saving the message. This ensures that the remoteId is always available before the message is appended.

Best Practices for Handling Asynchronous Operations

When dealing with asynchronous operations in React and similar frameworks, it's crucial to follow best practices to avoid timing issues and ensure smooth execution. Here are some recommendations:

  1. Always Await Asynchronous Calls: Make sure to use await when calling asynchronous functions, especially when the result is needed for subsequent operations. This ensures that the code waits for the asynchronous operation to complete before moving on.
  2. Manage Promises Effectively: Use Promises to handle asynchronous operations and manage their states (pending, fulfilled, rejected). Promises provide a clean way to handle asynchronous results and errors.
  3. Use Hooks for State Management: In React, hooks like useState and useMemo are powerful tools for managing state and memoizing values. They help in optimizing performance and preventing unnecessary re-renders.
  4. Centralize Initialization Logic: Keep the initialization logic in a central place, such as a dedicated function or hook, to ensure that it's executed only once and its result is available throughout the component.
  5. Implement Loading States: Provide visual feedback to the user by implementing loading states. This helps the user understand that an operation is in progress and prevents confusion.

Conclusion

Dealing with asynchronous operations and ensuring the correct timing of function calls is crucial for a smooth user experience in applications like Assistant UI. The issue of the first message being sent without a remoteId highlights the importance of synchronizing thread initialization. By using techniques such as useThreadListItemRuntime, modifying the append function, or employing Promises, you can effectively resolve this issue.

Remember, each solution has its trade-offs, and the best approach depends on the specific requirements and architecture of your application. By understanding the problem, analyzing the code, and implementing the appropriate solution, you can ensure that your Assistant UI functions flawlessly from the very first message.

For further reading and more in-depth information on related topics, consider exploring resources like React's official documentation on asynchronous programming.