# toAISdkV4Messages()

Converts messages from various input formats to AI SDK V4 UI message format. This function accepts messages in multiple formats (strings, AI SDK V4/V5 messages, Mastra DB messages, etc.) and normalizes them to the AI SDK V4 `UIMessage` format, which is suitable for use with AI SDK UI components like `useChat()`.

## Usage example

```typescript
import { toAISdkV4Messages } from "@mastra/ai-sdk";
import { useChat } from "ai/react"; // AI SDK V4

// Stored messages from your database, memory or API
const storedMessages = [
  { id: "1", role: "user", parts: [{ type: "text", text: "Hello" }] },
  { id: "2", role: "assistant", parts: [{ type: "text", text: "Hi there!" }] }
];

export default function Chat() {
  const { messages } = useChat({
    initialMessages: toAISdkV4Messages(storedMessages)
  });

  return (
    <div>
      {messages.map((message) => (
        <div key={message.id}>
          {message.role}: {message.content}
        </div>
      ))}
    </div>
  );
}
```

## Parameters

**messages:** (`MessageListInput`): Messages to convert. Can be a string, array of strings, a single message object, or an array of message objects in any supported format.

## Returns

Returns an array of AI SDK V4 `UIMessage` objects with the following structure:

**id:** (`string`): Unique message identifier.

**role:** (`'user' | 'assistant' | 'system'`): The role of the message sender.

**content:** (`string`): Text content of the message.

**parts:** (`UIMessagePart[]`): Array of UI parts including text, tool-invocation, file, reasoning, source, and step markers.

**createdAt:** (`Date`): Message creation timestamp.

**toolInvocations?:** (`ToolInvocation[]`): Array of tool invocations for assistant messages.

**experimental\_attachments?:** (`Attachment[]`): File attachments on the message.

**metadata?:** (`Record<string, unknown>`): Custom metadata attached to the message.

## Examples

### Converting simple text messages

```typescript
import { toAISdkV4Messages } from "@mastra/ai-sdk";

const messages = toAISdkV4Messages(["Hello", "How can I help you today?"]);
// Returns array of UIMessage objects with user role and content string
```

### Loading messages with Mastra client

```typescript
import { MastraClient } from "@mastra/client-js";
import { toAISdkV4Messages } from "@mastra/ai-sdk";

const client = new MastraClient();

const { messages } = await client.listThreadMessages("thread-id", { agentId: "myAgent" });
const uiMessages = toAISdkV4Messages(messages);
```