toAISdkMessages()

Converts messages from various input formats to AI SDK UI message format. toAISdkMessages() keeps the existing AI SDK v5/default behavior. If your app is typed against AI SDK v6, pass version: 'v6'.

version: 'v6' uses the MessageList AI SDK v6 UI output path. MessageList input detection and ingestion remain unchanged.

Usage example

app/chat/page.tsx

import { toAISdkMessages } from '@mastra/ai-sdk/ui'
import { useChat } from 'ai/react'

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

export default function Chat() {
  const { messages } = useChat({
    initialMessages: toAISdkMessages(storedMessages, { version: 'v6' }),
  })

  return (
    <div>
      {messages.map(message => (
        <div key={message.id}>
          {message.role}: {message.parts.map(part => (part.type === 'text' ? part.text : null))}
        </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.

options.version?:

'v5' | 'v6'

Selects the AI SDK message type to return. Omit it or pass `'v5'` for the existing default behavior. Pass `'v6'` when your app is typed against AI SDK v6 `useChat()` message types.

Returns

Returns an array of AI SDK UIMessage objects typed for the selected version.

id:

string

Unique message identifier.

role:

'user' | 'assistant' | 'system'

The role of the message sender.

parts:

UIMessagePart[]

Array of UI parts including text, tool results, files, reasoning, sources, and step markers.

metadata?:

Record<string, unknown>

Optional metadata including createdAt, threadId, resourceId, and custom fields.

Examples

Using the default AI SDK v5 types

import { toAISdkMessages } from '@mastra/ai-sdk/ui'

const messages = toAISdkMessages(['Hello', 'How can I help you today?'])

Returning AI SDK v6 message types

import { toAISdkMessages } from '@mastra/ai-sdk/ui'

const messages = toAISdkMessages(['Hello', 'How can I help you today?'], {
  version: 'v6',
})

Loading messages with Mastra client

import { MastraClient } from '@mastra/client-js'
import { toAISdkMessages } from '@mastra/ai-sdk/ui'

const client = new MastraClient()

const { messages } = await client.listThreadMessages('thread-id', { agentId: 'myAgent' })
const uiMessages = toAISdkMessages(messages)

Related

• toAISdkStream()
• toAISdkV5Messages()
• toAISdkV4Messages()