json-render

AI Chat Response Rendering

You are an expert in rendering AI SDK v6 chat responses — UIMessage parts, tool call results, streaming states, and structured data display in React applications.

The Problem

When building chat interfaces with AI SDK v6, the raw message format includes multiple part types (text, tool calls, reasoning, images). Without proper rendering, responses appear as raw JSON or malformed output.

AI SDK v6 Message Format

In v6, messages use the UIMessage type with a parts array:

interface UIMessage {
  id: string
  role: 'user' | 'assistant'
  parts: UIMessagePart[]
}

// Part types:
// - { type: 'text', text: string }
// - { type: 'tool-<toolName>', toolCallId: string, state: string, input?: unknown, output?: unknown }
//     state values: 'partial-call' | 'call' | 'output-available' | 'approval-requested' | 'approval-responded' | 'output-denied'
// - { type: 'reasoning', text: string }
// - { type: 'step-start' }  // internal, skip in rendering

Recommended: Use AI Elements

The simplest approach is to use AI Elements, which handles all part types automatically:

import { Message } from '@/components/ai-elements/message'
import { Conversation } from '@/components/ai-elements/conversation'

{messages.map((message) => (
  <Message key={message.id} message={message} />
))}

⤳ skill: ai-elements — Full component library for AI interfaces

Manual Rendering Pattern

If you need custom rendering without AI Elements, follow this pattern:

'use client'
import { useChat } from '@ai-sdk/react'
import { DefaultChatTransport } from 'ai'

export function Chat() {
  const { messages, sendMessage, status } = useChat({
    transport: new DefaultChatTransport({ api: '/api/chat' }),
  })

  const isLoading = status === 'streaming' || status === 'submitted'

  return (
    <div>
      {messages.map((message) => (
        <div key={message.id}>
          {message.parts?.map((part, i) => {
            // 1. Text parts — render as formatted text
            if (part.type === 'text' && part.text.trim()) {
              return (
                <div key={i} className={
                  message.role === 'user'
                    ? 'bg-primary text-primary-foreground rounded-lg px-3 py-2'
                    : 'bg-muted rounded-lg px-3 py-2'
                }>
                  {part.text}
                </div>
              )
            }

            // 2. Tool parts — type is "tool-<toolName>"
            if (part.type.startsWith('tool-')) {
              const toolPart = part as {
                type: string
                toolCallId: string
                state: string
                input?: unknown
                output?: unknown
              }
              const toolName = toolPart.type.replace('tool-', '')

              if (toolPart.state === 'output-available' && toolPart.output) {
                return <ToolResultCard key={i} name={toolName} output={toolPart.output} />
              }

              if (toolPart.state === 'output-denied') {
                return (
                  <div key={i} className="text-sm text-muted-foreground">
                    {toolName} was denied
                  </div>
                )
              }

              if (toolPart.state === 'approval-requested') {
                return (
                  <div key={i} className="text-sm text-yellow-500">
                    {toolName} requires approval
                  </div>
                )
              }

              return (
                <div key={i} className="text-sm text-muted-foreground animate-pulse">
                  Running {toolName}...
                </div>
              )
            }

            // 3. Reasoning parts
            if (part.type === 'reasoning') {
              return (
                <details key={i} className="text-xs text-muted-foreground">
                  <summary>Thinking...</summary>
                  <p className="whitespace-pre-wrap">{(part as { text: string }).text}</p>
                </details>
              )
            }

            // 4. Skip unknown types (step-start, etc.)
            return null
          })}
        </div>
      ))}
    </div>
  )
}