standardize chat on AI SDK contracts

Author: NickB03

app/api/chat/__tests__/route.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it, vi } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 // Mock all dependencies
 vi.mock('next/cache', () => ({
@@ -87,6 +87,24 @@ function createRequest(body: any, headers?: Record<string, string>): Request {
 }
 
 describe('POST /api/chat', () => {
+  beforeEach(() => {
+    vi.mocked(getCurrentUserId).mockReset()
+    vi.mocked(getCurrentUserId).mockResolvedValue('user-123')
+
+    vi.mocked(isProviderEnabled).mockReset()
+    vi.mocked(isProviderEnabled).mockReturnValue(true)
+
+    vi.mocked(createChatStreamResponse).mockReset()
+    vi.mocked(createChatStreamResponse).mockResolvedValue(
+      new Response('stream', { status: 200 })
+    )
+
+    vi.mocked(createEphemeralChatStreamResponse).mockReset()
+    vi.mocked(createEphemeralChatStreamResponse).mockResolvedValue(
+      new Response('ephemeral-stream', { status: 200 })
+    )
+  })
+
   it('returns 400 for unknown trigger', async () => {
     const req = createRequest({
       message: 'hi',
@@ -132,12 +150,17 @@ describe('POST /api/chat', () => {
     const res = await POST(req)
     expect(res.status).toBe(400)
     const json = await res.json()
-    expect(json.message).toContain('message')
+    expect(json.message).toContain('messages')
   })
 
   it('returns 403 for requests from share pages', async () => {
     const req = createRequest(
-      { message: 'hi', chatId: 'c1', trigger: 'submit-message' },
+      {
+        message: 'hi',
+        messages: [{ role: 'user', parts: [{ type: 'text', text: 'hi' }] }],
+        chatId: 'c1',
+        trigger: 'submit-message'
+      },
       { referer: 'http://localhost/share/abc123' }
     )
 
@@ -153,6 +176,7 @@ describe('POST /api/chat', () => {
 
     const req = createRequest({
       message: 'hi',
+      messages: [{ role: 'user', parts: [{ type: 'text', text: 'hi' }] }],
       chatId: 'c1',
       trigger: 'submit-message'
     })
@@ -166,6 +190,7 @@ describe('POST /api/chat', () => {
 
     const req = createRequest({
       message: 'hi',
+      messages: [{ role: 'user', parts: [{ type: 'text', text: 'hi' }] }],
       chatId: 'c1',
       trigger: 'submit-message'
     })
@@ -177,6 +202,7 @@ describe('POST /api/chat', () => {
   it('calls createChatStreamResponse for authenticated users', async () => {
     const req = createRequest({
       message: { role: 'user', parts: [{ type: 'text', text: 'hello' }] },
+      messages: [{ role: 'user', parts: [{ type: 'text', text: 'hello' }] }],
       chatId: 'c1',
       trigger: 'submit-message',
       isNewChat: true

app/api/chat/route.ts

@@ -41,6 +41,12 @@ export async function POST(req: Request) {
       guestCanvasToken
     } = body
 
+    const normalizedMessages = Array.isArray(messages)
+      ? messages
+      : typeof messages === 'undefined' && message?.parts
+        ? [message]
+        : messages
+
     perfLog(
       `API Route - Start: chatId=${chatId}, trigger=${trigger}, isNewChat=${isNewChat}`
     )
@@ -84,10 +90,13 @@ export async function POST(req: Request) {
         `[tool-result] Received continuation: chatId=${chatId}, toolCallId=${toolResult.toolCallId}`
       )
     } else if (validatedTrigger === 'submit-message') {
-      if (!message) {
+      if (
+        !Array.isArray(normalizedMessages) ||
+        normalizedMessages.length === 0
+      ) {
         return jsonError(
           'BAD_REQUEST',
-          'message is required for submission',
+          'messages are required for submission',
           400
         )
       }
@@ -171,9 +180,9 @@ export async function POST(req: Request) {
     // Validate guest messages shape at the system boundary
     if (isGuest) {
       if (
-        !Array.isArray(messages) ||
-        messages.length === 0 ||
-        !messages.every(
+        !Array.isArray(normalizedMessages) ||
+        normalizedMessages.length === 0 ||
+        !normalizedMessages.every(
           (m: any) =>
             (m.role === 'user' || m.role === 'assistant') &&
             Array.isArray(m.parts) &&
@@ -198,11 +207,9 @@ export async function POST(req: Request) {
     }
 
     // Validate file parts for all users (guests and authenticated)
-    const messagesToValidate = isGuest
-      ? messages
-      : message?.parts
-        ? [message]
-        : []
+    const messagesToValidate = Array.isArray(normalizedMessages)
+      ? normalizedMessages
+      : []
 
     for (const msg of messagesToValidate) {
       if (!Array.isArray(msg.parts)) continue
@@ -218,7 +225,7 @@ export async function POST(req: Request) {
 
     const response = isGuest
       ? await createEphemeralChatStreamResponse({
-          messages,
+          messages: normalizedMessages ?? [],
           model: selectedModel,
           abortSignal,
           searchMode,
@@ -231,6 +238,9 @@ export async function POST(req: Request) {
         })
       : await createChatStreamResponse({
           message: validatedTrigger === 'tool-result' ? null : message,
+          messages: Array.isArray(normalizedMessages)
+            ? normalizedMessages
+            : undefined,
           model: selectedModel,
           chatId,
           userId: userId, // userId is guaranteed to be non-null after authentication check above

components/chat-request.test.ts

@@ -27,7 +27,7 @@ describe('chat request helpers', () => {
     })
   })
 
-  it('builds a tool-result continuation request for guest users', () => {
+  it('builds a submit-message continuation request with canonical messages', () => {
     const request = buildChatRequestBody({
       messages: [
         {
@@ -52,13 +52,12 @@ describe('chat request helpers', () => {
 
     expect(request).toEqual({
       body: {
-        trigger: 'tool-result',
+        trigger: 'submit-message',
         chatId: 'chat-1',
-        toolResult: {
-          toolCallId: 'tool-1',
-          output: { value: 'dark' }
-        },
-        messages: expect.any(Array)
+        messageId: undefined,
+        messages: expect.any(Array),
+        message: expect.any(Object),
+        isNewChat: false
       }
     })
   })

components/chat-request.ts

@@ -1,5 +1,4 @@
 import type { CanvasArtifactStatusData, UIMessage } from '@/lib/types/ai'
-import { isInteractiveToolPart } from '@/lib/types/dynamic-tools'
 
 /**
  * Search messages for the most recent `data-canvasArtifactStatus` part
@@ -32,7 +31,7 @@ export function buildChatRequestBody({
   trigger,
   messageId,
   chatId,
-  isGuest,
+  isGuest: _isGuest,
   savedMessagesCount,
   guestCanvasToken
 }: {
@@ -50,43 +49,12 @@ export function buildChatRequestBody({
       ? messages.find(message => message.id === messageId)
       : undefined
 
-  const isToolResultContinuation =
-    trigger === 'submit-message' && lastMessage?.role === 'assistant'
-
-  if (isToolResultContinuation) {
-    // Use findLast to get the most recently resolved interactive tool part.
-    // When multiple displayOptionList calls are resolved sequentially,
-    // the first one is already persisted — we need the latest one.
-    const resolvedPart = lastMessage?.parts?.findLast(
-      part =>
-        isInteractiveToolPart(part) &&
-        'state' in part &&
-        part.state === 'output-available' &&
-        'output' in part
-    ) as { toolCallId: string; output: unknown } | undefined
-
-    if (resolvedPart && resolvedPart.output !== undefined) {
-      return {
-        body: {
-          trigger: 'tool-result' as const,
-          chatId,
-          toolResult: {
-            toolCallId: resolvedPart.toolCallId,
-            output: resolvedPart.output
-          },
-          ...(isGuest ? { messages } : {}),
-          ...(guestCanvasToken ? { guestCanvasToken } : {})
-        }
-      }
-    }
-  }
-
   return {
     body: {
       trigger,
       chatId,
       messageId,
-      ...(isGuest ? { messages } : {}),
+      messages,
       ...(guestCanvasToken ? { guestCanvasToken } : {}),
       message:
         trigger === 'regenerate-message' && messageToRegenerate?.role === 'user'

components/chat.test.tsx

@@ -90,7 +90,7 @@ function makeUseChatReturnValue(messages: UIMessage[] = []) {
     stop: vi.fn(),
     sendMessage: vi.fn(),
     regenerate: vi.fn(),
-    addToolResult: vi.fn(),
+    addToolOutput: vi.fn(),
     error: null
   }
 }
@@ -107,7 +107,8 @@ vi.mock('@ai-sdk/react', () => ({
 }))
 
 vi.mock('ai', () => ({
-  DefaultChatTransport: class DefaultChatTransport {}
+  DefaultChatTransport: class DefaultChatTransport {},
+  lastAssistantMessageIsCompleteWithToolCalls: vi.fn(() => false)
 }))
 
 vi.mock('sonner', () => ({

components/chat.tsx

@@ -11,7 +11,10 @@ import {
 import { useRouter } from 'next/navigation'
 
 import { useChat } from '@ai-sdk/react'
-import { DefaultChatTransport } from 'ai'
+import {
+  DefaultChatTransport,
+  lastAssistantMessageIsCompleteWithToolCalls
+} from 'ai'
 import { toast } from 'sonner'
 
 import { generateId } from '@/lib/db/schema'
@@ -27,7 +30,6 @@ import type {
 } from '@/lib/types/ai'
 import {
   isDynamicToolPart,
-  isInteractiveToolPart,
   isToolCallPart,
   isToolTypePart
 } from '@/lib/types/dynamic-tools'
@@ -115,7 +117,6 @@ export function Chat({
     // Clear other chat-related state that persists due to Next.js 16 component caching
     setInput('')
     setUploadedFiles([])
-    autoSendFiredRef.current.clear()
     setErrorModal({
       open: false,
       type: 'general',
@@ -163,7 +164,6 @@ export function Chat({
     canvasRef.current.setGuestCanvasToken(token)
   }, [savedMessages])
 
-  const autoSendFiredRef = useRef<Set<string>>(new Set())
   const scrollContainerRef = useRef<HTMLDivElement>(null)
   const stopVoiceRef = useRef<(() => void) | null>(null)
   const lastVoiceErrorRef = useRef<string | null>(null)
@@ -195,7 +195,7 @@ export function Chat({
     stop,
     sendMessage,
     regenerate,
-    addToolResult,
+    addToolOutput,
     error
   } = useChat({
     id: chatId, // use the client-generated or provided chatId
@@ -326,36 +326,7 @@ export function Chat({
         toast.error(`Error in chat: ${errorMessage}`)
       }
     },
-    sendAutomaticallyWhen: ({ messages: msgs }) => {
-      const lastMsg = msgs[msgs.length - 1]
-      if (!lastMsg || lastMsg.role !== 'assistant') return false
-      const parts = lastMsg.parts
-      if (!parts) return false
-      // Check if any interactive tool parts are still pending (waiting for user input)
-      const hasPendingTools = parts.some(
-        p =>
-          isInteractiveToolPart(p) &&
-          'state' in p &&
-          p.state === 'input-available' &&
-          !('output' in p)
-      )
-      if (hasPendingTools) return false
-      // Auto-continue when a displayOptionList has been resolved with a selection.
-      // Use a ref to track which toolCallIds have already triggered auto-send
-      // to prevent re-triggering on subsequent evaluations.
-      // Find the first resolved part that hasn't already triggered auto-send
-      // (not just the first resolved part — earlier ones may already be fired).
-      const resolvedOptionPart = parts.find(
-        (p: any) =>
-          isInteractiveToolPart(p) &&
-          'state' in p &&
-          p.state === 'output-available' &&
-          !autoSendFiredRef.current.has(p.toolCallId)
-      ) as { toolCallId: string } | undefined
-      if (!resolvedOptionPart) return false
-      autoSendFiredRef.current.add(resolvedOptionPart.toolCallId)
-      return true
-    },
+    sendAutomaticallyWhen: lastAssistantMessageIsCompleteWithToolCalls,
     experimental_throttle: 100,
     generateId
   })
@@ -378,7 +349,6 @@ export function Chat({
     setChatId(providedId)
     setInput('')
     setUploadedFiles([])
-    autoSendFiredRef.current.clear()
     setErrorModal({
       open: false,
       type: 'general',
@@ -944,7 +914,7 @@ export function Chat({
               }
             }
 
-            addToolResult({ tool: toolName, toolCallId, output: result })
+            addToolOutput({ tool: toolName, toolCallId, output: result })
           }}
           scrollContainerRef={scrollContainerRef}
           onUpdateMessage={handleUpdateAndReloadMessage}