Fix: generate title from user message — use only text parts (#1279)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

app/(chat)/actions.ts

@@ -4,11 +4,13 @@ import { generateText, type UIMessage } from "ai";
 import { cookies } from "next/headers";
 import type { VisibilityType } from "@/components/visibility-selector";
 import { myProvider } from "@/lib/ai/providers";
+import { titlePrompt } from "@/lib/ai/prompts";
 import {
   deleteMessagesByChatIdAfterTimestamp,
   getMessageById,
   updateChatVisiblityById,
 } from "@/lib/db/queries";
+import { getTextFromMessage } from "@/lib/utils";
 
 export async function saveChatModelAsCookie(model: string) {
   const cookieStore = await cookies();
@@ -22,12 +24,8 @@ export async function generateTitleFromUserMessage({
 }) {
   const { text: title } = await generateText({
     model: myProvider.languageModel("title-model"),
-    system: `\n
-    - you will generate a short title based on the first message a user begins a conversation with
-    - ensure it is not more than 80 characters long
-    - the title should be a summary of the user's message
-    - do not use quotes or colons`,
-    prompt: JSON.stringify(message),
+    system: titlePrompt,
+    prompt: getTextFromMessage(message),
   });
 
   return title;

lib/ai/prompts.ts

@@ -112,3 +112,9 @@ export const updateDocumentPrompt = (
 
 ${currentContent}`;
 };
+
+export const titlePrompt = `\n
+    - you will generate a short title based on the first message a user begins a conversation with
+    - ensure it is not more than 80 characters long
+    - the title should be a summary of the user's message
+    - do not use quotes or colons`

lib/utils.ts

@@ -108,9 +108,9 @@ export function convertToUIMessages(messages: DBMessage[]): ChatMessage[] {
   }));
 }
 
-export function getTextFromMessage(message: ChatMessage): string {
+export function getTextFromMessage(message: ChatMessage | UIMessage): string {
   return message.parts
     .filter((part) => part.type === 'text')
-    .map((part) => part.text)
+    .map((part) => (part as { type: 'text'; text: string}).text)
     .join('');
 }