diff --git a/tools/server/webui/src/lib/services/chat.service.ts b/tools/server/webui/src/lib/services/chat.service.ts
index 9abe0515ff..0003875ce8 100644
--- a/tools/server/webui/src/lib/services/chat.service.ts
+++ b/tools/server/webui/src/lib/services/chat.service.ts
@@ -4,7 +4,13 @@ import {
 	ATTACHMENT_LABEL_PDF_FILE,
 	ATTACHMENT_LABEL_MCP_PROMPT
 } from '$lib/constants/attachment-labels';
-import { AttachmentType, ContentPartType, MessageRole, ReasoningFormat } from '$lib/enums';
+import {
+	AttachmentType,
+	ContentPartType,
+	MessageRole,
+	ReasoningFormat,
+	UrlPrefix
+} from '$lib/enums';
 import type { ApiChatMessageContentPart, ApiChatCompletionToolCall } from '$lib/types/api';
 import type { DatabaseMessageExtraMcpPrompt } from '$lib/types';
 import { modelsStore } from '$lib/stores/models.svelte';
@@ -427,7 +433,7 @@ export class ChatService {
 				for (const line of lines) {
 					if (abortSignal?.aborted) break;
 
-					if (line.startsWith('data: ')) {
+					if (line.startsWith(UrlPrefix.DATA)) {
 						const data = line.slice(6);
 						if (data === '[DONE]') {
 							streamFinished = true;