diff --git a/packages/api/src/mcp/parsers.ts b/packages/api/src/mcp/parsers.ts
index f3fc3a6778..aaf20e1145 100644
--- a/packages/api/src/mcp/parsers.ts
+++ b/packages/api/src/mcp/parsers.ts
@@ -106,7 +106,7 @@ export function formatToolContent(
   const formattedContent: t.FormattedContent[] = [];
   const imageUrls: t.FormattedContent[] = [];
   let currentTextBlock = '';
-  let uiResources: t.UIResource[] = [];
+  const uiResources: UIResource[] = [];
 
   type ContentHandler = undefined | ((item: t.ToolContentPart) => void);
 
@@ -176,11 +176,17 @@ export function formatToolContent(
     formattedContent.push({ type: 'text', text: currentTextBlock });
   }
 
+  let artifacts: t.Artifacts = imageUrls.length ? { content: imageUrls } : undefined;
+
   if (uiResources.length) {
-    formattedContent.push({ type: 'text', metadata: 'ui_resources', text: btoa(JSON.stringify(uiResources))});
+    artifacts = {
+      ...artifacts,
+      [Tools.ui_resources]: {
+        data: uiResources,
+      },
+    };
   }
 
-  const artifacts = imageUrls.length ? { content: imageUrls } : undefined;
   if (CONTENT_ARRAY_PROVIDERS.has(provider)) {
     return [formattedContent, artifacts];
   }