diff --git a/index.d.ts b/index.d.ts
index 7292c2f..c453a7e 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -9,6 +9,7 @@ interface ClientSetOptions {
 
 type EmbedCallback = (context: {
   parameters: { [k: string]: unknown }
+  userAgent: string
 }) => Promise<string>
 
 type WidgetCallback = () => Promise<string>