diff --git a/src/tools/builtin/messaging.ts b/src/tools/builtin/messaging.ts
index 44886c0..22a4b49 100644
--- a/src/tools/builtin/messaging.ts
+++ b/src/tools/builtin/messaging.ts
@@ -20,7 +20,7 @@ const SendMessageSchema = z.object({
 });
 
 const ReceiveMessagesSchema = z.object({
-  limit: z.number().default(10),
+  limit: z.number().optional(),
 });
 
 type SendMessageInput = z.infer<typeof SendMessageSchema>;