diff --git a/space/proto/space.proto b/space/proto/space.proto
index 7ae2165..857c441 100644
--- a/space/proto/space.proto
+++ b/space/proto/space.proto
@@ -144,6 +144,6 @@ message UploadRequest {
 }
 
 message UploadResponse {
-	// a presigned url to be used for uploading
+	// a presigned url to be used for uploading. To use the URL call it with HTTP PUT and pass the object as the request data
 	string url = 1;
 }