diff --git a/cmd/protogen/main.go b/cmd/protogen/main.go
index 572332b0..087bdd55 100644
--- a/cmd/protogen/main.go
+++ b/cmd/protogen/main.go
@@ -305,6 +305,6 @@ func main() {
 		outputDescriptorPath: outputDescriptorPath,
 	})
 	if err != nil {
-		fail(err.Error())
+		fail("%s", err)
 	}
 }