diff --git a/dev/mod.ts b/dev/mod.ts
index a1e7278b..c2367ffd 100644
--- a/dev/mod.ts
+++ b/dev/mod.ts
@@ -4,7 +4,7 @@ import { join } from "@std/path";
 import { build as tailwindBuild } from "./tailwind.ts";
 
 const DECO_FOLDER = ".deco";
-export const build = async () => {
+export const build = async (): Promise<void> => {
   await tailwindBuild();
   const decoFolder = join(Deno.cwd(), DECO_FOLDER);
   if (