diff --git a/src/Result/functions.php b/src/Result/functions.php
index 80aa6c0..9ac05e0 100644
--- a/src/Result/functions.php
+++ b/src/Result/functions.php
@@ -16,7 +16,7 @@
  * @param  U            $value
  * @return Result\Ok<U>
  */
-function ok(mixed $value): Result\Ok
+function ok(mixed $value = true): Result\Ok
 {
     return Result\Ok::unit($value);
 }