diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/scheme/Specification.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/scheme/Specification.kt
index c2c6f8bb..d4685926 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/scheme/Specification.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/scheme/Specification.kt
@@ -17,8 +17,6 @@ interface Specification<T : Configurable> {
         return wrap(config).apply(action)
     }
 
-    operator fun invoke(action: T.() -> Unit) = empty().apply(action)
-
     fun empty() = wrap()
 
     /**
@@ -37,6 +35,8 @@ interface Specification<T : Configurable> {
     fun wrap(default: Meta): T = wrap(Config()) { default[it] }
 }
 
+inline operator fun <T : Configurable> Specification<T>.invoke(action: T.() -> Unit) = empty().apply(action)
+
 /**
  * Apply specified configuration to configurable
  */