diff --git a/build.gradle.kts b/build.gradle.kts
index 0c2a30ab..67b8fec3 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -2,7 +2,7 @@ plugins {
     id("ru.mipt.npm.project")
 }
 
-val dataforgeVersion by extra("0.2.0-dev-4")
+val dataforgeVersion by extra("0.2.0-dev-6")
 
 val bintrayRepo by extra("dataforge")
 val githubProject by extra("dataforge-core")
diff --git a/dataforge-context/api/dataforge-context.api b/dataforge-context/api/dataforge-context.api
index 5443d3b3..51349c64 100644
--- a/dataforge-context/api/dataforge-context.api
+++ b/dataforge-context/api/dataforge-context.api
@@ -229,6 +229,35 @@ public abstract interface annotation class hep/dataforge/descriptors/ValueDef :
 	public abstract fun type ()[Lhep/dataforge/values/ValueType;
 }
 
+public final class hep/dataforge/properties/ConfigProperty : hep/dataforge/properties/Property {
+	public fun <init> (Lhep/dataforge/meta/Config;Lhep/dataforge/names/Name;Lhep/dataforge/meta/transformations/MetaConverter;)V
+	public final fun getConfig ()Lhep/dataforge/meta/Config;
+	public final fun getConverter ()Lhep/dataforge/meta/transformations/MetaConverter;
+	public final fun getName ()Lhep/dataforge/names/Name;
+	public fun getValue ()Ljava/lang/Object;
+	public fun onChange (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)V
+	public fun removeChangeListener (Ljava/lang/Object;)V
+	public fun setValue (Ljava/lang/Object;)V
+}
+
+public abstract interface class hep/dataforge/properties/Property {
+	public abstract fun getValue ()Ljava/lang/Object;
+	public abstract fun onChange (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)V
+	public abstract fun removeChangeListener (Ljava/lang/Object;)V
+	public abstract fun setValue (Ljava/lang/Object;)V
+}
+
+public final class hep/dataforge/properties/Property$DefaultImpls {
+	public static synthetic fun onChange$default (Lhep/dataforge/properties/Property;Ljava/lang/Object;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)V
+	public static synthetic fun removeChangeListener$default (Lhep/dataforge/properties/Property;Ljava/lang/Object;ILjava/lang/Object;)V
+}
+
+public final class hep/dataforge/properties/PropertyKt {
+	public static final fun bind (Lhep/dataforge/properties/Property;Lhep/dataforge/properties/Property;)V
+	public static final fun mirror (Lhep/dataforge/properties/Property;Lhep/dataforge/properties/Property;Lkotlinx/coroutines/CoroutineScope;)V
+	public static final fun toFlow (Lhep/dataforge/properties/Property;)Lkotlinx/coroutines/flow/StateFlow;
+}
+
 public final class hep/dataforge/provider/DfTypeKt {
 	public static final fun getDfType (Lkotlin/reflect/KClass;)Ljava/lang/String;
 }
diff --git a/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/ConfigProperty.kt b/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/ConfigProperty.kt
new file mode 100644
index 00000000..329662b5
--- /dev/null
+++ b/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/ConfigProperty.kt
@@ -0,0 +1,33 @@
+package hep.dataforge.properties
+
+import hep.dataforge.meta.Config
+import hep.dataforge.meta.DFExperimental
+import hep.dataforge.meta.get
+import hep.dataforge.meta.transformations.MetaConverter
+import hep.dataforge.meta.transformations.nullableItemToObject
+import hep.dataforge.meta.transformations.nullableObjectToMetaItem
+import hep.dataforge.names.Name
+
+@DFExperimental
+public class ConfigProperty<T : Any>(
+    public val config: Config,
+    public val name: Name,
+    public val converter: MetaConverter<T>,
+) : Property<T?> {
+
+    override var value: T?
+        get() = converter.nullableItemToObject(config[name])
+        set(value) {
+            config.setItem(name,converter.nullableObjectToMetaItem(value))
+        }
+
+    override fun onChange(owner: Any?, callback: (T?) -> Unit) {
+        config.onChange(owner) { name, oldItem, newItem ->
+            if (name == this.name && oldItem != newItem) callback(converter.nullableItemToObject(newItem))
+        }
+    }
+
+    override fun removeChangeListener(owner: Any?) {
+        config.removeListener(owner)
+    }
+}
\ No newline at end of file
diff --git a/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/Property.kt b/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/Property.kt
new file mode 100644
index 00000000..987cfe4c
--- /dev/null
+++ b/dataforge-context/src/commonMain/kotlin/hep/dataforge/properties/Property.kt
@@ -0,0 +1,48 @@
+package hep.dataforge.properties
+
+import hep.dataforge.meta.DFExperimental
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+@DFExperimental
+public interface Property<T> {
+    public var value: T
+
+    public fun onChange(owner: Any? = null, callback: (T) -> Unit)
+    public fun removeChangeListener(owner: Any? = null)
+}
+
+@DFExperimental
+@OptIn(ExperimentalCoroutinesApi::class)
+public fun <T> Property<T>.toFlow(): StateFlow<T> = MutableStateFlow(value).also { stateFlow ->
+    onChange {
+        stateFlow.value = it
+    }
+}
+
+/**
+ * Reflect all changes in the [source] property onto this property
+ *
+ * @return a mirroring job
+ */
+@DFExperimental
+public fun <T> Property<T>.mirror(source: Property<T>, scope: CoroutineScope) {
+    source.onChange(this) {
+        this.value = it
+    }
+}
+
+/**
+ * Bi-directional connection between properties
+ */
+@DFExperimental
+public fun <T> Property<T>.bind(other: Property<T>) {
+    onChange(other) {
+        other.value = it
+    }
+    other.onChange {
+        this.value = it
+    }
+}
\ No newline at end of file
diff --git a/dataforge-context/src/jsMain/kotlin/hep/dataforge/properties/bindings.kt b/dataforge-context/src/jsMain/kotlin/hep/dataforge/properties/bindings.kt
new file mode 100644
index 00000000..05818cae
--- /dev/null
+++ b/dataforge-context/src/jsMain/kotlin/hep/dataforge/properties/bindings.kt
@@ -0,0 +1,32 @@
+package hep.dataforge.properties
+
+import hep.dataforge.meta.DFExperimental
+import org.w3c.dom.HTMLInputElement
+
+@DFExperimental
+fun HTMLInputElement.bindValue(property: Property<String>) {
+    if (this.onchange != null) error("Input element already bound")
+    this.onchange = {
+        property.value = this.value
+        Unit
+    }
+    property.onChange(this) {
+        if (value != it) {
+            value = it
+        }
+    }
+}
+
+@DFExperimental
+fun HTMLInputElement.bindChecked(property: Property<Boolean>) {
+    if (this.onchange != null) error("Input element already bound")
+    this.onchange = {
+        property.value = this.checked
+        Unit
+    }
+    property.onChange(this) {
+        if (checked != it) {
+            checked = it
+        }
+    }
+}
\ No newline at end of file
diff --git a/dataforge-data/api/dataforge-data.api b/dataforge-data/api/dataforge-data.api
index 60392496..06e99242 100644
--- a/dataforge-data/api/dataforge-data.api
+++ b/dataforge-data/api/dataforge-data.api
@@ -93,7 +93,6 @@ public final class hep/dataforge/data/DataFilter : hep/dataforge/meta/Scheme {
 	public final fun getFrom ()Ljava/lang/String;
 	public final fun getPattern ()Ljava/lang/String;
 	public final fun getTo ()Ljava/lang/String;
-	public final fun isEmpty ()Z
 	public final fun setFrom (Ljava/lang/String;)V
 	public final fun setPattern (Ljava/lang/String;)V
 	public final fun setTo (Ljava/lang/String;)V
diff --git a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataFilter.kt b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataFilter.kt
index 51e58ac6..8369080e 100644
--- a/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataFilter.kt
+++ b/dataforge-data/src/commonMain/kotlin/hep/dataforge/data/DataFilter.kt
@@ -20,8 +20,6 @@ public class DataFilter : Scheme() {
 //    val prefix by string()
 //    val suffix by string()
 
-    public fun isEmpty(): Boolean = config.isEmpty()
-
     public companion object : SchemeSpec<DataFilter>(::DataFilter)
 }
 
diff --git a/dataforge-meta/api/dataforge-meta.api b/dataforge-meta/api/dataforge-meta.api
index 5fed772c..743f482a 100644
--- a/dataforge-meta/api/dataforge-meta.api
+++ b/dataforge-meta/api/dataforge-meta.api
@@ -6,8 +6,8 @@ public abstract class hep/dataforge/meta/AbstractMetaNode : hep/dataforge/meta/M
 
 public abstract class hep/dataforge/meta/AbstractMutableMeta : hep/dataforge/meta/AbstractMetaNode, hep/dataforge/meta/MutableMeta {
 	public fun <init> ()V
+	protected final fun getChildren ()Ljava/util/Map;
 	public fun getItems ()Ljava/util/Map;
-	protected final fun get_items ()Ljava/util/Map;
 	protected fun replaceItem (Lhep/dataforge/names/NameToken;Lhep/dataforge/meta/MetaItem;Lhep/dataforge/meta/MetaItem;)V
 	public fun setItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
 	protected final fun wrapItem (Lhep/dataforge/meta/MetaItem;)Lhep/dataforge/meta/MetaItem;
@@ -38,21 +38,15 @@ public final class hep/dataforge/meta/ConfigKt {
 	public static final fun get (Lhep/dataforge/meta/Config;Lhep/dataforge/names/NameToken;)Lhep/dataforge/meta/MetaItem;
 }
 
-public abstract interface class hep/dataforge/meta/Configurable : hep/dataforge/meta/MutableItemProvider, hep/dataforge/meta/descriptors/Described {
+public abstract interface class hep/dataforge/meta/Configurable : hep/dataforge/meta/MutableItemProvider {
 	public abstract fun getConfig ()Lhep/dataforge/meta/Config;
-	public abstract fun getDefaultItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
-	public abstract fun getDescriptor ()Lhep/dataforge/meta/descriptors/NodeDescriptor;
 	public abstract fun getItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
 	public abstract fun setItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
-	public abstract fun validateItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)Z
 }
 
 public final class hep/dataforge/meta/Configurable$DefaultImpls {
-	public static fun getDefaultItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
-	public static fun getDescriptor (Lhep/dataforge/meta/Configurable;)Lhep/dataforge/meta/descriptors/NodeDescriptor;
 	public static fun getItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
 	public static fun setItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
-	public static fun validateItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)Z
 }
 
 public final class hep/dataforge/meta/ConfigurableKt {
@@ -60,18 +54,6 @@ public final class hep/dataforge/meta/ConfigurableKt {
 	public static synthetic fun config$default (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
 	public static final fun configure (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Meta;)Lhep/dataforge/meta/Configurable;
 	public static final fun configure (Lhep/dataforge/meta/Configurable;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public static final fun getItem (Lhep/dataforge/meta/Configurable;Ljava/lang/String;)Lhep/dataforge/meta/MetaItem;
-	public static final fun node (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
-	public static synthetic fun node$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
-	public static final fun setItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;Lhep/dataforge/meta/Meta;)V
-	public static final fun setItem (Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;Lhep/dataforge/values/Value;)V
-	public static final fun setItem (Lhep/dataforge/meta/Configurable;Ljava/lang/String;Lhep/dataforge/meta/Meta;)V
-	public static final fun setItem (Lhep/dataforge/meta/Configurable;Ljava/lang/String;Lhep/dataforge/meta/MetaItem;)V
-	public static final fun setItem (Lhep/dataforge/meta/Configurable;Ljava/lang/String;Lhep/dataforge/values/Value;)V
-	public static final fun spec (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
-	public static final fun spec (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
-	public static synthetic fun spec$default (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Configurable;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
-	public static synthetic fun spec$default (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
 }
 
 public abstract interface annotation class hep/dataforge/meta/DFBuilder : java/lang/annotation/Annotation {
@@ -196,9 +178,12 @@ public abstract interface class hep/dataforge/meta/Meta : hep/dataforge/meta/Ite
 	public static final field Companion Lhep/dataforge/meta/Meta$Companion;
 	public static final field TYPE Ljava/lang/String;
 	public static final field VALUE_KEY Ljava/lang/String;
+	public abstract fun equals (Ljava/lang/Object;)Z
 	public abstract fun getItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
 	public abstract fun getItems ()Ljava/util/Map;
+	public abstract fun hashCode ()I
 	public abstract fun toMeta ()Lhep/dataforge/meta/Meta;
+	public abstract fun toString ()Ljava/lang/String;
 }
 
 public final class hep/dataforge/meta/Meta$Companion {
@@ -358,14 +343,6 @@ public abstract interface class hep/dataforge/meta/MetaRepr {
 	public abstract fun toMeta ()Lhep/dataforge/meta/Meta;
 }
 
-public class hep/dataforge/meta/MetaScheme : hep/dataforge/meta/Scheme {
-	public fun <init> (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/descriptors/NodeDescriptor;Lhep/dataforge/meta/Config;)V
-	public synthetic fun <init> (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/descriptors/NodeDescriptor;Lhep/dataforge/meta/Config;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public fun getDefaultLayer ()Lhep/dataforge/meta/Meta;
-	public synthetic fun getDescriptor ()Lhep/dataforge/meta/descriptors/ItemDescriptor;
-	public fun getDescriptor ()Lhep/dataforge/meta/descriptors/NodeDescriptor;
-}
-
 public final class hep/dataforge/meta/MetaSerializer : kotlinx/serialization/KSerializer {
 	public static final field INSTANCE Lhep/dataforge/meta/MetaSerializer;
 	public fun deserialize (Lkotlinx/serialization/encoding/Decoder;)Lhep/dataforge/meta/Meta;
@@ -375,6 +352,18 @@ public final class hep/dataforge/meta/MetaSerializer : kotlinx/serialization/KSe
 	public synthetic fun serialize (Lkotlinx/serialization/encoding/Encoder;Ljava/lang/Object;)V
 }
 
+public final class hep/dataforge/meta/MetaWithDefault : hep/dataforge/meta/MetaBase {
+	public fun <init> (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;)V
+	public final fun getDefault ()Lhep/dataforge/meta/ItemProvider;
+	public fun getItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
+	public fun getItems ()Ljava/util/Map;
+	public final fun getMeta ()Lhep/dataforge/meta/Meta;
+}
+
+public final class hep/dataforge/meta/MetaWithDefaultKt {
+	public static final fun withDefault (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/MetaWithDefault;
+}
+
 public final class hep/dataforge/meta/MutableItemDelegateKt {
 	public static final fun boolean (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
 	public static final fun boolean (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Lkotlin/jvm/functions/Function0;)Lkotlin/properties/ReadWriteProperty;
@@ -437,6 +426,29 @@ public abstract interface class hep/dataforge/meta/MutableItemProvider : hep/dat
 	public abstract fun setItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
 }
 
+public final class hep/dataforge/meta/MutableItemProviderKt {
+	public static final fun getItem (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;)Lhep/dataforge/meta/MetaItem;
+	public static final fun node (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
+	public static synthetic fun node$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
+	public static final fun remove (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;)V
+	public static final fun remove (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Iterable;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Object;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/NameToken;Ljava/lang/Object;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Ljava/lang/Iterable;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Ljava/lang/Object;)V
+	public static final fun set (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Object;)V
+	public static final fun setIndexed (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;)V
+	public static synthetic fun setIndexed$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
+	public static final fun setIndexedItems (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;)V
+	public static synthetic fun setIndexedItems$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
+	public static final fun setItem (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Lhep/dataforge/meta/MetaItem;)V
+	public static final fun setNode (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Lhep/dataforge/meta/Meta;)V
+	public static final fun setNode (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Lhep/dataforge/meta/Meta;)V
+	public static final fun setValue (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/names/Name;Lhep/dataforge/values/Value;)V
+	public static final fun setValue (Lhep/dataforge/meta/MutableItemProvider;Ljava/lang/String;Lhep/dataforge/values/Value;)V
+}
+
 public abstract interface class hep/dataforge/meta/MutableMeta : hep/dataforge/meta/MetaNode, hep/dataforge/meta/MutableItemProvider {
 	public abstract fun getItems ()Ljava/util/Map;
 }
@@ -450,24 +462,6 @@ public final class hep/dataforge/meta/MutableMetaKt {
 	public static final fun append (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Object;)V
 	public static final fun append (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Ljava/lang/Object;)V
 	public static final fun edit (Lhep/dataforge/meta/AbstractMutableMeta;Lhep/dataforge/names/Name;Lkotlin/jvm/functions/Function1;)V
-	public static final fun remove (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;)V
-	public static final fun remove (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Iterable;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Object;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/NameToken;Ljava/lang/Object;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Ljava/lang/Iterable;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Ljava/lang/Object;)V
-	public static final fun set (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Object;)V
-	public static final fun setIndexed (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;)V
-	public static synthetic fun setIndexed$default (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
-	public static final fun setIndexedItems (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;)V
-	public static synthetic fun setIndexedItems$default (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Ljava/lang/Iterable;Lkotlin/jvm/functions/Function2;ILjava/lang/Object;)V
-	public static final fun setItem (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Lhep/dataforge/meta/MetaItem;)V
-	public static final fun setNode (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Lhep/dataforge/meta/Meta;)V
-	public static final fun setNode (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Lhep/dataforge/meta/Meta;)V
-	public static final fun setValue (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/names/Name;Lhep/dataforge/values/Value;)V
-	public static final fun setValue (Lhep/dataforge/meta/MutableMeta;Ljava/lang/String;Lhep/dataforge/values/Value;)V
 	public static final fun update (Lhep/dataforge/meta/MutableMeta;Lhep/dataforge/meta/Meta;)V
 }
 
@@ -483,22 +477,23 @@ public final class hep/dataforge/meta/ObservableMeta$DefaultImpls {
 
 public class hep/dataforge/meta/Scheme : hep/dataforge/meta/Configurable, hep/dataforge/meta/MetaRepr, hep/dataforge/meta/descriptors/Described {
 	public fun <init> ()V
-	public fun <init> (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;)V
+	public fun <init> (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;Lhep/dataforge/meta/descriptors/NodeDescriptor;)V
+	public synthetic fun <init> (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;Lhep/dataforge/meta/descriptors/NodeDescriptor;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun getConfig ()Lhep/dataforge/meta/Config;
-	public fun getDefaultItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
+	public final fun getDefaultItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
 	public fun getDefaultLayer ()Lhep/dataforge/meta/Meta;
-	public final fun getDefaultProvider ()Lhep/dataforge/meta/ItemProvider;
 	public synthetic fun getDescriptor ()Lhep/dataforge/meta/descriptors/ItemDescriptor;
 	public fun getDescriptor ()Lhep/dataforge/meta/descriptors/NodeDescriptor;
 	public fun getItem (Lhep/dataforge/names/Name;)Lhep/dataforge/meta/MetaItem;
+	public final fun isEmpty ()Z
 	public fun setItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)V
 	public fun toMeta ()Lhep/dataforge/meta/Laminate;
 	public synthetic fun toMeta ()Lhep/dataforge/meta/Meta;
-	public fun validateItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)Z
+	public final fun validateItem (Lhep/dataforge/names/Name;Lhep/dataforge/meta/MetaItem;)Z
 }
 
 public final class hep/dataforge/meta/SchemeKt {
-	public static final fun asScheme (Lhep/dataforge/meta/Meta;)Lhep/dataforge/meta/MetaScheme;
+	public static final fun asScheme (Lhep/dataforge/meta/Meta;)Lhep/dataforge/meta/Scheme;
 	public static final fun invoke (Lhep/dataforge/meta/Scheme;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Scheme;
 	public static final fun toScheme (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
 	public static synthetic fun toScheme$default (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;ILjava/lang/Object;)Lhep/dataforge/meta/Configurable;
@@ -507,12 +502,8 @@ public final class hep/dataforge/meta/SchemeKt {
 public class hep/dataforge/meta/SchemeSpec : hep/dataforge/meta/Specification {
 	public fun <init> (Lkotlin/jvm/functions/Function0;)V
 	public fun <init> (Lkotlin/jvm/functions/Function2;)V
-	public synthetic fun empty ()Lhep/dataforge/meta/Configurable;
-	public fun empty ()Lhep/dataforge/meta/Scheme;
-	public synthetic fun invoke (Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public final fun invoke (Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Scheme;
-	public synthetic fun wrap (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/Configurable;
-	public fun wrap (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/Scheme;
+	public synthetic fun wrap (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/MutableItemProvider;
+	public fun wrap (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/Scheme;
 }
 
 public final class hep/dataforge/meta/SealedMeta : hep/dataforge/meta/AbstractMetaNode {
@@ -520,25 +511,27 @@ public final class hep/dataforge/meta/SealedMeta : hep/dataforge/meta/AbstractMe
 }
 
 public abstract interface class hep/dataforge/meta/Specification {
-	public abstract fun empty ()Lhep/dataforge/meta/Configurable;
-	public abstract fun invoke (Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public abstract fun wrap (Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/Configurable;
+	public abstract fun wrap (Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;)Lhep/dataforge/meta/MutableItemProvider;
 }
 
 public final class hep/dataforge/meta/Specification$DefaultImpls {
-	public static fun empty (Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/Configurable;
-	public static fun invoke (Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public static synthetic fun wrap$default (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Config;Lhep/dataforge/meta/ItemProvider;ILjava/lang/Object;)Lhep/dataforge/meta/Configurable;
+	public static synthetic fun wrap$default (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Meta;Lhep/dataforge/meta/ItemProvider;ILjava/lang/Object;)Lhep/dataforge/meta/MutableItemProvider;
 }
 
 public final class hep/dataforge/meta/SpecificationKt {
-	public static final fun configSpec (Lhep/dataforge/meta/MetaItem;Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/Configurable;
-	public static final fun configure (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
+	public static final fun configSpec (Lhep/dataforge/meta/MetaItem;Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/MutableItemProvider;
+	public static final fun configure (Lhep/dataforge/meta/MetaRepr;Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/MetaRepr;
 	public static final fun createStyle (Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Meta;
-	public static final fun spec (Lhep/dataforge/meta/MetaItem;Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/Configurable;
+	public static final fun empty (Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/MutableItemProvider;
+	public static final fun invoke (Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/MutableItemProvider;
+	public static final fun spec (Lhep/dataforge/meta/MetaItem;Lhep/dataforge/meta/Specification;)Lhep/dataforge/meta/MutableItemProvider;
+	public static final fun spec (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Scheme;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
+	public static final fun spec (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/meta/Specification;Lhep/dataforge/names/Name;)Lkotlin/properties/ReadWriteProperty;
+	public static synthetic fun spec$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Scheme;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
+	public static synthetic fun spec$default (Lhep/dataforge/meta/MutableItemProvider;Lhep/dataforge/meta/Specification;Lhep/dataforge/names/Name;ILjava/lang/Object;)Lkotlin/properties/ReadWriteProperty;
 	public static final fun update (Lhep/dataforge/meta/Configurable;Lhep/dataforge/meta/Specification;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public static final fun update (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Config;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/Configurable;
-	public static final fun wrap (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Meta;)Lhep/dataforge/meta/Configurable;
+	public static final fun update (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Meta;Lkotlin/jvm/functions/Function1;)Lhep/dataforge/meta/MutableItemProvider;
+	public static final fun wrap (Lhep/dataforge/meta/Specification;Lhep/dataforge/meta/Meta;)Lhep/dataforge/meta/MutableItemProvider;
 }
 
 public abstract interface class hep/dataforge/meta/descriptors/Described {
@@ -775,7 +768,6 @@ public final class hep/dataforge/names/NameKt {
 	public static final fun get (Ljava/util/Map;Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;
 	public static synthetic fun get$default (Ljava/util/Map;Ljava/lang/String;Ljava/lang/String;ILjava/lang/Object;)Ljava/lang/Object;
 	public static final fun getLength (Lhep/dataforge/names/Name;)I
-	public static final fun hasIndex (Lhep/dataforge/names/NameToken;)Z
 	public static final fun isEmpty (Lhep/dataforge/names/Name;)Z
 	public static final fun lastOrNull (Lhep/dataforge/names/Name;)Lhep/dataforge/names/NameToken;
 	public static final fun plus (Lhep/dataforge/names/Name;Lhep/dataforge/names/Name;)Lhep/dataforge/names/Name;
@@ -787,7 +779,6 @@ public final class hep/dataforge/names/NameKt {
 	public static final fun startsWith (Lhep/dataforge/names/Name;Lhep/dataforge/names/NameToken;)Z
 	public static final fun toName (Ljava/lang/String;)Lhep/dataforge/names/Name;
 	public static final fun withIndex (Lhep/dataforge/names/Name;Ljava/lang/String;)Lhep/dataforge/names/Name;
-	public static final fun withIndex (Lhep/dataforge/names/NameToken;Ljava/lang/String;)Lhep/dataforge/names/NameToken;
 }
 
 public final class hep/dataforge/names/NameToken {
@@ -814,6 +805,11 @@ public final class hep/dataforge/names/NameToken$Companion : kotlinx/serializati
 	public final fun serializer ()Lkotlinx/serialization/KSerializer;
 }
 
+public final class hep/dataforge/names/NameTokenKt {
+	public static final fun hasIndex (Lhep/dataforge/names/NameToken;)Z
+	public static final fun withIndex (Lhep/dataforge/names/NameToken;Ljava/lang/String;)Lhep/dataforge/names/NameToken;
+}
+
 public final class hep/dataforge/values/DoubleArrayValue : hep/dataforge/values/Value {
 	public fun <init> ([D)V
 	public fun equals (Ljava/lang/Object;)Z
diff --git a/dataforge-meta/build.gradle.kts b/dataforge-meta/build.gradle.kts
index 2d4aac0c..980924a7 100644
--- a/dataforge-meta/build.gradle.kts
+++ b/dataforge-meta/build.gradle.kts
@@ -1,16 +1,12 @@
-import ru.mipt.npm.gradle.KScienceVersions
-
 plugins {
     id("ru.mipt.npm.mpp")
     id("ru.mipt.npm.native")
 }
 
 kscience {
-    useSerialization()
+    useSerialization{
+        json()
+    }
 }
 
-description = "Meta definition and basic operations on meta"
-
-dependencies{
-    commonMainApi("org.jetbrains.kotlinx:kotlinx-serialization-json:${KScienceVersions.serializationVersion}")
-}
\ No newline at end of file
+description = "Meta definition and basic operations on meta"
\ No newline at end of file
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Config.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Config.kt
index d1691e4e..2674d0a8 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Config.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Config.kt
@@ -4,10 +4,8 @@ import hep.dataforge.names.Name
 import hep.dataforge.names.NameToken
 import hep.dataforge.names.asName
 import hep.dataforge.names.plus
-import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.Serializer
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
@@ -53,12 +51,12 @@ public class Config() : AbstractMutableMeta<Config>(), ObservableMeta {
 
     override fun replaceItem(key: NameToken, oldItem: MetaItem<Config>?, newItem: MetaItem<Config>?) {
         if (newItem == null) {
-            _items.remove(key)
+            children.remove(key)
             if (oldItem != null && oldItem is MetaItem.NodeItem<Config>) {
                 oldItem.node.removeListener(this)
             }
         } else {
-            _items[key] = newItem
+            children[key] = newItem
             if (newItem is MetaItem.NodeItem) {
                 newItem.node.onChange(this) { name, oldChild, newChild ->
                     itemChanged(key + name, oldChild, newChild)
@@ -75,8 +73,6 @@ public class Config() : AbstractMutableMeta<Config>(), ObservableMeta {
 
     override fun empty(): Config = Config()
 
-    @OptIn(ExperimentalSerializationApi::class)
-    @Serializer(Config::class)
     public companion object ConfigSerializer : KSerializer<Config> {
 
         public fun empty(): Config = Config()
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Configurable.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Configurable.kt
index 9fd6cdb3..2308bef2 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Configurable.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Configurable.kt
@@ -1,67 +1,30 @@
 package hep.dataforge.meta
 
-import hep.dataforge.meta.descriptors.*
 import hep.dataforge.names.Name
-import hep.dataforge.names.asName
-import hep.dataforge.names.toName
-import hep.dataforge.values.Value
 import kotlin.properties.ReadWriteProperty
-import kotlin.reflect.KProperty
 
 /**
- * A container that holds a [Config] and a default item provider.
- * Default item provider could be use for example to reference parent configuration.
- * It is not possible to know if some property is declared by provider just by looking on [Configurable],
- * this information should be provided externally.
+ * A container that holds a [Config].
  */
-public interface Configurable : Described, MutableItemProvider {
+public interface Configurable : MutableItemProvider {
     /**
      * Backing config
      */
     public val config: Config
 
-    /**
-     * Default meta item provider
-     */
-    public fun getDefaultItem(name: Name): MetaItem<*>? = null
-
-    /**
-     * Check if property with given [name] could be assigned to [item]
-     */
-    public fun validateItem(name: Name, item: MetaItem<*>?): Boolean {
-        val descriptor = descriptor?.get(name)
-        return descriptor?.validateItem(item) ?: true
-    }
-
-    override val descriptor: NodeDescriptor? get() = null
-
     /**
      * Get a property with default
      */
-    override fun getItem(name: Name): MetaItem<*>? =
-        config[name] ?: getDefaultItem(name) ?: descriptor?.get(name)?.defaultItem()
+    override fun getItem(name: Name): MetaItem<*>? = config[name]
 
     /**
      * Set a configurable property
      */
     override fun setItem(name: Name, item: MetaItem<*>?) {
-        if (validateItem(name, item)) {
-            config.setItem(name, item)
-        } else {
-            error("Validation failed for property $name with value $item")
-        }
+        config.setItem(name, item)
     }
 }
 
-public fun Configurable.getItem(key: String): MetaItem<*>? = getItem(key.toName())
-
-public fun Configurable.setItem(name: Name, value: Value?): Unit = setItem(name, value?.let { MetaItem.ValueItem(value) })
-public fun Configurable.setItem(name: Name, meta: Meta?): Unit = setItem(name, meta?.let { MetaItem.NodeItem(meta) })
-
-public fun Configurable.setItem(key: String, item: MetaItem<*>?): Unit = setItem(key.toName(), item)
-
-public fun Configurable.setItem(key: String, value: Value?): Unit = setItem(key, value?.let { MetaItem.ValueItem(value) })
-public fun Configurable.setItem(key: String, meta: Meta?): Unit = setItem(key, meta?.let { MetaItem.NodeItem(meta) })
 
 public fun <T : Configurable> T.configure(meta: Meta): T = this.apply { config.update(meta) }
 
@@ -70,39 +33,4 @@ public inline fun <T : Configurable> T.configure(action: Config.() -> Unit): T =
 
 /* Node delegates */
 
-public fun Configurable.config(key: Name? = null): ReadWriteProperty<Any?, Config?> =
-    config.node(key)
-
-public fun MutableItemProvider.node(key: Name? = null): ReadWriteProperty<Any?, Meta?> = item(key).convert(
-    reader = { it.node },
-    writer = { it?.let { MetaItem.NodeItem(it) } }
-)
-
-public fun <T : Configurable> Configurable.spec(
-    spec: Specification<T>, key: Name? = null
-): ReadWriteProperty<Any?, T?> = object : ReadWriteProperty<Any?, T?> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): T? {
-        val name = key ?: property.name.asName()
-        return config[name].node?.let { spec.wrap(it) }
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
-        val name = key ?: property.name.asName()
-        config[name] = value?.config
-    }
-}
-
-public fun <T : Configurable> Configurable.spec(
-    spec: Specification<T>, default: T, key: Name? = null
-): ReadWriteProperty<Any?, T> = object : ReadWriteProperty<Any?, T> {
-    override fun getValue(thisRef: Any?, property: KProperty<*>): T {
-        val name = key ?: property.name.asName()
-        return config[name].node?.let { spec.wrap(it) } ?: default
-    }
-
-    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
-        val name = key ?: property.name.asName()
-        config[name] = value.config
-    }
-}
-
+public fun Configurable.config(key: Name? = null): ReadWriteProperty<Any?, Config?> = config.node(key)
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Meta.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Meta.kt
index 5c992c6b..c8ed6755 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Meta.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Meta.kt
@@ -66,6 +66,7 @@ public fun <M : Meta> M.asMetaItem(): NodeItem<M> = NodeItem(this)
  * The object that could be represented as [Meta]. Meta provided by [toMeta] method should fully represent object state.
  * Meaning that two states with the same meta are equal.
  */
+@Serializable(MetaSerializer::class)
 public interface MetaRepr {
     public fun toMeta(): Meta
 }
@@ -104,12 +105,11 @@ public interface Meta : MetaRepr, ItemProvider {
 
     override fun toMeta(): Meta = seal()
 
-    //TODO to be restored on 1.4.30 after https://youtrack.jetbrains.com/issue/KT-41765 si fixed
-//    override fun equals(other: Any?): Boolean
-//
-//    override fun hashCode(): Int
-//
-//    override fun toString(): String
+    override fun equals(other: Any?): Boolean
+
+    override fun hashCode(): Int
+
+    override fun toString(): String
 
     public companion object {
         public const val TYPE: String = "meta"
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaBuilder.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaBuilder.kt
index b6e933f6..cd041275 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaBuilder.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaBuilder.kt
@@ -68,7 +68,7 @@ public class MetaBuilder : AbstractMutableMeta<MetaBuilder>() {
 
     @JvmName("putMetas")
     public infix fun String.put(value: Iterable<Meta>) {
-        this@MetaBuilder[this] = value.toList()
+        set(this,value.toList())
     }
 
     public infix fun String.put(metaBuilder: MetaBuilder.() -> Unit) {
@@ -110,7 +110,7 @@ public class MetaBuilder : AbstractMutableMeta<MetaBuilder>() {
 
     @JvmName("putMetas")
     public infix fun Name.put(value: Iterable<Meta>) {
-        this@MetaBuilder[this] = value.toList()
+        set(this, value.toList())
     }
 
     public infix fun Name.put(metaBuilder: MetaBuilder.() -> Unit) {
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaSerializer.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaSerializer.kt
index 7184ae3a..b20adba8 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaSerializer.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaSerializer.kt
@@ -5,7 +5,6 @@ import hep.dataforge.values.ValueSerializer
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.InternalSerializationApi
 import kotlinx.serialization.KSerializer
-import kotlinx.serialization.Serializer
 import kotlinx.serialization.builtins.MapSerializer
 import kotlinx.serialization.descriptors.*
 import kotlinx.serialization.encoding.*
@@ -52,8 +51,6 @@ public object MetaItemSerializer : KSerializer<MetaItem<*>> {
 /**
  * Serialized for meta
  */
-@OptIn(ExperimentalSerializationApi::class)
-@Serializer(Meta::class)
 public object MetaSerializer : KSerializer<Meta> {
 
     private val mapSerializer: KSerializer<Map<NameToken, MetaItem<Meta>>> = MapSerializer(
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaWithDefault.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaWithDefault.kt
new file mode 100644
index 00000000..2a225121
--- /dev/null
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MetaWithDefault.kt
@@ -0,0 +1,18 @@
+package hep.dataforge.meta
+
+import hep.dataforge.names.Name
+import hep.dataforge.names.NameToken
+
+/**
+ * Meta object with default provider for items not present in the initial meta.
+ */
+public class MetaWithDefault(public val meta: Meta, public val default: ItemProvider) : MetaBase() {
+    override val items: Map<NameToken, MetaItem<*>>
+        get() = meta.items
+
+    override fun getItem(name: Name): MetaItem<*>? {
+        return meta[name] ?: default.getItem(name)
+    }
+}
+
+public fun Meta.withDefault(default: ItemProvider): MetaWithDefault = MetaWithDefault(this, default)
\ No newline at end of file
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableItemProvider.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableItemProvider.kt
new file mode 100644
index 00000000..6a43af6e
--- /dev/null
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableItemProvider.kt
@@ -0,0 +1,88 @@
+package hep.dataforge.meta
+
+import hep.dataforge.names.*
+import hep.dataforge.values.Value
+import kotlin.properties.ReadWriteProperty
+
+public interface MutableItemProvider : ItemProvider {
+    public fun setItem(name: Name, item: MetaItem<*>?)
+}
+
+public fun MutableItemProvider.getItem(key: String): MetaItem<*>? = getItem(key.toName())
+
+public fun MutableItemProvider.setValue(name: Name, value: Value?): Unit =
+    setItem(name, value?.let { MetaItem.ValueItem(value) })
+
+public fun MutableItemProvider.setNode(name: Name, meta: Meta?): Unit =
+    setItem(name, meta?.let { MetaItem.NodeItem(meta) })
+
+public fun MutableItemProvider.setItem(key: String, item: MetaItem<*>?): Unit = setItem(key.toName(), item)
+
+public fun MutableItemProvider.setValue(key: String, value: Value?): Unit =
+    setItem(key, value?.let { MetaItem.ValueItem(value) })
+
+public fun MutableItemProvider.setNode(key: String, meta: Meta?): Unit =
+    setItem(key, meta?.let { MetaItem.NodeItem(meta) })
+
+public fun MutableItemProvider.node(key: Name? = null): ReadWriteProperty<Any?, Meta?> = item(key).convert(
+    reader = { it.node },
+    writer = { it?.let { MetaItem.NodeItem(it) } }
+)
+
+@Suppress("NOTHING_TO_INLINE")
+public inline fun MutableItemProvider.remove(name: Name): Unit = setItem(name, null)
+
+@Suppress("NOTHING_TO_INLINE")
+public inline fun MutableItemProvider.remove(name: String): Unit = remove(name.toName())
+
+
+/**
+ * Universal unsafe set method
+ */
+public operator fun MutableItemProvider.set(name: Name, value: Any?) {
+    when (value) {
+        null -> remove(name)
+        is MetaItem<*> -> setItem(name, value)
+        is Meta -> setNode(name, value)
+        is Configurable -> setNode(name, value.config)
+        else -> setValue(name, Value.of(value))
+    }
+}
+
+public operator fun MutableItemProvider.set(name: NameToken, value: Any?): Unit =
+    set(name.asName(), value)
+
+public operator fun MutableItemProvider.set(key: String, value: Any?): Unit =
+    set(key.toName(), value)
+
+public operator fun MutableItemProvider.set(key: String, index: String, value: Any?): Unit =
+    set(key.toName().withIndex(index), value)
+
+
+
+/* Same name siblings generation */
+
+public fun MutableItemProvider.setIndexedItems(
+    name: Name,
+    items: Iterable<MetaItem<*>>,
+    indexFactory: (MetaItem<*>, index: Int) -> String = { _, index -> index.toString() }
+) {
+    val tokens = name.tokens.toMutableList()
+    val last = tokens.last()
+    items.forEachIndexed { index, meta ->
+        val indexedToken = NameToken(last.body, last.index + indexFactory(meta, index))
+        tokens[tokens.lastIndex] = indexedToken
+        setItem(Name(tokens), meta)
+    }
+}
+
+public fun MutableItemProvider.setIndexed(
+    name: Name,
+    metas: Iterable<Meta>,
+    indexFactory: (Meta, index: Int) -> String = { _, index -> index.toString() }
+) {
+    setIndexedItems(name, metas.map { MetaItem.NodeItem(it) }) { item, index -> indexFactory(item.node!!, index) }
+}
+
+public operator fun MutableItemProvider.set(name: Name, metas: Iterable<Meta>): Unit = setIndexed(name, metas)
+public operator fun MutableItemProvider.set(name: String, metas: Iterable<Meta>): Unit = setIndexed(name.toName(), metas)
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableMeta.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableMeta.kt
index 25cf003f..7903ba87 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableMeta.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/MutableMeta.kt
@@ -1,11 +1,6 @@
 package hep.dataforge.meta
 
 import hep.dataforge.names.*
-import hep.dataforge.values.Value
-
-public interface MutableItemProvider : ItemProvider {
-    public fun setItem(name: Name, item: MetaItem<*>?)
-}
 
 public interface MutableMeta<out M : MutableMeta<M>> : MetaNode<M>, MutableItemProvider {
     override val items: Map<NameToken, MetaItem<M>>
@@ -19,18 +14,18 @@ public interface MutableMeta<out M : MutableMeta<M>> : MetaNode<M>, MutableItemP
  * Changes in Meta are not thread safe.
  */
 public abstract class AbstractMutableMeta<M : MutableMeta<M>> : AbstractMetaNode<M>(), MutableMeta<M> {
-    protected val _items: MutableMap<NameToken, MetaItem<M>> = LinkedHashMap()
+    protected val children: MutableMap<NameToken, MetaItem<M>> = LinkedHashMap()
 
     override val items: Map<NameToken, MetaItem<M>>
-        get() = _items
+        get() = children
 
     //protected abstract fun itemChanged(name: Name, oldItem: MetaItem<*>?, newItem: MetaItem<*>?)
 
     protected open fun replaceItem(key: NameToken, oldItem: MetaItem<M>?, newItem: MetaItem<M>?) {
         if (newItem == null) {
-            _items.remove(key)
+            children.remove(key)
         } else {
-            _items[key] = newItem
+            children[key] = newItem
         }
         //itemChanged(key.asName(), oldItem, newItem)
     }
@@ -72,48 +67,6 @@ public abstract class AbstractMutableMeta<M : MutableMeta<M>> : AbstractMetaNode
     }
 }
 
-
-@Suppress("NOTHING_TO_INLINE")
-public inline fun MutableMeta<*>.remove(name: Name): Unit = setItem(name, null)
-
-@Suppress("NOTHING_TO_INLINE")
-public inline fun MutableMeta<*>.remove(name: String): Unit = remove(name.toName())
-
-public operator fun MutableMeta<*>.set(name: Name, item: MetaItem<*>?): Unit = setItem(name, item)
-
-public fun MutableMeta<*>.setValue(name: Name, value: Value): Unit = setItem(name, MetaItem.ValueItem(value))
-
-public fun MutableMeta<*>.setValue(name: String, value: Value): Unit = set(name.toName(), value)
-
-public fun MutableMeta<*>.setItem(name: String, item: MetaItem<*>?): Unit = setItem(name.toName(), item)
-
-public fun MutableMeta<*>.setNode(name: Name, node: Meta): Unit =
-    setItem(name, MetaItem.NodeItem(node))
-
-public fun MutableMeta<*>.setNode(name: String, node: Meta): Unit = setNode(name.toName(), node)
-
-/**
- * Universal unsafe set method
- */
-public operator fun MutableMeta<*>.set(name: Name, value: Any?) {
-    when (value) {
-        null -> remove(name)
-        is MetaItem<*> -> setItem(name, value)
-        is Meta -> setNode(name, value)
-        is Configurable -> setNode(name, value.config)
-        else -> setValue(name, Value.of(value))
-    }
-}
-
-public operator fun MutableMeta<*>.set(name: NameToken, value: Any?): Unit =
-    set(name.asName(), value)
-
-public operator fun MutableMeta<*>.set(key: String, value: Any?): Unit =
-    set(key.toName(), value)
-
-public operator fun MutableMeta<*>.set(key: String, index: String, value: Any?): Unit =
-    set(key.toName().withIndex(index), value)
-
 /**
  * Update existing mutable node with another node. The rules are following:
  *  * value replaces anything
@@ -130,33 +83,6 @@ public fun <M : MutableMeta<M>> M.update(meta: Meta) {
     }
 }
 
-/* Same name siblings generation */
-
-public fun MutableMeta<*>.setIndexedItems(
-    name: Name,
-    items: Iterable<MetaItem<*>>,
-    indexFactory: (MetaItem<*>, index: Int) -> String = { _, index -> index.toString() }
-) {
-    val tokens = name.tokens.toMutableList()
-    val last = tokens.last()
-    items.forEachIndexed { index, meta ->
-        val indexedToken = NameToken(last.body, last.index + indexFactory(meta, index))
-        tokens[tokens.lastIndex] = indexedToken
-        setItem(Name(tokens), meta)
-    }
-}
-
-public fun MutableMeta<*>.setIndexed(
-    name: Name,
-    metas: Iterable<Meta>,
-    indexFactory: (Meta, index: Int) -> String = { _, index -> index.toString() }
-) {
-    setIndexedItems(name, metas.map { MetaItem.NodeItem(it) }) { item, index -> indexFactory(item.node!!, index) }
-}
-
-public operator fun MutableMeta<*>.set(name: Name, metas: Iterable<Meta>): Unit = setIndexed(name, metas)
-public operator fun MutableMeta<*>.set(name: String, metas: Iterable<Meta>): Unit = setIndexed(name.toName(), metas)
-
 /**
  * Append the node with a same-name-sibling, automatically generating numerical index
  */
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Scheme.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Scheme.kt
index 913f5a3d..a85e464f 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Scheme.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Scheme.kt
@@ -1,31 +1,49 @@
 package hep.dataforge.meta
 
-import hep.dataforge.meta.descriptors.Described
-import hep.dataforge.meta.descriptors.NodeDescriptor
-import hep.dataforge.meta.descriptors.defaultItem
-import hep.dataforge.meta.descriptors.get
+import hep.dataforge.meta.descriptors.*
 import hep.dataforge.names.Name
 import hep.dataforge.names.NameToken
 import hep.dataforge.names.asName
 
 /**
  * A base for delegate-based or descriptor-based scheme. [Scheme] has an empty constructor to simplify usage from [Specification].
+ * Default item provider and [NodeDescriptor] are optional
  */
 public open class Scheme(
-    config: Config,
-    defaultProvider: ItemProvider,
+    config: Config = Config(),
+    internal var default: ItemProvider? = null,
+    override val descriptor: NodeDescriptor? = null,
 ) : Configurable, Described, MetaRepr {
 
     override var config: Config = config
         internal set
 
-    public var defaultProvider: ItemProvider = defaultProvider
-        internal set
+    public fun getDefaultItem(name: Name): MetaItem<*>? {
+        return default?.getItem(name) ?: descriptor?.get(name)?.defaultItem()
+    }
 
-    public constructor() : this(Config(), ItemProvider { null })
+    /**
+     * Get a property with default
+     */
+    override fun getItem(name: Name): MetaItem<*>? = config[name] ?: getDefaultItem(name)
 
-    override fun getDefaultItem(name: Name): MetaItem<*>? {
-        return defaultProvider.getItem(name) ?: descriptor?.get(name)?.defaultItem()
+    /**
+     * Check if property with given [name] could be assigned to [item]
+     */
+    public fun validateItem(name: Name, item: MetaItem<*>?): Boolean {
+        val descriptor = descriptor?.get(name)
+        return descriptor?.validateItem(item) ?: true
+    }
+
+    /**
+     * Set a configurable property
+     */
+    override fun setItem(name: Name, item: MetaItem<*>?) {
+        if (validateItem(name, item)) {
+            super.setItem(name, item)
+        } else {
+            error("Validation failed for property $name with value $item")
+        }
     }
 
     /**
@@ -33,22 +51,23 @@ public open class Scheme(
      * values if default value is unavailable.
      * Values from [defaultProvider] completely replace
      */
-    public open val defaultLayer: Meta get() = DefaultLayer()
-
-    override fun toMeta(): Laminate = Laminate(config, defaultLayer)
-
-    private inner class DefaultLayer : MetaBase() {
-        override val items: Map<NameToken, MetaItem<*>> = buildMap {
-            descriptor?.items?.forEach { (key, itemDescriptor) ->
-                val token = NameToken(key)
-                val name = token.asName()
-                val item = defaultProvider.getItem(name) ?: itemDescriptor.defaultItem()
-                if (item != null) {
-                    put(token, item)
+    public open val defaultLayer: Meta
+        get() = object : MetaBase() {
+            override val items: Map<NameToken, MetaItem<*>> = buildMap {
+                descriptor?.items?.forEach { (key, itemDescriptor) ->
+                    val token = NameToken(key)
+                    val name = token.asName()
+                    val item = default?.getItem(name) ?: itemDescriptor.defaultItem()
+                    if (item != null) {
+                        put(token, item)
+                    }
                 }
             }
         }
-    }
+
+    override fun toMeta(): Laminate = Laminate(config, defaultLayer)
+
+    public fun isEmpty(): Boolean = config.isEmpty()
 }
 
 /**
@@ -66,30 +85,32 @@ public open class SchemeSpec<T : Scheme>(
     public constructor(emptyBuilder: () -> T) : this({ config: Config, defaultProvider: ItemProvider ->
         emptyBuilder().apply {
             this.config = config
-            this.defaultProvider = defaultProvider
+            this.default = defaultProvider
         }
     })
 
-    override fun empty(): T = builder(Config(), ItemProvider.EMPTY)
-
-    override fun wrap(config: Config, defaultProvider: ItemProvider): T = builder(config, defaultProvider)
-
-    @Suppress("OVERRIDE_BY_INLINE")
-    final override inline operator fun invoke(action: T.() -> Unit): T = empty().apply(action)
+    /**
+     * If the provided [Meta] is a [Config] use it as a scheme base, otherwise use it as default.
+     */
+    override fun wrap(meta: Meta, defaultProvider: ItemProvider): T = if (meta is Config) {
+        builder(meta, defaultProvider)
+    } else {
+        builder(Config(), meta.withDefault(defaultProvider))
+    }
 }
 
-/**
- * A scheme that uses [Meta] as a default layer
- */
-public open class MetaScheme(
-    private val meta: Meta,
-    override val descriptor: NodeDescriptor? = null,
-    config: Config = Config(),
-) : Scheme(config, meta) {
-    override val defaultLayer: Meta get() = Laminate(meta, descriptor?.defaultItem().node)
-}
+///**
+// * A scheme that uses [Meta] as a default layer
+// */
+//public open class MetaScheme(
+//    private val meta: Meta,
+//    override val descriptor: NodeDescriptor? = null,
+//    config: Config = Config(),
+//) : Scheme(config, meta) {
+//    override val defaultLayer: Meta get() = Laminate(meta, descriptor?.defaultItem().node)
+//}
 
-public fun Meta.asScheme(): MetaScheme = MetaScheme(this)
+public fun Meta.asScheme(): Scheme = Scheme(this.asConfig(), null, null)
 
 public fun <T : Configurable> Meta.toScheme(spec: Specification<T>, block: T.() -> Unit = {}): T =
     spec.wrap(this).apply(block)
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Specification.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Specification.kt
index 7988f0c1..03bc36b6 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Specification.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/meta/Specification.kt
@@ -1,32 +1,36 @@
 package hep.dataforge.meta
 
+import hep.dataforge.names.Name
+import hep.dataforge.names.asName
 import kotlin.jvm.JvmName
+import kotlin.properties.ReadWriteProperty
+import kotlin.reflect.KProperty
 
 /**
  * Allows to apply custom configuration in a type safe way to simple untyped configuration.
  * By convention [Scheme] companion should inherit this class
  *
  */
-public interface Specification<T : Configurable> {
-    public fun empty(): T = wrap()
-
+public interface Specification<T : MutableItemProvider> {
     /**
      * Wrap generic configuration producing instance of desired type
      */
-    public fun wrap(config: Config = Config(), defaultProvider: ItemProvider = ItemProvider{ null }): T
-
-    public operator fun invoke(action: T.() -> Unit): T = empty().apply(action)
+    public fun wrap(meta: Meta, defaultProvider: ItemProvider = ItemProvider.EMPTY): T
 }
 
+public operator fun <T : MutableItemProvider> Specification<T>.invoke(action: T.() -> Unit): T = empty().apply(action)
+
+public fun <T : MutableItemProvider> Specification<T>.empty(): T = wrap(Config())
+
 /**
  * Update given configuration using given type as a builder
  */
-public fun <T : Configurable> Specification<T>.update(config: Config, action: T.() -> Unit): T = wrap(config).apply(action)
+public fun <T : MutableItemProvider> Specification<T>.update(meta: Meta, action: T.() -> Unit): T = wrap(meta).apply(action)
 
 /**
- * Wrap a configuration using static meta as default
+ * Create a read-only version of
  */
-public fun <T : Configurable> Specification<T>.wrap(source: Meta): T {
+public fun <T : MutableItemProvider> Specification<T>.wrap(source: Meta): T {
     val default = source.seal()
     return wrap(source.asConfig(), default)
 }
@@ -34,26 +38,56 @@ public fun <T : Configurable> Specification<T>.wrap(source: Meta): T {
 /**
  * Apply specified configuration to configurable
  */
-public fun <T : Configurable, C : Configurable, S : Specification<C>> T.configure(spec: S, action: C.() -> Unit): T =
-    apply { spec.update(config, action) }
+public fun <T : MetaRepr, C : MutableItemProvider, S : Specification<C>> T.configure(spec: S, action: C.() -> Unit): T =
+    apply { spec.update(toMeta(), action) }
 
 /**
  * Update configuration using given specification
  */
-public fun <C : Configurable, S : Specification<C>> Configurable.update(spec: S, action: C.() -> Unit): Configurable =
+public fun <C : MutableItemProvider, S : Specification<C>> Configurable.update(spec: S, action: C.() -> Unit): Configurable =
     apply { spec.update(config, action) }
 
 /**
  * Create a style based on given specification
  */
-public fun <C : Configurable, S : Specification<C>> S.createStyle(action: C.() -> Unit): Meta =
+public fun <C : MutableItemProvider, S : Specification<C>> S.createStyle(action: C.() -> Unit): Meta =
     Config().also { update(it, action) }
 
-public fun <T : Configurable> MetaItem<*>.spec(spec: Specification<T>): T? = node?.let {
+public fun <T : MutableItemProvider> MetaItem<*>.spec(spec: Specification<T>): T? = node?.let {
     spec.wrap(
         Config(), it
     )
 }
 
 @JvmName("configSpec")
-public fun <T : Configurable> MetaItem<Config>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(it) }
+public fun <T : MutableItemProvider> MetaItem<Config>.spec(spec: Specification<T>): T? = node?.let { spec.wrap(it) }
+
+public fun <T : Scheme> MutableItemProvider.spec(
+    spec: Specification<T>, key: Name? = null
+): ReadWriteProperty<Any?, T?> = object : ReadWriteProperty<Any?, T?> {
+    override fun getValue(thisRef: Any?, property: KProperty<*>): T? {
+        val name = key ?: property.name.asName()
+        return getItem(name).node?.let { spec.wrap(it) }
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
+        val name = key ?: property.name.asName()
+        setItem(name, value?.toMeta()?.asMetaItem())
+    }
+}
+
+public fun <T : Scheme> MutableItemProvider.spec(
+    spec: Specification<T>,
+    default: T,
+    key: Name? = null
+): ReadWriteProperty<Any?, T> = object : ReadWriteProperty<Any?, T> {
+    override fun getValue(thisRef: Any?, property: KProperty<*>): T {
+        val name = key ?: property.name.asName()
+        return getItem(name).node?.let { spec.wrap(it) } ?: default
+    }
+
+    override fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
+        val name = key ?: property.name.asName()
+        setItem(name, value.toMeta().asMetaItem())
+    }
+}
\ No newline at end of file
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/Name.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/Name.kt
index 0791e080..9cce4314 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/Name.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/Name.kt
@@ -1,9 +1,7 @@
 package hep.dataforge.names
 
-import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.Serializer
 import kotlinx.serialization.descriptors.PrimitiveKind
 import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
 import kotlinx.serialization.descriptors.SerialDescriptor
@@ -16,7 +14,7 @@ import kotlinx.serialization.encoding.Encoder
  * The name is a dot separated list of strings like `token1.token2.token3`.
  * Each token could contain additional index in square brackets.
  */
-@Serializable
+@Serializable(Name.Companion::class)
 public class Name(public val tokens: List<NameToken>) {
     //TODO to be transformed into inline class after they are supported with serialization
 
@@ -38,8 +36,6 @@ public class Name(public val tokens: List<NameToken>) {
         }
     }
 
-    @OptIn(ExperimentalSerializationApi::class)
-    @Serializer(Name::class)
     public companion object : KSerializer<Name> {
         public const val NAME_SEPARATOR: String = "."
 
@@ -82,55 +78,6 @@ public fun Name.lastOrNull(): NameToken? = tokens.lastOrNull()
  */
 public fun Name.firstOrNull(): NameToken? = tokens.firstOrNull()
 
-/**
- * A single name token. Body is not allowed to be empty.
- * Following symbols are prohibited in name tokens: `{}.:\`.
- * A name token could have appendix in square brackets called *index*
- */
-@Serializable
-public data class NameToken(val body: String, val index: String? = null) {
-
-    init {
-        if (body.isEmpty()) error("Syntax error: Name token body is empty")
-    }
-
-    private fun String.escape() =
-        replace("\\", "\\\\")
-            .replace(".", "\\.")
-            .replace("[", "\\[")
-            .replace("]", "\\]")
-
-    override fun toString(): String = if (hasIndex()) {
-        "${body.escape()}[$index]"
-    } else {
-        body.escape()
-    }
-
-    @OptIn(ExperimentalSerializationApi::class)
-    @Serializer(NameToken::class)
-    public companion object : KSerializer<NameToken> {
-        override val descriptor: SerialDescriptor =
-            PrimitiveSerialDescriptor("hep.dataforge.names.NameToken", PrimitiveKind.STRING)
-
-        override fun deserialize(decoder: Decoder): NameToken {
-            return decoder.decodeString().toName().firstOrNull()!!
-        }
-
-        override fun serialize(encoder: Encoder, value: NameToken) {
-            encoder.encodeString(value.toString())
-        }
-    }
-}
-
-/**
- * Check if index is defined for this token
- */
-public fun NameToken.hasIndex(): Boolean = index != null
-
-/**
- * Add or replace index part of this token
- */
-public fun NameToken.withIndex(newIndex: String): NameToken = NameToken(body, newIndex)
 
 /**
  * Convert a [String] to name parsing it and extracting name tokens and index syntax.
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/NameToken.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/NameToken.kt
new file mode 100644
index 00000000..d010ac5a
--- /dev/null
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/names/NameToken.kt
@@ -0,0 +1,60 @@
+package hep.dataforge.names
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+/**
+ * A single name token. Body is not allowed to be empty.
+ * Following symbols are prohibited in name tokens: `{}.:\`.
+ * A name token could have appendix in square brackets called *index*
+ */
+@Serializable(NameToken.Companion::class)
+public data class NameToken(val body: String, val index: String? = null) {
+
+    init {
+        if (body.isEmpty()) error("Syntax error: Name token body is empty")
+    }
+
+    private fun String.escape() =
+        replace("\\", "\\\\")
+            .replace(".", "\\.")
+            .replace("[", "\\[")
+            .replace("]", "\\]")
+
+    override fun toString(): String = if (hasIndex()) {
+        "${body.escape()}[$index]"
+    } else {
+        body.escape()
+    }
+
+    public companion object : KSerializer<NameToken> {
+        override val descriptor: SerialDescriptor =
+            PrimitiveSerialDescriptor("hep.dataforge.names.NameToken", PrimitiveKind.STRING)
+
+        override fun deserialize(decoder: Decoder): NameToken {
+            return decoder.decodeString().toName().firstOrNull()!!
+        }
+
+        override fun serialize(
+            encoder: Encoder,
+            value: NameToken,
+        ) {
+            encoder.encodeString(value.toString())
+        }
+    }
+}
+
+/**
+ * Check if index is defined for this token
+ */
+public fun NameToken.hasIndex(): Boolean = index != null
+
+/**
+ * Add or replace index part of this token
+ */
+public fun NameToken.withIndex(newIndex: String): NameToken = NameToken(body, newIndex)
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/Value.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/Value.kt
index 9136d525..ca78f0ae 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/Value.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/Value.kt
@@ -19,6 +19,7 @@ public enum class ValueType {
  *
  * Value can represent a list of value objects.
  */
+@Serializable(ValueSerializer::class)
 public interface Value {
     /**
      * Get raw value of this value
diff --git a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/ValueSerializer.kt b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/ValueSerializer.kt
index f7693646..08b87c18 100644
--- a/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/ValueSerializer.kt
+++ b/dataforge-meta/src/commonMain/kotlin/hep/dataforge/values/ValueSerializer.kt
@@ -1,8 +1,6 @@
 package hep.dataforge.values
 
-import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
-import kotlinx.serialization.Serializer
 import kotlinx.serialization.builtins.ListSerializer
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.descriptors.buildClassSerialDescriptor
@@ -10,8 +8,6 @@ import kotlinx.serialization.descriptors.element
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
 
-@OptIn(ExperimentalSerializationApi::class)
-@Serializer(Value::class)
 public object ValueSerializer : KSerializer<Value> {
     private val listSerializer by lazy { ListSerializer(ValueSerializer) }
 
diff --git a/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/MetaDelegateTest.kt b/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/MetaDelegateTest.kt
index 925ee36c..6b8442d1 100644
--- a/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/MetaDelegateTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/MetaDelegateTest.kt
@@ -1,5 +1,6 @@
 package hep.dataforge.meta
 
+import hep.dataforge.values.asValue
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -29,7 +30,7 @@ class MetaDelegateTest {
     fun delegateTest() {
 
         val testObject = TestScheme.empty()
-        testObject.config["myValue"] = "theString"
+        testObject.setValue("myValue","theString".asValue())
         testObject.enumValue = TestEnum.NO
 
         testObject.inner = InnerSpec { innerValue = "ddd" }
diff --git a/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/SpecificationTest.kt b/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/SpecificationTest.kt
index e74c7bb3..bf73ba8c 100644
--- a/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/SpecificationTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/hep/dataforge/meta/SpecificationTest.kt
@@ -9,10 +9,8 @@ class SpecificationTest {
         var list by numberList(1, 2, 3)
 
         companion object : Specification<TestStyled> {
-            override fun wrap(
-                config: Config,
-                defaultProvider: ItemProvider
-            ): TestStyled = TestStyled(config, defaultProvider)
+            override fun wrap(meta: Meta, defaultProvider: ItemProvider): TestStyled =
+                TestStyled(meta.asConfig(), defaultProvider)
         }
     }
 
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MutableTable.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MutableTable.kt
index 7a1e0376..f4070146 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MutableTable.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/MutableTable.kt
@@ -1,6 +1,7 @@
 package hep.dataforge.tables
 
 import hep.dataforge.meta.Meta
+import hep.dataforge.meta.invoke
 import hep.dataforge.values.Value
 import kotlin.reflect.KClass
 
diff --git a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/numericColumns.kt b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/numericColumns.kt
index cc386c35..86868a22 100644
--- a/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/numericColumns.kt
+++ b/dataforge-tables/src/commonMain/kotlin/hep/dataforge/tables/numericColumns.kt
@@ -1,6 +1,7 @@
 package hep.dataforge.tables
 
 import hep.dataforge.meta.Meta
+import hep.dataforge.meta.invoke
 import kotlin.reflect.KClass
 
 
diff --git a/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/Dependency.kt b/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/Dependency.kt
index 10bf38d6..e58a988b 100644
--- a/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/Dependency.kt
+++ b/dataforge-workspace/src/commonMain/kotlin/hep/dataforge/workspace/Dependency.kt
@@ -29,7 +29,7 @@ public class DataDependency(private val filter: DataFilter, private val placemen
     }
 
     override fun toMeta(): Meta = Meta {
-        "data" put filter.config
+        "data" put filter.toMeta()
         "to" put placement.toString()
     }
 }