diff --git a/CHANGELOG.md b/CHANGELOG.md
index df34ec50..efa70834 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,14 +5,17 @@
 - Experimental `listOfSpec` delegate.
 
 ### Changed
+- **API breaking** Config is deprecated, use `ObservableMeta` instead.
 - **API breaking** Descriptor no has a member property `defaultValue` instead of `defaultItem()` extension. It caches default value state on the first call. It is done because computing default on each call is too expensive.
 - Kotlin 1.5.10
 - Build tools 0.10.0
 - Relaxed type restriction on `MetaConverter`. Now nullables are available.
 
 ### Deprecated
+- Direct use of `Config`
 
 ### Removed
+- Public PluginManager mutability
 
 ### Fixed
 - Proper json array index treatment
diff --git a/build.gradle.kts b/build.gradle.kts
index 3c9b82ac..8cf2014a 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -4,7 +4,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.4.4-dev-1"
+    version = "0.5.0-dev-1"
 }
 
 subprojects {
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
index 2451048d..3c2cf28b 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Context.kt
@@ -26,6 +26,7 @@ import kotlin.jvm.Synchronized
 public open class Context internal constructor(
     final override val name: Name,
     public val parent: Context?,
+    plugins: Set<Plugin>,
     meta: Meta,
 ) : Named, MetaRepr, Provider, CoroutineScope {
 
@@ -42,7 +43,7 @@ public open class Context internal constructor(
     /**
      * A [PluginManager] for current context
      */
-    public val plugins: PluginManager by lazy { PluginManager(this) }
+    public val plugins: PluginManager by lazy { PluginManager(this, plugins) }
 
     override val defaultTarget: String get() = Plugin.TARGET
 
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/ContextBuilder.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/ContextBuilder.kt
index 30005912..52db8dae 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/ContextBuilder.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/ContextBuilder.kt
@@ -64,12 +64,32 @@ public class ContextBuilder internal constructor(
 
     public fun build(): Context {
         val contextName = name ?: "@auto[${hashCode().toUInt().toString(16)}]".toName()
-        return Context(contextName, parent, meta.seal()).apply {
-            factories.forEach { (factory, meta) ->
-                @Suppress("DEPRECATION")
-                plugins.fetch(factory, meta)
+        val plugins = HashMap<PluginTag, Plugin>()
+
+        fun addPlugin(factory: PluginFactory<*>, meta: Meta) {
+            val existing = plugins[factory.tag]
+            // Add if does not exist
+            if (existing == null) {
+                //TODO bypass if parent already has plugin with given meta?
+                val plugin = factory(meta, parent)
+
+                for ((depFactory, deoMeta) in plugin.dependsOn()) {
+                    addPlugin(depFactory, deoMeta)
+                }
+
+                parent.logger.info { "Loading plugin ${plugin.name} into $contextName" }
+                plugins[plugin.tag] = plugin
+            } else if (existing.meta != meta) {
+                error("Plugin with tag ${factory.tag} and meta $meta already exists in $contextName")
             }
+            //bypass if exists with the same meta
         }
+
+        factories.forEach { (factory, meta) ->
+            addPlugin(factory, meta)
+        }
+
+        return Context(contextName, parent, plugins.values.toSet(), meta.seal())
     }
 }
 
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Global.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Global.kt
index 59450fdb..9ace5800 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Global.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/Global.kt
@@ -13,7 +13,7 @@ internal expect val globalLoggerFactory: PluginFactory<out LogManager>
  * A global root context. Closing [Global] terminates the framework.
  */
 @ThreadLocal
-private object GlobalContext : Context("GLOBAL".asName(), null, Meta.EMPTY) {
+private object GlobalContext : Context("GLOBAL".asName(), null, emptySet(), Meta.EMPTY) {
     override val coroutineContext: CoroutineContext = Job() + CoroutineName("GlobalContext")
 }
 
diff --git a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/PluginManager.kt b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/PluginManager.kt
index 748c2359..81d455c7 100644
--- a/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/PluginManager.kt
+++ b/dataforge-context/src/commonMain/kotlin/space/kscience/dataforge/context/PluginManager.kt
@@ -1,7 +1,6 @@
 package space.kscience.dataforge.context
 
 import space.kscience.dataforge.meta.Meta
-import space.kscience.dataforge.meta.MetaBuilder
 import kotlin.reflect.KClass
 
 
@@ -11,12 +10,10 @@ import kotlin.reflect.KClass
  * @property context A context for this plugin manager
  * @author Alexander Nozik
  */
-public class PluginManager(override val context: Context) : ContextAware, Iterable<Plugin> {
-
-    /**
-     * A set of loaded plugins
-     */
-    private val plugins: HashSet<Plugin> = HashSet()
+public class PluginManager internal constructor(
+    override val context: Context,
+    private val plugins: Set<Plugin>
+) : ContextAware, Iterable<Plugin> {
 
     init {
         plugins.forEach { it.attach(context) }
@@ -76,64 +73,7 @@ public class PluginManager(override val context: Context) : ContextAware, Iterab
     public inline operator fun <reified T : Plugin> get(factory: PluginFactory<T>, recursive: Boolean = true): T? =
         get(factory.type, factory.tag, recursive)
 
-    /**
-     * Load given plugin into this manager and return loaded instance.
-     * Throw error if plugin of the same type and tag already exists in manager.
-     *
-     * @param plugin
-     * @return
-     */
-    private fun <T : Plugin> load(plugin: T): T {
-        if (get(plugin::class, plugin.tag, recursive = false) != null) {
-            error("Plugin with tag ${plugin.tag} already exists in ${context.name}")
-        } else {
-            for ((factory, meta) in plugin.dependsOn()) {
-                @Suppress("DEPRECATION")
-                fetch(factory, meta, true)
-            }
-
-            logger.info { "Loading plugin ${plugin.name} into ${context.name}" }
-            plugin.attach(context)
-            plugins.add(plugin)
-            return plugin
-        }
-    }
-
-
-    /**
-     * Remove a plugin from [PluginManager]
-     */
-    @Deprecated("Use immutable contexts instead")
-    public fun remove(plugin: Plugin) {
-        if (plugins.contains(plugin)) {
-            Global.logger.info { "Removing plugin ${plugin.name} from ${context.name}" }
-            plugin.detach()
-            plugins.remove(plugin)
-        }
-    }
-
-    /**
-     * Get an existing plugin with given meta or load new one using provided factory
-     */
-    @Deprecated("Use immutable contexts instead")
-    public fun <T : Plugin> fetch(factory: PluginFactory<T>, meta: Meta = Meta.EMPTY, recursive: Boolean = true): T {
-        val loaded = get(factory.type, factory.tag, recursive)
-        return when {
-            loaded == null -> load(factory(meta, context))
-            loaded.meta == meta -> loaded // if meta is the same, return existing plugin
-            else -> throw RuntimeException("Can't load plugin with tag ${factory.tag}. Plugin with this tag and different configuration already exists in context.")
-        }
-    }
-
-    @Deprecated("Use immutable contexts instead")
-    public fun <T : Plugin> fetch(
-        factory: PluginFactory<T>,
-        recursive: Boolean = true,
-        metaBuilder: MetaBuilder.() -> Unit,
-    ): T = fetch(factory, Meta(metaBuilder), recursive)
-
     override fun iterator(): Iterator<Plugin> = plugins.iterator()
-
 }
 
 /**
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Config.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Config.kt
deleted file mode 100644
index 14beb87b..00000000
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Config.kt
+++ /dev/null
@@ -1,110 +0,0 @@
-package space.kscience.dataforge.meta
-
-import kotlinx.serialization.KSerializer
-import kotlinx.serialization.Serializable
-import kotlinx.serialization.descriptors.SerialDescriptor
-import kotlinx.serialization.encoding.Decoder
-import kotlinx.serialization.encoding.Encoder
-import space.kscience.dataforge.names.Name
-import space.kscience.dataforge.names.NameToken
-import space.kscience.dataforge.names.asName
-import space.kscience.dataforge.names.plus
-import kotlin.collections.set
-import kotlin.jvm.Synchronized
-
-//TODO add validator to configuration
-
-/**
- * Mutable meta representing object state
- */
-@Serializable(Config.Companion::class)
-public class Config : AbstractMutableMeta<Config>(), ItemPropertyProvider {
-
-    private val listeners = HashSet<ItemListener>()
-
-    @Synchronized
-    private fun itemChanged(name: Name, oldItem: MetaItem?, newItem: MetaItem?) {
-        listeners.forEach { it.action(name, oldItem, newItem) }
-    }
-
-    /**
-     * Add change listener to this meta. Owner is declared to be able to remove listeners later. Listener without owner could not be removed
-     */
-    @Synchronized
-    override fun onChange(owner: Any?, action: (Name, MetaItem?, MetaItem?) -> Unit) {
-        listeners.add(ItemListener(owner, action))
-    }
-
-    /**
-     * Remove all listeners belonging to given owner
-     */
-    @Synchronized
-    override fun removeListener(owner: Any?) {
-        listeners.removeAll { it.owner === owner }
-    }
-
-    override fun replaceItem(key: NameToken, oldItem: TypedMetaItem<Config>?, newItem: TypedMetaItem<Config>?) {
-        if (newItem == null) {
-            children.remove(key)
-            if (oldItem != null && oldItem is MetaItemNode<Config>) {
-                oldItem.node.removeListener(this)
-            }
-        } else {
-            children[key] = newItem
-            if (newItem is MetaItemNode) {
-                newItem.node.onChange(this) { name, oldChild, newChild ->
-                    itemChanged(key + name, oldChild, newChild)
-                }
-            }
-        }
-        itemChanged(key.asName(), oldItem, newItem)
-    }
-
-    /**
-     * Attach configuration node instead of creating one
-     */
-    override fun wrapNode(meta: Meta): Config = meta.asConfig()
-
-    override fun empty(): Config = Config()
-
-    public companion object ConfigSerializer : KSerializer<Config> {
-
-        public fun empty(): Config = Config()
-        override val descriptor: SerialDescriptor get() = MetaSerializer.descriptor
-
-        override fun deserialize(decoder: Decoder): Config {
-            return MetaSerializer.deserialize(decoder).asConfig()
-        }
-
-        override fun serialize(encoder: Encoder, value: Config) {
-            MetaSerializer.serialize(encoder, value)
-        }
-    }
-}
-
-public operator fun Config.get(token: NameToken): TypedMetaItem<Config>? = items[token]
-
-/**
- * Create a mutable copy of this [Meta]. The copy is created event if initial [Meta] is a [Config].
- * Listeners are not preserved
- */
-public fun Meta.toConfig(): Config = Config().also { builder ->
-    this.items.mapValues { entry ->
-        val item = entry.value
-        builder[entry.key.asName()] = when (item) {
-            is MetaItemValue -> item.value
-            is MetaItemNode -> MetaItemNode(item.node.asConfig())
-        }
-    }
-}
-
-/**
- * Create a copy of this config, optionally applying the given [block].
- * The listeners of the original Config are not retained.
- */
-public inline fun Config.copy(block: Config.() -> Unit = {}): Config = toConfig().apply(block)
-
-/**
- * Return this [Meta] as [Config] if it is [Config] and create a new copy otherwise
- */
-public fun Meta.asConfig(): Config = this as? Config ?: toConfig()
\ No newline at end of file
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Configurable.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Configurable.kt
index 3f4b154e..dbd22f21 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Configurable.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Configurable.kt
@@ -5,21 +5,21 @@ import space.kscience.dataforge.names.Name
 import kotlin.properties.ReadWriteProperty
 
 /**
- * A container that holds a [Config].
+ * A container that holds a [ObservableMeta].
  */
 public interface Configurable {
     /**
      * Backing config
      */
-    public val config: Config
+    public val config: ObservableMeta
 }
 
 
 public fun <T : Configurable> T.configure(meta: Meta): T = this.apply { config.update(meta) }
 
 @DFBuilder
-public inline fun <T : Configurable> T.configure(action: Config.() -> Unit): T = apply { config.apply(action) }
+public inline fun <T : Configurable> T.configure(action: ObservableMeta.() -> Unit): T = apply { config.apply(action) }
 
 /* Node delegates */
 
-public fun Configurable.config(key: Name? = null): ReadWriteProperty<Any?, Config?> = config.node(key)
+public fun Configurable.config(key: Name? = null): ReadWriteProperty<Any?, ObservableMeta?> = config.node(key)
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableItemProvider.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableItemProvider.kt
index b6dc78e7..331c333e 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableItemProvider.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableItemProvider.kt
@@ -1,9 +1,14 @@
 package space.kscience.dataforge.meta
 
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import space.kscience.dataforge.misc.DFExperimental
-import space.kscience.dataforge.names.Name
-import space.kscience.dataforge.names.asName
-import space.kscience.dataforge.names.startsWith
+import space.kscience.dataforge.names.*
+import kotlin.js.JsName
+import kotlin.jvm.Synchronized
 import kotlin.reflect.KProperty1
 
 
@@ -12,13 +17,105 @@ internal data class ItemListener(
     val action: (name: Name, oldItem: MetaItem?, newItem: MetaItem?) -> Unit,
 )
 
-
-public interface ObservableItemProvider : ItemProvider {
+/**
+ * An item provider that could be observed and mutated
+ */
+public interface ObservableItemProvider : ItemProvider, MutableItemProvider {
+    /**
+     * Add change listener to this meta. Owner is declared to be able to remove listeners later. Listener without owner could not be removed
+     */
     public fun onChange(owner: Any?, action: (name: Name, oldItem: MetaItem?, newItem: MetaItem?) -> Unit)
+
+    /**
+     * Remove all listeners belonging to given owner
+     */
     public fun removeListener(owner: Any?)
 }
 
-public interface ItemPropertyProvider: ObservableItemProvider, MutableItemProvider
+private open class ObservableItemProviderWrapper(
+    open val itemProvider: MutableItemProvider,
+    open val parent: Pair<ObservableItemProviderWrapper, Name>? = null
+) : ObservableItemProvider {
+
+    override fun getItem(name: Name): MetaItem? = itemProvider.getItem(name)
+
+    private val listeners = HashSet<ItemListener>()
+
+    @Synchronized
+    private fun itemChanged(name: Name, oldItem: MetaItem?, newItem: MetaItem?) {
+        listeners.forEach { it.action(name, oldItem, newItem) }
+    }
+
+    override fun setItem(name: Name, item: MetaItem?) {
+        val oldItem = getItem(name)
+        itemProvider.setItem(name, item)
+        itemChanged(name, oldItem, item)
+
+        //Recursively send update to parent listeners
+        parent?.let { (parentNode, token) ->
+            parentNode.itemChanged(token + name, oldItem, item)
+        }
+    }
+
+    @Synchronized
+    override fun onChange(owner: Any?, action: (Name, MetaItem?, MetaItem?) -> Unit) {
+        listeners.add(ItemListener(owner, action))
+    }
+
+    @Synchronized
+    override fun removeListener(owner: Any?) {
+        listeners.removeAll { it.owner === owner }
+    }
+}
+
+public fun MutableItemProvider.asObservable(): ObservableItemProvider =
+    (this as? ObservableItemProvider) ?: ObservableItemProviderWrapper(this)
+
+/**
+ * A Meta instance that could be both mutated and observed.
+ */
+@Serializable(ObservableMetaSerializer::class)
+public interface ObservableMeta : ObservableItemProvider, MutableMeta<ObservableMeta>
+
+/**
+ * A wrapper class that creates observable meta node from regular meta node
+ */
+private class ObservableMetaWrapper<M : MutableMeta<M>>(
+    override val itemProvider: M,
+    override val parent: Pair<ObservableMetaWrapper<M>, Name>? = null
+) : ObservableItemProviderWrapper(itemProvider, parent), ObservableMeta {
+    override fun equals(other: Any?): Boolean = (itemProvider == other)
+
+    override fun hashCode(): Int = itemProvider.hashCode()
+
+    override fun toString(): String = itemProvider.toString()
+
+    private fun wrapItem(name: Name, item: TypedMetaItem<M>): TypedMetaItem<ObservableMeta> {
+        return when (item) {
+            is MetaItemValue -> item
+            is MetaItemNode<M> -> ObservableMetaWrapper(item.node, this to name).asMetaItem()
+        }
+    }
+
+    override fun getItem(name: Name): TypedMetaItem<ObservableMeta>? = itemProvider[name]?.let {
+        wrapItem(name, it)
+    }
+
+    override val items: Map<NameToken, TypedMetaItem<ObservableMeta>>
+        get() = itemProvider.items.mapValues { (token, childItem: TypedMetaItem<M>) ->
+            wrapItem(token.asName(), childItem)
+        }
+}
+
+/**
+ * If this meta is observable return itself. Otherwise return an observable wrapper. The changes of initial meta are
+ * reflected on wrapper but are **NOT** observed.
+ */
+public fun <M : MutableMeta<M>> M.asObservable(): ObservableMeta =
+    (this as? ObservableMeta) ?: ObservableMetaWrapper(this)
+
+@JsName("buildObservableMeta")
+public fun ObservableMeta(): ObservableMeta = MetaBuilder().asObservable()
 
 /**
  * Use the value of the property in a [callBack].
@@ -39,4 +136,26 @@ public fun <O : ObservableItemProvider, T> O.useProperty(
             callBack(property.get(this))
         }
     }
-}
\ No newline at end of file
+}
+
+public object ObservableMetaSerializer : KSerializer<ObservableMeta> {
+    public fun empty(): ObservableMeta = ObservableMeta()
+    override val descriptor: SerialDescriptor get() = MetaSerializer.descriptor
+
+    override fun deserialize(decoder: Decoder): ObservableMeta {
+        return MetaSerializer.deserialize(decoder).toMutableMeta().asObservable()
+    }
+
+    override fun serialize(encoder: Encoder, value: ObservableMeta) {
+        MetaSerializer.serialize(encoder, value)
+    }
+}
+
+public operator fun ObservableMeta.get(token: NameToken): TypedMetaItem<ObservableMeta>? = items[token]
+
+/**
+ * Create a copy of this config, optionally applying the given [block].
+ * The listeners of the original Config are not retained.
+ */
+public inline fun ObservableMeta.copy(block: ObservableMeta.() -> Unit = {}): ObservableMeta =
+    asObservable().apply(block)
\ No newline at end of file
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
index c8118954..2edc3ab3 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
@@ -13,16 +13,11 @@ import kotlin.jvm.Synchronized
  * 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() : Described, MetaRepr, ItemPropertyProvider {
-
-    private var items: MutableItemProvider = Config()
-
-    private val listeners = HashSet<ItemListener>()
-
+public open class Scheme(
+    private var items: ObservableItemProvider = ObservableMeta(),
+    final override var descriptor: NodeDescriptor? = null,
     private var default: ItemProvider? = null
-
-    final override var descriptor: NodeDescriptor? = null
-
+) : Described, MetaRepr, ObservableItemProvider, MutableItemProvider {
 
     /**
      * Add a listener to this scheme changes. If the inner provider is observable, then listening will be delegated to it.
@@ -30,8 +25,7 @@ public open class Scheme() : Described, MetaRepr, ItemPropertyProvider {
      */
     @Synchronized
     override fun onChange(owner: Any?, action: (Name, MetaItem?, MetaItem?) -> Unit) {
-        (items as? ObservableItemProvider)?.onChange(owner, action)
-            ?: run { listeners.add(ItemListener(owner, action)) }
+        items.onChange(owner, action)
     }
 
     /**
@@ -39,8 +33,7 @@ public open class Scheme() : Described, MetaRepr, ItemPropertyProvider {
      */
     @Synchronized
     override fun removeListener(owner: Any?) {
-        (items as? ObservableItemProvider)?.removeListener(owner)
-            ?: listeners.removeAll { it.owner === owner }
+        items.removeListener(owner)
     }
 
     internal fun wrap(
@@ -51,11 +44,11 @@ public open class Scheme() : Described, MetaRepr, ItemPropertyProvider {
         //use properties in the init block as default
         this.default = this.items.withDefault(default)
         //reset values, defaults are already saved
-        this.items = items
+        this.items = items.asObservable()
         this.descriptor = descriptor
     }
 
-    private fun getDefaultItem(name: Name): MetaItem? {
+    protected open fun getDefaultItem(name: Name): MetaItem? {
         return default?.get(name) ?: descriptor?.get(name)?.defaultValue
     }
 
@@ -79,7 +72,6 @@ public open class Scheme() : Described, MetaRepr, ItemPropertyProvider {
         val oldItem = items[name]
         if (validateItem(name, item)) {
             items[name] = item
-            listeners.forEach { it.action(name, oldItem, item) }
         } else {
             error("Validation failed for property $name with value $item")
         }
@@ -105,7 +97,7 @@ public open class Scheme() : Described, MetaRepr, ItemPropertyProvider {
             }
         }
 
-    override fun toMeta(): Laminate = Laminate(items[Name.EMPTY].node, defaultLayer)
+    override fun toMeta(): Laminate = Laminate(items.rootNode, defaultLayer)
 }
 
 /**
@@ -145,7 +137,7 @@ public open class SchemeSpec<out T : Scheme>(
 
     override fun empty(): T = builder()
 
-    override fun read(items: ItemProvider): T = wrap(Config(), items, descriptor)
+    override fun read(items: ItemProvider): T = wrap(ObservableMeta(), items, descriptor)
 
     override fun write(target: MutableItemProvider, defaultProvider: ItemProvider): T =
         wrap(target, defaultProvider, descriptor)
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ItemDescriptor.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ItemDescriptor.kt
index 8e9c4d20..29e6e2dd 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ItemDescriptor.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ItemDescriptor.kt
@@ -52,7 +52,7 @@ public sealed interface ItemDescriptor: MetaRepr {
  * The builder for [ItemDescriptor]
  */
 @DFBuilder
-public sealed class ItemDescriptorBuilder(final override val config: Config) : Configurable, ItemDescriptor {
+public sealed class ItemDescriptorBuilder(final override val config: ObservableMeta) : Configurable, ItemDescriptor {
 
     /**
      * True if same name siblings with this name are allowed
@@ -75,7 +75,7 @@ public sealed class ItemDescriptorBuilder(final override val config: Config) : C
      *
      * @return
      */
-    override var attributes: Config? by config.node()
+    override var attributes: ObservableMeta? by config.node()
 
     /**
      * An index field by which this node is identified in case of same name siblings construct
@@ -94,8 +94,8 @@ public sealed class ItemDescriptorBuilder(final override val config: Config) : C
 /**
  * Configure attributes of the descriptor, creating an attributes node if needed.
  */
-public inline fun ItemDescriptorBuilder.attributes(block: Config.() -> Unit) {
-    (attributes ?: Config().also { this.attributes = it }).apply(block)
+public inline fun ItemDescriptorBuilder.attributes(block: ObservableMeta.() -> Unit) {
+    (attributes ?: ObservableMeta().also { this.attributes = it }).apply(block)
 }
 
 /**
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/NodeDescriptor.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/NodeDescriptor.kt
index 772ae221..71cb1cf9 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/NodeDescriptor.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/NodeDescriptor.kt
@@ -41,7 +41,7 @@ public sealed interface NodeDescriptor : ItemDescriptor {
      *
      * @return
      */
-    public val default: Config?
+    public val default: Meta?
 
     /**
      * The map of children item descriptors (both nodes and values)
@@ -74,7 +74,7 @@ public sealed interface NodeDescriptor : ItemDescriptor {
 
 
 @DFBuilder
-public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBuilder(config), NodeDescriptor {
+public class NodeDescriptorBuilder(config: ObservableMeta = ObservableMeta()) : ItemDescriptorBuilder(config), NodeDescriptor {
     init {
         config[IS_NODE_KEY] = true
     }
@@ -91,7 +91,7 @@ public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBu
      *
      * @return
      */
-    override var default: Config? by config.node()
+    override var default: ObservableMeta? by config.node()
 
     /**
      * The map of children item descriptors (both nodes and values)
@@ -101,9 +101,9 @@ public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBu
             if (name == null) error("Child item index should not be null")
             val node = item.node ?: error("Node descriptor must be a node")
             if (node[IS_NODE_KEY].boolean == true) {
-                name to NodeDescriptorBuilder(node as Config)
+                name to NodeDescriptorBuilder(node as ObservableMeta)
             } else {
-                name to ValueDescriptorBuilder(node as Config)
+                name to ValueDescriptorBuilder(node as ObservableMeta)
             }
         }
 
@@ -117,7 +117,7 @@ public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBu
         }.associate { (name, item) ->
             if (name == null) error("Child node index should not be null")
             val node = item.node ?: error("Node descriptor must be a node")
-            name to NodeDescriptorBuilder(node as Config)
+            name to NodeDescriptorBuilder(node as ObservableMeta)
         }
 
     /**
@@ -129,7 +129,7 @@ public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBu
         }.associate { (name, item) ->
             if (name == null) error("Child value index should not be null")
             val node = item.node ?: error("Node descriptor must be a node")
-            name to ValueDescriptorBuilder(node as Config)
+            name to ValueDescriptorBuilder(node as ObservableMeta)
         }
 
     private fun buildNode(name: Name): NodeDescriptorBuilder {
@@ -137,7 +137,7 @@ public class NodeDescriptorBuilder(config: Config = Config()) : ItemDescriptorBu
             0 -> this
             1 -> {
                 val token = NameToken(ITEM_KEY.toString(), name.toString())
-                val config: Config = config[token].node ?: Config().also {
+                val config: ObservableMeta = config[token].node ?: ObservableMeta().also {
                     it[IS_NODE_KEY] = true
                     config[token] = it
                 }
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ValueDescriptor.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ValueDescriptor.kt
index dd530ed2..a58248bd 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ValueDescriptor.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/descriptors/ValueDescriptor.kt
@@ -5,7 +5,6 @@ import space.kscience.dataforge.misc.DFBuilder
 import space.kscience.dataforge.values.*
 
 
-
 /**
  * A descriptor for meta value
  *
@@ -14,7 +13,7 @@ import space.kscience.dataforge.values.*
  * @author Alexander Nozik
  */
 @DFBuilder
-public sealed interface ValueDescriptor: ItemDescriptor{
+public sealed interface ValueDescriptor : ItemDescriptor {
 
     /**
      * True if the value is required
@@ -37,6 +36,7 @@ public sealed interface ValueDescriptor: ItemDescriptor{
      * @return
      */
     public val type: List<ValueType>?
+
     /**
      * Check if given value is allowed for here. The type should be allowed and
      * if it is value should be within allowed values
@@ -61,7 +61,9 @@ public sealed interface ValueDescriptor: ItemDescriptor{
  * A builder fir [ValueDescriptor]
  */
 @DFBuilder
-public class ValueDescriptorBuilder(config: Config = Config()) : ItemDescriptorBuilder(config), ValueDescriptor {
+public class ValueDescriptorBuilder(
+    config: ObservableMeta = ObservableMeta()
+) : ItemDescriptorBuilder(config), ValueDescriptor {
 
     /**
      * True if the value is required
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/transformations/MetaTransformation.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/transformations/MetaTransformation.kt
index 3a35dbf8..8bce8aec 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/transformations/MetaTransformation.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/transformations/MetaTransformation.kt
@@ -105,7 +105,7 @@ public value class MetaTransformation(private val transformations: Collection<Tr
      * Generate an observable configuration that contains only elements defined by transformation rules and changes with the source
      */
     @DFExperimental
-    public fun generate(source: Config): ObservableItemProvider = Config().apply {
+    public fun generate(source: ObservableMeta): ObservableItemProvider = ObservableMeta().apply {
         transformations.forEach { rule ->
             rule.selectItems(source).forEach { name ->
                 rule.transformItem(name, source[name], this)
@@ -131,7 +131,7 @@ public value class MetaTransformation(private val transformations: Collection<Tr
     /**
      * Listens for changes in the source node and translates them into second node if transformation set contains a corresponding rule.
      */
-    public fun <M : MutableMeta<M>> bind(source: Config, target: M) {
+    public fun <M : MutableMeta<M>> bind(source: ObservableMeta, target: M) {
         source.onChange(target) { name, _, newItem ->
             transformations.forEach { t ->
                 if (t.matches(name, newItem)) {
diff --git a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/ConfigTest.kt b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/ConfigTest.kt
index 3ea8d7d3..3ec27c97 100644
--- a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/ConfigTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/ConfigTest.kt
@@ -6,7 +6,7 @@ import kotlin.test.assertEquals
 class ConfigTest {
     @Test
     fun testIndexedWrite(){
-        val config = Config()
+        val config = MetaBuilder()
         config["a[1].b"] = 1
         assertEquals(null, config["a.b"].int)
         assertEquals(1, config["a[1].b"].int)
diff --git a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/MutableMetaTest.kt b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/MutableMetaTest.kt
index 55a0a6de..51503f29 100644
--- a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/MutableMetaTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/MutableMetaTest.kt
@@ -14,7 +14,7 @@ class MutableMetaTest{
                 "b" put 22
                 "c" put "StringValue"
             }
-        }.asConfig()
+        }.asObservable()
 
         meta.remove("aNode.c")
         assertEquals(meta["aNode.c"], null)
diff --git a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SchemeTest.kt b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SchemeTest.kt
index 2b55658e..4d614d21 100644
--- a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SchemeTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SchemeTest.kt
@@ -8,7 +8,7 @@ import kotlin.test.assertEquals
 class SchemeTest {
     @Test
     fun testSchemeWrappingBeforeEdit(){
-        val config = Config()
+        val config = MetaBuilder()
         val scheme = TestScheme.wrap(config)
         scheme.a = 29
         assertEquals(29, config["a"].int)
@@ -18,7 +18,7 @@ class SchemeTest {
     fun testSchemeWrappingAfterEdit(){
         val scheme = TestScheme.empty()
         scheme.a = 29
-        val config = Config()
+        val config = MetaBuilder()
         scheme.retarget(config)
         assertEquals(29, scheme.a)
     }
diff --git a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SpecificationTest.kt b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SpecificationTest.kt
index 66e749be..dfd9de19 100644
--- a/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SpecificationTest.kt
+++ b/dataforge-meta/src/commonTest/kotlin/space/kscience/dataforge/meta/SpecificationTest.kt
@@ -13,7 +13,7 @@ internal class TestScheme : Scheme() {
         override fun empty(): TestScheme = TestScheme()
 
         override fun read(items: ItemProvider): TestScheme =
-            wrap(Config(), items)
+            wrap(MetaBuilder(), items)
 
         override fun write(target: MutableItemProvider, defaultProvider: ItemProvider): TestScheme =
             wrap(target, defaultProvider)
@@ -58,7 +58,7 @@ class SpecificationTest {
 
     @Test
     fun testChildModification() {
-        val config = Config()
+        val config = MetaBuilder()
         val child = config.getChild("child")
         val scheme = TestScheme.write(child)
         scheme.a = 22
@@ -69,7 +69,7 @@ class SpecificationTest {
 
     @Test
     fun testChildUpdate() {
-        val config = Config()
+        val config = MetaBuilder()
         val child = config.getChild("child")
         child.update(TestScheme) {
             a = 22
diff --git a/dataforge-scripting/src/jvmMain/kotlin/space/kscience/dataforge/scripting/Builders.kt b/dataforge-scripting/src/jvmMain/kotlin/space/kscience/dataforge/scripting/Builders.kt
index 28f05216..19c6e640 100644
--- a/dataforge-scripting/src/jvmMain/kotlin/space/kscience/dataforge/scripting/Builders.kt
+++ b/dataforge-scripting/src/jvmMain/kotlin/space/kscience/dataforge/scripting/Builders.kt
@@ -51,7 +51,7 @@ public object Builders {
         return builder.build()
     }
 
-    public fun buildWorkspace(file: File): Workspace = buildWorkspace(file.toScriptSource())
+    public fun buildWorkspace(scriptFile: File): Workspace = buildWorkspace(scriptFile.toScriptSource())
 
-    public fun buildWorkspace(string: String): Workspace = buildWorkspace(string.toScriptSource())
+    public fun buildWorkspace(scriptString: String): Workspace = buildWorkspace(scriptString.toScriptSource())
 }
\ No newline at end of file
diff --git a/dataforge-scripting/src/jvmTest/kotlin/space/kscience/dataforge/scripting/BuildersKtTest.kt b/dataforge-scripting/src/jvmTest/kotlin/space/kscience/dataforge/scripting/BuildersKtTest.kt
index c0f557e4..36ad16fb 100644
--- a/dataforge-scripting/src/jvmTest/kotlin/space/kscience/dataforge/scripting/BuildersKtTest.kt
+++ b/dataforge-scripting/src/jvmTest/kotlin/space/kscience/dataforge/scripting/BuildersKtTest.kt
@@ -3,7 +3,7 @@ package space.kscience.dataforge.scripting
 import space.kscience.dataforge.context.Global
 import space.kscience.dataforge.meta.get
 import space.kscience.dataforge.meta.int
-import space.kscience.dataforge.workspace.WorkspaceBuilder
+import space.kscience.dataforge.workspace.Workspace
 import space.kscience.dataforge.workspace.target
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -12,7 +12,7 @@ import kotlin.test.assertEquals
 class BuildersKtTest {
     @Test
     fun checkBuilder() {
-        val workspace = WorkspaceBuilder(Global).apply {
+        Workspace(Global){
             println("I am working")
 
             context { name("test") }
diff --git a/dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/WorkspaceBuilder.kt b/dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/WorkspaceBuilder.kt
index 68598714..c17c5991 100644
--- a/dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/WorkspaceBuilder.kt
+++ b/dataforge-workspace/src/commonMain/kotlin/space/kscience/dataforge/workspace/WorkspaceBuilder.kt
@@ -91,6 +91,5 @@ public inline fun WorkspaceBuilder.target(name: String, metaBuilder: MetaBuilder
     target(name, Meta(metaBuilder))
 
 @DFBuilder
-public fun Workspace(parentContext: Context = Global, builder: WorkspaceBuilder.() -> Unit): Workspace {
-    return WorkspaceBuilder(parentContext).apply(builder).build()
-}
\ No newline at end of file
+public fun Workspace(parentContext: Context = Global, builder: WorkspaceBuilder.() -> Unit): Workspace =
+    WorkspaceBuilder(parentContext).apply(builder).build()
\ No newline at end of file