diff --git a/common/readme.md b/common/readme.md
--- a/common/readme.md
+++ b/common/readme.md
@@ -3,7 +3,7 @@
 ## NAME
 
 `gradle-common/common` — набор плагинов для моделирования вариантов сборки,
-материализации source sets и интеграции этой модели с toolchain-адаптерами.
+регистрации source sets и интеграции этой модели с toolchain-адаптерами.
 
 ## SYNOPSIS
 
@@ -46,7 +46,7 @@ variantSources {
 Модуль состоит из трех логических частей:
 
 - `variants` — декларативная доменная модель сборки;
-- `sources` — модель физически материализуемых source sets;
+- `sources` — модель физически регистрируемых source sets;
 - `variantSources` — адаптер, который связывает первые две модели.
 
 Ниже раскрытие каждой части.
@@ -77,14 +77,14 @@ outputs. Это уже "физический" уровень, к которому удобно привязывать задачи,
 
 ### variantSources
 
-`variantSources` материализует source sets на основе `variants`, применяет
+`variantSources` регистрирует source sets на основе `variants`, применяет
 конфигурацию layer-bindings и отдает события (`whenRegistered`, `whenBound`) для
 адаптеров других плагинов.
 
 Практический смысл:
 
 - переводить логическую модель `variants` в executable-модель `sources`;
-- навешивать политики toolchain на materialized source sets;
+- навешивать политики toolchain на зарегистрированные source sets;
 - синхронизировать плагины через replayable callback-контракт.
 
 ## DOMAIN MODEL
@@ -92,10 +92,10 @@ outputs. Это уже "физический" уровень, к которому удобно привязывать задачи,
 - `BuildLayer` — глобальный идентификатор слоя.
 - `BuildVariant` — агрегат ролей, связей, атрибутов, артефактных слотов.
 - `BuildRole` — роль внутри варианта, содержит ссылки на layer names.
-- `BuildLink` — ориентированная связь `from -> to` в графе определенного `kind`.
-- `GenericSourceSet` — materialized набор исходников и outputs.
-- `BuildLayerBinding` — правила materialization source set для конкретного layer.
-- `SourceSetContext` — контекст callback-событий materialization.
+- `LayerLink` — ориентированная связь `from -> to` в графе определенного `kind`.
+- `GenericSourceSet` — зарегистрированный набор исходников и outputs.
+- `BuildLayerBinding` — правила registration source set для конкретного layer.
+- `SourceSetContext` — контекст callback-событий registration.
 
 ## EVENT CONTRACT
 
@@ -117,7 +117,7 @@ Closure callbacks работают в delegate-first режиме (`@DelegatesTo`). Для
 - `BuildVariantsExtension` — корневой API модели вариантов.
 - `BuildVariant` — API ролей, links, attributes и artifact slots варианта.
 - `VariantsSourcesPlugin` — применяет `variants` + `sources` и запускает адаптер.
-- `VariantSourcesExtension` — API bind/events materialization.
+- `VariantSourcesExtension` — API bind/events registration.
 - `BuildLayerBinding` — слой-конкретный DSL для имени и конфигурации source set.
 - `SourceSetContext` — payload событий и sugar `configureSourceSet(...)`.
 
diff --git a/common/src/main/java/org/implab/gradle/common/sources/BuildLink.java b/common/src/main/java/org/implab/gradle/common/sources/BuildLink.java
deleted file mode 100644
--- a/common/src/main/java/org/implab/gradle/common/sources/BuildLink.java
+++ /dev/null
@@ -1,41 +0,0 @@
-package org.implab.gradle.common.sources;
-
-import javax.inject.Inject;
-
-import org.gradle.api.Named;
-import org.gradle.api.provider.Property;
-
-/**
- * Directed relation between two layers within a variant.
- */
-public abstract class BuildLink implements Named {
-    private final String name;
-
-    @Inject
-    public BuildLink(String name) {
-        this.name = name;
-    }
-
-    @Override
-    public String getName() {
-        return name;
-    }
-
-    public abstract Property<String> getFrom();
-
-    public abstract Property<String> getTo();
-
-    public abstract Property<String> getKind();
-
-    public void from(String value) {
-        getFrom().set(value);
-    }
-
-    public void to(String value) {
-        getTo().set(value);
-    }
-
-    public void kind(String value) {
-        getKind().set(value);
-    }
-}
diff --git a/common/src/main/java/org/implab/gradle/common/sources/BuildRole.java b/common/src/main/java/org/implab/gradle/common/sources/BuildRole.java
--- a/common/src/main/java/org/implab/gradle/common/sources/BuildRole.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/BuildRole.java
@@ -5,6 +5,7 @@ import java.util.Objects;
 
 import javax.inject.Inject;
 
+import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.Named;
 import org.gradle.api.provider.ListProperty;
 
@@ -13,6 +14,7 @@ import org.gradle.api.provider.ListPrope
  */
 public abstract class BuildRole implements Named {
     private final String name;
+    private boolean finalized;
 
     @Inject
     public BuildRole(String name) {
@@ -30,6 +32,8 @@ public abstract class BuildRole implemen
      * Binds this role to one or more declared layers.
      */
     public void layers(String layer, String... extra) {
+        ensureMutable("add role layers");
+
         var values = new ArrayList<String>(1 + extra.length);
 
         values.add(Objects.requireNonNull(layer, "Layer name is required"));
@@ -38,4 +42,18 @@ public abstract class BuildRole implemen
 
         getLayers().addAll(values);
     }
+
+    void finalizeModel() {
+        if (finalized)
+            return;
+
+        getLayers().finalizeValue();
+        getLayers().disallowChanges();
+        finalized = true;
+    }
+
+    private void ensureMutable(String operation) {
+        if (finalized)
+            throw new InvalidUserDataException("Role '" + name + "' is finalized and cannot " + operation);
+    }
 }
diff --git a/common/src/main/java/org/implab/gradle/common/sources/BuildVariant.java b/common/src/main/java/org/implab/gradle/common/sources/BuildVariant.java
--- a/common/src/main/java/org/implab/gradle/common/sources/BuildVariant.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/BuildVariant.java
@@ -1,16 +1,18 @@
 package org.implab.gradle.common.sources;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
-import java.util.regex.Pattern;
 
 import javax.inject.Inject;
 
 import org.implab.gradle.common.core.lang.Closures;
 import org.gradle.api.Action;
+import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.Named;
 import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.provider.Provider;
@@ -20,17 +22,16 @@ import org.gradle.api.attributes.Attribu
 import groovy.lang.Closure;
 
 public abstract class BuildVariant implements Named {
-    private static final Pattern INVALID_NAME_CHAR = Pattern.compile("[^A-Za-z0-9_.-]");
-
     private final String name;
     private final ObjectFactory objects;
+    private boolean finalized;
 
     /**
      * Variant aggregate parts.
      */
     private final VariantAttributes attributes;
     private final LinkedHashMap<String, BuildRole> roles = new LinkedHashMap<>();
-    private final LinkedHashMap<String, BuildLink> links = new LinkedHashMap<>();
+    private final List<LayerLink> links = new ArrayList<>();
     private final LinkedHashMap<String, BuildArtifactSlot> artifactSlots = new LinkedHashMap<>();
 
     @Inject
@@ -53,6 +54,7 @@ public abstract class BuildVariant imple
     }
 
     public void attributes(Action<? super AttributesSpec> action) {
+        ensureMutable("configure attributes");
         action.execute(new AttributesSpec(attributes));
     }
 
@@ -61,10 +63,12 @@ public abstract class BuildVariant imple
     }
 
     public <T> void attribute(Attribute<T> key, T value) {
+        ensureMutable("set attributes");
         attributes.attribute(key, value);
     }
 
     public <T> void attributeProvider(Attribute<T> key, Provider<? extends T> value) {
+        ensureMutable("set attributes");
         attributes.attributeProvider(key, value);
     }
 
@@ -73,6 +77,7 @@ public abstract class BuildVariant imple
     }
 
     public void roles(Action<? super RolesSpec> action) {
+        ensureMutable("configure roles");
         action.execute(new RolesSpec());
     }
 
@@ -81,6 +86,7 @@ public abstract class BuildVariant imple
     }
 
     public BuildRole role(String name, Action<? super BuildRole> configure) {
+        ensureMutable("configure roles");
         var role = roles.computeIfAbsent(name, this::newRole);
         configure.execute(role);
         return role;
@@ -99,11 +105,12 @@ public abstract class BuildVariant imple
         return roles.get(name);
     }
 
-    public Collection<BuildLink> getLinks() {
-        return Collections.unmodifiableCollection(links.values());
+    public Collection<LayerLink> getLinks() {
+        return Collections.unmodifiableList(links);
     }
 
     public void links(Action<? super LinksSpec> action) {
+        ensureMutable("configure links");
         action.execute(new LinksSpec());
     }
 
@@ -111,43 +118,19 @@ public abstract class BuildVariant imple
         links(Closures.action(configure));
     }
 
-    public BuildLink link(String from, String to, String kind, Action<? super BuildLink> configure) {
-        return link(defaultLinkName(from, to, kind), link -> {
-            link.from(from);
-            link.to(to);
-            link.kind(kind);
-            configure.execute(link);
-        });
-    }
-
-    public BuildLink link(String from, String to, String kind, Closure<?> configure) {
-        return link(from, to, kind, Closures.action(configure));
-    }
-
-    public BuildLink link(String from, String to, String kind) {
-        return link(from, to, kind, it -> {
-        });
-    }
-
-    public BuildLink link(String name, Action<? super BuildLink> configure) {
-        var link = links.computeIfAbsent(name, this::newLink);
-        configure.execute(link);
+    public LayerLink link(String from, String to, String kind) {
+        ensureMutable("add links");
+        var link = new LayerLink(from, to, kind);
+        links.add(link);
         return link;
     }
 
-    public BuildLink link(String name, Closure<?> configure) {
-        return link(name, Closures.action(configure));
-    }
-
-    public BuildLink getLinkByName(String name) {
-        return links.get(name);
-    }
-
     public Collection<BuildArtifactSlot> getArtifactSlots() {
         return Collections.unmodifiableCollection(artifactSlots.values());
     }
 
     public void artifactSlots(Action<? super ArtifactSlotsSpec> action) {
+        ensureMutable("configure artifact slots");
         action.execute(new ArtifactSlotsSpec());
     }
 
@@ -161,6 +144,7 @@ public abstract class BuildVariant imple
     }
 
     public BuildArtifactSlot artifactSlot(String name, Action<? super BuildArtifactSlot> configure) {
+        ensureMutable("configure artifact slots");
         var slot = artifactSlots.computeIfAbsent(name, this::newArtifactSlot);
         configure.execute(slot);
         return slot;
@@ -183,24 +167,28 @@ public abstract class BuildVariant imple
         return result;
     }
 
+    void finalizeModel() {
+        if (finalized)
+            return;
+
+        for (var role : roles.values())
+            role.finalizeModel();
+
+        attributes.finalizeModel();
+        finalized = true;
+    }
+
     private BuildRole newRole(String roleName) {
         return objects.newInstance(BuildRole.class, roleName);
     }
 
-    private BuildLink newLink(String linkName) {
-        return objects.newInstance(BuildLink.class, linkName);
-    }
-
     private BuildArtifactSlot newArtifactSlot(String slotName) {
         return objects.newInstance(BuildArtifactSlot.class, slotName);
     }
 
-    private static String defaultLinkName(String from, String to, String kind) {
-        return "link_" + sanitize(from) + "__" + sanitize(to) + "__" + sanitize(kind);
-    }
-
-    private static String sanitize(String value) {
-        return INVALID_NAME_CHAR.matcher(String.valueOf(value)).replaceAll("_");
+    private void ensureMutable(String operation) {
+        if (finalized)
+            throw new InvalidUserDataException("Variant '" + name + "' is finalized and cannot " + operation);
     }
 
     public final class RolesSpec {
@@ -226,25 +214,13 @@ public abstract class BuildVariant imple
     }
 
     public final class LinksSpec {
-        public BuildLink link(String from, String to, String kind, Action<? super BuildLink> configure) {
-            return BuildVariant.this.link(from, to, kind, configure);
-        }
-
-        public BuildLink link(String from, String to, String kind, Closure<?> configure) {
-            return BuildVariant.this.link(from, to, kind, configure);
-        }
-
-        public BuildLink link(String from, String to, String kind) {
+        public LayerLink link(String from, String to, String kind) {
             return BuildVariant.this.link(from, to, kind);
         }
 
-        public Collection<BuildLink> getAll() {
+        public Collection<LayerLink> getAll() {
             return BuildVariant.this.getLinks();
         }
-
-        public BuildLink getByName(String name) {
-            return BuildVariant.this.getLinkByName(name);
-        }
     }
 
     public final class ArtifactSlotsSpec {
diff --git a/common/src/main/java/org/implab/gradle/common/sources/BuildVariantsExtension.java b/common/src/main/java/org/implab/gradle/common/sources/BuildVariantsExtension.java
--- a/common/src/main/java/org/implab/gradle/common/sources/BuildVariantsExtension.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/BuildVariantsExtension.java
@@ -31,6 +31,18 @@ public abstract class BuildVariantsExten
     public BuildVariantsExtension(ObjectFactory objects) {
         layers = objects.domainObjectContainer(BuildLayer.class);
         variants = objects.domainObjectContainer(BuildVariant.class);
+
+        layers.all(layer -> {
+            if (finalized)
+                throw new InvalidUserDataException(
+                        "Variants model is finalized and cannot add layer '" + layer.getName() + "'");
+        });
+
+        variants.all(variant -> {
+            if (finalized)
+                throw new InvalidUserDataException(
+                        "Variants model is finalized and cannot add variant '" + variant.getName() + "'");
+        });
     }
 
     public NamedDomainObjectContainer<BuildLayer> getLayers() {
@@ -42,6 +54,7 @@ public abstract class BuildVariantsExten
     }
 
     public void layers(Action<? super NamedDomainObjectContainer<BuildLayer>> action) {
+        ensureMutable("configure layers");
         action.execute(layers);
     }
 
@@ -50,6 +63,7 @@ public abstract class BuildVariantsExten
     }
 
     public void variants(Action<? super NamedDomainObjectContainer<BuildVariant>> action) {
+        ensureMutable("configure variants");
         action.execute(variants);
     }
 
@@ -58,6 +72,7 @@ public abstract class BuildVariantsExten
     }
 
     public BuildLayer layer(String name, Action<? super BuildLayer> configure) {
+        ensureMutable("configure layers");
         var layer = layers.maybeCreate(name);
         configure.execute(layer);
         return layer;
@@ -73,6 +88,7 @@ public abstract class BuildVariantsExten
     }
 
     public BuildVariant variant(String name, Action<? super BuildVariant> configure) {
+        ensureMutable("configure variants");
         var variant = variants.maybeCreate(name);
         configure.execute(variant);
         return variant;
@@ -126,6 +142,10 @@ public abstract class BuildVariantsExten
             return;
 
         validate();
+
+        for (var variant : variants)
+            variant.finalizeModel();
+
         finalized = true;
 
         var actions = new ArrayList<>(finalizedActions);
@@ -187,24 +207,23 @@ public abstract class BuildVariantsExten
         var edgesByKind = new HashMap<String, Map<String, Set<String>>>();
 
         for (var link : variant.getLinks()) {
-            var from = normalize(link.getFrom().getOrNull());
-            var to = normalize(link.getTo().getOrNull());
-            var kind = normalize(link.getKind().getOrNull());
+            var from = normalize(link.from());
+            var to = normalize(link.to());
+            var kind = normalize(link.kind());
 
             if (from == null || to == null || kind == null) {
-                errors.add("Variant '" + variant.getName() + "' has incomplete link '" + link.getName()
-                        + "' (from/to/kind are required)");
+                errors.add("Variant '" + variant.getName() + "' has incomplete link (from/to/kind are required)");
                 continue;
             }
 
             if (!variantLayers.contains(from)) {
-                errors.add("Variant '" + variant.getName() + "' link '" + link.getName() + "' references unknown source layer '"
+                errors.add("Variant '" + variant.getName() + "' link references unknown source layer '"
                         + from + "'");
                 continue;
             }
 
             if (!variantLayers.contains(to)) {
-                errors.add("Variant '" + variant.getName() + "' link '" + link.getName() + "' references unknown target layer '"
+                errors.add("Variant '" + variant.getName() + "' link references unknown target layer '"
                         + to + "'");
                 continue;
             }
@@ -268,4 +287,9 @@ public abstract class BuildVariantsExten
     private static boolean isBlank(String value) {
         return normalize(value) == null;
     }
+
+    private void ensureMutable(String operation) {
+        if (finalized)
+            throw new InvalidUserDataException("Variants model is finalized and cannot " + operation);
+    }
 }
diff --git a/common/src/main/java/org/implab/gradle/common/sources/LayerLink.java b/common/src/main/java/org/implab/gradle/common/sources/LayerLink.java
new file mode 100644
--- /dev/null
+++ b/common/src/main/java/org/implab/gradle/common/sources/LayerLink.java
@@ -0,0 +1,7 @@
+package org.implab.gradle.common.sources;
+
+/**
+ * Directed relation between two layers within a variant.
+ */
+public record LayerLink(String from, String to, String kind) {
+}
diff --git a/common/src/main/java/org/implab/gradle/common/sources/SourcesPlugin.java b/common/src/main/java/org/implab/gradle/common/sources/SourcesPlugin.java
--- a/common/src/main/java/org/implab/gradle/common/sources/SourcesPlugin.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/SourcesPlugin.java
@@ -19,6 +19,7 @@ public abstract class SourcesPlugin impl
 
     @Override
     public void apply(Project target) {
+        logger.debug("Registering '{}' extension on project '{}'", SOURCES_EXTENSION_NAME, target.getPath());
         var sources = target.getObjects().domainObjectContainer(GenericSourceSet.class);
         target.getExtensions().add(SOURCES_EXTENSION_NAME, sources);
     }
@@ -27,10 +28,13 @@ public abstract class SourcesPlugin impl
         var extensions = target.getExtensions();
 
         @SuppressWarnings("unchecked")
-        var extension = (NamedDomainObjectContainer<GenericSourceSet>)extensions.getByName(SOURCES_EXTENSION_NAME);
+        var extension = (NamedDomainObjectContainer<GenericSourceSet>) extensions.findByName(SOURCES_EXTENSION_NAME);
 
-        if (extension == null)
+        if (extension == null) {
+            logger.error("Sources extension '{}' isn't found on project '{}'", SOURCES_EXTENSION_NAME, target.getPath());
             throw new GradleException("Sources extension isn't found");
+        }
+        logger.debug("Resolved '{}' extension on project '{}'", SOURCES_EXTENSION_NAME, target.getPath());
         return extension;
     }
 }
diff --git a/common/src/main/java/org/implab/gradle/common/sources/VariantAttributes.java b/common/src/main/java/org/implab/gradle/common/sources/VariantAttributes.java
--- a/common/src/main/java/org/implab/gradle/common/sources/VariantAttributes.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/VariantAttributes.java
@@ -4,6 +4,7 @@ import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.attributes.Attribute;
 import org.gradle.api.provider.ProviderFactory;
 import org.gradle.api.provider.Provider;
@@ -14,16 +15,19 @@ import org.gradle.api.provider.Provider;
 public final class VariantAttributes {
     private final ProviderFactory providers;
     private final LinkedHashMap<Attribute<?>, Provider<?>> values = new LinkedHashMap<>();
+    private boolean finalized;
 
     VariantAttributes(ProviderFactory providers) {
         this.providers = providers;
     }
 
     public <T> void attribute(Attribute<T> key, T value) {
+        ensureMutable("set attribute '" + key.getName() + "'");
         attributeProvider(key, providers.provider(() -> value));
     }
 
     public <T> void attributeProvider(Attribute<T> key, Provider<? extends T> value) {
+        ensureMutable("set attribute provider '" + key.getName() + "'");
         values.put(key, value);
     }
 
@@ -43,4 +47,13 @@ public final class VariantAttributes {
     public Map<Attribute<?>, Provider<?>> asMap() {
         return Collections.unmodifiableMap(values);
     }
+
+    void finalizeModel() {
+        finalized = true;
+    }
+
+    private void ensureMutable(String operation) {
+        if (finalized)
+            throw new InvalidUserDataException("Variant attributes are finalized and cannot " + operation);
+    }
 }
diff --git a/common/src/main/java/org/implab/gradle/common/sources/VariantSourcesExtension.java b/common/src/main/java/org/implab/gradle/common/sources/VariantSourcesExtension.java
--- a/common/src/main/java/org/implab/gradle/common/sources/VariantSourcesExtension.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/VariantSourcesExtension.java
@@ -17,15 +17,18 @@ import org.gradle.api.InvalidUserDataExc
 import org.gradle.api.NamedDomainObjectContainer;
 import org.gradle.api.NamedDomainObjectProvider;
 import org.gradle.api.model.ObjectFactory;
+import org.gradle.api.logging.Logger;
+import org.gradle.api.logging.Logging;
 
 import groovy.lang.Closure;
 import groovy.lang.DelegatesTo;
 
 /**
- * Adapter extension that materializes source sets for variant/layer pairs.
+ * Adapter extension that registers source sets for variant/layer pairs.
  */
 @NonNullByDefault
 public abstract class VariantSourcesExtension {
+    private static final Logger logger = Logging.getLogger(VariantSourcesExtension.class);
     private static final Pattern INVALID_NAME_CHAR = Pattern.compile("[^A-Za-z0-9_.-]");
     private static final Pattern SOURCE_SET_NAME_TOKEN = Pattern.compile("\\{([A-Za-z][A-Za-z0-9]*)\\}");
 
@@ -135,7 +138,25 @@ public abstract class VariantSourcesExte
 
     void registerSourceSets(BuildVariantsExtension variants, NamedDomainObjectContainer<GenericSourceSet> sources) {
         validateBindings(variants);
-        layerUsages(variants).forEach(usage -> materializeLayerUsage(usage, sources));
+
+        var usages = layerUsages(variants).toList();
+        var registeredBefore = registeredContexts.size();
+        var boundBefore = boundContexts.size();
+
+        logger.debug(
+                "Starting variant source-set registration (variants={}, layers={}, bindings={}, usages={})",
+                variants.getVariants().size(),
+                variants.getLayers().size(),
+                bindings.size(),
+                usages.size());
+
+        usages.forEach(usage -> registerLayerUsage(usage, sources));
+
+        logger.debug(
+                "Completed variant source-set registration (newSourceSets={}, newBounds={}, totalSourceSets={})",
+                registeredContexts.size() - registeredBefore,
+                boundContexts.size() - boundBefore,
+                sourceSetsByName.size());
     }
 
     private Stream<LayerUsage> layerUsages(BuildVariantsExtension variants) {
@@ -148,7 +169,7 @@ public abstract class VariantSourcesExte
                                         normalize(layerName)))));
     }
 
-    private void materializeLayerUsage(LayerUsage usage, NamedDomainObjectContainer<GenericSourceSet> sources) {
+    private void registerLayerUsage(LayerUsage usage, NamedDomainObjectContainer<GenericSourceSet> sources) {
         var resolvedBinding = bind(usage.layerName());
         var sourceSetNamePattern = resolvedBinding.getSourceSetNamePattern();
         sourceSetNamePattern.finalizeValueOnRead();
diff --git a/common/src/main/java/org/implab/gradle/common/sources/VariantsPlugin.java b/common/src/main/java/org/implab/gradle/common/sources/VariantsPlugin.java
--- a/common/src/main/java/org/implab/gradle/common/sources/VariantsPlugin.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/VariantsPlugin.java
@@ -3,24 +3,36 @@ package org.implab.gradle.common.sources
 import org.gradle.api.GradleException;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.logging.Logger;
+import org.gradle.api.logging.Logging;
 
 /**
  * Registers {@code variants} extension for build-variant modeling.
  */
 public abstract class VariantsPlugin implements Plugin<Project> {
+    private static final Logger logger = Logging.getLogger(VariantsPlugin.class);
     public static final String VARIANTS_EXTENSION_NAME = "variants";
 
     @Override
     public void apply(Project target) {
+        logger.debug("Registering '{}' extension on project '{}'", VARIANTS_EXTENSION_NAME, target.getPath());
         var variants = target.getExtensions().create(VARIANTS_EXTENSION_NAME, BuildVariantsExtension.class);
-        target.afterEvaluate(project -> variants.finalizeModel());
+        target.afterEvaluate(project -> {
+            logger.debug("Finalizing variants model on project '{}'", project.getPath());
+            variants.finalizeModel();
+            logger.debug("Variants model finalized on project '{}'", project.getPath());
+        });
     }
 
     public static BuildVariantsExtension getVariantsExtension(Project target) {
         var extension = target.getExtensions().findByType(BuildVariantsExtension.class);
 
-        if (extension == null)
+        if (extension == null) {
+            logger.error("Variants extension '{}' isn't found on project '{}'", VARIANTS_EXTENSION_NAME, target.getPath());
             throw new GradleException("Variants extension isn't found");
+        }
+
+        logger.debug("Resolved '{}' extension on project '{}'", VARIANTS_EXTENSION_NAME, target.getPath());
 
         return extension;
     }
diff --git a/common/src/main/java/org/implab/gradle/common/sources/VariantsSourcesPlugin.java b/common/src/main/java/org/implab/gradle/common/sources/VariantsSourcesPlugin.java
--- a/common/src/main/java/org/implab/gradle/common/sources/VariantsSourcesPlugin.java
+++ b/common/src/main/java/org/implab/gradle/common/sources/VariantsSourcesPlugin.java
@@ -2,15 +2,19 @@ package org.implab.gradle.common.sources
 
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.logging.Logger;
+import org.gradle.api.logging.Logging;
 
 /**
- * Binds variant layers to materialized source sets.
+ * Binds variant layers to registered source sets.
  */
 public abstract class VariantsSourcesPlugin implements Plugin<Project> {
+    private static final Logger logger = Logging.getLogger(VariantsSourcesPlugin.class);
     public static final String VARIANT_SOURCES_EXTENSION_NAME = "variantSources";
 
     @Override
     public void apply(Project target) {
+        logger.debug("Applying variant-sources plugin on project '{}'", target.getPath());
         target.getPluginManager().apply(VariantsPlugin.class);
         target.getPluginManager().apply(SourcesPlugin.class);
 
@@ -20,6 +24,10 @@ public abstract class VariantsSourcesPlu
         var variantSources = target.getExtensions()
                 .create(VARIANT_SOURCES_EXTENSION_NAME, VariantSourcesExtension.class);
 
-        variants.whenFinalized(model -> variantSources.registerSourceSets(model, sources));
+        variants.whenFinalized(model -> {
+            logger.debug("Registering source sets for variants on project '{}'", target.getPath());
+            variantSources.registerSourceSets(model, sources);
+            logger.debug("Registered source sets on project '{}'", target.getPath());
+        });
     }
 }
diff --git a/common/src/test/java/org/implab/gradle/common/sources/VariantsPluginFunctionalTest.java b/common/src/test/java/org/implab/gradle/common/sources/VariantsPluginFunctionalTest.java
--- a/common/src/test/java/org/implab/gradle/common/sources/VariantsPluginFunctionalTest.java
+++ b/common/src/test/java/org/implab/gradle/common/sources/VariantsPluginFunctionalTest.java
@@ -153,13 +153,10 @@ class VariantsPluginFunctionalTest {
                     role('main') {
                         layers('a', 'b')
                     }
-                    link('l1') {
-                        from('a')
-                        to('b')
-                    }
+                    link('a', 'b', null)
                 }
             }
-            """, "has incomplete link 'l1'");
+            """, "has incomplete link (from/to/kind are required)");
     }
 
     @Test
@@ -177,16 +174,8 @@ class VariantsPluginFunctionalTest {
                     role('main') {
                         layers('a', 'b')
                     }
-                    link('first') {
-                        from('a')
-                        to('b')
-                        kind('ts:api')
-                    }
-                    link('second') {
-                        from('a')
-                        to('b')
-                        kind('ts:api')
-                    }
+                    link('a', 'b', 'ts:api')
+                    link('a', 'b', 'ts:api')
                 }
             }
             """, "has duplicated link tuple (from='a', to='b', kind='ts:api')");
@@ -207,11 +196,7 @@ class VariantsPluginFunctionalTest {
                     role('main') {
                         layers('a')
                     }
-                    link('l1') {
-                        from('missing')
-                        to('a')
-                        kind('ts:api')
-                    }
+                    link('missing', 'a', 'ts:api')
                 }
             }
             """, "references unknown source layer 'missing'");
@@ -232,16 +217,52 @@ class VariantsPluginFunctionalTest {
                     role('main') {
                         layers('a')
                     }
-                    link('l1') {
-                        from('a')
-                        to('missing')
-                        kind('ts:api')
-                    }
+                    link('a', 'missing', 'ts:api')
                 }
             }
             """, "references unknown target layer 'missing'");
     }
 
+    @Test
+    void failsOnLateLayerMutationAfterFinalize() throws Exception {
+        assertBuildFails("""
+            plugins {
+                id 'org.implab.gradle-variants'
+            }
+
+            variants {
+                layer('a')
+                variant('browser') {
+                    role('main') { layers('a') }
+                }
+            }
+
+            afterEvaluate {
+                variants.layer('late')
+            }
+            """, "Variants model is finalized and cannot configure layers");
+    }
+
+    @Test
+    void failsOnLateVariantMutationAfterFinalize() throws Exception {
+        assertBuildFails("""
+            plugins {
+                id 'org.implab.gradle-variants'
+            }
+
+            variants {
+                layer('a')
+                variant('browser') {
+                    role('main') { layers('a') }
+                }
+            }
+
+            afterEvaluate {
+                variants.getByName('browser').role('late') { layers('a') }
+            }
+            """, "Variant 'browser' is finalized and cannot configure roles");
+    }
+
     private GradleRunner runner(String... arguments) {
         return GradleRunner.create()
                 .withProjectDir(testProjectDir.toFile())
diff --git a/common/src/test/java/org/implab/gradle/common/sources/VariantsSourcesPluginFunctionalTest.java b/common/src/test/java/org/implab/gradle/common/sources/VariantsSourcesPluginFunctionalTest.java
--- a/common/src/test/java/org/implab/gradle/common/sources/VariantsSourcesPluginFunctionalTest.java
+++ b/common/src/test/java/org/implab/gradle/common/sources/VariantsSourcesPluginFunctionalTest.java
@@ -26,7 +26,7 @@ class VariantsSourcesPluginFunctionalTes
     Path testProjectDir;
 
     @Test
-    void materializesVariantSourceSetsAndFiresCallbacks() throws Exception {
+    void registersVariantSourceSetsAndFiresCallbacks() throws Exception {
         writeFile(SETTINGS_FILE, ROOT_NAME);
         writeFile(BUILD_FILE, """
                 plugins {
@@ -194,7 +194,7 @@ class VariantsSourcesPluginFunctionalTes
     }
 
     @Test
-    void replaysLateBindingsAndCallbacksAfterMaterialization() throws Exception {
+    void replaysLateBindingsAndCallbacksAfterRegistration() throws Exception {
         writeFile(SETTINGS_FILE, ROOT_NAME);
         writeFile(BUILD_FILE, """
                 plugins {
diff --git a/common/variant-sources-plugin.md b/common/variant-sources-plugin.md
--- a/common/variant-sources-plugin.md
+++ b/common/variant-sources-plugin.md
@@ -40,13 +40,13 @@ variantSources {
 ## DESCRIPTION
 
 `VariantsSourcesPlugin` применяет `VariantsPlugin` и `SourcesPlugin`, затем
-материализует source sets из модели `variants`.
+регистрирует source sets из модели `variants`.
 
-Точка запуска materialization:
+Точка запуска registration:
 
 - `variants.whenFinalized(model -> registerSourceSets(...))`
 
-### materialization
+### registration
 
 Для каждой usage-связки `variant/role/layer` вычисляется имя source set,
 регистрируется `GenericSourceSet` (если он еще не существует), затем
@@ -63,7 +63,7 @@ variantSources {
 
 ### sourceSetNamePattern
 
-`sourceSetNamePattern` определяет naming policy materialized source set.
+`sourceSetNamePattern` определяет naming policy зарегистрированного source set.
 
 Default:
 
@@ -139,7 +139,7 @@ Sugar:
 
 ## NOTES
 
-- `sourceSetNamePattern` фиксируется при первом чтении в materialization
+- `sourceSetNamePattern` фиксируется при первом чтении в registration
   (`finalizeValueOnRead`).
 - Closure callbacks используют delegate-first.
 - Для вложенных closure лучше явный параметр (`ctx -> ...`).
diff --git a/common/variants-plugin.md b/common/variants-plugin.md
--- a/common/variants-plugin.md
+++ b/common/variants-plugin.md
@@ -88,6 +88,7 @@ Typed-атрибуты (`Attribute<T> -> Provider<T>`) для передачи параметров в
 ## LIFECYCLE
 
 - `VariantsPlugin` вызывает `variants.finalizeModel()` на `afterEvaluate`.
+- после `finalizeModel()` мутации модели запрещены.
 - `whenFinalized(...)` replayable.
 
 ## API
@@ -117,7 +118,7 @@ Typed-атрибуты (`Attribute<T> -> Provider<T>`) для передачи параметров в
 - `BuildVariant` — агрегатная модель варианта.
 - `BuildLayer` — модель слоя.
 - `BuildRole` — модель роли.
-- `BuildLink` — модель направленной связи.
+- `LayerLink` — модель направленной связи.
 - `BuildArtifactSlot` — модель артефактного слота.
 - `VariantAttributes` — typed wrapper для variant attributes.