diff --git a/headers/meta.hpp/meta_detail/state_registry.hpp b/headers/meta.hpp/meta_detail/state_registry.hpp
index 9d5b7e2..c17f3e0 100644
--- a/headers/meta.hpp/meta_detail/state_registry.hpp
+++ b/headers/meta.hpp/meta_detail/state_registry.hpp
@@ -19,28 +19,29 @@ namespace meta_hpp::detail
         }
 
         [[nodiscard]] scope get_scope_by_name(std::string_view name) const noexcept {
+            const std::lock_guard<std::mutex> lock{mutex_};
+
             if ( auto iter = scopes_.find(name); iter != scopes_.end() ) {
                 return iter->second;
             }
+
             return scope{};
         }
 
         [[nodiscard]] scope resolve_scope(std::string_view name) {
-            return ensure_scope(name);
-        }
-    private:
-        state_registry() = default;
+            const std::lock_guard<std::mutex> lock{mutex_};
 
-        scope ensure_scope(std::string_view name) {
             if ( auto iter = scopes_.find(name); iter != scopes_.end() ) {
                 return iter->second;
             }
 
-            return scopes_.emplace(
-                std::string{name},
-                scope_state::make(std::string{name})).first->second;
+            auto state = scope_state::make(std::string{name}, metadata_map{});
+            return scopes_.emplace(std::string{name}, std::move(state)).first->second;
         }
     private:
+        state_registry() = default;
+    private:
+        mutable std::mutex mutex_;
         std::map<std::string, scope, std::less<>> scopes_;
     };
 }
diff --git a/headers/meta.hpp/meta_detail/type_registry.hpp b/headers/meta.hpp/meta_detail/type_registry.hpp
index ea03e40..d7a59e1 100644
--- a/headers/meta.hpp/meta_detail/type_registry.hpp
+++ b/headers/meta.hpp/meta_detail/type_registry.hpp
@@ -20,17 +20,21 @@ namespace meta_hpp::detail
 
         [[nodiscard]] any_type get_type_by_id(type_id id) const noexcept {
             const std::lock_guard<std::mutex> lock{mutex_};
+
             if ( auto iter = type_by_id_.find(id); iter != type_by_id_.end() ) {
                 return iter->second;
             }
+
             return any_type{};
         }
 
         [[nodiscard]] any_type get_type_by_rtti(const std::type_index& index) const noexcept {
             const std::lock_guard<std::mutex> lock{mutex_};
+
             if ( auto iter = type_by_rtti_.find(index); iter != type_by_rtti_.end() ) {
                 return iter->second;
             }
+
             return any_type{};
         }