diff --git a/doc/thinking/2026-04-26-namespace-manager-step24.md b/doc/thinking/2026-04-26-namespace-manager-step24.md
new file mode 100644
index 00000000..7e584523
--- /dev/null
+++ b/doc/thinking/2026-04-26-namespace-manager-step24.md
@@ -0,0 +1,16 @@
+# 2026-04-26 — NamespaceManager rewrite, step 24
+
+## Цель шага
+
+Подготовить `executor/multitenant` к subscriber adapter без смены текущего watcher behavior.
+
+## Что меняем
+
+1. Выделяем отдельный helper для прогона `AddNamespace()` по executor type-ам.
+2. Оставляем `EnsureNamespaceSA()` в текущем `registerNamespace()`.
+3. Добавляем unit test на успешный прогон и propagation ошибок.
+
+## Что НЕ меняем
+
+- не подключаем `NamespaceManager`;
+- не меняем внешний API watcher-а.
\ No newline at end of file
diff --git a/pkg/executor/multitenant/ns_watcher.go b/pkg/executor/multitenant/ns_watcher.go
index 0cbbf303..86fce199 100644
--- a/pkg/executor/multitenant/ns_watcher.go
+++ b/pkg/executor/multitenant/ns_watcher.go
@@ -61,6 +61,7 @@ package multitenant
 
 import (
 	"context"
+	"errors"
 	"time"
 
 	"go.uber.org/zap"
@@ -156,6 +157,18 @@ func registerNamespace(
 	utils.DefaultNSResolver().AddNamespace(ns)
 	// Ensure fission-fetcher SA exists in the new namespace so pool pods can start.
 	utils.EnsureNamespaceSA(ctx, kubernetesClient, logger, ns)
+	registerExecutorTypes(ctx, logger, ns, executorTypes, mgr)
+	logger.Info("multitenant.NSWatcher: registered namespace", zap.String("namespace", ns))
+}
+
+func registerExecutorTypes(
+	ctx context.Context,
+	logger *zap.Logger,
+	ns string,
+	executorTypes map[fv1.ExecutorType]executortype.ExecutorType,
+	mgr manager.Interface,
+) error {
+	var joinErr error
 
 	for _, et := range executorTypes {
 		if err := et.AddNamespace(ctx, ns, mgr); err != nil {
@@ -163,9 +176,10 @@ func registerNamespace(
 				zap.String("namespace", ns),
 				zap.Error(err),
 			)
+			joinErr = errors.Join(joinErr, err)
 		}
 	}
-	logger.Info("multitenant.NSWatcher: registered namespace", zap.String("namespace", ns))
+	return joinErr
 }
 
 // namespaceName extracts the namespace name from an informer event object.
diff --git a/pkg/executor/multitenant/ns_watcher_test.go b/pkg/executor/multitenant/ns_watcher_test.go
new file mode 100644
index 00000000..d332eefc
--- /dev/null
+++ b/pkg/executor/multitenant/ns_watcher_test.go
@@ -0,0 +1,74 @@
+package multitenant
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"go.uber.org/zap"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	fv1 "github.com/fission/fission/pkg/apis/core/v1"
+	"github.com/fission/fission/pkg/executor/executortype"
+	"github.com/fission/fission/pkg/executor/fscache"
+	"github.com/fission/fission/pkg/utils/manager"
+)
+
+type fakeExecutorType struct {
+	addCalls      int
+	lastNamespace string
+	addErr        error
+}
+
+func (f *fakeExecutorType) Run(context.Context, manager.Interface) {}
+func (f *fakeExecutorType) GetTypeName(context.Context) fv1.ExecutorType { return fv1.ExecutorTypePoolmgr }
+func (f *fakeExecutorType) GetFuncSvc(context.Context, *fv1.Function) (*fscache.FuncSvc, error) {
+	return nil, nil
+}
+func (f *fakeExecutorType) GetFuncSvcFromCache(context.Context, *fv1.Function) (*fscache.FuncSvc, error) {
+	return nil, nil
+}
+func (f *fakeExecutorType) DumpDebugInfo(context.Context) error { return nil }
+func (f *fakeExecutorType) DeleteFuncSvcFromCache(context.Context, *fscache.FuncSvc) {}
+func (f *fakeExecutorType) TapService(context.Context, string) error { return nil }
+func (f *fakeExecutorType) UnTapService(context.Context, *metav1.ObjectMeta, string) {}
+func (f *fakeExecutorType) MarkSpecializationFailure(context.Context, *metav1.ObjectMeta) {}
+func (f *fakeExecutorType) IsValid(context.Context, *fscache.FuncSvc) bool { return true }
+func (f *fakeExecutorType) RefreshFuncPods(context.Context, *zap.Logger, fv1.Function) error { return nil }
+func (f *fakeExecutorType) AdoptExistingResources(context.Context) {}
+func (f *fakeExecutorType) CleanupOldExecutorObjects(context.Context) {}
+func (f *fakeExecutorType) AddNamespace(ctx context.Context, ns string, mgr manager.Interface) error {
+	f.addCalls++
+	f.lastNamespace = ns
+	return f.addErr
+}
+
+var _ executortype.ExecutorType = (*fakeExecutorType)(nil)
+
+func TestRegisterExecutorTypes(t *testing.T) {
+	poolmgr := &fakeExecutorType{}
+	container := &fakeExecutorType{}
+	err := registerExecutorTypes(context.Background(), zap.NewNop(), "tenant-executor-a", map[fv1.ExecutorType]executortype.ExecutorType{
+		fv1.ExecutorTypePoolmgr:   poolmgr,
+		fv1.ExecutorTypeContainer: container,
+	}, nil)
+	if err != nil {
+		t.Fatalf("expected registration success: %v", err)
+	}
+	if poolmgr.addCalls != 1 || container.addCalls != 1 {
+		t.Fatalf("expected all executor types to receive AddNamespace")
+	}
+}
+
+func TestRegisterExecutorTypesAggregatesErrors(t *testing.T) {
+	err := registerExecutorTypes(context.Background(), zap.NewNop(), "tenant-executor-a", map[fv1.ExecutorType]executortype.ExecutorType{
+		fv1.ExecutorTypePoolmgr: &fakeExecutorType{addErr: errors.New("poolmgr failed")},
+		fv1.ExecutorTypeContainer: &fakeExecutorType{},
+	}, nil)
+	if err == nil {
+		t.Fatalf("expected aggregated error")
+	}
+	if err.Error() != "poolmgr failed" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
\ No newline at end of file