diff --git a/app/app/Services/Supplier/Channel/FailoverProjectChannel.php b/app/app/Services/Supplier/Channel/FailoverProjectChannel.php
index 7bcea610..90192e57 100644
--- a/app/app/Services/Supplier/Channel/FailoverProjectChannel.php
+++ b/app/app/Services/Supplier/Channel/FailoverProjectChannel.php
@@ -53,6 +53,17 @@ final class FailoverProjectChannel implements SupplierProjectChannel
      */
     public function createProjectForLiderra(Project $project, SupplierProjectDto $dto): int
     {
+        // Spec §4.4 шаг 2: портальная сверка через listProjects() до любого create.
+        // Защита от дубля при полу-успехе яруса 1 в прошлом запуске.
+        try {
+            $existing = $this->findOnPortal($dto);
+            if ($existing !== null) {
+                return $existing;
+            }
+        } catch (Throwable) {
+            // listProjects недоступен — продолжаем, ярус-эскалация и так покроет.
+        }
+
         try {
             return $this->tier1->createProject($dto);
         } catch (WindowDeferredException $e) {
@@ -146,6 +157,26 @@ final class FailoverProjectChannel implements SupplierProjectChannel
             ));
     }
 
+    /**
+     * Портальная сверка: ищет уже существующий проект на портале по тройке
+     * (platform, signal_type, unique_key). Возвращает external_id найденного
+     * или null. Spec §4.4 шаг 2, §7.
+     */
+    private function findOnPortal(SupplierProjectDto $dto): ?int
+    {
+        foreach ($this->tier1->listProjects() as $row) {
+            if (
+                ($row['platform'] ?? null) === $dto->platform
+                && ($row['signal_type'] ?? null) === $dto->signalType
+                && ($row['unique_key'] ?? null) === $dto->uniqueKey
+            ) {
+                return (int) ($row['id'] ?? 0) ?: null;
+            }
+        }
+
+        return null;
+    }
+
     private function classifyTier2Failure(Throwable $e): string
     {
         $msg = mb_strtolower($e->getMessage());
diff --git a/app/tests/Feature/Supplier/Channel/FailoverProjectChannelTest.php b/app/tests/Feature/Supplier/Channel/FailoverProjectChannelTest.php
index 02d4ca46..63fae09b 100644
--- a/app/tests/Feature/Supplier/Channel/FailoverProjectChannelTest.php
+++ b/app/tests/Feature/Supplier/Channel/FailoverProjectChannelTest.php
@@ -271,3 +271,35 @@ it('createProject — WindowDeferred: no queue, no escalation, op rescheduled (r
     expect(SupplierManualSyncQueue::count())->toBe(0);
     Mail::assertNothingQueued();
 });
+
+it('createProject — portal already has project (listProjects match): adopts external_id, skips create', function (): void {
+    $tenant = Tenant::factory()->create();
+    $project = Project::factory()->for($tenant)->create();
+
+    $tier1CreateCalled = false;
+    $tier1 = new class($tier1CreateCalled) implements SupplierProjectChannel
+    {
+        public function __construct(public bool &$createCalled) {}
+
+        public function createProject(SupplierProjectDto $dto): int
+        {
+            $this->createCalled = true;
+
+            return 0;
+        }
+
+        public function updateProject(int $externalId, SupplierProjectDto $dto): void {}
+
+        public function listProjects(): array
+        {
+            return [
+                ['id' => 555555, 'platform' => 'B1', 'signal_type' => 'site', 'unique_key' => 'foo.com'],
+            ];
+        }
+    };
+
+    $id = makeFailover($tier1)->createProjectForLiderra($project, makeDto());
+
+    expect($id)->toBe(555555);
+    expect($tier1CreateCalled)->toBeFalse();
+});