diff --git a/lib/CompositionManager.php b/lib/CompositionManager.php
index e0be254..9e25e2a 100644
--- a/lib/CompositionManager.php
+++ b/lib/CompositionManager.php
@@ -440,7 +440,14 @@ class CompositionManager {
             ];
         }
 
-        $source = null;
+        // Reuse the synced remote draft (if any) so the provider can natively clean it up
+        $remoteEntity = $this->remoteEntityIdentifier($composed['remote']['entity'] ?? null);
+        $source = ($remoteEntity !== null
+            && $remoteEntity->provider() === $service->provider()
+            && (string)$remoteEntity->service() === (string)$service->identifier())
+            ? $remoteEntity
+            : null;
+
         $properties = $this->buildMessageProperties(
             service: $service,
             sender: $senderObject,
diff --git a/tests/php/Unit/CompositionSynchronizationTest.php b/tests/php/Unit/CompositionSynchronizationTest.php
index e8eae67..925af4f 100644
--- a/tests/php/Unit/CompositionSynchronizationTest.php
+++ b/tests/php/Unit/CompositionSynchronizationTest.php
@@ -285,6 +285,77 @@ final class CompositionSynchronizationTest extends TestCase {
         ));
     }
 
+    public function testSendReusesSyncedRemoteDraftAsSubmissionSource(): void {
+        $this->stageComposition('provider:service:drafts:remote-1');
+        $properties = $this->createStub(MessagePropertiesMutableInterface::class);
+        $service = $this->createMockForIntersectionOfInterfaces([
+            ServiceBaseInterface::class,
+            ServiceEntitySubmitInterface::class,
+        ]);
+        $entity = $this->createStub(EntityMutableInterface::class);
+        $entity->method('getProperties')->willReturn($properties);
+        $service->method('provider')->willReturn('provider');
+        $service->method('identifier')->willReturn('service');
+        $service->method('getEnabled')->willReturn(true);
+        $service->method('entityFresh')->willReturn($entity);
+        $service->expects($this->once())
+            ->method('entitySubmit')
+            ->with(
+                $this->anything(),
+                $this->callback(static fn(?EntityIdentifier $source): bool => $source !== null
+                    && (string)$source === 'provider:service:drafts:remote-1'),
+                $properties,
+            )
+            ->willReturn(new EntitySubmitResult(EntitySubmitResult::DISPOSITION_SENT));
+
+        $mailManager = $this->createStub(\KTXM\MailManager\Manager::class);
+        $mailManager->method('serviceFindByAddress')->willReturn($service);
+
+        $result = $this->compositionManager($mailManager)->send(
+            self::TENANT_ID,
+            self::USER_ID,
+            self::COMPOSITION_ID,
+            ['address' => 'sender@example.com'],
+            ['subject' => 'Sent draft'],
+            [],
+        );
+
+        $this->assertSame('sent', $result['disposition']);
+    }
+
+    public function testSendIgnoresRemoteDraftBelongingToAnotherService(): void {
+        $this->stageComposition('provider:other-service:drafts:remote-1');
+        $properties = $this->createStub(MessagePropertiesMutableInterface::class);
+        $service = $this->createMockForIntersectionOfInterfaces([
+            ServiceBaseInterface::class,
+            ServiceEntitySubmitInterface::class,
+        ]);
+        $entity = $this->createStub(EntityMutableInterface::class);
+        $entity->method('getProperties')->willReturn($properties);
+        $service->method('provider')->willReturn('provider');
+        $service->method('identifier')->willReturn('service');
+        $service->method('getEnabled')->willReturn(true);
+        $service->method('entityFresh')->willReturn($entity);
+        $service->expects($this->once())
+            ->method('entitySubmit')
+            ->with($this->anything(), $this->isNull(), $properties)
+            ->willReturn(new EntitySubmitResult(EntitySubmitResult::DISPOSITION_SENT));
+
+        $mailManager = $this->createStub(\KTXM\MailManager\Manager::class);
+        $mailManager->method('serviceFindByAddress')->willReturn($service);
+
+        $result = $this->compositionManager($mailManager)->send(
+            self::TENANT_ID,
+            self::USER_ID,
+            self::COMPOSITION_ID,
+            ['address' => 'sender@example.com'],
+            ['subject' => 'Sent draft'],
+            [],
+        );
+
+        $this->assertSame('sent', $result['disposition']);
+    }
+
     public function testSendFailureKeepsLocalComposition(): void {
         $this->stageComposition();
         $properties = $this->createStub(MessagePropertiesMutableInterface::class);
@@ -357,6 +428,7 @@ final class CompositionSynchronizationTest extends TestCase {
         ]);
         $entity = $this->createStub(EntityMutableInterface::class);
         $entity->method('getProperties')->willReturn($properties);
+        $service->method('provider')->willReturn('provider');
         $service->method('identifier')->willReturn('service');
         $service->method('getEnabled')->willReturn(true);
         $service->method('entityFresh')->willReturn($entity);