diff --git a/lib/CompositionManager.php b/lib/CompositionManager.php
index 46e6070..e01600d 100644
--- a/lib/CompositionManager.php
+++ b/lib/CompositionManager.php
@@ -46,6 +46,11 @@ class CompositionManager {
             'sender' => $sender,
             'message' => $message,
             'attachments' => [],
+            'remote' => [
+                'status' => 'dirty',
+                'entity' => null,
+                'error' => null,
+            ],
         ];
 
         // Construct the snapshot mutation that will run while the composition is locked.
@@ -111,7 +116,9 @@ class CompositionManager {
             $saveComposition,
         ) ?? $snapshot;
 
-        return $snapshot;
+        $response = $snapshot;
+        unset($response['remote']);
+        return $response;
     }
 
     public function patch(string $tenantId, string $userId, string $identifier, array $data): array {
@@ -140,6 +147,7 @@ class CompositionManager {
             $composed['revision'] = $data['revision'];
             $composed['sender'] = $data['sender'] ?? [];
             $composed['message'] = $data['message'] ?? [];
+            $composed = $this->markRemoteDirty($composed);
             $result = [
                 'identifier' => $identifier,
                 'disposition' => 'patched',
@@ -175,7 +183,7 @@ class CompositionManager {
 
             $composed['sender'] = $sender;
             $composed['message'] = $message;
-            return $composed;
+            return $this->markRemoteDirty($composed);
         };
 
         // Execute the mutation and atomically persist the snapshot it returns.
@@ -367,6 +375,12 @@ class CompositionManager {
                 $failed = $this->attachmentAddFromDocuments($tenantId, $userId, $composition, $documents, $composed);
             }
 
+            $deviceAttachmentsChanged = $uploads !== [];
+            $documentAttachmentsChanged = count($failed) < count($documents);
+            if ($deviceAttachmentsChanged || $documentAttachmentsChanged) {
+                $composed = $this->markRemoteDirty($composed);
+            }
+
             return $composed;
         };
 
@@ -551,6 +565,7 @@ class CompositionManager {
             }
 
             unset($composed['attachments'][$identifier]);
+            $composed = $this->markRemoteDirty($composed);
             $result['disposition'] = 'removed';
             return $composed;
         };
@@ -566,6 +581,19 @@ class CompositionManager {
         return $result;
     }
 
+    private function markRemoteDirty(array $composed): array {
+        $remote = isset($composed['remote']) && is_array($composed['remote'])
+            ? $composed['remote']
+            : [];
+
+        $remote['status'] = 'dirty';
+        $remote['entity'] ??= null;
+        $remote['error'] = null;
+        $composed['remote'] = $remote;
+
+        return $composed;
+    }
+
     /**
      * @param array<int,array|string> $entries
      * @return array<int,Address>
diff --git a/tests/php/Unit/CompositionManagerTest.php b/tests/php/Unit/CompositionManagerTest.php
index e802740..88f97b4 100644
--- a/tests/php/Unit/CompositionManagerTest.php
+++ b/tests/php/Unit/CompositionManagerTest.php
@@ -52,6 +52,61 @@ final class CompositionManagerTest extends TestCase {
         $this->deleteDir($this->rootDir);
     }
 
+    public function testStageInitializesDirtyRemoteState(): void {
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        $manager = $this->makeManager($documentsManager);
+
+        $response = $manager->stage(
+            self::TENANT_ID,
+            self::USER_ID,
+            'draft-new',
+            'new',
+            ['address' => 'sender@example.com'],
+            ['subject' => 'Draft'],
+        );
+
+        $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, 'draft-new');
+        $this->assertArrayNotHasKey('remote', $response);
+        $this->assertSame([
+            'status' => 'dirty',
+            'entity' => null,
+            'error' => null,
+        ], $snapshot['remote']);
+    }
+
+    public function testPatchMarksExistingRemoteStateDirty(): void {
+        $compositionId = $this->stageEmptyComposition();
+        $setSynced = static function (?array $snapshot): array {
+            $snapshot['revision'] = 1;
+            $snapshot['remote'] = [
+                'status' => 'synced',
+                'entity' => 'provider:service:drafts:123',
+                'error' => 'old error',
+            ];
+            return $snapshot;
+        };
+        $this->compositionStore->compositionSave(
+            self::TENANT_ID,
+            self::USER_ID,
+            $compositionId,
+            $setSynced,
+        );
+
+        $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
+        $manager = $this->makeManager($documentsManager);
+        $result = $manager->patch(self::TENANT_ID, self::USER_ID, $compositionId, [
+            'revision' => 2,
+            'sender' => ['address' => 'sender@example.com'],
+            'message' => ['subject' => 'Changed'],
+        ]);
+
+        $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, $compositionId);
+        $this->assertSame('patched', $result['disposition']);
+        $this->assertSame('dirty', $snapshot['remote']['status']);
+        $this->assertSame('provider:service:drafts:123', $snapshot['remote']['entity']);
+        $this->assertNull($snapshot['remote']['error']);
+    }
+
     public function testAttachmentAddFromDocumentsHappyPath(): void {
         $compositionId = $this->stageEmptyComposition();
         $documentsManager = $this->createStub(\KTXM\DocumentsManager\Manager::class);
@@ -78,6 +133,11 @@ final class CompositionManagerTest extends TestCase {
         $this->assertSame('hello.txt', $attachment['name']);
         $this->assertSame('text/plain', $attachment['type']);
         $this->assertSame(strlen('hello world'), $attachment['size']);
+
+        $snapshot = $this->compositionStore->compositionFetch(self::TENANT_ID, self::USER_ID, $compositionId);
+        $this->assertSame('dirty', $snapshot['remote']['status']);
+        $this->assertNull($snapshot['remote']['entity']);
+        $this->assertNull($snapshot['remote']['error']);
     }
 
     public function testAttachmentAddFromDocumentsPartialFailure(): void {