diff --git a/core/backend/apps/ai/migrations/0020_aitask_read_at.py b/core/backend/apps/ai/migrations/0020_aitask_read_at.py
new file mode 100644
index 0000000..a586560
--- /dev/null
+++ b/core/backend/apps/ai/migrations/0020_aitask_read_at.py
@@ -0,0 +1,21 @@
+# YYX#row22:AITask 增加 read_at(已读时间)+ (team, read_at) 索引,支撑未读生成任务角标。
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("ai", "0019_imageconversation_aitask_conversation_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="aitask",
+            name="read_at",
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+        migrations.AddIndex(
+            model_name="aitask",
+            index=models.Index(fields=["team", "read_at"], name="ai_aitask_team_read_idx"),
+        ),
+    ]