diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/actor/local/LocalActorMigrationCheckDomainService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/actor/local/LocalActorMigrationCheckDomainService.kt
index 01fd5aeb..dfa8c9c5 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/actor/local/LocalActorMigrationCheckDomainService.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/domain/service/actor/local/LocalActorMigrationCheckDomainService.kt
@@ -32,4 +32,6 @@ sealed class AccountMigrationCheck(
     class SelfReferences : AccountMigrationCheck(false)
 
     class AlreadyMoved(val message: String) : AccountMigrationCheck(false)
+
+    class AlsoKnownAsNotFound(val message: String) : AccountMigrationCheck(false)
 }
\ No newline at end of file
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/MigrationLocalActorApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/MigrationLocalActorApplicationService.kt
index a7dc73bd..9384eff1 100644
--- a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/MigrationLocalActorApplicationService.kt
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/MigrationLocalActorApplicationService.kt
@@ -48,6 +48,7 @@ class MigrationLocalActorApplicationService(
 
                 is CircularReferences -> TODO()
                 is SelfReferences -> TODO()
+                is AlsoKnownAsNotFound -> TODO()
             }
         }
 
diff --git a/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/SetAlsoKnownAsLocalActorApplicationService.kt b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/SetAlsoKnownAsLocalActorApplicationService.kt
new file mode 100644
index 00000000..772385d8
--- /dev/null
+++ b/hideout-core/src/main/kotlin/dev/usbharu/hideout/core/usecase/actor/SetAlsoKnownAsLocalActorApplicationService.kt
@@ -0,0 +1,8 @@
+package dev.usbharu.hideout.core.usecase.actor
+
+import org.springframework.stereotype.Service
+
+@Service
+interface SetAlsoKnownAsLocalActorApplicationService {
+    suspend fun setAlsoKnownAs(actorId: Long, alsoKnownAs: List<Long>)
+}
\ No newline at end of file