diff --git a/mirai-core/src/commonMain/kotlin/contact/AbstractUser.kt b/mirai-core/src/commonMain/kotlin/contact/AbstractUser.kt
index fc1e6c0c3..089e8b7bf 100644
--- a/mirai-core/src/commonMain/kotlin/contact/AbstractUser.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/AbstractUser.kt
@@ -18,8 +18,8 @@ import net.mamoe.mirai.data.UserInfo
 import net.mamoe.mirai.event.broadcast
 import net.mamoe.mirai.event.events.*
 import net.mamoe.mirai.internal.QQAndroidBot
-import net.mamoe.mirai.internal.message.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.message.contextualBugReportException
+import net.mamoe.mirai.internal.message.flags.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.message.image.*
 import net.mamoe.mirai.internal.network.components.BdhSession
 import net.mamoe.mirai.internal.network.highway.ChannelKind
diff --git a/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt b/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt
index 3a324215e..4d1718eef 100644
--- a/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/GroupImpl.kt
@@ -26,9 +26,9 @@ import net.mamoe.mirai.internal.QQAndroidBot
 import net.mamoe.mirai.internal.contact.announcement.AnnouncementsImpl
 import net.mamoe.mirai.internal.contact.file.RemoteFilesImpl
 import net.mamoe.mirai.internal.contact.info.MemberInfoImpl
-import net.mamoe.mirai.internal.message.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.message.OfflineAudioImpl
 import net.mamoe.mirai.internal.message.contextualBugReportException
+import net.mamoe.mirai.internal.message.flags.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.message.image.OfflineGroupImage
 import net.mamoe.mirai.internal.message.image.calculateImageInfo
 import net.mamoe.mirai.internal.message.image.getIdByImageType
diff --git a/mirai-core/src/commonMain/kotlin/contact/SendMessageHandler.kt b/mirai-core/src/commonMain/kotlin/contact/SendMessageHandler.kt
index 914fdf71f..eab30e924 100644
--- a/mirai-core/src/commonMain/kotlin/contact/SendMessageHandler.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/SendMessageHandler.kt
@@ -20,6 +20,9 @@ import net.mamoe.mirai.event.nextEvent
 import net.mamoe.mirai.internal.asQQAndroidBot
 import net.mamoe.mirai.internal.getMiraiImpl
 import net.mamoe.mirai.internal.message.*
+import net.mamoe.mirai.internal.message.flags.DontAsLongMessage
+import net.mamoe.mirai.internal.message.flags.ForceAsLongMessage
+import net.mamoe.mirai.internal.message.flags.IgnoreLengthCheck
 import net.mamoe.mirai.internal.message.image.FriendImage
 import net.mamoe.mirai.internal.message.image.OfflineGroupImage
 import net.mamoe.mirai.internal.message.source.OnlineMessageSourceToFriendImpl
diff --git a/mirai-core/src/commonMain/kotlin/contact/file/AbsoluteFolderImpl.kt b/mirai-core/src/commonMain/kotlin/contact/file/AbsoluteFolderImpl.kt
index 6b4bffa0a..125df5f85 100644
--- a/mirai-core/src/commonMain/kotlin/contact/file/AbsoluteFolderImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/contact/file/AbsoluteFolderImpl.kt
@@ -18,7 +18,7 @@ import net.mamoe.mirai.contact.file.AbsoluteFolder
 import net.mamoe.mirai.contact.isOperator
 import net.mamoe.mirai.internal.contact.GroupImpl
 import net.mamoe.mirai.internal.contact.file.RemoteFilesImpl.Companion.findFileByPath
-import net.mamoe.mirai.internal.message.MiraiInternalMessageFlag
+import net.mamoe.mirai.internal.message.flags.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.network.QQAndroidClient
 import net.mamoe.mirai.internal.network.components.ClockHolder.Companion.clock
 import net.mamoe.mirai.internal.network.highway.Highway
diff --git a/mirai-core/src/commonMain/kotlin/message/ForceAsLongMessage.kt b/mirai-core/src/commonMain/kotlin/message/flags/InternalFlagOnlyMessage.kt
similarity index 98%
rename from mirai-core/src/commonMain/kotlin/message/ForceAsLongMessage.kt
rename to mirai-core/src/commonMain/kotlin/message/flags/InternalFlagOnlyMessage.kt
index f97ad84a6..9f540e85c 100644
--- a/mirai-core/src/commonMain/kotlin/message/ForceAsLongMessage.kt
+++ b/mirai-core/src/commonMain/kotlin/message/flags/InternalFlagOnlyMessage.kt
@@ -9,7 +9,7 @@
 
 @file:Suppress("unused")
 
-package net.mamoe.mirai.internal.message
+package net.mamoe.mirai.internal.message.flags
 
 import net.mamoe.mirai.internal.message.visitor.ex
 import net.mamoe.mirai.message.data.AbstractMessageKey
@@ -19,6 +19,11 @@ import net.mamoe.mirai.message.data.MessageMetadata
 import net.mamoe.mirai.message.data.visitor.MessageVisitor
 import net.mamoe.mirai.utils.safeCast
 
+/**
+ * Ignore on transformation
+ */
+internal sealed interface InternalFlagOnlyMessage : MessageMetadata
+
 /**
  * 内部 flag, 放入 chain 强制作为 long 发送
  */
@@ -72,9 +77,4 @@ internal object MiraiInternalMessageFlag : MessageMetadata, ConstrainSingle, Int
             data
         )
     }
-}
-
-/**
- * Ignore on transformation
- */
-internal sealed interface InternalFlagOnlyMessage : MessageMetadata
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/mirai-core/src/commonMain/kotlin/message/messageToElems.kt b/mirai-core/src/commonMain/kotlin/message/messageToElems.kt
index 36260ea9b..00e276209 100644
--- a/mirai-core/src/commonMain/kotlin/message/messageToElems.kt
+++ b/mirai-core/src/commonMain/kotlin/message/messageToElems.kt
@@ -14,6 +14,7 @@ import net.mamoe.mirai.contact.AnonymousMember
 import net.mamoe.mirai.contact.ContactOrBot
 import net.mamoe.mirai.contact.Group
 import net.mamoe.mirai.contact.User
+import net.mamoe.mirai.internal.message.flags.InternalFlagOnlyMessage
 import net.mamoe.mirai.internal.message.image.*
 import net.mamoe.mirai.internal.message.source.MessageSourceInternal
 import net.mamoe.mirai.internal.network.protocol.data.proto.HummerCommelem
diff --git a/mirai-core/src/commonMain/kotlin/utils/RemoteFileImpl.kt b/mirai-core/src/commonMain/kotlin/utils/RemoteFileImpl.kt
index 87c5a5c33..b3b14b675 100644
--- a/mirai-core/src/commonMain/kotlin/utils/RemoteFileImpl.kt
+++ b/mirai-core/src/commonMain/kotlin/utils/RemoteFileImpl.kt
@@ -19,7 +19,7 @@ import net.mamoe.mirai.contact.isOperator
 import net.mamoe.mirai.internal.asQQAndroidBot
 import net.mamoe.mirai.internal.contact.groupCode
 import net.mamoe.mirai.internal.message.FileMessageImpl
-import net.mamoe.mirai.internal.message.MiraiInternalMessageFlag
+import net.mamoe.mirai.internal.message.flags.MiraiInternalMessageFlag
 import net.mamoe.mirai.internal.network.highway.Highway
 import net.mamoe.mirai.internal.network.highway.ResourceKind
 import net.mamoe.mirai.internal.network.protocol