diff --git a/lib/shared/messages/add-members-message-spec.js b/lib/shared/messages/add-members-message-spec.js
--- a/lib/shared/messages/add-members-message-spec.js
+++ b/lib/shared/messages/add-members-message-spec.js
@@ -9,9 +9,10 @@
 } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type AddMembersMessageData,
@@ -166,5 +167,9 @@
     return rawMessageInfo.addedUserIDs;
   },
 
+  canBeSidebarSource(rawMessageInfo: RawAddMembersMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawAddMembersMessageInfoValidator,
 });
diff --git a/lib/shared/messages/change-role-message-spec.js b/lib/shared/messages/change-role-message-spec.js
--- a/lib/shared/messages/change-role-message-spec.js
+++ b/lib/shared/messages/change-role-message-spec.js
@@ -12,9 +12,10 @@
 import { joinResult } from './utils.js';
 import type { PlatformDetails } from '../../types/device-types.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type ChangeRoleMessageData,
@@ -236,5 +237,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawChangeRoleMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawChangeRoleMessageInfoValidator,
 });
diff --git a/lib/shared/messages/change-settings-message-spec.js b/lib/shared/messages/change-settings-message-spec.js
--- a/lib/shared/messages/change-settings-message-spec.js
+++ b/lib/shared/messages/change-settings-message-spec.js
@@ -10,9 +10,10 @@
 } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type ChangeSettingsMessageData,
@@ -182,5 +183,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawChangeSettingsMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawChangeSettingsMessageInfoValidator,
 });
diff --git a/lib/shared/messages/create-entry-message-spec.js b/lib/shared/messages/create-entry-message-spec.js
--- a/lib/shared/messages/create-entry-message-spec.js
+++ b/lib/shared/messages/create-entry-message-spec.js
@@ -5,9 +5,10 @@
 import { pushTypes, type MessageSpec } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type CreateEntryMessageData,
@@ -121,5 +122,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawCreateEntryMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawCreateEntryMessageInfoValidator,
 });
diff --git a/lib/shared/messages/create-sidebar-message-spec.js b/lib/shared/messages/create-sidebar-message-spec.js
--- a/lib/shared/messages/create-sidebar-message-spec.js
+++ b/lib/shared/messages/create-sidebar-message-spec.js
@@ -12,9 +12,10 @@
 import { joinResult } from './utils.js';
 import type { PlatformDetails } from '../../types/device-types.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type CreateSidebarMessageData,
@@ -229,5 +230,9 @@
     return [parentThreadID];
   },
 
+  canBeSidebarSource(rawMessageInfo: RawCreateSidebarMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawCreateSidebarMessageInfoValidator,
 });
diff --git a/lib/shared/messages/create-sub-thread-message-spec.js b/lib/shared/messages/create-sub-thread-message-spec.js
--- a/lib/shared/messages/create-sub-thread-message-spec.js
+++ b/lib/shared/messages/create-sub-thread-message-spec.js
@@ -11,9 +11,10 @@
 import { assertSingleMessageInfo } from './utils.js';
 import { permissionLookup } from '../../permissions/thread-permissions.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type CreateSubthreadMessageData,
@@ -163,5 +164,9 @@
     return [rawMessageInfo.childThreadID];
   },
 
+  canBeSidebarSource(rawMessageInfo: RawCreateSubthreadMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawCreateSubthreadMessageInfoValidator,
 });
diff --git a/lib/shared/messages/create-thread-message-spec.js b/lib/shared/messages/create-thread-message-spec.js
--- a/lib/shared/messages/create-thread-message-spec.js
+++ b/lib/shared/messages/create-thread-message-spec.js
@@ -10,9 +10,10 @@
 } from './message-spec.js';
 import { assertSingleMessageInfo } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type CreateThreadMessageData,
@@ -202,5 +203,9 @@
     return parentThreadID ? [parentThreadID] : [];
   },
 
+  canBeSidebarSource(rawMessageInfo: RawCreateThreadMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawCreateThreadMessageInfoValidator,
 });
diff --git a/lib/shared/messages/delete-entry-message-spec.js b/lib/shared/messages/delete-entry-message-spec.js
--- a/lib/shared/messages/delete-entry-message-spec.js
+++ b/lib/shared/messages/delete-entry-message-spec.js
@@ -5,9 +5,10 @@
 import { pushTypes, type MessageSpec } from './message-spec.js';
 import { assertSingleMessageInfo } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type DeleteEntryMessageData,
@@ -136,5 +137,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawDeleteEntryMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawDeleteEntryMessageInfoValidator,
 });
diff --git a/lib/shared/messages/edit-entry-message-spec.js b/lib/shared/messages/edit-entry-message-spec.js
--- a/lib/shared/messages/edit-entry-message-spec.js
+++ b/lib/shared/messages/edit-entry-message-spec.js
@@ -5,9 +5,10 @@
 import { pushTypes, type MessageSpec } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type EditEntryMessageData,
@@ -121,5 +122,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawEditEntryMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawEditEntryMessageInfoValidator,
 });
diff --git a/lib/shared/messages/edit-message-spec.js b/lib/shared/messages/edit-message-spec.js
--- a/lib/shared/messages/edit-message-spec.js
+++ b/lib/shared/messages/edit-message-spec.js
@@ -8,7 +8,10 @@
   assertMessageType,
   messageTypes,
 } from '../../types/message-types-enum.js';
-import { type ClientDBMessageInfo } from '../../types/message-types.js';
+import {
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
+} from '../../types/message-types.js';
 import {
   type EditMessageData,
   type RawEditMessageInfo,
@@ -140,5 +143,9 @@
     return unwrapped;
   },
 
+  canBeSidebarSource(messageInfo: RawEditMessageInfo): boolean {
+    return !isInvalidSidebarSource(messageInfo);
+  },
+
   validator: rawEditMessageInfoValidator,
 });
diff --git a/lib/shared/messages/join-thread-message-spec.js b/lib/shared/messages/join-thread-message-spec.js
--- a/lib/shared/messages/join-thread-message-spec.js
+++ b/lib/shared/messages/join-thread-message-spec.js
@@ -5,9 +5,10 @@
 import type { MessageSpec, RobotextParams } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type JoinThreadMessageData,
@@ -119,5 +120,9 @@
     return joinResult(rawMessageInfo.type, rawMessageInfo.threadID);
   },
 
+  canBeSidebarSource(rawMessageInfo: RawJoinThreadMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawJoinThreadMessageInfoValidator,
 });
diff --git a/lib/shared/messages/leave-thread-message-spec.js b/lib/shared/messages/leave-thread-message-spec.js
--- a/lib/shared/messages/leave-thread-message-spec.js
+++ b/lib/shared/messages/leave-thread-message-spec.js
@@ -5,9 +5,10 @@
 import type { MessageSpec, RobotextParams } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type LeaveThreadMessageData,
@@ -119,5 +120,9 @@
     return joinResult(rawMessageInfo.type, rawMessageInfo.threadID);
   },
 
+  canBeSidebarSource(rawMessageInfo: RawLeaveThreadMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawLeaveThreadMessageInfoValidator,
 });
diff --git a/lib/shared/messages/message-spec.js b/lib/shared/messages/message-spec.js
--- a/lib/shared/messages/message-spec.js
+++ b/lib/shared/messages/message-spec.js
@@ -113,6 +113,7 @@
   +startsThread?: boolean,
   +threadIDs?: (rawMessageInfo: RawInfo) => $ReadOnlyArray<string>,
   +includedInRepliesCount?: boolean,
+  +canBeSidebarSource: (rawMessageInfo: RawInfo) => boolean,
   +useCreationSideEffectsFunc?: () => CreationSideEffectsFunc<RawInfo>,
   +validator: TType<RawInfo>,
 };
diff --git a/lib/shared/messages/multimedia-message-spec.js b/lib/shared/messages/multimedia-message-spec.js
--- a/lib/shared/messages/multimedia-message-spec.js
+++ b/lib/shared/messages/multimedia-message-spec.js
@@ -23,6 +23,7 @@
 import {
   isMediaMessageType,
   rawMultimediaMessageInfoValidator,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import type {
   MessageInfo,
@@ -351,6 +352,12 @@
 
   includedInRepliesCount: true,
 
+  canBeSidebarSource(
+    rawMessageInfo: RawMediaMessageInfo | RawImagesMessageInfo,
+  ): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawMultimediaMessageInfoValidator,
 });
 
diff --git a/lib/shared/messages/reaction-message-spec.js b/lib/shared/messages/reaction-message-spec.js
--- a/lib/shared/messages/reaction-message-spec.js
+++ b/lib/shared/messages/reaction-message-spec.js
@@ -17,6 +17,7 @@
 import {
   type MessageInfo,
   type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type ReactionMessageData,
@@ -218,5 +219,9 @@
     return action === 'add_reaction' ? pushTypes.NOTIF : pushTypes.RESCIND;
   },
 
+  canBeSidebarSource(rawMessageInfo: RawReactionMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawReactionMessageInfoValidator,
 });
diff --git a/lib/shared/messages/remove-members-message-spec.js b/lib/shared/messages/remove-members-message-spec.js
--- a/lib/shared/messages/remove-members-message-spec.js
+++ b/lib/shared/messages/remove-members-message-spec.js
@@ -9,9 +9,10 @@
 } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type RawRemoveMembersMessageInfo,
@@ -166,5 +167,9 @@
     return rawMessageInfo.removedUserIDs;
   },
 
+  canBeSidebarSource(messageInfo: RawRemoveMembersMessageInfo): boolean {
+    return !isInvalidSidebarSource(messageInfo);
+  },
+
   validator: rawRemoveMembersMessageInfoValidator,
 });
diff --git a/lib/shared/messages/restore-entry-message-spec.js b/lib/shared/messages/restore-entry-message-spec.js
--- a/lib/shared/messages/restore-entry-message-spec.js
+++ b/lib/shared/messages/restore-entry-message-spec.js
@@ -5,9 +5,10 @@
 import { pushTypes, type MessageSpec } from './message-spec.js';
 import { assertSingleMessageInfo } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type RawRestoreEntryMessageInfo,
@@ -136,5 +137,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(rawMessageInfo: RawRestoreEntryMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawRestoreEntryMessageInfoValidator,
 });
diff --git a/lib/shared/messages/sidebar-source-message-spec.js b/lib/shared/messages/sidebar-source-message-spec.js
--- a/lib/shared/messages/sidebar-source-message-spec.js
+++ b/lib/shared/messages/sidebar-source-message-spec.js
@@ -181,5 +181,9 @@
 
   startsThread: true,
 
+  canBeSidebarSource(rawMessageInfo: RawSidebarSourceMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawSidebarSourceMessageInfoValidator,
 });
diff --git a/lib/shared/messages/text-message-spec.js b/lib/shared/messages/text-message-spec.js
--- a/lib/shared/messages/text-message-spec.js
+++ b/lib/shared/messages/text-message-spec.js
@@ -15,9 +15,10 @@
   changeThreadSettings,
 } from '../../actions/thread-actions.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import {
   type RawTextMessageInfo,
@@ -314,5 +315,9 @@
     };
   },
 
+  canBeSidebarSource(rawMessageInfo: RawTextMessageInfo): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawTextMessageInfoValidator,
 });
diff --git a/lib/shared/messages/toggle-pin-message-spec.js b/lib/shared/messages/toggle-pin-message-spec.js
--- a/lib/shared/messages/toggle-pin-message-spec.js
+++ b/lib/shared/messages/toggle-pin-message-spec.js
@@ -9,7 +9,10 @@
 } from './message-spec.js';
 import type { PlatformDetails } from '../../types/device-types';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type { ClientDBMessageInfo } from '../../types/message-types.js';
+import {
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
+} from '../../types/message-types.js';
 import {
   type TogglePinMessageData,
   type TogglePinMessageInfo,
@@ -155,5 +158,9 @@
     return unwrapped;
   },
 
+  canBeSidebarSource(messageInfo: RawTogglePinMessageInfo): boolean {
+    return !isInvalidSidebarSource(messageInfo);
+  },
+
   validator: rawTogglePinMessageInfoValidator,
 });
diff --git a/lib/shared/messages/unsupported-message-spec.js b/lib/shared/messages/unsupported-message-spec.js
--- a/lib/shared/messages/unsupported-message-spec.js
+++ b/lib/shared/messages/unsupported-message-spec.js
@@ -4,7 +4,10 @@
 
 import { pushTypes, type MessageSpec } from './message-spec.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import { type ClientDBMessageInfo } from '../../types/message-types.js';
+import {
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
+} from '../../types/message-types.js';
 import {
   type RawUnsupportedMessageInfo,
   type UnsupportedMessageInfo,
@@ -74,5 +77,9 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(messageInfo: RawUnsupportedMessageInfo): boolean {
+    return !isInvalidSidebarSource(messageInfo);
+  },
+
   validator: rawUnsupportedMessageInfoValidator,
 });
diff --git a/lib/shared/messages/update-relationship-message-spec.js b/lib/shared/messages/update-relationship-message-spec.js
--- a/lib/shared/messages/update-relationship-message-spec.js
+++ b/lib/shared/messages/update-relationship-message-spec.js
@@ -10,9 +10,10 @@
 import { assertSingleMessageInfo } from './utils.js';
 import type { PlatformDetails } from '../../types/device-types.js';
 import { messageTypes } from '../../types/message-types-enum.js';
-import type {
-  MessageInfo,
-  ClientDBMessageInfo,
+import {
+  type MessageInfo,
+  type ClientDBMessageInfo,
+  isInvalidSidebarSource,
 } from '../../types/message-types.js';
 import type { RawUnsupportedMessageInfo } from '../../types/messages/unsupported.js';
 import {
@@ -177,5 +178,11 @@
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
+  canBeSidebarSource(
+    rawMessageInfo: RawUpdateRelationshipMessageInfo,
+  ): boolean {
+    return !isInvalidSidebarSource(rawMessageInfo);
+  },
+
   validator: rawUpdateRelationshipMessageInfoValidator,
 });