diff --git a/lib/shared/sidebar-utils.js b/lib/shared/sidebar-utils.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/sidebar-utils.js
@@ -0,0 +1,245 @@
+// @flow
+
+import invariant from 'invariant';
+
+import type { ParserRules } from './markdown.js';
+import { getMessageTitle, isInvalidSidebarSource } from './message-utils.js';
+import { relationshipBlockedInEitherDirection } from './relationship-utils.js';
+import {
+  createPendingThread,
+  getSingleOtherUser,
+  extractMentionedMembers,
+  useThreadHasPermission,
+  userIsMember,
+} from './thread-utils.js';
+import type { ChatMessageInfoItem } from '../selectors/chat-selectors.js';
+import { messageTypes } from '../types/message-types-enum.js';
+import type {
+  RobotextMessageInfo,
+  ComposableMessageInfo,
+} from '../types/message-types.js';
+import type { ThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
+import { threadPermissions } from '../types/thread-permission-types.js';
+import { threadTypes } from '../types/thread-types-enum.js';
+import type { LoggedInUserInfo } from '../types/user-types.js';
+import type { GetENSNames } from '../utils/ens-helpers.js';
+import {
+  entityTextToRawString,
+  getEntityTextAsString,
+} from '../utils/entity-text.js';
+import type { GetFCNames } from '../utils/farcaster-helpers.js';
+import { useSelector } from '../utils/redux-utils.js';
+import { trimText } from '../utils/text-utils.js';
+
+type SharedCreatePendingSidebarInput = {
+  +sourceMessageInfo: ComposableMessageInfo | RobotextMessageInfo,
+  +parentThreadInfo: ThreadInfo,
+  +loggedInUserInfo: LoggedInUserInfo,
+};
+
+type BaseCreatePendingSidebarInput = {
+  ...SharedCreatePendingSidebarInput,
+  +messageTitle: string,
+};
+
+type UserIDAndUsername = {
+  +id: string,
+  +username: string,
+  ...
+};
+
+function baseCreatePendingSidebar(
+  input: BaseCreatePendingSidebarInput,
+): ThreadInfo {
+  const {
+    sourceMessageInfo,
+    parentThreadInfo,
+    loggedInUserInfo,
+    messageTitle,
+  } = input;
+  const { color, type: parentThreadType } = parentThreadInfo;
+  const threadName = trimText(messageTitle, 30);
+
+  const initialMembers = new Map<string, UserIDAndUsername>();
+
+  const { id: viewerID, username: viewerUsername } = loggedInUserInfo;
+  initialMembers.set(viewerID, { id: viewerID, username: viewerUsername });
+
+  if (userIsMember(parentThreadInfo, sourceMessageInfo.creator.id)) {
+    const { id: sourceAuthorID, username: sourceAuthorUsername } =
+      sourceMessageInfo.creator;
+    invariant(
+      sourceAuthorUsername,
+      'sourceAuthorUsername should be set in createPendingSidebar',
+    );
+    const initialMemberUserInfo = {
+      id: sourceAuthorID,
+      username: sourceAuthorUsername,
+    };
+    initialMembers.set(sourceAuthorID, initialMemberUserInfo);
+  }
+
+  const singleOtherUser = getSingleOtherUser(parentThreadInfo, viewerID);
+  if (parentThreadType === threadTypes.PERSONAL && singleOtherUser) {
+    const singleOtherUsername = parentThreadInfo.members.find(
+      member => member.id === singleOtherUser,
+    )?.username;
+    invariant(
+      singleOtherUsername,
+      'singleOtherUsername should be set in createPendingSidebar',
+    );
+    const singleOtherUserInfo = {
+      id: singleOtherUser,
+      username: singleOtherUsername,
+    };
+    initialMembers.set(singleOtherUser, singleOtherUserInfo);
+  }
+
+  if (sourceMessageInfo.type === messageTypes.TEXT) {
+    const mentionedMembersOfParent = extractMentionedMembers(
+      sourceMessageInfo.text,
+      parentThreadInfo,
+    );
+    for (const [memberID, member] of mentionedMembersOfParent) {
+      initialMembers.set(memberID, member);
+    }
+  }
+
+  return createPendingThread({
+    viewerID,
+    threadType: threadTypes.SIDEBAR,
+    members: [...initialMembers.values()],
+    parentThreadInfo,
+    threadColor: color,
+    name: threadName,
+    sourceMessageID: sourceMessageInfo.id,
+  });
+}
+
+// The message title here may have ETH addresses that aren't resolved to ENS
+// names. This function should only be used in cases where we're sure that we
+// don't care about the thread title. We should prefer createPendingSidebar
+// wherever possible
+type CreateUnresolvedPendingSidebarInput = {
+  ...SharedCreatePendingSidebarInput,
+  +markdownRules: ParserRules,
+};
+
+function createUnresolvedPendingSidebar(
+  input: CreateUnresolvedPendingSidebarInput,
+): ThreadInfo {
+  const {
+    sourceMessageInfo,
+    parentThreadInfo,
+    loggedInUserInfo,
+    markdownRules,
+  } = input;
+
+  const messageTitleEntityText = getMessageTitle(
+    sourceMessageInfo,
+    parentThreadInfo,
+    parentThreadInfo,
+    markdownRules,
+  );
+  const messageTitle = entityTextToRawString(messageTitleEntityText, {
+    ignoreViewer: true,
+  });
+
+  return baseCreatePendingSidebar({
+    sourceMessageInfo,
+    parentThreadInfo,
+    messageTitle,
+    loggedInUserInfo,
+  });
+}
+
+type CreatePendingSidebarInput = {
+  ...SharedCreatePendingSidebarInput,
+  +markdownRules: ParserRules,
+  +getENSNames: ?GetENSNames,
+  +getFCNames: ?GetFCNames,
+};
+
+async function createPendingSidebar(
+  input: CreatePendingSidebarInput,
+): Promise<ThreadInfo> {
+  const {
+    sourceMessageInfo,
+    parentThreadInfo,
+    loggedInUserInfo,
+    markdownRules,
+    getENSNames,
+    getFCNames,
+  } = input;
+
+  const messageTitleEntityText = getMessageTitle(
+    sourceMessageInfo,
+    parentThreadInfo,
+    parentThreadInfo,
+    markdownRules,
+  );
+  const messageTitle = await getEntityTextAsString(
+    messageTitleEntityText,
+    { getENSNames, getFCNames },
+    { ignoreViewer: true },
+  );
+  invariant(
+    messageTitle !== null && messageTitle !== undefined,
+    'getEntityTextAsString only returns falsey when passed falsey',
+  );
+
+  return baseCreatePendingSidebar({
+    sourceMessageInfo,
+    parentThreadInfo,
+    messageTitle,
+    loggedInUserInfo,
+  });
+}
+
+function useCanCreateSidebarFromMessage(
+  threadInfo: ThreadInfo,
+  messageInfo: ComposableMessageInfo | RobotextMessageInfo,
+): boolean {
+  const messageCreatorUserInfo = useSelector(
+    state => state.userStore.userInfos[messageInfo.creator.id],
+  );
+  const hasCreateSidebarsPermission = useThreadHasPermission(
+    threadInfo,
+    threadPermissions.CREATE_SIDEBARS,
+  );
+  if (!hasCreateSidebarsPermission) {
+    return false;
+  }
+
+  if (
+    !messageInfo.id ||
+    threadInfo.sourceMessageID === messageInfo.id ||
+    isInvalidSidebarSource(messageInfo)
+  ) {
+    return false;
+  }
+
+  const messageCreatorRelationship = messageCreatorUserInfo?.relationshipStatus;
+  return (
+    !messageCreatorRelationship ||
+    !relationshipBlockedInEitherDirection(messageCreatorRelationship)
+  );
+}
+
+function useSidebarExistsOrCanBeCreated(
+  threadInfo: ThreadInfo,
+  messageItem: ChatMessageInfoItem,
+): boolean {
+  const canCreateSidebarFromMessage = useCanCreateSidebarFromMessage(
+    threadInfo,
+    messageItem.messageInfo,
+  );
+  return !!messageItem.threadCreatedFromMessage || canCreateSidebarFromMessage;
+}
+
+export {
+  createUnresolvedPendingSidebar,
+  createPendingSidebar,
+  useCanCreateSidebarFromMessage,
+  useSidebarExistsOrCanBeCreated,
+};
diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -9,9 +9,7 @@
 
 import { getUserAvatarForThread } from './avatar-utils.js';
 import { generatePendingThreadColor } from './color-utils.js';
-import { type ParserRules } from './markdown.js';
 import { extractUserMentionsFromText } from './mention-utils.js';
-import { getMessageTitle, isInvalidSidebarSource } from './message-utils.js';
 import { relationshipBlockedInEitherDirection } from './relationship-utils.js';
 import ashoat from '../facts/ashoat.js';
 import genesis from '../facts/genesis.js';
@@ -29,10 +27,7 @@
   getAllThreadPermissions,
   makePermissionsBlob,
 } from '../permissions/thread-permissions.js';
-import type {
-  ChatThreadItem,
-  ChatMessageInfoItem,
-} from '../selectors/chat-selectors.js';
+import type { ChatThreadItem } from '../selectors/chat-selectors.js';
 import {
   threadInfoSelector,
   pendingToRealizedThreadIDsSelector,
@@ -43,11 +38,6 @@
   getRelativeMemberInfos,
   usersWithPersonalThreadSelector,
 } from '../selectors/user-selectors.js';
-import { messageTypes } from '../types/message-types-enum.js';
-import {
-  type RobotextMessageInfo,
-  type ComposableMessageInfo,
-} from '../types/message-types.js';
 import type {
   RelativeMemberInfo,
   RawThreadInfo,
@@ -98,19 +88,14 @@
   LoggedInUserInfo,
   UserInfo,
 } from '../types/user-types.js';
-import type { GetENSNames } from '../utils/ens-helpers.js';
 import {
   ET,
-  entityTextToRawString,
-  getEntityTextAsString,
   type ThreadEntity,
   type UserEntity,
 } from '../utils/entity-text.js';
-import type { GetFCNames } from '../utils/farcaster-helpers.js';
 import { entries, values } from '../utils/objects.js';
 import { useSelector } from '../utils/redux-utils.js';
 import { firstLine } from '../utils/string-utils.js';
-import { trimText } from '../utils/text-utils.js';
 import { pendingThreadIDRegex } from '../utils/validation-utils.js';
 
 function threadHasPermission(
@@ -553,165 +538,6 @@
   return [...mentionedMembersOfParent.values()];
 }
 
-type SharedCreatePendingSidebarInput = {
-  +sourceMessageInfo: ComposableMessageInfo | RobotextMessageInfo,
-  +parentThreadInfo: ThreadInfo,
-  +loggedInUserInfo: LoggedInUserInfo,
-};
-
-type BaseCreatePendingSidebarInput = {
-  ...SharedCreatePendingSidebarInput,
-  +messageTitle: string,
-};
-
-function baseCreatePendingSidebar(
-  input: BaseCreatePendingSidebarInput,
-): ThreadInfo {
-  const {
-    sourceMessageInfo,
-    parentThreadInfo,
-    loggedInUserInfo,
-    messageTitle,
-  } = input;
-  const { color, type: parentThreadType } = parentThreadInfo;
-  const threadName = trimText(messageTitle, 30);
-
-  const initialMembers = new Map<string, UserIDAndUsername>();
-
-  const { id: viewerID, username: viewerUsername } = loggedInUserInfo;
-  initialMembers.set(viewerID, { id: viewerID, username: viewerUsername });
-
-  if (userIsMember(parentThreadInfo, sourceMessageInfo.creator.id)) {
-    const { id: sourceAuthorID, username: sourceAuthorUsername } =
-      sourceMessageInfo.creator;
-    invariant(
-      sourceAuthorUsername,
-      'sourceAuthorUsername should be set in createPendingSidebar',
-    );
-    const initialMemberUserInfo = {
-      id: sourceAuthorID,
-      username: sourceAuthorUsername,
-    };
-    initialMembers.set(sourceAuthorID, initialMemberUserInfo);
-  }
-
-  const singleOtherUser = getSingleOtherUser(parentThreadInfo, viewerID);
-  if (parentThreadType === threadTypes.PERSONAL && singleOtherUser) {
-    const singleOtherUsername = parentThreadInfo.members.find(
-      member => member.id === singleOtherUser,
-    )?.username;
-    invariant(
-      singleOtherUsername,
-      'singleOtherUsername should be set in createPendingSidebar',
-    );
-    const singleOtherUserInfo = {
-      id: singleOtherUser,
-      username: singleOtherUsername,
-    };
-    initialMembers.set(singleOtherUser, singleOtherUserInfo);
-  }
-
-  if (sourceMessageInfo.type === messageTypes.TEXT) {
-    const mentionedMembersOfParent = extractMentionedMembers(
-      sourceMessageInfo.text,
-      parentThreadInfo,
-    );
-    for (const [memberID, member] of mentionedMembersOfParent) {
-      initialMembers.set(memberID, member);
-    }
-  }
-
-  return createPendingThread({
-    viewerID,
-    threadType: threadTypes.SIDEBAR,
-    members: [...initialMembers.values()],
-    parentThreadInfo,
-    threadColor: color,
-    name: threadName,
-    sourceMessageID: sourceMessageInfo.id,
-  });
-}
-
-// The message title here may have ETH addresses that aren't resolved to ENS
-// names. This function should only be used in cases where we're sure that we
-// don't care about the thread title. We should prefer createPendingSidebar
-// wherever possible
-type CreateUnresolvedPendingSidebarInput = {
-  ...SharedCreatePendingSidebarInput,
-  +markdownRules: ParserRules,
-};
-
-function createUnresolvedPendingSidebar(
-  input: CreateUnresolvedPendingSidebarInput,
-): ThreadInfo {
-  const {
-    sourceMessageInfo,
-    parentThreadInfo,
-    loggedInUserInfo,
-    markdownRules,
-  } = input;
-
-  const messageTitleEntityText = getMessageTitle(
-    sourceMessageInfo,
-    parentThreadInfo,
-    parentThreadInfo,
-    markdownRules,
-  );
-  const messageTitle = entityTextToRawString(messageTitleEntityText, {
-    ignoreViewer: true,
-  });
-
-  return baseCreatePendingSidebar({
-    sourceMessageInfo,
-    parentThreadInfo,
-    messageTitle,
-    loggedInUserInfo,
-  });
-}
-
-type CreatePendingSidebarInput = {
-  ...SharedCreatePendingSidebarInput,
-  +markdownRules: ParserRules,
-  +getENSNames: ?GetENSNames,
-  +getFCNames: ?GetFCNames,
-};
-
-async function createPendingSidebar(
-  input: CreatePendingSidebarInput,
-): Promise<ThreadInfo> {
-  const {
-    sourceMessageInfo,
-    parentThreadInfo,
-    loggedInUserInfo,
-    markdownRules,
-    getENSNames,
-    getFCNames,
-  } = input;
-
-  const messageTitleEntityText = getMessageTitle(
-    sourceMessageInfo,
-    parentThreadInfo,
-    parentThreadInfo,
-    markdownRules,
-  );
-  const messageTitle = await getEntityTextAsString(
-    messageTitleEntityText,
-    { getENSNames, getFCNames },
-    { ignoreViewer: true },
-  );
-  invariant(
-    messageTitle !== null && messageTitle !== undefined,
-    'getEntityTextAsString only returns falsey when passed falsey',
-  );
-
-  return baseCreatePendingSidebar({
-    sourceMessageInfo,
-    parentThreadInfo,
-    messageTitle,
-    loggedInUserInfo,
-  });
-}
-
 function pendingThreadType(numberOfOtherMembers: number): 4 | 6 | 7 {
   if (numberOfOtherMembers === 0) {
     return threadTypes.PRIVATE;
@@ -1332,47 +1158,6 @@
   return false;
 }
 
-function useCanCreateSidebarFromMessage(
-  threadInfo: ThreadInfo,
-  messageInfo: ComposableMessageInfo | RobotextMessageInfo,
-): boolean {
-  const messageCreatorUserInfo = useSelector(
-    state => state.userStore.userInfos[messageInfo.creator.id],
-  );
-  const hasCreateSidebarsPermission = useThreadHasPermission(
-    threadInfo,
-    threadPermissions.CREATE_SIDEBARS,
-  );
-  if (!hasCreateSidebarsPermission) {
-    return false;
-  }
-
-  if (
-    !messageInfo.id ||
-    threadInfo.sourceMessageID === messageInfo.id ||
-    isInvalidSidebarSource(messageInfo)
-  ) {
-    return false;
-  }
-
-  const messageCreatorRelationship = messageCreatorUserInfo?.relationshipStatus;
-  return (
-    !messageCreatorRelationship ||
-    !relationshipBlockedInEitherDirection(messageCreatorRelationship)
-  );
-}
-
-function useSidebarExistsOrCanBeCreated(
-  threadInfo: ThreadInfo,
-  messageItem: ChatMessageInfoItem,
-): boolean {
-  const canCreateSidebarFromMessage = useCanCreateSidebarFromMessage(
-    threadInfo,
-    messageItem.messageInfo,
-  );
-  return !!messageItem.threadCreatedFromMessage || canCreateSidebarFromMessage;
-}
-
 function checkIfDefaultMembersAreVoiced(threadInfo: ThreadInfo): boolean {
   const defaultRoleID = Object.keys(threadInfo.roles).find(roleID =>
     roleIsDefaultRole(threadInfo.roles[roleID]),
@@ -1776,9 +1561,7 @@
   getPendingThreadID,
   parsePendingThreadID,
   createPendingThread,
-  createUnresolvedPendingSidebar,
   extractNewMentionedParentMembers,
-  createPendingSidebar,
   pendingThreadType,
   filterOutDisabledPermissions,
   getCurrentUser,
@@ -1800,8 +1583,6 @@
   useExistingThreadInfoFinder,
   getThreadTypeParentRequirement,
   threadMemberHasPermission,
-  useCanCreateSidebarFromMessage,
-  useSidebarExistsOrCanBeCreated,
   checkIfDefaultMembersAreVoiced,
   draftKeySuffix,
   draftKeyFromThreadID,
@@ -1820,4 +1601,5 @@
   useUserProfileThreadInfo,
   assertAllThreadInfosAreLegacy,
   useOnScreenEntryEditableThreadInfos,
+  extractMentionedMembers,
 };
diff --git a/native/chat/multimedia-message.react.js b/native/chat/multimedia-message.react.js
--- a/native/chat/multimedia-message.react.js
+++ b/native/chat/multimedia-message.react.js
@@ -10,7 +10,7 @@
 import { View } from 'react-native';
 
 import { messageKey } from 'lib/shared/message-utils.js';
-import { useCanCreateSidebarFromMessage } from 'lib/shared/thread-utils.js';
+import { useCanCreateSidebarFromMessage } from 'lib/shared/sidebar-utils.js';
 import type { MediaInfo } from 'lib/types/media-types.js';
 
 import ComposedMessage from './composed-message.react.js';
diff --git a/native/chat/robotext-message.react.js b/native/chat/robotext-message.react.js
--- a/native/chat/robotext-message.react.js
+++ b/native/chat/robotext-message.react.js
@@ -5,7 +5,7 @@
 import { View } from 'react-native';
 
 import { messageKey } from 'lib/shared/message-utils.js';
-import { useCanCreateSidebarFromMessage } from 'lib/shared/thread-utils.js';
+import { useCanCreateSidebarFromMessage } from 'lib/shared/sidebar-utils.js';
 
 import { inlineEngagementCenterStyle } from './chat-constants.js';
 import type { ChatNavigationProp } from './chat.react.js';
diff --git a/native/chat/sidebar-navigation.js b/native/chat/sidebar-navigation.js
--- a/native/chat/sidebar-navigation.js
+++ b/native/chat/sidebar-navigation.js
@@ -10,7 +10,7 @@
 import {
   createPendingSidebar,
   createUnresolvedPendingSidebar,
-} from 'lib/shared/thread-utils.js';
+} from 'lib/shared/sidebar-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type { ChatMentionCandidates } from 'lib/types/thread-types.js';
 import type { LoggedInUserInfo } from 'lib/types/user-types.js';
diff --git a/native/chat/text-message.react.js b/native/chat/text-message.react.js
--- a/native/chat/text-message.react.js
+++ b/native/chat/text-message.react.js
@@ -5,10 +5,8 @@
 import { View } from 'react-native';
 
 import { messageKey } from 'lib/shared/message-utils.js';
-import {
-  useCanCreateSidebarFromMessage,
-  useThreadHasPermission,
-} from 'lib/shared/thread-utils.js';
+import { useCanCreateSidebarFromMessage } from 'lib/shared/sidebar-utils.js';
+import { useThreadHasPermission } from 'lib/shared/thread-utils.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 
 import type { ChatNavigationProp } from './chat.react.js';
diff --git a/web/selectors/thread-selectors.js b/web/selectors/thread-selectors.js
--- a/web/selectors/thread-selectors.js
+++ b/web/selectors/thread-selectors.js
@@ -8,10 +8,8 @@
 import { NeynarClientContext } from 'lib/components/neynar-client-provider.react.js';
 import { useLoggedInUserInfo } from 'lib/hooks/account-hooks.js';
 import { useThreadChatMentionCandidates } from 'lib/hooks/chat-mention-hooks.js';
-import {
-  createPendingSidebar,
-  threadInHomeChatList,
-} from 'lib/shared/thread-utils.js';
+import { createPendingSidebar } from 'lib/shared/sidebar-utils.js';
+import { threadInHomeChatList } from 'lib/shared/thread-utils.js';
 import type {
   ComposableMessageInfo,
   RobotextMessageInfo,
diff --git a/web/tooltips/tooltip-action-utils.js b/web/tooltips/tooltip-action-utils.js
--- a/web/tooltips/tooltip-action-utils.js
+++ b/web/tooltips/tooltip-action-utils.js
@@ -13,10 +13,8 @@
 import { useCanEditMessage } from 'lib/shared/edit-messages-utils.js';
 import { createMessageReply } from 'lib/shared/message-utils.js';
 import { useCanCreateReactionFromMessage } from 'lib/shared/reaction-utils.js';
-import {
-  useSidebarExistsOrCanBeCreated,
-  useThreadHasPermission,
-} from 'lib/shared/thread-utils.js';
+import { useSidebarExistsOrCanBeCreated } from 'lib/shared/sidebar-utils.js';
+import { useThreadHasPermission } from 'lib/shared/thread-utils.js';
 import { messageTypes } from 'lib/types/message-types-enum.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';