diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
index 0e89fb839..bb48c2b9b 100644
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -1,714 +1,745 @@
 // @flow
 
 import invariant from 'invariant';
 import _filter from 'lodash/fp/filter.js';
 import _flow from 'lodash/fp/flow.js';
 import _map from 'lodash/fp/map.js';
 import _orderBy from 'lodash/fp/orderBy.js';
 import * as React from 'react';
 import { createSelector } from 'reselect';
 import { createObjectSelector } from 'reselect-map';
 
 import {
   threadInfoFromSourceMessageIDSelector,
   threadInfoSelector,
 } from './thread-selectors.js';
 import { sidebarInfoSelector } from '../selectors/sidebar-selectors.js';
 import {
   createMessageInfo,
   getMostRecentNonLocalMessageID,
   messageKey,
   robotextForMessageInfo,
   sortMessageInfoList,
 } from '../shared/message-utils.js';
+import { messageSpecs } from '../shared/messages/message-specs.js';
 import {
   threadInChatList,
   threadIsPending,
   threadIsTopLevel,
 } from '../shared/thread-utils.js';
 import { messageTypes } from '../types/message-types-enum.js';
 import {
   type ComposableMessageInfo,
   isComposableMessageType,
   type LocalMessageInfo,
   type MessageInfo,
   type MessageStore,
   type RobotextMessageInfo,
 } from '../types/message-types.js';
 import type {
   ThreadInfo,
   RawThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import type { BaseAppState } from '../types/redux-types.js';
 import { threadTypeIsSidebar } from '../types/thread-types-enum.js';
 import {
   maxReadSidebars,
   maxUnreadSidebars,
   type SidebarInfo,
 } from '../types/thread-types.js';
 import type {
   AccountUserInfo,
   RelativeUserInfo,
   UserInfo,
 } from '../types/user-types.js';
 import { threeDays } from '../utils/date-utils.js';
 import type { EntityText } from '../utils/entity-text.js';
 import memoize2 from '../utils/memoize.js';
 import { useSelector } from '../utils/redux-utils.js';
 
 export type SidebarItem =
   | {
       ...SidebarInfo,
       +type: 'sidebar',
     }
   | {
       +type: 'seeMore',
       +unread: boolean,
     }
   | { +type: 'spacer' };
 
 export type ChatThreadItem = {
   +type: 'chatThreadItem',
   +threadInfo: ThreadInfo,
   +mostRecentMessageInfo: ?MessageInfo,
   +mostRecentNonLocalMessage: ?string,
   +lastUpdatedTime: number,
   +lastUpdatedTimeIncludingSidebars: number,
   +sidebars: $ReadOnlyArray<SidebarItem>,
   +pendingPersonalThreadUserInfo?: UserInfo,
 };
 
 const messageInfoSelector: (state: BaseAppState<>) => {
   +[id: string]: ?MessageInfo,
 } = createObjectSelector(
   (state: BaseAppState<>) => state.messageStore.messages,
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<>) => state.userStore.userInfos,
   threadInfoSelector,
   createMessageInfo,
 );
 
 function isEmptyMediaMessage(messageInfo: MessageInfo): boolean {
   return (
     (messageInfo.type === messageTypes.MULTIMEDIA ||
       messageInfo.type === messageTypes.IMAGES) &&
     messageInfo.media.length === 0
   );
 }
 
 function getMostRecentMessageInfo(
   threadInfo: ThreadInfo,
   messageStore: MessageStore,
   messages: { +[id: string]: ?MessageInfo },
 ): ?MessageInfo {
   const thread = messageStore.threads[threadInfo.id];
   if (!thread) {
     return null;
   }
   for (const messageID of thread.messageIDs) {
     const messageInfo = messages[messageID];
     if (!messageInfo || isEmptyMediaMessage(messageInfo)) {
       continue;
     }
     return messageInfo;
   }
   return null;
 }
 
 function getLastUpdatedTime(
   threadInfo: ThreadInfo,
   mostRecentMessageInfo: ?MessageInfo,
 ): number {
   return mostRecentMessageInfo
     ? mostRecentMessageInfo.time
     : threadInfo.creationTime;
 }
 
 function createChatThreadItem(
   threadInfo: ThreadInfo,
   messageStore: MessageStore,
   messages: { +[id: string]: ?MessageInfo },
   sidebarInfos: ?$ReadOnlyArray<SidebarInfo>,
 ): ChatThreadItem {
   const mostRecentMessageInfo = getMostRecentMessageInfo(
     threadInfo,
     messageStore,
     messages,
   );
   const mostRecentNonLocalMessage = getMostRecentNonLocalMessageID(
     threadInfo.id,
     messageStore,
   );
   const lastUpdatedTime = getLastUpdatedTime(threadInfo, mostRecentMessageInfo);
 
   const sidebars = sidebarInfos ?? [];
   const allSidebarItems = sidebars.map(sidebarInfo => ({
     type: 'sidebar',
     ...sidebarInfo,
   }));
   const lastUpdatedTimeIncludingSidebars =
     allSidebarItems.length > 0
       ? Math.max(lastUpdatedTime, allSidebarItems[0].lastUpdatedTime)
       : lastUpdatedTime;
 
   const numUnreadSidebars = allSidebarItems.filter(
     sidebar => sidebar.threadInfo.currentUser.unread,
   ).length;
   let numReadSidebarsToShow = maxReadSidebars - numUnreadSidebars;
   const threeDaysAgo = Date.now() - threeDays;
 
   const sidebarItems: SidebarItem[] = [];
   for (const sidebar of allSidebarItems) {
     if (sidebarItems.length >= maxUnreadSidebars) {
       break;
     } else if (sidebar.threadInfo.currentUser.unread) {
       sidebarItems.push(sidebar);
     } else if (
       sidebar.lastUpdatedTime > threeDaysAgo &&
       numReadSidebarsToShow > 0
     ) {
       sidebarItems.push(sidebar);
       numReadSidebarsToShow--;
     }
   }
 
   const numReadButRecentSidebars = allSidebarItems.filter(
     sidebar =>
       !sidebar.threadInfo.currentUser.unread &&
       sidebar.lastUpdatedTime > threeDaysAgo,
   ).length;
   if (
     sidebarItems.length < numUnreadSidebars + numReadButRecentSidebars ||
     (sidebarItems.length < allSidebarItems.length && sidebarItems.length > 0)
   ) {
     sidebarItems.push({
       type: 'seeMore',
       unread: numUnreadSidebars > maxUnreadSidebars,
     });
   }
   if (sidebarItems.length !== 0) {
     sidebarItems.push({
       type: 'spacer',
     });
   }
 
   return {
     type: 'chatThreadItem',
     threadInfo,
     mostRecentMessageInfo,
     mostRecentNonLocalMessage,
     lastUpdatedTime,
     lastUpdatedTimeIncludingSidebars,
     sidebars: sidebarItems,
   };
 }
 
 const chatListData: (state: BaseAppState<>) => $ReadOnlyArray<ChatThreadItem> =
   createSelector(
     threadInfoSelector,
     (state: BaseAppState<>) => state.messageStore,
     messageInfoSelector,
     sidebarInfoSelector,
     (
       threadInfos: {
         +[id: string]: ThreadInfo,
       },
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
       sidebarInfos: { +[id: string]: $ReadOnlyArray<SidebarInfo> },
     ): $ReadOnlyArray<ChatThreadItem> =>
       getChatThreadItems(
         threadInfos,
         messageStore,
         messageInfos,
         sidebarInfos,
         threadIsTopLevel,
       ),
   );
 
 function useFlattenedChatListData(): $ReadOnlyArray<ChatThreadItem> {
   return useFilteredChatListData(threadInChatList);
 }
 
 function useFilteredChatListData(
   filterFunction: (threadInfo: ?(ThreadInfo | RawThreadInfo)) => boolean,
 ): $ReadOnlyArray<ChatThreadItem> {
   const threadInfos = useSelector(threadInfoSelector);
   const messageInfos = useSelector(messageInfoSelector);
   const sidebarInfos = useSelector(sidebarInfoSelector);
   const messageStore = useSelector(state => state.messageStore);
 
   return React.useMemo(
     () =>
       getChatThreadItems(
         threadInfos,
         messageStore,
         messageInfos,
         sidebarInfos,
         filterFunction,
       ),
     [messageInfos, messageStore, sidebarInfos, filterFunction, threadInfos],
   );
 }
 
 function getChatThreadItems(
   threadInfos: { +[id: string]: ThreadInfo },
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
   sidebarInfos: { +[id: string]: $ReadOnlyArray<SidebarInfo> },
   filterFunction: (threadInfo: ?(ThreadInfo | RawThreadInfo)) => boolean,
 ): $ReadOnlyArray<ChatThreadItem> {
   return _flow(
     _filter(filterFunction),
     _map((threadInfo: ThreadInfo): ChatThreadItem =>
       createChatThreadItem(
         threadInfo,
         messageStore,
         messageInfos,
         sidebarInfos[threadInfo.id],
       ),
     ),
     _orderBy('lastUpdatedTimeIncludingSidebars')('desc'),
   )(threadInfos);
 }
 
 export type RobotextChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'robotext',
   +messageInfos: $ReadOnlyArray<RobotextMessageInfo>,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +robotext: EntityText,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
 };
 export type ComposableChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'composable',
   +messageInfo: ComposableMessageInfo,
   +localMessageInfo: ?LocalMessageInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
   +hasBeenEdited: boolean,
   +isPinned: boolean,
 };
 export type ChatMessageInfoItem =
   | RobotextChatMessageInfoItem
   | ComposableChatMessageInfoItem;
 export type ChatMessageItem = { itemType: 'loader' } | ChatMessageInfoItem;
 
 export type ReactionInfo = { +[reaction: string]: MessageReactionInfo };
 type MessageReactionInfo = {
   +viewerReacted: boolean,
   +users: $ReadOnlyArray<RelativeUserInfo>,
 };
 type TargetMessageReactions = Map<string, Map<string, RelativeUserInfo>>;
 
 const msInFiveMinutes = 5 * 60 * 1000;
 function createChatMessageItems(
   threadID: string,
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
   threadInfos: { +[id: string]: ThreadInfo },
   threadInfoFromSourceMessageID: {
     +[id: string]: ThreadInfo,
   },
   additionalMessages: $ReadOnlyArray<MessageInfo>,
   viewerID: string,
 ): ChatMessageItem[] {
   const thread = messageStore.threads[threadID];
 
   const threadMessageInfos = (thread?.messageIDs ?? [])
     .map((messageID: string) => messageInfos[messageID])
     .filter(Boolean);
   const messages =
     additionalMessages.length > 0
       ? sortMessageInfoList([...threadMessageInfos, ...additionalMessages])
       : threadMessageInfos;
 
   const targetMessageReactionsMap = new Map<string, TargetMessageReactions>();
 
   // We need to iterate backwards to put the order of messages in chronological
   // order, starting with the oldest. This avoids the scenario where the most
   // recent message with the remove_reaction action may try to remove a user
   // that hasn't been added to the messageReactionUsersInfoMap, causing it
   // to be skipped.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.REACTION) {
       continue;
     }
 
     if (!targetMessageReactionsMap.has(messageInfo.targetMessageID)) {
       const reactsMap: TargetMessageReactions = new Map();
       targetMessageReactionsMap.set(messageInfo.targetMessageID, reactsMap);
     }
 
     const messageReactsMap = targetMessageReactionsMap.get(
       messageInfo.targetMessageID,
     );
     invariant(messageReactsMap, 'messageReactsInfo should be set');
 
     if (!messageReactsMap.has(messageInfo.reaction)) {
       const usersInfoMap = new Map<string, RelativeUserInfo>();
       messageReactsMap.set(messageInfo.reaction, usersInfoMap);
     }
 
     const messageReactionUsersInfoMap = messageReactsMap.get(
       messageInfo.reaction,
     );
     invariant(
       messageReactionUsersInfoMap,
       'messageReactionUsersInfoMap should be set',
     );
 
     if (messageInfo.action === 'add_reaction') {
       messageReactionUsersInfoMap.set(
         messageInfo.creator.id,
         messageInfo.creator,
       );
     } else {
       messageReactionUsersInfoMap.delete(messageInfo.creator.id);
     }
   }
 
   const targetMessageEditMap = new Map<string, string>();
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.EDIT_MESSAGE) {
       continue;
     }
     targetMessageEditMap.set(messageInfo.targetMessageID, messageInfo.text);
   }
 
   const targetMessagePinStatusMap = new Map<string, boolean>();
   // Once again, we iterate backwards to put the order of messages in
   // chronological order (i.e. oldest to newest) to handle pinned messages.
   // This is important because we want to make sure that the most recent pin
   // action is the one that is used to determine whether a message
   // is pinned or not.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.TOGGLE_PIN) {
       continue;
     }
 
     targetMessagePinStatusMap.set(
       messageInfo.targetMessageID,
       messageInfo.action === 'pin',
     );
   }
 
   const chatMessageItems: ChatMessageItem[] = [];
   let lastMessageInfo = null;
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
 
     if (
       messageInfo.type === messageTypes.REACTION ||
       messageInfo.type === messageTypes.EDIT_MESSAGE
     ) {
       continue;
     }
 
     let originalMessageInfo =
       messageInfo.type === messageTypes.SIDEBAR_SOURCE
         ? messageInfo.sourceMessage
         : messageInfo;
 
     if (isEmptyMediaMessage(originalMessageInfo)) {
       continue;
     }
 
     let hasBeenEdited = false;
     if (
       originalMessageInfo.type === messageTypes.TEXT &&
       originalMessageInfo.id
     ) {
       const newText = targetMessageEditMap.get(originalMessageInfo.id);
       if (newText !== undefined) {
         hasBeenEdited = true;
         originalMessageInfo = {
           ...originalMessageInfo,
           text: newText,
         };
       }
     }
 
     let startsConversation = true;
     let startsCluster = true;
     if (
       lastMessageInfo &&
       lastMessageInfo.time + msInFiveMinutes > originalMessageInfo.time
     ) {
       startsConversation = false;
       if (
         isComposableMessageType(lastMessageInfo.type) &&
         isComposableMessageType(originalMessageInfo.type) &&
         lastMessageInfo.creator.id === originalMessageInfo.creator.id
       ) {
         startsCluster = false;
       }
     }
     if (startsCluster && chatMessageItems.length > 0) {
       const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
       invariant(lastMessageItem.itemType === 'message', 'should be message');
       lastMessageItem.endsCluster = true;
     }
     const threadCreatedFromMessage =
       !threadTypeIsSidebar(threadInfos[threadID]?.type) && messageInfo.id
         ? threadInfoFromSourceMessageID[messageInfo.id]
         : undefined;
 
     const isPinned = !!(
       originalMessageInfo.id &&
       targetMessagePinStatusMap.get(originalMessageInfo.id)
     );
 
     const renderedReactions: ReactionInfo = (() => {
       const result: { [string]: MessageReactionInfo } = {};
 
       let messageReactsMap;
       if (originalMessageInfo.id) {
         messageReactsMap = targetMessageReactionsMap.get(
           originalMessageInfo.id,
         );
       }
 
       if (!messageReactsMap) {
         return result;
       }
 
       for (const reaction of messageReactsMap.keys()) {
         const reactionUsersInfoMap = messageReactsMap.get(reaction);
         invariant(reactionUsersInfoMap, 'reactionUsersInfoMap should be set');
 
         if (reactionUsersInfoMap.size === 0) {
           continue;
         }
 
         const reactionUserInfos = [...reactionUsersInfoMap.values()];
 
         const messageReactionInfo = {
           users: reactionUserInfos,
           viewerReacted: reactionUsersInfoMap.has(viewerID),
         };
 
         result[reaction] = messageReactionInfo;
       }
 
       return result;
     })();
 
+    const threadInfo = threadInfos[threadID];
+    const parentThreadInfo = threadInfo?.parentThreadID
+      ? threadInfos[threadInfo.parentThreadID]
+      : null;
+
+    const lastChatMessageItem =
+      chatMessageItems.length > 0
+        ? chatMessageItems[chatMessageItems.length - 1]
+        : undefined;
+    const messageSpec = messageSpecs[originalMessageInfo.type];
+    if (
+      !threadCreatedFromMessage &&
+      Object.keys(renderedReactions).length === 0 &&
+      !hasBeenEdited &&
+      !isPinned &&
+      lastChatMessageItem &&
+      lastChatMessageItem.itemType === 'message' &&
+      lastChatMessageItem.messageInfoType === 'robotext' &&
+      !lastChatMessageItem.threadCreatedFromMessage &&
+      Object.keys(lastChatMessageItem.reactions).length === 0 &&
+      !isComposableMessageType(originalMessageInfo.type) &&
+      messageSpec?.mergeIntoPrecedingRobotextMessageItem
+    ) {
+      const { mergeIntoPrecedingRobotextMessageItem } = messageSpec;
+      const mergeResult = mergeIntoPrecedingRobotextMessageItem(
+        originalMessageInfo,
+        lastChatMessageItem,
+        { threadInfo, parentThreadInfo },
+      );
+      if (mergeResult.shouldMerge) {
+        chatMessageItems[chatMessageItems.length - 1] = mergeResult.item;
+        continue;
+      }
+    }
+
     if (isComposableMessageType(originalMessageInfo.type)) {
       // We use these invariants instead of just checking the messageInfo.type
       // directly in the conditional above so that isComposableMessageType can
       // be the source of truth
       invariant(
         originalMessageInfo.type === messageTypes.TEXT ||
           originalMessageInfo.type === messageTypes.IMAGES ||
           originalMessageInfo.type === messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
       const localMessageInfo =
         messageStore.local[messageKey(originalMessageInfo)];
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'composable',
         messageInfo: originalMessageInfo,
         localMessageInfo,
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         reactions: renderedReactions,
         hasBeenEdited,
         isPinned,
       });
     } else {
       invariant(
         originalMessageInfo.type !== messageTypes.TEXT &&
           originalMessageInfo.type !== messageTypes.IMAGES &&
           originalMessageInfo.type !== messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
-      const threadInfo = threadInfos[threadID];
-      const parentThreadInfo = threadInfo?.parentThreadID
-        ? threadInfos[threadInfo.parentThreadID]
-        : null;
-
       const robotext = robotextForMessageInfo(
         originalMessageInfo,
         threadInfo,
         parentThreadInfo,
       );
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'robotext',
         messageInfos: [originalMessageInfo],
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         robotext,
         reactions: renderedReactions,
       });
     }
     lastMessageInfo = originalMessageInfo;
   }
   if (chatMessageItems.length > 0) {
     const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
     invariant(lastMessageItem.itemType === 'message', 'should be message');
     lastMessageItem.endsCluster = true;
   }
   chatMessageItems.reverse();
   const hideSpinner = thread ? thread.startReached : threadIsPending(threadID);
   if (hideSpinner) {
     return chatMessageItems;
   }
   return [...chatMessageItems, ({ itemType: 'loader' }: ChatMessageItem)];
 }
 
 const baseMessageListData = (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ): ((state: BaseAppState<>) => ?(ChatMessageItem[])) =>
   createSelector(
     (state: BaseAppState<>) => state.messageStore,
     messageInfoSelector,
     threadInfoSelector,
     threadInfoFromSourceMessageIDSelector,
     (state: BaseAppState<>) =>
       state.currentUserInfo && state.currentUserInfo.id,
     (
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
       threadInfos: {
         +[id: string]: ThreadInfo,
       },
       threadInfoFromSourceMessageID: {
         +[id: string]: ThreadInfo,
       },
       viewerID: ?string,
     ): ?(ChatMessageItem[]) => {
       if (!threadID || !viewerID) {
         return null;
       }
       return createChatMessageItems(
         threadID,
         messageStore,
         messageInfos,
         threadInfos,
         threadInfoFromSourceMessageID,
         additionalMessages,
         viewerID,
       );
     },
   );
 export type MessageListData = ?(ChatMessageItem[]);
 const messageListData: (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ) => (state: BaseAppState<>) => MessageListData = memoize2(baseMessageListData);
 
 export type UseMessageListDataArgs = {
   +searching: boolean,
   +userInfoInputArray: $ReadOnlyArray<AccountUserInfo>,
   +threadInfo: ?ThreadInfo,
 };
 
 function useMessageListData({
   searching,
   userInfoInputArray,
   threadInfo,
 }: UseMessageListDataArgs): MessageListData {
   const messageInfos = useSelector(messageInfoSelector);
 
   const containingThread = useSelector(state => {
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !threadInfo.containingThreadID
     ) {
       return null;
     }
     return state.messageStore.threads[threadInfo.containingThreadID];
   });
 
   const pendingSidebarEditMessageInfo = React.useMemo(() => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     const threadMessageInfos = (containingThread?.messageIDs ?? [])
       .map((messageID: string) => messageInfos[messageID])
       .filter(Boolean)
       .filter(
         message =>
           message.type === messageTypes.EDIT_MESSAGE &&
           message.targetMessageID === sourceMessageID,
       );
     if (threadMessageInfos.length === 0) {
       return null;
     }
     return threadMessageInfos[0];
   }, [threadInfo, containingThread, messageInfos]);
 
   const pendingSidebarSourceMessageInfo = useSelector(state => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !sourceMessageID
     ) {
       return null;
     }
     const thread = state.messageStore.threads[threadInfo.id];
     const shouldSourceBeAdded =
       !thread ||
       (thread.startReached &&
         thread.messageIDs.every(
           id => messageInfos[id]?.type !== messageTypes.SIDEBAR_SOURCE,
         ));
     return shouldSourceBeAdded ? messageInfos[sourceMessageID] : null;
   });
 
   invariant(
     !pendingSidebarSourceMessageInfo ||
       pendingSidebarSourceMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
     'sidebars can not be created from sidebar_source message',
   );
 
   const additionalMessages = React.useMemo(() => {
     if (!pendingSidebarSourceMessageInfo) {
       return ([]: MessageInfo[]);
     }
     const result: MessageInfo[] = [pendingSidebarSourceMessageInfo];
     if (pendingSidebarEditMessageInfo) {
       result.push(pendingSidebarEditMessageInfo);
     }
     return result;
   }, [pendingSidebarSourceMessageInfo, pendingSidebarEditMessageInfo]);
   const boundMessageListData = useSelector(
     messageListData(threadInfo?.id, additionalMessages),
   );
 
   return React.useMemo(() => {
     if (searching && userInfoInputArray.length === 0) {
       return [];
     }
     return boundMessageListData;
   }, [searching, userInfoInputArray.length, boundMessageListData]);
 }
 
 export {
   messageInfoSelector,
   createChatThreadItem,
   chatListData,
   createChatMessageItems,
   messageListData,
   useFlattenedChatListData,
   useFilteredChatListData,
   useMessageListData,
 };
diff --git a/lib/shared/messages/message-spec.js b/lib/shared/messages/message-spec.js
index 1042bd654..23ee23589 100644
--- a/lib/shared/messages/message-spec.js
+++ b/lib/shared/messages/message-spec.js
@@ -1,124 +1,134 @@
 // @flow
 
 import type { TType } from 'tcomb';
 
+import type { RobotextChatMessageInfoItem } from '../../selectors/chat-selectors.js';
 import type { PlatformDetails } from '../../types/device-types.js';
 import type { Media } from '../../types/media-types.js';
 import type {
   ClientDBMessageInfo,
   MessageInfo,
   RawComposableMessageInfo,
   RawMessageInfo,
   RawRobotextMessageInfo,
 } from '../../types/message-types.js';
 import type { RawUnsupportedMessageInfo } from '../../types/messages/unsupported.js';
 import type { ThreadInfo } from '../../types/minimally-encoded-thread-permissions-types.js';
 import type { NotifTexts } from '../../types/notif-types.js';
 import type { RelativeUserInfo, UserInfo } from '../../types/user-types.js';
 import type { EntityText } from '../../utils/entity-text.js';
 import { type ParserRules } from '../markdown.js';
 
 export type MessageTitleParam<Info> = {
   +messageInfo: Info,
   +threadInfo: ThreadInfo,
   +markdownRules: ParserRules,
 };
 
 export type RawMessageInfoFromServerDBRowParams = {
   +localID: ?string,
   +media?: $ReadOnlyArray<Media>,
   +derivedMessages?: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
 };
 
 export type CreateMessageInfoParams = {
   +threadInfos: {
     +[id: string]: ThreadInfo,
   },
   +createMessageInfoFromRaw: (rawInfo: RawMessageInfo) => ?MessageInfo,
   +createRelativeUserInfos: (
     userIDs: $ReadOnlyArray<string>,
   ) => RelativeUserInfo[],
 };
 
 export type RobotextParams = {
   +threadInfo: ?ThreadInfo,
   +parentThreadInfo: ?ThreadInfo,
 };
 
 export type NotificationTextsParams = {
   +notifTargetUserInfo: UserInfo,
   +parentThreadInfo: ?ThreadInfo,
 };
 
 export type GeneratesNotifsParams = {
   +notifTargetUserID: string,
   +userNotMemberOfSubthreads: Set<string>,
   +fetchMessageInfoByID: (messageID: string) => Promise<?RawMessageInfo>,
 };
 
 export const pushTypes = Object.freeze({
   NOTIF: 'notif',
   RESCIND: 'rescind',
 });
 export type PushType = $Values<typeof pushTypes>;
 
 export type CreationSideEffectsFunc<RawInfo> = (
   messageInfo: RawInfo,
   threadInfo: ThreadInfo,
   parentThreadInfo: ?ThreadInfo,
 ) => Promise<mixed>;
 
+export type MergeRobotextMessageItemResult =
+  | { +shouldMerge: false }
+  | { +shouldMerge: true, +item: RobotextChatMessageInfoItem };
+
 export type MessageSpec<Data, RawInfo, Info> = {
   +messageContentForServerDB?: (data: Data | RawInfo) => string,
   +messageContentForClientDB?: (data: RawInfo) => string,
   +messageTitle?: (param: MessageTitleParam<Info>) => EntityText,
   +rawMessageInfoFromServerDBRow?: (
     row: Object,
     params: RawMessageInfoFromServerDBRowParams,
   ) => ?RawInfo,
   +rawMessageInfoFromClientDB: (
     clientDBMessageInfo: ClientDBMessageInfo,
   ) => RawInfo,
   +createMessageInfo: (
     rawMessageInfo: RawInfo,
     creator: RelativeUserInfo,
     params: CreateMessageInfoParams,
   ) => ?Info,
   +rawMessageInfoFromMessageData?: (messageData: Data, id: ?string) => RawInfo,
   +robotext?: (messageInfo: Info, params: RobotextParams) => EntityText,
   +shimUnsupportedMessageInfo?: (
     rawMessageInfo: RawInfo,
     platformDetails: ?PlatformDetails,
   ) => RawInfo | RawUnsupportedMessageInfo,
   +unshimMessageInfo?: (
     unwrapped: RawInfo,
     messageInfo: RawMessageInfo,
   ) => ?RawMessageInfo,
   +notificationTexts?: (
     messageInfos: $ReadOnlyArray<MessageInfo>,
     threadInfo: ThreadInfo,
     params: NotificationTextsParams,
   ) => Promise<?NotifTexts>,
   +notificationCollapseKey?: (
     rawMessageInfo: RawInfo,
     messageData: Data,
   ) => ?string,
   +generatesNotifs?: (
     rawMessageInfo: RawInfo,
     messageData: Data,
     params: GeneratesNotifsParams,
   ) => Promise<?PushType>,
   +userIDs?: (rawMessageInfo: RawInfo) => $ReadOnlyArray<string>,
   +startsThread?: boolean,
   +threadIDs?: (rawMessageInfo: RawInfo) => $ReadOnlyArray<string>,
   +includedInRepliesCount?: boolean,
   +canBeSidebarSource: boolean,
   +canBePinned: boolean,
   +canBeRenderedIndependently?: boolean,
   +parseDerivedMessages?: (row: Object, requiredIDs: Set<string>) => void,
   +useCreationSideEffectsFunc?: () => CreationSideEffectsFunc<RawInfo>,
   +validator: TType<RawInfo>,
+  +mergeIntoPrecedingRobotextMessageItem?: (
+    messageInfo: Info,
+    precedingMessageInfoItem: RobotextChatMessageInfoItem,
+    params: RobotextParams,
+  ) => MergeRobotextMessageItemResult,
 };