[MM-67118] Add Agents to @ mention autocomplete in channel (#34881)

* Add support for autocomplete of plugin-created bots

* stashing

* Add support for including agents in the autocomplete list for @ mentions

* Change server response to be users rather than interface

* fix

server/channels/api4/user.go

@@ -1324,6 +1324,12 @@ func autocompleteUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 		autocomplete.Users = result
 	}
 
+	// Fetch agent users for autocomplete
+	agentUsers, appErr := c.App.GetUsersForAgents(c.AppContext, c.AppContext.Session().UserId)
+	if appErr == nil && agentUsers != nil {
+		autocomplete.Agents = agentUsers
+	}
+
 	if err := json.NewEncoder(w).Encode(autocomplete); err != nil {
 		c.Logger.Warn("Error while writing response", mlog.Err(err))
 	}

server/channels/app/agents.go

@@ -101,6 +101,35 @@ func (a *App) GetAgents(rctx request.CTX, userID string) ([]agentclient.BridgeAg
 	return agents, nil
 }
 
+// GetUsersForAgents retrieves the User objects for all available agents
+func (a *App) GetUsersForAgents(rctx request.CTX, userID string) ([]*model.User, *model.AppError) {
+	agents, appErr := a.GetAgents(rctx, userID)
+	if appErr != nil {
+		return nil, appErr
+	}
+
+	if len(agents) == 0 {
+		return []*model.User{}, nil
+	}
+
+	users := make([]*model.User, 0, len(agents))
+	for _, agent := range agents {
+		// Agents have a username field that corresponds to the bot user's username
+		user, err := a.Srv().Store().User().GetByUsername(agent.Username)
+		if err != nil {
+			rctx.Logger().Warn("Failed to get user for agent",
+				mlog.Err(err),
+				mlog.String("agent_id", agent.ID),
+				mlog.String("username", agent.Username),
+			)
+			continue
+		}
+		users = append(users, user)
+	}
+
+	return users, nil
+}
+
 // GetLLMServices retrieves all available LLM services from the bridge API
 func (a *App) GetLLMServices(rctx request.CTX, userID string) ([]agentclient.BridgeServiceInfo, *model.AppError) {
 	// Check if the AI plugin is active and supports the bridge API (v1.5.0+)

server/public/model/user_autocomplete.go

@@ -15,4 +15,5 @@ type UserAutocompleteInTeam struct {
 type UserAutocomplete struct {
 	Users        []*User `json:"users"`
 	OutOfChannel []*User `json:"out_of_channel,omitempty"`
+	Agents       []*User `json:"agents,omitempty"`
 }

webapp/channels/src/components/suggestion/at_mention_provider/at_mention_provider.tsx

@@ -1,8 +1,10 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
+import React from 'react';
 import {defineMessage} from 'react-intl';
 
+import {CreationOutlineIcon} from '@mattermost/compass-icons/components';
 import type {Group} from '@mattermost/types/groups';
 import type {UserProfile} from '@mattermost/types/users';
 
@@ -306,6 +308,17 @@ export default class AtMentionProvider extends Provider {
         // Combine the local and remote members, sorting to mix the results together.
         const localAndRemoteMembers = localMembers.concat(remoteMembers).sort(orderUsers);
 
+        // Get agents - these are already User objects from the backend
+        // Only show agents if bridge is enabled (indicated by presence of agents data)
+        let agents: CreatedProfile[] = [];
+        if (this.data && this.data.agents && Array.isArray(this.data.agents) && this.data.agents.length > 0) {
+            const agentUsers = this.data.agents as UserProfileWithLastViewAt[];
+            agents = agentUsers.
+                filter((user: UserProfileWithLastViewAt) => this.filterProfile(user)).
+                map((user: UserProfileWithLastViewAt) => this.createFromProfile(user)).
+                sort(orderUsers);
+        }
+
         // handle groups
         const localGroups = this.localGroups();
 
@@ -345,6 +358,9 @@ export default class AtMentionProvider extends Provider {
         if (priorityProfiles.length > 0 || localAndRemoteMembers.length > 0) {
             items.push(membersGroup([...priorityProfiles, ...localAndRemoteMembers]));
         }
+        if (agents.length > 0) {
+            items.push(agentsGroup(agents));
+        }
         if (localAndRemoteGroups.length > 0) {
             items.push(groupsGroup(localAndRemoteGroups));
         }
@@ -453,6 +469,17 @@ export function membersGroup(items: CreatedProfile[]) {
     };
 }
 
+export function agentsGroup(items: CreatedProfile[]) {
+    return {
+        key: 'agents',
+        label: defineMessage({id: 'suggestion.mention.agents', defaultMessage: 'Agents'}),
+        icon: <CreationOutlineIcon size={16}/>,
+        items,
+        terms: items.map((profile) => '@' + profile.username),
+        component: AtMentionSuggestion,
+    };
+}
+
 export function groupsGroup(items: Group[]) {
     return {
         key: 'groups',

webapp/channels/src/i18n/en.json

@@ -5990,6 +5990,7 @@
   "suggestion.emoji": "Emoji",
   "suggestion.group_channel": "Group channel",
   "suggestion.group.members": "{member_count} {member_count, plural, one {member} other {members}}",
+  "suggestion.mention.agents": "Agents",
   "suggestion.mention.all": "Notifies everyone in this channel",
   "suggestion.mention.channel": "Notifies everyone in this channel",
   "suggestion.mention.channels": "My Channels",