Add Default Agent Support and promote Agents to be part of suite (#35091)

* Add default agent support and App Bar integration

- Add Agents section to App Bar, separating it from Core Products.
- Implement Default Agent logic in AtMentionProvider:
  - Promote default agent to top of suggestions for empty '@' prefix.
  - Filter duplicate agent entry from main list when default is shown.
- Add `AgentTag` component for UI distinction.
- Update `mattermost-plugin-ai` and `server/public` dependencies.
- Add unit tests for default agent suggestion logic.

* Add missing files (server deps, types)

* Fix pre-commit check failures

- Fix TypeScript errors in test files:
  - Add missing displayName property to defaultAgent in at_mention_provider test
  - Add missing fetchAgents mock in textbox test
- Fix Go assignment mismatch in integration_action_test.go (CreatePostAsUser returns 3 values)
- Fix license copyright year in plugins/mattermost-ai/assets/embed.go
- Update i18n translations (add tag.default.agent)
- Regenerate Go serialized files, mmctl docs, and update go.mod/go.sum

* Update snapshot tests for textbox and at_mention_suggestion

* Undo mmctl docs changes

* Undo more changes

* revert package-lock.json

* Update dep for ai plugin

* Update again

* Update at_mention_provider to filter out agent duplicates and add .cursor/ to gitignore

- Filter agent usernames from priorityProfiles and localAndRemoteMembers to prevent duplicate entries in autocomplete suggestions
- Add .cursor/ directory to .gitignore

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -163,3 +163,4 @@ docker-compose.override.yaml
 **/CLAUDE.local.md
 **/CLAUDE.md
 .cursorrules
+.cursor/

server/go.mod

@@ -43,8 +43,8 @@ require (
 	github.com/mattermost/gosaml2 v0.10.0
 	github.com/mattermost/ldap v0.0.0-20231116144001-0f480c025956
 	github.com/mattermost/logr/v2 v2.0.22
-	github.com/mattermost/mattermost-plugin-ai v1.5.0
-	github.com/mattermost/mattermost/server/public v0.1.20
+	github.com/mattermost/mattermost-plugin-ai v1.8.1
+	github.com/mattermost/mattermost/server/public v0.1.22-0.20251105210629-8bf4a00724e2
 	github.com/mattermost/morph v1.1.0
 	github.com/mattermost/rsc v0.0.0-20160330161541-bbaefb05eaa0
 	github.com/mattermost/squirrel v0.5.0
@@ -131,7 +131,7 @@ require (
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/gomodule/redigo v2.0.0+incompatible // indirect
 	github.com/google/btree v1.1.3 // indirect
-	github.com/google/jsonschema-go v0.2.3 // indirect
+	github.com/google/jsonschema-go v0.3.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/css v1.0.1 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect

server/go.sum

@@ -267,8 +267,8 @@ github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX
 github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
 github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
-github.com/google/jsonschema-go v0.2.3 h1:dkP3B96OtZKKFvdrUSaDkL+YDx8Uw9uC4Y+eukpCnmM=
-github.com/google/jsonschema-go v0.2.3/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
+github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
+github.com/google/jsonschema-go v0.3.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/pprof v0.0.0-20181206194817-3ea8567a2e57/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
 github.com/google/pprof v0.0.0-20190515194954-54271f7e092f/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
@@ -406,10 +406,14 @@ github.com/mattermost/ldap v0.0.0-20231116144001-0f480c025956 h1:Y1Tu/swM31pVwwb
 github.com/mattermost/ldap v0.0.0-20231116144001-0f480c025956/go.mod h1:SRl30Lb7/QoYyohYeVBuqYvvmXSZJxZgiV3Zf6VbxjI=
 github.com/mattermost/logr/v2 v2.0.22 h1:npFkXlkAWR9J8payh8ftPcCZvLbHSI125mAM5/r/lP4=
 github.com/mattermost/logr/v2 v2.0.22/go.mod h1:0sUKpO+XNMZApeumaid7PYaUZPBIydfuWZ0dqixXo+s=
-github.com/mattermost/mattermost-plugin-ai v1.5.0 h1:64P8CadbrglgiQMiYqE9kZngrvIb5Ze7Jv+iK832RbI=
-github.com/mattermost/mattermost-plugin-ai v1.5.0/go.mod h1:sgR9+nLFCjYSE9vlqxLZxHZ+6Kz2NJw9Qko+ywVX2k0=
-github.com/mattermost/mattermost/server/public v0.1.20 h1:N39ZOyYvCVZXABetpb0tVrm/08Od3q7d/D45QZjJ63s=
-github.com/mattermost/mattermost/server/public v0.1.20/go.mod h1:ZSdLCHIFYDTmX5FNCJ7LoI2CLZ1rQqZcfJ3ZF81QadY=
+github.com/mattermost/mattermost-plugin-ai v1.7.3-0.20260128145904-ae362cf86c17 h1:Mz9ZbcFPF3OItbDtor/FGJRHNfi7QFnPESjgCmL876A=
+github.com/mattermost/mattermost-plugin-ai v1.7.3-0.20260128145904-ae362cf86c17/go.mod h1:giiKPJpaLV4qv/odeGMyO7ltkgaWZzsbUA92Wi7EMkA=
+github.com/mattermost/mattermost-plugin-ai v1.8.1-0.20260205142725-644bf6ed9297 h1:oojqLsPxMAY7tMOG6cQZ0BAfiYZvGMarRi3dq7krzpU=
+github.com/mattermost/mattermost-plugin-ai v1.8.1-0.20260205142725-644bf6ed9297/go.mod h1:Uco4K7ypsrZWcD256ezvgZDqolJfHYiExN2lYiHmVDo=
+github.com/mattermost/mattermost-plugin-ai v1.8.1 h1:qymxDayy3vJPhm59XA8q0oLR8uobPgx0SOB7IMG9ZMM=
+github.com/mattermost/mattermost-plugin-ai v1.8.1/go.mod h1:Uco4K7ypsrZWcD256ezvgZDqolJfHYiExN2lYiHmVDo=
+github.com/mattermost/mattermost/server/public v0.1.22-0.20251105210629-8bf4a00724e2 h1:RJtCnj9nF/wb0Fb+O0qAPgUoWP5CTTDnHzHD5ciGlJ8=
+github.com/mattermost/mattermost/server/public v0.1.22-0.20251105210629-8bf4a00724e2/go.mod h1:X0RG3lk0XK0SFSH67JS/xporlz3TxItHEPlFIrsQIa8=
 github.com/mattermost/morph v1.1.0 h1:Q9vrJbeM3s2jfweGheq12EFIzdNp9a/6IovcbvOQ6Cw=
 github.com/mattermost/morph v1.1.0/go.mod h1:gD+EaqX2UMyyuzmF4PFh4r33XneQ8Nzi+0E8nXjMa3A=
 github.com/mattermost/msgpack/v5 v5.0.0-20260120151306-2f9c67d7e57f h1:tAXeRJSWo6EK7wDq1TcxMHIxHRyjrE62ihvsigdg4Q0=
@@ -542,13 +546,8 @@ github.com/reflog/dateconstraints v0.2.1 h1:Hz1n2Q1vEm0Rj5gciDQcCN1iPBwfFjxUJy32
 github.com/reflog/dateconstraints v0.2.1/go.mod h1:Ax8AxTBcJc3E/oVS2hd2j7RDM/5MDtuPwuR7lIHtPLo=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
-github.com/richardlehane/mscfb v1.0.4 h1:WULscsljNPConisD5hR0+OyZjwK46Pfyr6mPu5ZawpM=
-github.com/richardlehane/mscfb v1.0.4/go.mod h1:YzVpcZg9czvAuhk9T+a3avCpcFPMUWm7gK3DypaEsUk=
 github.com/richardlehane/mscfb v1.0.6 h1:eN3bvvZCp00bs7Zf52bxNwAx5lJDBK1tCuH19qq5aC8=
 github.com/richardlehane/mscfb v1.0.6/go.mod h1:pe0+IUIc0AHh0+teNzBlJCtSyZdFOGgV4ZK9bsoV+Jo=
-github.com/richardlehane/msoleps v1.0.1/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
-github.com/richardlehane/msoleps v1.0.4 h1:WuESlvhX3gH2IHcd8UqyCuFY5yiq/GR/yqaSM/9/g00=
-github.com/richardlehane/msoleps v1.0.4/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
 github.com/richardlehane/msoleps v1.0.5 h1:kNlmACZuwC8ZWPLoJtD+HtZOsKJgYn7gXgUIcRB7dbo=
 github.com/richardlehane/msoleps v1.0.5/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
 github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=

server/public/go.mod

@@ -40,7 +40,6 @@ require (
 	github.com/fatih/color v1.18.0 // indirect
 	github.com/go-asn1-ber/asn1-ber v1.5.7 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
-	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/yamux v0.1.2 // indirect
@@ -59,7 +58,6 @@ require (
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
 	github.com/wiggin77/merror v1.0.5 // indirect
 	github.com/wiggin77/srslog v1.0.1 // indirect
-	go.opentelemetry.io/otel v1.35.0 // indirect
 	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.37.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251007200510-49b9836ed3ff // indirect

server/public/go.sum

@@ -167,6 +167,7 @@ github.com/rogpeppe/go-internal v1.6.1/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTE
 github.com/rogpeppe/go-internal v1.8.0/go.mod h1:WmiCO8CzOY8rg0OYDC4/i/2WRWAB6poM+XZ2dLUbcbE=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
+github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
 github.com/russellhaering/goxmldsig v1.2.0/go.mod h1:gM4MDENBQf7M+V824SGfyIUVFWydB7n0KkEubVJl+Tw=
 github.com/russellhaering/goxmldsig v1.5.0 h1:AU2UkkYIUOTyZRbe08XMThaOCelArgvNfYapcmSjBNw=
 github.com/russellhaering/goxmldsig v1.5.0/go.mod h1:x98CjQNFJcWfMxeOrMnMKg70lvDP6tE0nTaeUnjXDmk=

webapp/channels/src/components/__snapshots__/textbox.test.tsx.snap

@@ -100,6 +100,7 @@ exports[`components/TextBox should match snapshot with additional, optional prop
           "channelId": "channelId",
           "currentUserId": "currentUserId",
           "data": null,
+          "defaultAgent": undefined,
           "disableDispatches": false,
           "forceDispatch": false,
           "getProfilesInChannel": [Function],
@@ -242,6 +243,7 @@ exports[`components/TextBox should match snapshot with required props 1`] = `
           "channelId": "channelId",
           "currentUserId": "currentUserId",
           "data": null,
+          "defaultAgent": undefined,
           "disableDispatches": false,
           "forceDispatch": false,
           "getProfilesInChannel": [Function],
@@ -384,6 +386,7 @@ exports[`components/TextBox should throw error when new property is too long 1`]
           "channelId": "channelId",
           "currentUserId": "currentUserId",
           "data": null,
+          "defaultAgent": undefined,
           "disableDispatches": false,
           "forceDispatch": false,
           "getProfilesInChannel": [Function],
@@ -526,6 +529,7 @@ exports[`components/TextBox should throw error when value is too long 1`] = `
           "channelId": "channelId",
           "currentUserId": "currentUserId",
           "data": null,
+          "defaultAgent": undefined,
           "disableDispatches": false,
           "forceDispatch": false,
           "getProfilesInChannel": [Function],

webapp/channels/src/components/app_bar/app_bar.tsx

@@ -43,16 +43,27 @@ export default function AppBar() {
     }
 
     const coreProductsPluginIds = [suitePluginIds.focalboard, suitePluginIds.playbooks];
+    const agentsPluginId = suitePluginIds.agents;
 
+    // Partition app bar components: Playbooks/Boards vs other plugins
     const [coreProductComponents, pluginComponents] = partition(appBarPluginComponents, ({pluginId}) => {
         return coreProductsPluginIds.includes(pluginId);
     });
 
+    // Partition channel header components: Agents vs others
+    const [agentsComponents, otherChannelHeaderComponents] = partition(channelHeaderComponents, ({pluginId}) => {
+        return pluginId === agentsPluginId;
+    });
+
     const items = [
+        ...agentsComponents,
         ...coreProductComponents,
-        getDivider(coreProductComponents.length, (pluginComponents.length + channelHeaderComponents.length + appBarBindings.length)),
+        getDivider(
+            agentsComponents.length + coreProductComponents.length,
+            pluginComponents.length + otherChannelHeaderComponents.length + appBarBindings.length,
+        ),
         ...pluginComponents,
-        ...channelHeaderComponents,
+        ...otherChannelHeaderComponents,
         ...appBarBindings,
     ].map((x) => {
         if (!x) {

webapp/channels/src/components/suggestion/at_mention_provider/__snapshots__/at_mention_suggestion.test.tsx.snap

@@ -21,6 +21,7 @@ exports[`at mention suggestion should display nick name of non signed in user 1`
   <SuggestionContainer
     aria-describedby="test-suggestion-1-description test-suggestion-1-youElement test-suggestion-1-status test-suggestion-1-botTag test-suggestion-1-sharedIcon test-suggestion-1-guestTag test-suggestion-1-groupMembers"
     aria-labelledby="test-suggestion-1-atMention"
+    className=""
     data-testid="mentionSuggestion_user2"
     id="test-suggestion-1"
     isSelection={false}
@@ -130,6 +131,7 @@ exports[`at mention suggestion should not display nick name of the signed in use
   <SuggestionContainer
     aria-describedby="test-suggestion-1-description test-suggestion-1-youElement test-suggestion-1-status test-suggestion-1-botTag test-suggestion-1-sharedIcon test-suggestion-1-guestTag test-suggestion-1-groupMembers"
     aria-labelledby="test-suggestion-1-atMention"
+    className=""
     data-testid="mentionSuggestion_user"
     id="test-suggestion-1"
     isSelection={false}

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

@@ -1,7 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-import AtMentionProvider, {groupsGroup, membersGroup, nonMembersGroup, otherMembersGroup, specialMentionsGroup, type Props} from 'components/suggestion/at_mention_provider/at_mention_provider';
+import AtMentionProvider, {groupsGroup, membersGroup, nonMembersGroup, otherMembersGroup, specialMentionsGroup, defaultAgentGroup, type Props} from 'components/suggestion/at_mention_provider/at_mention_provider';
 
 import {TestHelper} from 'utils/test_helper';
 
@@ -30,6 +30,7 @@ describe('components/suggestion/at_mention_provider/AtMentionProvider', () => {
         useChannelMentions: true,
         searchAssociatedGroupsForReference: jest.fn().mockResolvedValue(false),
         priorityProfiles: [],
+        defaultAgent: undefined,
     };
 
     it('should ignore pretexts that are not at-mentions', () => {
@@ -145,6 +146,164 @@ describe('components/suggestion/at_mention_provider/AtMentionProvider', () => {
         });
     });
 
+    it('should suggest default agent for "@" when configured', async () => {
+        const pretext = '@';
+        const matchedPretext = '@';
+        const agentUser = TestHelper.getUserMock({id: 'agentId', username: 'ai-agent', first_name: 'AI', last_name: 'Agent', is_bot: true});
+        const defaultAgent = {
+            id: 'agentId',
+            displayName: 'AI Agent',
+            username: 'ai-agent',
+            service_id: 'serviceId',
+            service_type: 'type',
+            is_default: true,
+        };
+
+        const itemsCall = [
+            defaultAgentGroup({...agentUser, isAgent: true, isDefaultAgent: true}),
+            membersGroup([
+                userid10,
+                userid3,
+                userid1,
+                userid2,
+                userid4,
+            ]),
+            groupsGroup([
+                groupid1,
+                groupid2,
+                groupid3,
+            ]),
+            specialMentionsGroup([
+                {username: 'here'},
+                {username: 'channel'},
+                {username: 'all'},
+            ]),
+            nonMembersGroup([
+                userid5,
+                userid6,
+            ]),
+        ];
+
+        const params = {
+            ...baseParams,
+            defaultAgent,
+            autocompleteUsersInChannel: jest.fn().mockImplementation(() => new Promise((resolve) => {
+                resolve({data: {
+                    users: [userid4],
+                    out_of_channel: [userid5, userid6],
+                    agents: [agentUser],
+                }});
+            })),
+            searchAssociatedGroupsForReference: jest.fn().mockImplementation(() => new Promise((resolve) => {
+                resolve({
+                    data: [groupid1, groupid2, groupid3],
+                });
+                provider.updateMatches(resultCallback, itemsCall, matchedPretext);
+            })),
+        };
+
+        const provider = new AtMentionProvider(params);
+        jest.spyOn(provider, 'getProfilesWithLastViewAtInChannel').mockImplementation(() => [userid10, userid3, userid1, userid2]);
+
+        const resultCallback = jest.fn();
+        expect(provider.handlePretextChanged(pretext, resultCallback)).toEqual(true);
+
+        await Promise.resolve().then(() => {
+            expect(resultCallback).toHaveBeenLastCalledWith({
+                matchedPretext,
+                groups: itemsCall,
+            });
+        });
+    });
+
+    it('should keep pinned default agent out of members and agents when agent is also a member or priority profile', async () => {
+        const pretext = '@';
+        const defaultAgentUser = TestHelper.getUserMock({id: 'defaultAgentId', username: 'default-agent', first_name: 'Default', last_name: 'Agent', is_bot: true});
+        const otherAgentUser = TestHelper.getUserMock({id: 'otherAgentId', username: 'other-agent', first_name: 'Other', last_name: 'Agent', is_bot: true});
+
+        const defaultAgent = {
+            id: 'defaultAgentId',
+            displayName: 'Default Agent',
+            username: 'default-agent',
+            service_id: 'serviceId',
+            service_type: 'type',
+            is_default: true,
+        };
+
+        const params = {
+            ...baseParams,
+            defaultAgent,
+            priorityProfiles: [defaultAgentUser],
+            autocompleteUsersInChannel: jest.fn().mockResolvedValue({data: {
+                users: [defaultAgentUser, userid4],
+                out_of_channel: [userid5, userid6],
+                agents: [defaultAgentUser, otherAgentUser],
+            }}),
+            searchAssociatedGroupsForReference: jest.fn().mockResolvedValue({
+                data: [groupid1, groupid2, groupid3],
+            }),
+        };
+
+        const provider = new AtMentionProvider(params);
+        jest.spyOn(provider, 'getProfilesWithLastViewAtInChannel').mockImplementation(() => [defaultAgentUser, userid10, userid3, userid1, userid2]);
+
+        const resultCallback = jest.fn();
+        expect(provider.handlePretextChanged(pretext, resultCallback)).toEqual(true);
+
+        await Promise.resolve();
+        await Promise.resolve();
+
+        const lastResult = resultCallback.mock.lastCall?.[0];
+        expect(lastResult).toBeDefined();
+
+        const groups = lastResult.groups;
+        expect(groups[0].key).toBe('defaultAgent');
+
+        const pinnedDefaultAgent = groups.find((group: {key: string}) => group.key === 'defaultAgent');
+        const members = groups.find((group: {key: string}) => group.key === 'members');
+        const agents = groups.find((group: {key: string}) => group.key === 'agents');
+
+        expect(pinnedDefaultAgent?.items[0].username).toBe(defaultAgentUser.username);
+        expect(members?.items.map((item: {username: string}) => item.username)).not.toContain(defaultAgentUser.username);
+        expect(agents?.items.map((item: {username: string}) => item.username)).not.toContain(defaultAgentUser.username);
+    });
+
+    it('should keep non-default agents out of channel members when they are also in channel', async () => {
+        const pretext = '@';
+        const agentUser = TestHelper.getUserMock({id: 'agentId', username: 'member-agent', first_name: 'Member', last_name: 'Agent', is_bot: true});
+
+        const params = {
+            ...baseParams,
+            autocompleteUsersInChannel: jest.fn().mockResolvedValue({data: {
+                users: [agentUser, userid4],
+                out_of_channel: [userid5, userid6],
+                agents: [agentUser],
+            }}),
+            searchAssociatedGroupsForReference: jest.fn().mockResolvedValue({
+                data: [groupid1, groupid2, groupid3],
+            }),
+        };
+
+        const provider = new AtMentionProvider(params);
+        jest.spyOn(provider, 'getProfilesWithLastViewAtInChannel').mockImplementation(() => [agentUser, userid10, userid3, userid1, userid2]);
+
+        const resultCallback = jest.fn();
+        expect(provider.handlePretextChanged(pretext, resultCallback)).toEqual(true);
+
+        await Promise.resolve();
+        await Promise.resolve();
+
+        const lastResult = resultCallback.mock.lastCall?.[0];
+        expect(lastResult).toBeDefined();
+
+        const groups = lastResult.groups;
+        const members = groups.find((group: {key: string}) => group.key === 'members');
+        const agents = groups.find((group: {key: string}) => group.key === 'agents');
+
+        expect(agents?.items.map((item: {username: string}) => item.username)).toContain(agentUser.username);
+        expect(members?.items.map((item: {username: string}) => item.username)).not.toContain(agentUser.username);
+    });
+
     it('should have priorityProfiles at the top', async () => {
         const userid11 = TestHelper.getUserMock({id: 'userid11', username: 'user11', first_name: 'firstname11', last_name: 'lastname11', nickname: 'nickname11'});
         const userid12 = TestHelper.getUserMock({id: 'userid12', username: 'user12', first_name: 'firstname12', last_name: 'lastname12', nickname: 'nickname12'});

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

@@ -5,6 +5,7 @@ import React from 'react';
 import {defineMessage} from 'react-intl';
 
 import {CreationOutlineIcon} from '@mattermost/compass-icons/components';
+import type {Agent} from '@mattermost/types/agents';
 import type {Group} from '@mattermost/types/groups';
 import type {UserProfile} from '@mattermost/types/users';
 
@@ -34,6 +35,8 @@ type UserProfileWithLastViewAt = UserProfile & {last_viewed_at?: number};
 type CreatedProfile = UserProfile & {
     isCurrentUser?: boolean;
     last_viewed_at?: number;
+    isAgent?: boolean;
+    isDefaultAgent?: boolean;
 };
 
 type SpecialMention = {
@@ -46,10 +49,19 @@ export type Props = {
     autocompleteUsersInChannel: (prefix: string) => Promise<ActionResult>;
     useChannelMentions: boolean;
     autocompleteGroups: Group[] | null;
-    searchAssociatedGroupsForReference: (prefix: string) => Promise<{data: any}>;
+    searchAssociatedGroupsForReference: (prefix: string) => Promise<{data: Group[]}>;
     priorityProfiles: UserProfile[] | undefined;
+    defaultAgent?: Agent;
 }
 
+// Data structure returned by autocomplete API
+type AutocompleteData = {
+    users?: UserProfileWithLastViewAt[];
+    groups?: Group[];
+    out_of_channel?: UserProfileWithLastViewAt[];
+    agents?: UserProfileWithLastViewAt[];
+};
+
 // The AtMentionProvider provides matches for at mentions, including @here, @channel, @all,
 // users in the channel and users not in the channel. It mixes together results from the local
 // store with results fetched from the server.
@@ -59,10 +71,11 @@ export default class AtMentionProvider extends Provider {
     public autocompleteUsersInChannel: (prefix: string) => Promise<ActionResult>;
     public useChannelMentions: boolean;
     public autocompleteGroups: Group[] | null;
-    public searchAssociatedGroupsForReference: (prefix: string) => Promise<{data: any}>;
+    public searchAssociatedGroupsForReference: (prefix: string) => Promise<{data: Group[]}>;
     public priorityProfiles: UserProfile[] | undefined;
+    public defaultAgent?: Agent;
 
-    public data: any;
+    public data: AutocompleteData | null;
     public lastCompletedWord: string;
     public lastPrefixWithNoResults: string;
     public triggerCharacter: string = '@';
@@ -72,7 +85,7 @@ export default class AtMentionProvider extends Provider {
     constructor(props: Props) {
         super();
 
-        const {currentUserId, channelId, autocompleteUsersInChannel, useChannelMentions, autocompleteGroups, searchAssociatedGroupsForReference, priorityProfiles} = props;
+        const {currentUserId, channelId, autocompleteUsersInChannel, useChannelMentions, autocompleteGroups, searchAssociatedGroupsForReference, priorityProfiles, defaultAgent} = props;
 
         this.currentUserId = currentUserId;
         this.channelId = channelId;
@@ -81,6 +94,7 @@ export default class AtMentionProvider extends Provider {
         this.autocompleteGroups = autocompleteGroups;
         this.searchAssociatedGroupsForReference = searchAssociatedGroupsForReference;
         this.priorityProfiles = priorityProfiles;
+        this.defaultAgent = defaultAgent;
 
         this.data = null;
         this.lastCompletedWord = '';
@@ -90,7 +104,7 @@ export default class AtMentionProvider extends Provider {
         this.addLastViewAtToProfiles = makeAddLastViewAtToProfiles();
     }
 
-    setProps({currentUserId, channelId, autocompleteUsersInChannel, useChannelMentions, autocompleteGroups, searchAssociatedGroupsForReference, priorityProfiles}: Props) {
+    setProps({currentUserId, channelId, autocompleteUsersInChannel, useChannelMentions, autocompleteGroups, searchAssociatedGroupsForReference, priorityProfiles, defaultAgent}: Props) {
         this.currentUserId = currentUserId;
         this.channelId = channelId;
         this.autocompleteUsersInChannel = autocompleteUsersInChannel;
@@ -98,6 +112,7 @@ export default class AtMentionProvider extends Provider {
         this.autocompleteGroups = autocompleteGroups;
         this.searchAssociatedGroupsForReference = searchAssociatedGroupsForReference;
         this.priorityProfiles = priorityProfiles;
+        this.defaultAgent = defaultAgent;
     }
 
     // specialMentions matches one of @here, @channel or @all, unless using /msg.
@@ -315,10 +330,18 @@ export default class AtMentionProvider extends Provider {
             const agentUsers = this.data.agents as UserProfileWithLastViewAt[];
             agents = agentUsers.
                 filter((user: UserProfileWithLastViewAt) => this.filterProfile(user)).
-                map((user: UserProfileWithLastViewAt) => this.createFromProfile(user)).
+                map((user: UserProfileWithLastViewAt) => ({...this.createFromProfile(user), isAgent: true})).
                 sort(orderUsers);
         }
 
+        const agentUsernames = new Set(agents.map((agent) => agent.username));
+        let filteredPriorityProfiles = priorityProfiles;
+        let filteredLocalAndRemoteMembers = localAndRemoteMembers;
+        if (this.data?.agents && agentUsernames.size > 0) {
+            filteredPriorityProfiles = priorityProfiles.filter((member) => !agentUsernames.has(member.username));
+            filteredLocalAndRemoteMembers = localAndRemoteMembers.filter((member) => !agentUsernames.has(member.username));
+        }
+
         // handle groups
         const localGroups = this.localGroups();
 
@@ -355,11 +378,26 @@ export default class AtMentionProvider extends Provider {
 
         const items = [];
 
-        if (priorityProfiles.length > 0 || localAndRemoteMembers.length > 0) {
-            items.push(membersGroup([...priorityProfiles, ...localAndRemoteMembers]));
+        const shouldShowDefaultAgentAtTop = this.latestPrefix === '';
+        if (shouldShowDefaultAgentAtTop && this.defaultAgent) {
+            const defaultAgentUser = this.findAgentUser(this.defaultAgent);
+            if (defaultAgentUser) {
+                items.push(defaultAgentGroup({...this.createFromProfile(defaultAgentUser), isAgent: true, isDefaultAgent: true}));
+            }
         }
-        if (agents.length > 0) {
-            items.push(agentsGroup(agents));
+
+        if (filteredPriorityProfiles.length > 0 || filteredLocalAndRemoteMembers.length > 0) {
+            items.push(membersGroup([...filteredPriorityProfiles, ...filteredLocalAndRemoteMembers]));
+        }
+
+        // Filter out default agent from agents group when shown at top to avoid duplicate entries
+        let agentsToShow = agents;
+        if (shouldShowDefaultAgentAtTop && this.defaultAgent) {
+            agentsToShow = agents.filter((agent) => agent.username !== this.defaultAgent?.username);
+        }
+
+        if (agentsToShow.length > 0) {
+            items.push(agentsGroup(agentsToShow));
         }
         if (localAndRemoteGroups.length > 0) {
             items.push(groupsGroup(localAndRemoteGroups));
@@ -457,6 +495,15 @@ export default class AtMentionProvider extends Provider {
 
         return profile;
     }
+
+    findAgentUser(agent: Agent): UserProfileWithLastViewAt | undefined {
+        if (!this.data?.agents || !Array.isArray(this.data.agents)) {
+            return undefined;
+        }
+        return (this.data.agents as UserProfileWithLastViewAt[]).find(
+            (user) => user.username === agent.username,
+        );
+    }
 }
 
 export function membersGroup(items: CreatedProfile[]) {
@@ -469,6 +516,15 @@ export function membersGroup(items: CreatedProfile[]) {
     };
 }
 
+export function defaultAgentGroup(item: CreatedProfile) {
+    return {
+        key: 'defaultAgent',
+        items: [item],
+        terms: ['@' + item.username],
+        component: AtMentionSuggestion,
+    };
+}
+
 export function agentsGroup(items: CreatedProfile[]) {
     return {
         key: 'agents',

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

@@ -1,6 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
+import classNames from 'classnames';
 import React from 'react';
 import type {ReactNode} from 'react';
 import {FormattedMessage} from 'react-intl';
@@ -13,6 +14,7 @@ import usePrefixedIds, {joinIds} from 'components/common/hooks/usePrefixedIds';
 import CustomStatusEmoji from 'components/custom_status/custom_status_emoji';
 import SharedUserIndicator from 'components/shared_user_indicator';
 import StatusIcon from 'components/status_icon';
+import AgentTag from 'components/widgets/tag/agent_tag';
 import BotTag from 'components/widgets/tag/bot_tag';
 import GuestTag from 'components/widgets/tag/guest_tag';
 import Tag from 'components/widgets/tag/tag';
@@ -25,6 +27,8 @@ import type {SuggestionProps} from '../suggestion';
 
 export interface Item extends UserProfile {
     isCurrentUser: boolean;
+    isAgent?: boolean;
+    isDefaultAgent?: boolean;
 }
 
 interface Group extends Item {
@@ -199,6 +203,7 @@ const AtMentionSuggestion = React.forwardRef<HTMLLIElement, SuggestionProps<Item
         <SuggestionContainer
             ref={ref}
             {...props}
+            className={classNames({'suggestion-list__item--default-agent': item.isDefaultAgent})}
             aria-labelledby={ids.atMention}
             aria-describedby={joinIds(ids.description, ids.youElement, ids.status, ids.botTag, ids.sharedIcon, ids.guestTag, ids.groupMembers)}
             data-testid={`mentionSuggestion_${itemname}`}
@@ -211,7 +216,7 @@ const AtMentionSuggestion = React.forwardRef<HTMLLIElement, SuggestionProps<Item
                 >
                     {'@' + itemname}
                 </span>
-                {item.is_bot && <span id={ids.botTag}><BotTag/></span>}
+                {item.is_bot && <span id={ids.botTag}>{item.isAgent ? <AgentTag/> : <BotTag/>}</span>}
                 {description && <span id={ids.description}>{description}</span>}
                 {youElement}
                 {customStatus}

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

@@ -30,6 +30,7 @@ const SuggestionContainer = React.forwardRef<HTMLLIElement, SuggestionProps<unkn
         onMouseMove,
 
         tabIndex = -1,
+        className,
         ...otherProps
     } = props;
 
@@ -50,7 +51,7 @@ const SuggestionContainer = React.forwardRef<HTMLLIElement, SuggestionProps<unkn
     return (
         <li
             ref={ref}
-            className={classNames('suggestion-list__item', {'suggestion--selected': isSelection})}
+            className={classNames('suggestion-list__item', {'suggestion--selected': isSelection}, className)}
             role='option'
             onClick={handleClick}
             onMouseMove={handleMouseMove}

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

@@ -212,10 +212,21 @@ function GroupedSuggestionsGroup({
 }: {
     children: React.ReactNode;
     groupKey: string | undefined;
-    labelMessage: MessageDescriptor | string;
+    labelMessage?: MessageDescriptor | string;
 }) {
     const labelId = `suggestionListGroup-${groupKey}`;
 
+    // If no label is provided, render the group without a header
+    if (!labelMessage) {
+        return (
+            <ul
+                role='group'
+            >
+                {children}
+            </ul>
+        );
+    }
+
     return (
         <ul
             role='group'

webapp/channels/src/components/suggestion/suggestion_results.ts

@@ -26,9 +26,10 @@ export type SuggestionResultsGroup<Item = unknown> = {
     key: string;
 
     /**
-     * The label for the group displayed to the user
+     * The label for the group displayed to the user.
+     * If omitted, the group will be rendered without a header.
      */
-    label: MessageDescriptor;
+    label?: MessageDescriptor;
 
     /**
      * A list of strings which the previously typed text may be replaced by.
@@ -197,7 +198,7 @@ export type ProviderResultsGrouped<Item = unknown> = {
 
 export type ProviderResultsGroup<Item = unknown> = {
     key: string;
-    label: MessageDescriptor;
+    label?: MessageDescriptor;
 
     terms: string[];
     items: Array<Item | Loading>;

webapp/channels/src/components/textbox.test.tsx

@@ -27,6 +27,7 @@ describe('components/TextBox', () => {
             autocompleteUsersInChannel: jest.fn(),
             autocompleteChannels: jest.fn(),
             searchAssociatedGroupsForReference: jest.fn(),
+            fetchAgents: jest.fn(),
         },
         useChannelMentions: true,
         tabIndex: 0,

webapp/channels/src/components/textbox/index.ts

@@ -7,7 +7,9 @@ import type {Dispatch} from 'redux';
 
 import type {GlobalState} from '@mattermost/types/store';
 
+import {getAgents} from 'mattermost-redux/actions/agents';
 import Permissions from 'mattermost-redux/constants/permissions';
+import {getDefaultAgent} from 'mattermost-redux/selectors/entities/agents';
 import {getConfig, getLicense} from 'mattermost-redux/selectors/entities/general';
 import {getAssociatedGroupsForReference} from 'mattermost-redux/selectors/entities/groups';
 import {makeGetProfilesForThread} from 'mattermost-redux/selectors/entities/posts';
@@ -47,6 +49,7 @@ const makeMapStateToProps = () => {
             autocompleteGroups,
             priorityProfiles: getProfilesForThread(state, ownProps.rootId ?? ''),
             delayChannelAutocomplete: getConfig(state).DelayChannelAutocomplete === 'true',
+            defaultAgent: getDefaultAgent(state),
         };
     };
 };
@@ -56,6 +59,7 @@ const mapDispatchToProps = (dispatch: Dispatch) => ({
         autocompleteUsersInChannel,
         autocompleteChannels,
         searchAssociatedGroupsForReference,
+        fetchAgents: getAgents,
     }, dispatch),
 });
 

webapp/channels/src/components/textbox/textbox.tsx

@@ -6,6 +6,7 @@ import React from 'react';
 import type {ChangeEvent, ElementType, FocusEvent, KeyboardEvent, MouseEvent} from 'react';
 import {FormattedMessage} from 'react-intl';
 
+import type {Agent} from '@mattermost/types/agents';
 import type {Channel} from '@mattermost/types/channels';
 import type {Group} from '@mattermost/types/groups';
 import type {UserProfile} from '@mattermost/types/users';
@@ -64,11 +65,13 @@ export type Props = {
         autocompleteUsersInChannel: (prefix: string, channelId: string) => Promise<ActionResult>;
         autocompleteChannels: (term: string, success: (channels: Channel[]) => void, error: () => void) => Promise<ActionResult>;
         searchAssociatedGroupsForReference: (prefix: string, teamId: string, channelId: string | undefined) => Promise<{ data: any }>;
+        fetchAgents: () => Promise<ActionResult>;
     };
     useChannelMentions: boolean;
     inputComponent?: ElementType;
     openWhenEmpty?: boolean;
     priorityProfiles?: UserProfile[];
+    defaultAgent?: Agent;
     hasLabels?: boolean;
     hasError?: boolean;
 };
@@ -110,6 +113,7 @@ export default class Textbox extends React.PureComponent<Props> {
                 autocompleteGroups: this.props.autocompleteGroups,
                 searchAssociatedGroupsForReference: (prefix: string) => this.props.actions.searchAssociatedGroupsForReference(prefix, this.props.currentTeamId, this.props.channelId),
                 priorityProfiles: this.props.priorityProfiles,
+                defaultAgent: this.props.defaultAgent,
             }),
             new ChannelMentionProvider(props.actions.autocompleteChannels, props.delayChannelAutocomplete),
             new EmoticonProvider(),
@@ -129,6 +133,12 @@ export default class Textbox extends React.PureComponent<Props> {
         this.preview = React.createRef();
     }
 
+    componentDidMount() {
+        // Fetch agents once when the component mounts to populate Redux store
+        // This ensures defaultAgent is available for @ mention suggestions
+        this.props.actions.fetchAgents();
+    }
+
     handleChange = (e: React.ChangeEvent<HTMLInputElement>) => {
         this.props.onChange(e);
     };
@@ -139,7 +149,8 @@ export default class Textbox extends React.PureComponent<Props> {
             this.props.autocompleteGroups !== prevProps.autocompleteGroups ||
             this.props.useChannelMentions !== prevProps.useChannelMentions ||
             this.props.currentTeamId !== prevProps.currentTeamId ||
-            this.props.priorityProfiles !== prevProps.priorityProfiles) {
+            this.props.priorityProfiles !== prevProps.priorityProfiles ||
+            this.props.defaultAgent !== prevProps.defaultAgent) {
             // Update channel id for AtMentionProvider.
             for (const provider of this.suggestionProviders) {
                 if (provider instanceof AtMentionProvider) {
@@ -151,6 +162,7 @@ export default class Textbox extends React.PureComponent<Props> {
                         autocompleteGroups: this.props.autocompleteGroups,
                         searchAssociatedGroupsForReference: (prefix: string) => this.props.actions.searchAssociatedGroupsForReference(prefix, this.props.currentTeamId, this.props.channelId),
                         priorityProfiles: this.props.priorityProfiles,
+                        defaultAgent: this.props.defaultAgent,
                     });
                 }
             }

webapp/channels/src/components/widgets/tag/agent_tag.tsx

@@ -0,0 +1,31 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import classNames from 'classnames';
+import React from 'react';
+import {useIntl} from 'react-intl';
+
+import Tag from './tag';
+import type {TagSize} from './tag';
+
+type Props = {
+    className?: string;
+    size?: TagSize;
+}
+
+const AgentTag = ({className = '', size = 'xs'}: Props) => {
+    const {formatMessage} = useIntl();
+    return (
+        <Tag
+            uppercase={true}
+            size={size}
+            className={classNames('AgentTag', className)}
+            text={formatMessage({
+                id: 'tag.default.agent',
+                defaultMessage: 'AGENT',
+            })}
+        />
+    );
+};
+
+export default AgentTag;

webapp/channels/src/i18n/en.json

@@ -6244,6 +6244,7 @@
   "system_policy_indicator.more_policies": "{count} more",
   "system_policy_indicator.multiple_policies_title": "Multiple system access policies applied to this {resourceType}",
   "system_policy_indicator.single_policy_title": "System access policy applied to this {resourceType}",
+  "tag.default.agent": "AGENT",
   "tag.default.beta": "BETA",
   "tag.default.bot": "BOT",
   "tag.default.guest": "GUEST",

webapp/channels/src/packages/mattermost-redux/src/selectors/entities/agents.ts

@@ -5,7 +5,7 @@ import type {Agent, LLMService} from '@mattermost/types/agents';
 import type {GlobalState} from '@mattermost/types/store';
 
 export function getAgents(state: GlobalState): Agent[] {
-    return state.entities.agents?.agents;
+    return state.entities.agents?.agents || [];
 }
 
 export function getAgentsStatus(state: GlobalState): {available: boolean; reason?: string} {
@@ -17,6 +17,11 @@ export function getAgent(state: GlobalState, agentId: string): Agent | undefined
     return agents.find((agent) => agent.id === agentId);
 }
 
+export function getDefaultAgent(state: GlobalState): Agent | undefined {
+    const agents = getAgents(state);
+    return agents?.find((agent) => agent.is_default === true);
+}
+
 export function getLLMServices(state: GlobalState): LLMService[] {
     return state.entities.agents?.llmServices || [];
 }

webapp/channels/src/sass/components/_suggestion-list.scss

@@ -384,3 +384,7 @@
         }
     }
 }
+
+.suggestion-list__item--default-agent {
+    margin-top: 1.2rem;
+}

webapp/channels/src/utils/constants.tsx

@@ -175,6 +175,7 @@ export const TrialPeriodDays = {
 };
 
 export const suitePluginIds = {
+    agents: 'mattermost-ai',
     playbooks: 'playbooks',
     focalboard: 'focalboard',
 

webapp/platform/types/src/agents.ts

@@ -7,6 +7,7 @@ export type Agent = {
     username: string;
     service_id: string;
     service_type: string;
+    is_default?: boolean;
 };
 
 export type LLMService = {