feat: Implement extension and bot limitations across services and UI (#1991)

- Added checks for maximum allowed extensions, bots, and pipelines in the backend services (PluginsRouterGroup, BotService, MCPService, PipelineService).
- Updated system configuration to include limitation settings for max_bots, max_pipelines, and max_extensions.
- Enhanced frontend components to handle limitations, providing user feedback when limits are reached.
- Added internationalization support for limitation messages in English, Japanese, Simplified Chinese, and Traditional Chinese.

src/langbot/pkg/api/http/controller/groups/plugins.py

@@ -14,6 +14,18 @@ from langbot_plugin.runtime.plugin.mgr import PluginInstallSource
 
 @group.group_class('plugins', '/api/v1/plugins')
 class PluginsRouterGroup(group.RouterGroup):
+    async def _check_extensions_limit(self) -> str | None:
+        """Check if extensions limit is reached. Returns error response if limit exceeded, None otherwise."""
+        limitation = self.ap.instance_config.data.get('system', {}).get('limitation', {})
+        max_extensions = limitation.get('max_extensions', -1)
+        if max_extensions >= 0:
+            plugins = await self.ap.plugin_connector.list_plugins()
+            mcp_servers = await self.ap.mcp_service.get_mcp_servers()
+            total_extensions = len(plugins) + len(mcp_servers)
+            if total_extensions >= max_extensions:
+                return self.http_status(400, -1, f'Maximum number of extensions ({max_extensions}) reached')
+        return None
+
     async def initialize(self) -> None:
         @self.route('', methods=['GET'], auth_type=group.AuthType.USER_TOKEN_OR_API_KEY)
         async def _() -> str:
@@ -239,6 +251,10 @@ class PluginsRouterGroup(group.RouterGroup):
         @self.route('/install/github', methods=['POST'], auth_type=group.AuthType.USER_TOKEN_OR_API_KEY)
         async def _() -> str:
             """Install plugin from GitHub release asset"""
+            limit_error = await self._check_extensions_limit()
+            if limit_error is not None:
+                return limit_error
+
             data = await quart.request.json
             asset_url = data.get('asset_url', '')
             owner = data.get('owner', '')
@@ -273,6 +289,10 @@ class PluginsRouterGroup(group.RouterGroup):
             auth_type=group.AuthType.USER_TOKEN_OR_API_KEY,
         )
         async def _() -> str:
+            limit_error = await self._check_extensions_limit()
+            if limit_error is not None:
+                return limit_error
+
             data = await quart.request.json
 
             ctx = taskmgr.TaskContext.new()
@@ -288,6 +308,10 @@ class PluginsRouterGroup(group.RouterGroup):
 
         @self.route('/install/local', methods=['POST'], auth_type=group.AuthType.USER_TOKEN_OR_API_KEY)
         async def _() -> str:
+            limit_error = await self._check_extensions_limit()
+            if limit_error is not None:
+                return limit_error
+
             file = (await quart.request.files).get('file')
             if file is None:
                 return self.http_status(400, -1, 'file is required')

src/langbot/pkg/api/http/controller/groups/system.py

@@ -13,6 +13,7 @@ class SystemRouterGroup(group.RouterGroup):
                 data={
                     'version': constants.semantic_version,
                     'debug': constants.debug_mode,
+                    'edition': constants.edition,
                     'enable_marketplace': self.ap.instance_config.data.get('plugin', {}).get(
                         'enable_marketplace', True
                     ),
@@ -25,6 +26,7 @@ class SystemRouterGroup(group.RouterGroup):
                     'disable_models_service': self.ap.instance_config.data.get('space', {}).get(
                         'disable_models_service', False
                     ),
+                    'limitation': self.ap.instance_config.data.get('system', {}).get('limitation', {}),
                 }
             )
 

src/langbot/pkg/api/http/service/bot.py

@@ -83,6 +83,14 @@ class BotService:
 
     async def create_bot(self, bot_data: dict) -> str:
         """Create bot"""
+        # Check limitation
+        limitation = self.ap.instance_config.data.get('system', {}).get('limitation', {})
+        max_bots = limitation.get('max_bots', -1)
+        if max_bots >= 0:
+            existing_bots = await self.get_bots()
+            if len(existing_bots) >= max_bots:
+                raise ValueError(f'Maximum number of bots ({max_bots}) reached')
+
         # TODO: 检查配置信息格式
         bot_data['uuid'] = str(uuid.uuid4())
 

src/langbot/pkg/api/http/service/mcp.py

@@ -38,6 +38,16 @@ class MCPService:
         return serialized_servers
 
     async def create_mcp_server(self, server_data: dict) -> str:
+        # Check limitation (extensions = MCP servers + plugins)
+        limitation = self.ap.instance_config.data.get('system', {}).get('limitation', {})
+        max_extensions = limitation.get('max_extensions', -1)
+        if max_extensions >= 0:
+            existing_mcp_servers = await self.get_mcp_servers()
+            plugins = await self.ap.plugin_connector.list_plugins()
+            total_extensions = len(existing_mcp_servers) + len(plugins)
+            if total_extensions >= max_extensions:
+                raise ValueError(f'Maximum number of extensions ({max_extensions}) reached')
+
         server_data['uuid'] = str(uuid.uuid4())
         await self.ap.persistence_mgr.execute_async(sqlalchemy.insert(persistence_mcp.MCPServer).values(server_data))
 

src/langbot/pkg/api/http/service/pipeline.py

@@ -76,6 +76,14 @@ class PipelineService:
     async def create_pipeline(self, pipeline_data: dict, default: bool = False) -> str:
         from ....utils import paths as path_utils
 
+        # Check limitation
+        limitation = self.ap.instance_config.data.get('system', {}).get('limitation', {})
+        max_pipelines = limitation.get('max_pipelines', -1)
+        if max_pipelines >= 0:
+            existing_pipelines = await self.get_pipelines()
+            if len(existing_pipelines) >= max_pipelines:
+                raise ValueError(f'Maximum number of pipelines ({max_pipelines}) reached')
+
         pipeline_data['uuid'] = str(uuid.uuid4())
         pipeline_data['for_version'] = self.ap.ver_mgr.get_current_version()
         pipeline_data['stages'] = default_stage_order.copy()
@@ -153,6 +161,14 @@ class PipelineService:
 
     async def copy_pipeline(self, pipeline_uuid: str) -> str:
         """Copy a pipeline with all its configurations"""
+        # Check limitation
+        limitation = self.ap.instance_config.data.get('system', {}).get('limitation', {})
+        max_pipelines = limitation.get('max_pipelines', -1)
+        if max_pipelines >= 0:
+            existing_pipelines = await self.get_pipelines()
+            if len(existing_pipelines) >= max_pipelines:
+                raise ValueError(f'Maximum number of pipelines ({max_pipelines}) reached')
+
         # Get the original pipeline
         result = await self.ap.persistence_mgr.execute_async(
             sqlalchemy.select(persistence_pipeline.LegacyPipeline).where(

src/langbot/pkg/core/stages/load_config.py

@@ -156,8 +156,10 @@ class LoadConfigStage(stage.BootingStage):
         )
 
         constants.instance_id = ap.instance_id.data['instance_id']
+        constants.edition = ap.instance_config.data.get('system', {}).get('edition', 'community')
 
         print(f'LangBot instance id: {constants.instance_id}')
+        print(f'LangBot edition: {constants.edition}')
 
         await ap.instance_id.dump_config()
 

src/langbot/templates/config.yaml

@@ -15,8 +15,13 @@ proxy:
     http: ''
     https: ''
 system:
+    edition: community
     recovery_key: ''
     allow_modify_login_info: true
+    limitation:
+        max_bots: -1
+        max_pipelines: -1
+        max_extensions: -1
     jwt:
         expire: 604800
         secret: ''

web/src/app/home/bots/page.tsx

@@ -12,6 +12,7 @@ import { useTranslation } from 'react-i18next';
 import { extractI18nObject } from '@/i18n/I18nProvider';
 import BotDetailDialog from '@/app/home/bots/BotDetailDialog';
 import { CustomApiError } from '@/app/infra/entities/common';
+import { systemInfo } from '@/app/infra/http';
 
 export default function BotConfigPage() {
   const { t } = useTranslation();
@@ -60,6 +61,11 @@ export default function BotConfigPage() {
   }
 
   function handleCreateBotClick() {
+    const maxBots = systemInfo.limitation?.max_bots ?? -1;
+    if (maxBots >= 0 && botList.length >= maxBots) {
+      toast.error(t('limitation.maxBotsReached', { max: maxBots }));
+      return;
+    }
     setSelectedBotId('');
     setDetailDialogOpen(true);
   }

web/src/app/home/pipelines/page.tsx

@@ -15,6 +15,7 @@ import {
   SelectTrigger,
   SelectValue,
 } from '@/components/ui/select';
+import { systemInfo } from '@/app/infra/http';
 
 export default function PluginConfigPage() {
   const { t } = useTranslation();
@@ -87,6 +88,11 @@ export default function PluginConfigPage() {
   };
 
   const handleCreateNew = () => {
+    const maxPipelines = systemInfo.limitation?.max_pipelines ?? -1;
+    if (maxPipelines >= 0 && pipelineList.length >= maxPipelines) {
+      toast.error(t('limitation.maxPipelinesReached', { max: maxPipelines }));
+      return;
+    }
     setIsEditForm(false);
     setSelectedPipelineId('');
     setDialogOpen(true);

web/src/app/home/plugins/mcp-server/mcp-form/MCPFormDialog.tsx

@@ -453,7 +453,10 @@ export default function MCPFormDialog({
       onSuccess?.();
     } catch (error) {
       console.error('Failed to save MCP server:', error);
-      toast.error(isEditMode ? t('mcp.updateFailed') : t('mcp.createFailed'));
+      const errMsg = (error as CustomApiError).msg || '';
+      toast.error(
+        (isEditMode ? t('mcp.updateFailed') : t('mcp.createFailed')) + errMsg,
+      );
     }
   }
 

web/src/app/home/plugins/page.tsx

@@ -186,6 +186,28 @@ export default function PluginConfigPage() {
     setFetchingAssets(false);
   }
 
+  async function checkExtensionsLimit(): Promise<boolean> {
+    const maxExtensions = systemInfo.limitation?.max_extensions ?? -1;
+    if (maxExtensions < 0) return true;
+    try {
+      const [pluginsResp, mcpResp] = await Promise.all([
+        httpClient.getPlugins(),
+        httpClient.getMCPServers(),
+      ]);
+      const total =
+        (pluginsResp.plugins?.length ?? 0) + (mcpResp.servers?.length ?? 0);
+      if (total >= maxExtensions) {
+        toast.error(
+          t('limitation.maxExtensionsReached', { max: maxExtensions }),
+        );
+        return false;
+      }
+    } catch {
+      // If we can't check, let backend handle it
+    }
+    return true;
+  }
+
   async function fetchGithubReleases() {
     if (!githubURL.trim()) {
       toast.error(t('plugins.enterRepoUrl'));
@@ -328,6 +350,8 @@ export default function PluginConfigPage() {
         return;
       }
 
+      if (!(await checkExtensionsLimit())) return;
+
       setModalOpen(true);
       setPluginInstallStatus(PluginInstallStatus.INSTALLING);
       setInstallError(null);
@@ -336,7 +360,8 @@ export default function PluginConfigPage() {
     [t, pluginSystemStatus, installPlugin],
   );
 
-  const handleFileSelect = useCallback(() => {
+  const handleFileSelect = useCallback(async () => {
+    if (!(await checkExtensionsLimit())) return;
     if (fileInputRef.current) {
       fileInputRef.current.click();
     }
@@ -633,7 +658,8 @@ export default function PluginConfigPage() {
                 {activeTab === 'mcp-servers' ? (
                   <>
                     <DropdownMenuItem
-                      onClick={() => {
+                      onClick={async () => {
+                        if (!(await checkExtensionsLimit())) return;
                         setActiveTab('mcp-servers');
                         setIsEditMode(false);
                         setEditingServerName(null);
@@ -661,7 +687,8 @@ export default function PluginConfigPage() {
                       {t('plugins.uploadLocal')}
                     </DropdownMenuItem>
                     <DropdownMenuItem
-                      onClick={() => {
+                      onClick={async () => {
+                        if (!(await checkExtensionsLimit())) return;
                         setInstallSource('github');
                         setPluginInstallStatus(PluginInstallStatus.WAIT_INPUT);
                         setInstallError(null);
@@ -683,7 +710,8 @@ export default function PluginConfigPage() {
         </TabsContent>
         <TabsContent value="market" className="flex-1 overflow-y-auto mt-0">
           <MarketPage
-            installPlugin={(plugin: PluginV4) => {
+            installPlugin={async (plugin: PluginV4) => {
+              if (!(await checkExtensionsLimit())) return;
               setInstallSource('marketplace');
               setInstallInfo({
                 plugin_author: plugin.author,

web/src/app/infra/entities/api/index.ts

@@ -240,13 +240,21 @@ export interface PluginReorderElement {
 }
 
 // system
+export interface SystemLimitation {
+  max_bots: number;
+  max_pipelines: number;
+  max_extensions: number;
+}
+
 export interface ApiRespSystemInfo {
   debug: boolean;
   version: string;
+  edition: string;
   cloud_service_url: string;
   enable_marketplace: boolean;
   allow_modify_login_info: boolean;
   disable_models_service: boolean;
+  limitation: SystemLimitation;
 }
 
 export interface ApiRespPluginSystemStatus {

web/src/app/infra/http/index.ts

@@ -6,10 +6,16 @@ import { ApiRespSystemInfo } from '@/app/infra/entities/api';
 export let systemInfo: ApiRespSystemInfo = {
   debug: false,
   version: '',
+  edition: 'community',
   enable_marketplace: true,
   cloud_service_url: '',
   allow_modify_login_info: true,
   disable_models_service: false,
+  limitation: {
+    max_bots: -1,
+    max_pipelines: -1,
+    max_extensions: -1,
+  },
 };
 
 // 用户信息

web/src/i18n/locales/en-US.ts

@@ -962,6 +962,14 @@ const enUS = {
       sessions: 'Sessions',
     },
   },
+  limitation: {
+    maxBotsReached:
+      'Maximum number of bots ({{max}}) reached. Please remove an existing bot before creating a new one.',
+    maxPipelinesReached:
+      'Maximum number of pipelines ({{max}}) reached. Please remove an existing pipeline before creating a new one.',
+    maxExtensionsReached:
+      'Maximum number of extensions ({{max}}) reached. Please remove an existing MCP server or plugin before adding a new one.',
+  },
 };
 
 export default enUS;

web/src/i18n/locales/ja-JP.ts

@@ -949,6 +949,14 @@ const jaJP = {
       sessions: 'セッション',
     },
   },
+  limitation: {
+    maxBotsReached:
+      'ボット数が上限（{{max}}個）に達しました。新しいボットを作成するには、既存のボットを削除してください。',
+    maxPipelinesReached:
+      'パイプライン数が上限（{{max}}個）に達しました。新しいパイプラインを作成するには、既存のパイプラインを削除してください。',
+    maxExtensionsReached:
+      '拡張機能数が上限（{{max}}個）に達しました。新しい MCP サーバーやプラグインを追加するには、既存のものを削除してください。',
+  },
 };
 
 export default jaJP;

web/src/i18n/locales/zh-Hans.ts

@@ -922,6 +922,14 @@ const zhHans = {
       sessions: '会话记录',
     },
   },
+  limitation: {
+    maxBotsReached:
+      '已达到机器人数量上限（{{max}}个）。请先删除已有机器人后再创建新的。',
+    maxPipelinesReached:
+      '已达到流水线数量上限（{{max}}个）。请先删除已有流水线后再创建新的。',
+    maxExtensionsReached:
+      '已达到扩展数量上限（{{max}}个）。请先删除已有的 MCP 服务器或插件后再添加新的。',
+  },
 };
 
 export default zhHans;

web/src/i18n/locales/zh-Hant.ts

@@ -897,6 +897,14 @@ const zhHant = {
       sessions: '會話記錄',
     },
   },
+  limitation: {
+    maxBotsReached:
+      '已達到機器人數量上限（{{max}}個）。請先刪除已有機器人後再建立新的。',
+    maxPipelinesReached:
+      '已達到流水線數量上限（{{max}}個）。請先刪除已有流水線後再建立新的。',
+    maxExtensionsReached:
+      '已達到擴充功能數量上限（{{max}}個）。請先刪除已有的 MCP 伺服器或外掛後再新增。',
+  },
 };
 
 export default zhHant;