diff --git a/src-frontend/config/i18next.config.ts b/src-frontend/config/i18next.config.ts
index 1414738..d85b7ba 100644
--- a/src-frontend/config/i18next.config.ts
+++ b/src-frontend/config/i18next.config.ts
@@ -8,6 +8,10 @@ export default defineConfig({
   extract: {
     input: "src/**/*.{js,jsx,ts,tsx}",
     output: "src/i18n/locales/{{language}}/{{namespace}}.json",
+    preservePatterns: [
+      "error:*",
+      "sidebar:toolsets.status.*",
+    ],
     defaultNS: false,
   }
 });
diff --git a/src-frontend/src/api/orval-mutator/custom-fetch.ts b/src-frontend/src/api/orval-mutator/custom-fetch.ts
index f28a2c1..d54fafc 100644
--- a/src-frontend/src/api/orval-mutator/custom-fetch.ts
+++ b/src-frontend/src/api/orval-mutator/custom-fetch.ts
@@ -1,19 +1,29 @@
 import { API_BASE } from "..";
+import { ApiErrorCode, McpConnectErrorCode, ServiceErrorCode } from "../generated/schemas";
+
+export type ErrorCode = 
+  | ApiErrorCode
+  | McpConnectErrorCode
+  | ServiceErrorCode
+  | "NETWORK_ERROR"
+  | "UNEXPECTED_ERROR";
 
 export type ErrorResponse = {
-  error_code: string;
+  error_code: ErrorCode;
   message: string;
 };
 
 export class FetchError<E extends ErrorResponse> extends Error {
   statusCode: number;
-  errorCode: string;
+  errorCode: ErrorCode;
+  message: string;
 
   constructor(statusCode: number, error: E) {
     super(error.message);
     this.name = "FetchError";
     this.statusCode = statusCode;
     this.errorCode = error.error_code;
+    this.message = error.message;
   }
 }
 
@@ -24,7 +34,16 @@ export async function fetchApi<T>(
   init?: RequestInit
 ): Promise<T> {
   const url = new URL(input.toString(), API_BASE);
-  const res = await fetch(url, init);
+  let res: Response;
+  try {
+    res = await fetch(url, init);
+  } catch {
+    throw new FetchError(500, {
+      error_code: "NETWORK_ERROR",
+      message: "Network error when fetching",
+    });
+  }
+
   if (res.ok) {
     if (res.status === 204) {
       return undefined as T;
@@ -32,16 +51,15 @@ export async function fetchApi<T>(
     return (await res.json()) as T;
   }
 
+  let errorBody: ErrorResponse;
   try {
-    const errorBody = (await res.json()) as ErrorResponse;
-    throw new FetchError(res.status, errorBody);
+    errorBody = (await res.json()) as ErrorResponse;
   } catch {
-    console.warn(
-      `Failed to parse error response as JSON: ${res.status} ${res.statusText}`
-    );
+    console.warn(`Failed to parse error response as JSON: ${res.status} ${res.statusText}`);
     throw new FetchError(res.status, {
-      error_code: "HTTP_ERROR",
+      error_code: "UNEXPECTED_ERROR",
       message: res.statusText,
     });
   }
+  throw new FetchError(res.status, errorBody);
 }
diff --git a/src-frontend/src/api/toolset.ts b/src-frontend/src/api/toolset.ts
index 8e8bc6b..b1f7e0b 100644
--- a/src-frontend/src/api/toolset.ts
+++ b/src-frontend/src/api/toolset.ts
@@ -2,7 +2,7 @@ export {
   getGetToolsetQueryKey,
   getGetToolsetsQueryKey,
   getGetToolsetsBriefQueryKey,
-  useCreateMcpToolset,
+  useCreateToolset,
   useDeleteToolset,
   useGetToolsetSuspense,
   useGetToolsetsSuspense,
diff --git a/src-frontend/src/components/custom/AsyncBoundary.tsx b/src-frontend/src/components/custom/AsyncBoundary.tsx
index d9ea76d..011efd1 100644
--- a/src-frontend/src/components/custom/AsyncBoundary.tsx
+++ b/src-frontend/src/components/custom/AsyncBoundary.tsx
@@ -6,17 +6,14 @@ import { FailedToLoad } from "./FailedToLoad";
 type AsyncBoundaryProps = {
   children: React.ReactNode;
   skeleton?: React.ReactNode;
+  errorRender?: (props: FallbackProps) => React.ReactNode;
   onError?: (error: unknown, info: React.ErrorInfo) => void;
-} & MustOneOf<{
-  errorDescription: string | ((error: unknown) => string);
-  errorRender: (props: FallbackProps) => React.ReactNode;
-}>;
+};
 
 export function AsyncBoundary({
   children,
   skeleton,
   onError,
-  errorDescription,
   errorRender,
 }: AsyncBoundaryProps) {
   return (
@@ -29,12 +26,8 @@ export function AsyncBoundary({
             errorRender ??
             ((props) => (
               <FailedToLoad
-                refetch={props.resetErrorBoundary}
-                description={
-                  typeof errorDescription === "string"
-                    ? errorDescription
-                    : errorDescription(props.error)
-                }
+                error={props.error}
+                retry={props.resetErrorBoundary}
               />
             ))
           }
diff --git a/src-frontend/src/components/custom/FailedToLoad.tsx b/src-frontend/src/components/custom/FailedToLoad.tsx
index a911839..cbc4d69 100644
--- a/src-frontend/src/components/custom/FailedToLoad.tsx
+++ b/src-frontend/src/components/custom/FailedToLoad.tsx
@@ -1,4 +1,5 @@
 import { RefreshCcwIcon } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import {
   Empty,
@@ -6,24 +7,46 @@ import {
   EmptyDescription,
   EmptyTitle,
 } from "@/components/ui/empty";
+import { FetchError } from "@/api/orval-mutator/custom-fetch";
+import { getErrorMessage } from "@/i18n/error-message";
+import { COMPONENTS_CUSTOM_NAMESPACE } from "@/i18n/resources";
+import { i18n } from "@/i18n";
 
 type FailedToLoadProps = {
-  refetch: () => void;
+  className?: string;
+  retry?: () => void;
+  title?: string;
+} & MustOneOf<{
   description: string;
-};
+  error: unknown;
+}>;
+
+export function FailedToLoad({
+  className,
+  title = i18n.t("load_failed.title", { ns: COMPONENTS_CUSTOM_NAMESPACE }),
+  description,
+  error,
+  retry,
+}: FailedToLoadProps) {
+  const { t } = useTranslation(COMPONENTS_CUSTOM_NAMESPACE);
+  let errorDescription: string;
+  if (description) {
+    errorDescription = description;
+  } else if (error instanceof FetchError) {
+    errorDescription = getErrorMessage(error.errorCode);
+  } else {
+    errorDescription = getErrorMessage("UNEXPECTED_ERROR");
+  }
 
-export function FailedToLoad({ refetch, description }: FailedToLoadProps) {
   return (
-    <Empty>
+    <Empty className={className}>
       <EmptyContent>
-        <EmptyTitle>加载失败</EmptyTitle>
-        <EmptyDescription>
-          <div>{description}</div>
-        </EmptyDescription>
+        <EmptyTitle>{title}</EmptyTitle>
+        <EmptyDescription>{errorDescription}</EmptyDescription>
         <EmptyContent>
-          <Button size="sm" variant="outline" onClick={() => refetch()}>
+          <Button size="sm" variant="outline" onClick={() => retry?.()}>
             <RefreshCcwIcon />
-            重试
+            {t("load_failed.retry")}
           </Button>
         </EmptyContent>
       </EmptyContent>
diff --git a/src-frontend/src/components/custom/dialog/resource-dialog/ModelSelectDialog.tsx b/src-frontend/src/components/custom/dialog/resource-dialog/ModelSelectDialog.tsx
index 3b2804a..115064d 100644
--- a/src-frontend/src/components/custom/dialog/resource-dialog/ModelSelectDialog.tsx
+++ b/src-frontend/src/components/custom/dialog/resource-dialog/ModelSelectDialog.tsx
@@ -98,10 +98,7 @@ export function ModelSelectDialog({ value, onChange: onSelect }: ModelSelectDial
       <SelectDialogContent>
         <SelectDialogSearch placeholder={t("resource.model.search_placeholder")} />
         <SelectDialogList className="max-h-96">
-          <AsyncBoundary
-            skeleton={<SelectDialogSkeleton />}
-            errorDescription={t("resource.model.load_error")}
-          >
+          <AsyncBoundary skeleton={<SelectDialogSkeleton />}>
             <ModelQueryList />
           </AsyncBoundary>
         </SelectDialogList>
diff --git a/src-frontend/src/components/custom/dialog/resource-dialog/ToolMultiSelectDialog.tsx b/src-frontend/src/components/custom/dialog/resource-dialog/ToolMultiSelectDialog.tsx
index 0deb77d..8f1dd55 100644
--- a/src-frontend/src/components/custom/dialog/resource-dialog/ToolMultiSelectDialog.tsx
+++ b/src-frontend/src/components/custom/dialog/resource-dialog/ToolMultiSelectDialog.tsx
@@ -73,10 +73,7 @@ export function ToolMultiSelectDialog({ value, onChange }: ToolMultiSelectDialog
         <SelectDialogSearch placeholder={t("resource.tool.search_placeholder")} />
         <SelectDialogList>
           <SelectDialogEmpty>{t("resource.tool.empty")}</SelectDialogEmpty>
-          <AsyncBoundary
-            skeleton={<SelectDialogSkeleton />}
-            errorDescription={t("resource.tool.load_error")}
-          >
+          <AsyncBoundary skeleton={<SelectDialogSkeleton />}>
             <ToolQueryList onFetched={handleFetched} />
           </AsyncBoundary>
         </SelectDialogList>
diff --git a/src-frontend/src/components/custom/form/FormShell.tsx b/src-frontend/src/components/custom/form/FormShell.tsx
index 1a47af7..c4b438e 100644
--- a/src-frontend/src/components/custom/form/FormShell.tsx
+++ b/src-frontend/src/components/custom/form/FormShell.tsx
@@ -35,7 +35,7 @@ export function FormShell<T extends FieldValues>({
         onSubmit={methods.handleSubmit(onSubmit)}
         className={cn(
           "py-4",
-          "pr-1", // prevent outline of form controls from being cut off
+          "px-1", // prevent outline of form controls from being cut off
           className)}
       >
         <FieldGroup className="gap-y-2">{children}</FieldGroup>
diff --git a/src-frontend/src/components/custom/form/fields/DirectoryField.tsx b/src-frontend/src/components/custom/form/fields/DirectoryField.tsx
index 7bed7bd..7a3fbc5 100644
--- a/src-frontend/src/components/custom/form/fields/DirectoryField.tsx
+++ b/src-frontend/src/components/custom/form/fields/DirectoryField.tsx
@@ -29,6 +29,7 @@ export function DirectoryField({
 
   async function chooseDirectory() {
     try {
+      // TODO: use unified api
       const selected = await open({ directory: true });
       if (typeof selected === "string") {
         setValue(fieldName, selected, {
diff --git a/src-frontend/src/features/SideBar/views/AgentsView/AgentList.tsx b/src-frontend/src/features/SideBar/views/AgentsView/AgentList.tsx
index e25b0ea..f128047 100644
--- a/src-frontend/src/features/SideBar/views/AgentsView/AgentList.tsx
+++ b/src-frontend/src/features/SideBar/views/AgentsView/AgentList.tsx
@@ -106,26 +106,6 @@ export function AgentList() {
   const { t } = useTranslation("sidebar");
   const removeTabs = useTabsStore((state) => state.remove);
 
-  const asyncConfirm = useAsyncConfirm<AgentBrief>({
-    async onConfirm(agent) {
-      await deleteAgentMutation.mutateAsync({ agentId: agent.id });
-      await invalidateAgentQueries(agent.id);
-
-      removeTabs((tab) => (tab.type === "agent" &&
-                           tab.metadata.mode === "edit" &&
-                           tab.metadata.id === agent.id));
-
-      toast.success(t("agents.toast.delete_success_title"), {
-        description: t("agents.toast.delete_success_description"),
-      });
-    },
-    onError(error: Error) {
-      toast.error(t("agents.toast.delete_error_title"), {
-        description: error.message || t("agents.toast.delete_error_description"),
-      });
-    },
-  });
-
   const query = useGetAgentsSuspenseInfinite(undefined, {
     query: PAGINATED_QUERY_DEFAULT_OPTIONS,
   });
@@ -137,22 +117,38 @@ export function AgentList() {
         toast.success(t("agents.toast.delete_success_title"), {
           description: t("agents.toast.delete_success_description"),
         });
-      },
-      onError(error: Error) {
-        toast.error(t("agents.toast.delete_error_title"), {
-          description: error.message || t("agents.toast.delete_error_description"),
-        });
-      },
+      }
     },
   });
 
+  const asyncConfirm = useAsyncConfirm<AgentBrief>({
+    async onConfirm(agent) {
+      await deleteAgentMutation.mutateAsync({ agentId: agent.id });
+      await invalidateAgentQueries(agent.id);
+
+      removeTabs((tab) => (tab.type === "agent" &&
+                           tab.metadata.mode === "edit" &&
+                           tab.metadata.id === agent.id));
+
+      toast.success(t("agents.toast.delete_success_title"), {
+        description: t("agents.toast.delete_success_description"),
+      });
+    }
+  });
+
   return (
     <>
       <ScrollArea className="flex-1">
         <InfiniteScroll
           query={query}
           selectItems={(page) => page.items}
-          itemRender={(agent) => <AgentItem key={agent.id} agent={agent} onDelete={asyncConfirm.trigger} />}
+          itemRender={(agent) => (
+            <AgentItem
+              key={agent.id}
+              agent={agent}
+              onDelete={asyncConfirm.trigger}
+            />
+          )}
         />
       </ScrollArea>
       <ConfirmDeleteDialog
diff --git a/src-frontend/src/features/SideBar/views/AgentsView/index.tsx b/src-frontend/src/features/SideBar/views/AgentsView/index.tsx
index 9b23c7f..30b65af 100644
--- a/src-frontend/src/features/SideBar/views/AgentsView/index.tsx
+++ b/src-frontend/src/features/SideBar/views/AgentsView/index.tsx
@@ -33,10 +33,7 @@ export function AgentsView() {
         />
       </SideBarHeader>
       <div className="flex-1">
-        <AsyncBoundary
-          skeleton={<SideBarListSkeleton />}
-          errorDescription={t("agents.list.error_load")}
-        >
+        <AsyncBoundary skeleton={<SideBarListSkeleton />}>
           <AgentList />
         </AsyncBoundary>
       </div>
diff --git a/src-frontend/src/features/SideBar/views/SettingsView/HelperModelSettings/index.tsx b/src-frontend/src/features/SideBar/views/SettingsView/HelperModelSettings/index.tsx
index 58dde4c..95b9b71 100644
--- a/src-frontend/src/features/SideBar/views/SettingsView/HelperModelSettings/index.tsx
+++ b/src-frontend/src/features/SideBar/views/SettingsView/HelperModelSettings/index.tsx
@@ -30,10 +30,9 @@ export function HelperModelSettings() {
             <Skeleton className="h-9 w-24" />
           </SettingItem>
         )}
-        errorDescription={t("settings.helper_model.flash_model.error_load")}
       >
         <SettingItem title={t("settings.helper_model.flash_model.title")}>
-            <HelperModelSettingsSuspense />
+          <HelperModelSettingsSuspense />
         </SettingItem>
       </AsyncBoundary>
     </div>
diff --git a/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/ProviderList.tsx b/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/ProviderList.tsx
index 4c93a63..e68084d 100644
--- a/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/ProviderList.tsx
+++ b/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/ProviderList.tsx
@@ -125,12 +125,7 @@ export function ProviderList() {
         toast.success(t("settings.providers.toast.delete_success_title"), {
           description: t("settings.providers.toast.delete_success_description"),
         });
-      },
-      onError(error: Error) {
-        toast.error(t("settings.providers.toast.delete_error_title"), {
-          description: error.message || t("settings.providers.toast.delete_error_description"),
-        });
-      },
+      }
     },
   });
 
diff --git a/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/index.tsx b/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/index.tsx
index 12f36a0..d5e3fdf 100644
--- a/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/index.tsx
+++ b/src-frontend/src/features/SideBar/views/SettingsView/ProviderSettings/index.tsx
@@ -31,10 +31,7 @@ export function ProviderSettings() {
 
   return (
     <div className="flex flex-col">
-      <AsyncBoundary
-        skeleton={<ProviderListSkeleton />}
-        errorDescription={t("settings.providers.list.error_load")}
-      >
+      <AsyncBoundary skeleton={<ProviderListSkeleton />}>
         <ProviderList />
       </AsyncBoundary>
 
diff --git a/src-frontend/src/features/SideBar/views/TasksView/TaskList.tsx b/src-frontend/src/features/SideBar/views/TasksView/TaskList.tsx
index 7a3f797..e52f4c6 100644
--- a/src-frontend/src/features/SideBar/views/TasksView/TaskList.tsx
+++ b/src-frontend/src/features/SideBar/views/TasksView/TaskList.tsx
@@ -119,7 +119,7 @@ export function TaskList({ workspaceId }: TaskListProps) {
   const queryClient = useQueryClient();
   const deleteTaskMutation = useDeleteTask();
 
-  useEffect(() => 
+  useEffect(() =>
     SseDispatcher.subscribe("TASK_TITLE_UPDATED", ({ task_id, title }: TaskTitleUpdatedEvent) => {
       const queryKey = getGetTasksInfiniteQueryKey({ workspace_id: workspaceId });
       queryClient.setQueryData<InfiniteData<PageTaskBrief>>(
@@ -151,21 +151,12 @@ export function TaskList({ workspaceId }: TaskListProps) {
       toast.success(t("tasks.toast.delete_success_title"), {
         description: t("tasks.toast.delete_success_description"),
       });
-    },
-    onError(error: Error) {
-      toast.error(t("tasks.toast.delete_error_title"), {
-        description: error.message || t("tasks.toast.delete_error_description"),
-      });
-    },
+    }
   });
 
   const query = useGetTasksSuspenseInfinite(
-    {
-      workspace_id: workspaceId,
-    },
-    {
-      query: PAGINATED_QUERY_DEFAULT_OPTIONS,
-    }
+    { workspace_id: workspaceId },
+    { query: PAGINATED_QUERY_DEFAULT_OPTIONS }
   );
 
   if (query.data.pages.length === 0) {
diff --git a/src-frontend/src/features/SideBar/views/TasksView/index.tsx b/src-frontend/src/features/SideBar/views/TasksView/index.tsx
index 0a0854b..77bc297 100644
--- a/src-frontend/src/features/SideBar/views/TasksView/index.tsx
+++ b/src-frontend/src/features/SideBar/views/TasksView/index.tsx
@@ -40,7 +40,7 @@ export function TasksView() {
     }
 
     return (
-      <AsyncBoundary skeleton={<SideBarListSkeleton />} errorDescription={t("tasks.list.error_load")}>
+      <AsyncBoundary skeleton={<SideBarListSkeleton />}>
         <TaskList workspaceId={currentWorkspace.id} />
       </AsyncBoundary>
     );
diff --git a/src-frontend/src/features/SideBar/views/ToolsetsView/ToolsetList.tsx b/src-frontend/src/features/SideBar/views/ToolsetsView/ToolsetList.tsx
index 05859bf..ded7e97 100644
--- a/src-frontend/src/features/SideBar/views/ToolsetsView/ToolsetList.tsx
+++ b/src-frontend/src/features/SideBar/views/ToolsetsView/ToolsetList.tsx
@@ -31,8 +31,10 @@ import { tabIdFactory } from "@/lib/tab";
 import { cn } from "@/lib/utils";
 import { useTabsStore } from "@/stores/tabs-store";
 import type { Tab, ToolsetTabMetadata } from "@/types/tab";
+import { getErrorMessage } from "@/i18n/error-message";
 import { ToolsetIcon } from "./ToolsetIcon";
 
+
 function getStatusColor(status: McpToolsetStatus): string {
   switch (status) {
     case "connected":
@@ -121,9 +123,9 @@ function ToolsetItem({ toolset, onDelete }: ToolsetItemProps) {
               {toolset.name}
               {
                 <TooltipProvider>
-                  <Tooltip>
+                  <Tooltip delayDuration={0}>
                     <TooltipTrigger asChild>
-                      <span
+                      <div
                         className={cn(
                           "inline-block size-2 rounded-full",
                           getStatusColor(toolset.status)
@@ -131,7 +133,11 @@ function ToolsetItem({ toolset, onDelete }: ToolsetItemProps) {
                       />
                     </TooltipTrigger>
                     <TooltipContent>
-                      <p>{t(`toolsets.status.${toolset.status}`)}</p>
+                      <p>{
+                        toolset.error_code
+                          ? getErrorMessage(toolset.error_code)
+                          : t(`toolsets.status.${toolset.status}`)
+                      }</p>
                     </TooltipContent>
                   </Tooltip>
                 </TooltipProvider>
@@ -171,19 +177,11 @@ export function ToolsetList() {
       toast.success(t("toolsets.toast.delete_success_title"), {
         description: t("toolsets.toast.delete_success_description"),
       });
-    },
-    onError(error: Error) {
-      toast.error(t("toolsets.toast.delete_error_title"), {
-        description: error.message || t("toolsets.toast.delete_error_description"),
-      });
-    },
+    }
   });
 
   const { data: toolsets } = useGetToolsetsBriefSuspense({
-    query: {
-      // TODO: replace refetch polling with sse
-      refetchInterval: 3000,
-    },
+    query: { refetchInterval: 3000 },
   });
 
   return (
diff --git a/src-frontend/src/features/SideBar/views/ToolsetsView/index.tsx b/src-frontend/src/features/SideBar/views/ToolsetsView/index.tsx
index 5dac57e..09c3bda 100644
--- a/src-frontend/src/features/SideBar/views/ToolsetsView/index.tsx
+++ b/src-frontend/src/features/SideBar/views/ToolsetsView/index.tsx
@@ -32,10 +32,7 @@ export function ToolsetsView() {
         />
       </SideBarHeader>
       <div className="flex-1">
-        <AsyncBoundary
-          skeleton={<SideBarListSkeleton />}
-          errorDescription={t("toolsets.list.error_load")}
-        >
+        <AsyncBoundary skeleton={<SideBarListSkeleton />}>
           <ToolsetList />
         </AsyncBoundary>
       </div>
diff --git a/src-frontend/src/features/SideBar/views/WorkspacesView/WorkspaceList.tsx b/src-frontend/src/features/SideBar/views/WorkspacesView/WorkspaceList.tsx
index 86a5df2..bd06d80 100644
--- a/src-frontend/src/features/SideBar/views/WorkspacesView/WorkspaceList.tsx
+++ b/src-frontend/src/features/SideBar/views/WorkspacesView/WorkspaceList.tsx
@@ -112,7 +112,7 @@ function WorkspaceItem({ workspace, disabled, isSelected, onSelect, onDelete }:
       <ActionableItemMenu>
         <ActionableItemMenuItem onClick={handleSelect} disabled={isSelected}>
           <CircleIcon />
-          <span>设为当前工作区</span>
+          <span>{t("workspaces.menu.select")}</span>
         </ActionableItemMenuItem>
         <ActionableItemMenuItem onClick={handleEdit}>
           <PencilIcon />
@@ -151,12 +151,7 @@ export function WorkspaceList() {
       toast.success(t("workspaces.toast.delete_success_title"), {
         description: t("workspaces.toast.delete_success_description"),
       });
-    },
-    onError(error: Error) {
-      toast.error(t("workspaces.toast.delete_error_title"), {
-        description: error.message || t("workspaces.toast.delete_error_description"),
-      });
-    },
+    }
   });
 
   const query = useGetWorkspacesSuspenseInfinite(undefined, {
diff --git a/src-frontend/src/features/SideBar/views/WorkspacesView/index.tsx b/src-frontend/src/features/SideBar/views/WorkspacesView/index.tsx
index 804048f..23680b8 100644
--- a/src-frontend/src/features/SideBar/views/WorkspacesView/index.tsx
+++ b/src-frontend/src/features/SideBar/views/WorkspacesView/index.tsx
@@ -33,10 +33,7 @@ export function WorkspacesView() {
         />
       </SideBarHeader>
       <div className="flex-1">
-        <AsyncBoundary
-          skeleton={<SideBarListSkeleton />}
-          errorDescription={t("workspaces.list.error_load")}
-        >
+        <AsyncBoundary skeleton={<SideBarListSkeleton />}>
           <WorkspaceList />
         </AsyncBoundary>
       </div>
diff --git a/src-frontend/src/features/Tabs/AgentPanel/AgentCreateForm.tsx b/src-frontend/src/features/Tabs/AgentPanel/AgentCreateForm.tsx
index b347f19..e251e0b 100644
--- a/src-frontend/src/features/Tabs/AgentPanel/AgentCreateForm.tsx
+++ b/src-frontend/src/features/Tabs/AgentPanel/AgentCreateForm.tsx
@@ -26,11 +26,6 @@ export function AgentCreateForm({ onConfirm }: AgentCreateFormProps) {
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.create.error_title"), {
-          description: error.message || t("toast.create.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/AgentPanel/AgentEditForm.tsx b/src-frontend/src/features/Tabs/AgentPanel/AgentEditForm.tsx
index ade21ad..3d6c4cf 100644
--- a/src-frontend/src/features/Tabs/AgentPanel/AgentEditForm.tsx
+++ b/src-frontend/src/features/Tabs/AgentPanel/AgentEditForm.tsx
@@ -29,11 +29,6 @@ export function AgentEditForm({ agent, onConfirm }: AgentEditFormProps) {
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.update.error_title"), {
-          description: error.message || t("toast.update.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/AgentPanel/fields/ToolMultiSelectField.tsx b/src-frontend/src/features/Tabs/AgentPanel/fields/ToolMultiSelectField.tsx
index 491d449..91688f2 100644
--- a/src-frontend/src/features/Tabs/AgentPanel/fields/ToolMultiSelectField.tsx
+++ b/src-frontend/src/features/Tabs/AgentPanel/fields/ToolMultiSelectField.tsx
@@ -77,7 +77,7 @@ export function ToolMultiSelectField() {
         <ToolMultiSelectDialog value={selectedToolIds} onChange={onChange} />
       </FieldItem>
 
-      <AsyncBoundary errorDescription={t("form.usable_tools.load_error")}>
+      <AsyncBoundary>
         <ToolSelectedList selectedToolIds={selectedToolIds} />
       </AsyncBoundary>
     </div>
diff --git a/src-frontend/src/features/Tabs/AgentPanel/index.tsx b/src-frontend/src/features/Tabs/AgentPanel/index.tsx
index 414b023..c8174f4 100644
--- a/src-frontend/src/features/Tabs/AgentPanel/index.tsx
+++ b/src-frontend/src/features/Tabs/AgentPanel/index.tsx
@@ -1,6 +1,4 @@
-import { useTranslation } from "react-i18next";
 import { useGetAgentSuspense } from "@/api/agent";
-import { FailedToLoad } from "@/components/custom/FailedToLoad";
 import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
 import { AgentCreateForm } from "@/features/Tabs/AgentPanel/AgentCreateForm";
 import { AgentEditForm } from "@/features/Tabs/AgentPanel/AgentEditForm";
@@ -41,7 +39,6 @@ export function AgentPanel({
   tabId,
   metadata,
 }: TabPanelProps<AgentTabMetadata>) {
-  const { t } = useTranslation("tabs-agent");
   if (metadata.mode === "create") {
     return (
       <ScrollArea className="h-full px-8">
@@ -52,14 +49,7 @@ export function AgentPanel({
   }
 
   return (
-    <TabPanelFrame
-      errorRender={({ resetErrorBoundary }) => (
-        <FailedToLoad
-          refetch={resetErrorBoundary}
-          description={t("panel.error.load_description")}
-        />
-      )}
-    >
+    <TabPanelFrame>
       <AgentEditPanel tabId={tabId} agentId={metadata.id} />
     </TabPanelFrame>
   );
diff --git a/src-frontend/src/features/Tabs/ProviderPanel/ProviderCreateForm.tsx b/src-frontend/src/features/Tabs/ProviderPanel/ProviderCreateForm.tsx
index aceae7e..70d0706 100644
--- a/src-frontend/src/features/Tabs/ProviderPanel/ProviderCreateForm.tsx
+++ b/src-frontend/src/features/Tabs/ProviderPanel/ProviderCreateForm.tsx
@@ -27,11 +27,6 @@ export function ProviderCreateForm({ onConfirm }: ProviderCreateFormProps) {
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.create.error_title"), {
-          description: error.message || t("toast.create.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/ProviderPanel/ProviderEditForm.tsx b/src-frontend/src/features/Tabs/ProviderPanel/ProviderEditForm.tsx
index c462c0e..4d429c1 100644
--- a/src-frontend/src/features/Tabs/ProviderPanel/ProviderEditForm.tsx
+++ b/src-frontend/src/features/Tabs/ProviderPanel/ProviderEditForm.tsx
@@ -31,11 +31,6 @@ export function ProviderEditForm({
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.update.error_title"), {
-          description: error.message || t("toast.update.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelEditDialog.tsx b/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelEditDialog.tsx
index 621837d..8489f10 100644
--- a/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelEditDialog.tsx
+++ b/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelEditDialog.tsx
@@ -25,6 +25,8 @@ type ModelEditDialogProps = {
   onCancel?: () => void;
 };
 
+// TODO: refactor form
+
 export function ModelEditDialog({
   children,
   model,
diff --git a/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelSelectDialog.tsx b/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelSelectDialog.tsx
index 03c6321..b12a4bb 100644
--- a/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelSelectDialog.tsx
+++ b/src-frontend/src/features/Tabs/ProviderPanel/fields/ModelsField/ModelSelectDialog.tsx
@@ -75,10 +75,7 @@ export function ModelSelectDialog({
         <SelectDialogSearch placeholder={t("models.select.search_placeholder")} />
         <SelectDialogList>
           <SelectDialogGroup>
-            <AsyncBoundary
-              skeleton={<SelectDialogSkeleton />}
-              errorDescription={t("models.select.error_load")}
-            >
+            <AsyncBoundary skeleton={<SelectDialogSkeleton />}>
               <ModelQueryList enabled={open} provider={provider} />
             </AsyncBoundary>
           </SelectDialogGroup>
diff --git a/src-frontend/src/features/Tabs/ProviderPanel/index.tsx b/src-frontend/src/features/Tabs/ProviderPanel/index.tsx
index d938093..8b6d859 100644
--- a/src-frontend/src/features/Tabs/ProviderPanel/index.tsx
+++ b/src-frontend/src/features/Tabs/ProviderPanel/index.tsx
@@ -1,6 +1,4 @@
-import { useTranslation } from "react-i18next";
 import { useGetProviderSuspense } from "@/api/provider";
-import { FailedToLoad } from "@/components/custom/FailedToLoad";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { ProviderCreateForm } from "@/features/Tabs/ProviderPanel/ProviderCreateForm";
 import { ProviderEditForm } from "@/features/Tabs/ProviderPanel/ProviderEditForm";
@@ -34,8 +32,6 @@ export function ProviderPanel({
   tabId,
   metadata,
 }: TabPanelProps<ProviderTabMetadata>) {
-  const { t } = useTranslation("tabs-provider");
-
   if (metadata.mode === "create") {
     return (
       <ScrollArea className="h-full px-8">
@@ -45,14 +41,7 @@ export function ProviderPanel({
   }
 
   return (
-    <TabPanelFrame
-      errorRender={({ resetErrorBoundary }) => (
-        <FailedToLoad
-          refetch={resetErrorBoundary}
-          description={t("panel.error.load_description")}
-        />
-      )}
-    >
+    <TabPanelFrame>
       <ProviderEditPanel tabId={tabId} providerId={metadata.id} />
     </TabPanelFrame>
   );
diff --git a/src-frontend/src/features/Tabs/TabPanelFrame.tsx b/src-frontend/src/features/Tabs/TabPanelFrame.tsx
index d8d321a..070ce52 100644
--- a/src-frontend/src/features/Tabs/TabPanelFrame.tsx
+++ b/src-frontend/src/features/Tabs/TabPanelFrame.tsx
@@ -1,7 +1,7 @@
-import type { FallbackProps } from "react-error-boundary";
 import { AsyncBoundary } from "@/components/custom/AsyncBoundary";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { Skeleton } from "@/components/ui/skeleton";
+import { FailedToLoad } from "@/components/custom/FailedToLoad";
 
 function TabPanelFrameSkeleton() {
   return (
@@ -33,16 +33,15 @@ function TabPanelFrameSkeleton() {
 
 type TabPanelFrameProps = {
   children: React.ReactNode;
-  errorRender: (props: FallbackProps) => React.ReactNode;
 };
 
-export function TabPanelFrame({ children, errorRender }: TabPanelFrameProps) {
+export function TabPanelFrame({ children }: TabPanelFrameProps) {
   return (
     <AsyncBoundary
       skeleton={<TabPanelFrameSkeleton />}
       errorRender={(props) => (
         <div className="flex h-full items-center justify-center p-4">
-          {errorRender(props)}
+          <FailedToLoad error={props.error} retry={props.resetErrorBoundary} />
         </div>
       )}
     >
diff --git a/src-frontend/src/features/Tabs/TaskPanel/components/PromptInput/ContextSelectPopover.tsx b/src-frontend/src/features/Tabs/TaskPanel/components/PromptInput/ContextSelectPopover.tsx
index bd6b6cf..ca92378 100644
--- a/src-frontend/src/features/Tabs/TaskPanel/components/PromptInput/ContextSelectPopover.tsx
+++ b/src-frontend/src/features/Tabs/TaskPanel/components/PromptInput/ContextSelectPopover.tsx
@@ -91,8 +91,11 @@ function FilesMenu({ onSelect }: { onSelect?: OnSelectHandler }) {
           <SearchResults query={debouncedQuery} onSelect={onSelect} />
         ) : (
           <AsyncBoundary
-            skeleton={<div className="p-3 text-muted-foreground text-sm">{t("prompt.context.loading")}</div>}
-            errorDescription={t("prompt.context.load_error")}
+            skeleton={(
+              <div className="p-3 text-muted-foreground text-sm">
+                {t("prompt.context.loading")}
+              </div>
+            )}
           >
             <FileTreeSuspense onSelect={onSelect} />
           </AsyncBoundary>
diff --git a/src-frontend/src/features/Tabs/TaskPanel/hooks/use-agent-task/index.tsx b/src-frontend/src/features/Tabs/TaskPanel/hooks/use-agent-task/index.tsx
index 487377c..5dcfb2b 100644
--- a/src-frontend/src/features/Tabs/TaskPanel/hooks/use-agent-task/index.tsx
+++ b/src-frontend/src/features/Tabs/TaskPanel/hooks/use-agent-task/index.tsx
@@ -2,6 +2,7 @@ import { createContext, useCallback, useContext, useMemo, useRef, useState } fro
 import { useTranslation } from "react-i18next";
 import { produce } from "immer";
 import { toast } from "sonner";
+import { useQueryClient } from "@tanstack/react-query";
 import { TABS_TASK_NAMESPACE } from "@/i18n/resources";
 import {
   BuiltInTools,
@@ -21,6 +22,7 @@ import {
 } from "@/api/generated/schemas";
 import {
   continueTask,
+  getGetTaskQueryKey,
   type TaskSseCallbacks,
   toolAnswer,
   toolReview,
@@ -29,15 +31,15 @@ import {
 import { UpdateTodosSchema } from "@/api/tool-schema";
 import { tryParseSchema } from "@/lib/utils";
 import { UiUserMessage, type SdkMessage } from "@/types/message";
-import { useMessageLifecycle } from "./use-message-lifecycle";
 import { UiMessage } from "@/types/message";
 import { toUiMessage } from "@/types/message";
 import { sendNotification } from "@/lib/notification";
 import { useTabsStore } from "@/stores/tabs-store";
+import { isForeground } from "@/lib/is-foreground";
 import { useTaskStream } from "./use-task-stream";
 import { useTextBuffer } from "./use-text-buffer";
 import { useToolCallBuffer } from "./use-tool-call-buffer";
-import { isForeground } from "@/lib/is-foreground";
+import { useMessageLifecycle } from "./use-message-lifecycle";
 
 export type TaskState = "idle" | "waiting" | "running" | "error";
 
@@ -89,6 +91,7 @@ type AgentTaskProviderProps = {
 
 export function AgentTaskProvider({ taskId, children }: AgentTaskProviderProps) {
   const { t } = useTranslation(TABS_TASK_NAMESPACE);
+  const queryClient = useQueryClient();
   const setActiveTab = useTabsStore((state) => state.setActive);
   const backToCurrentTab = () => setActiveTab((tab) => (
     tab.type === "task" &&
@@ -211,7 +214,10 @@ export function AgentTaskProvider({ taskId, children }: AgentTaskProviderProps)
     });
   };
 
-  const onClose = () => messageLifecycle.handleClose();
+  const onClose = () => {
+    messageLifecycle.handleClose();
+    queryClient.invalidateQueries({ queryKey: getGetTaskQueryKey(taskId) });
+  }
 
   sseCallbacksRef.current = {
     onMessageStart,
diff --git a/src-frontend/src/features/Tabs/TaskPanel/index.tsx b/src-frontend/src/features/Tabs/TaskPanel/index.tsx
index 5918cc4..9af7ddc 100644
--- a/src-frontend/src/features/Tabs/TaskPanel/index.tsx
+++ b/src-frontend/src/features/Tabs/TaskPanel/index.tsx
@@ -1,5 +1,4 @@
 import { useRef } from "react";
-import { useTranslation } from "react-i18next";
 import { AsyncBoundary } from "@/components/custom/AsyncBoundary";
 import { i18n } from "@/i18n";
 import { TABS_TASK_NAMESPACE } from "@/i18n/resources";
@@ -12,7 +11,6 @@ import { SessionView, SessionViewSkeleton } from "./SessionView";
 export const DEFAULT_TAB_TITLE = i18n.t("tab.default_title", { ns: TABS_TASK_NAMESPACE });
 
 export function TaskPanel({ tabId, metadata }: TabPanelProps<TaskTabMetadata>) {
-  const { t } = useTranslation("tabs-task");
   const isInitialDraft = useRef(metadata.isDraft);
 
   if (metadata.isDraft) {
@@ -20,10 +18,7 @@ export function TaskPanel({ tabId, metadata }: TabPanelProps<TaskTabMetadata>) {
   }
 
   return (
-    <AsyncBoundary
-      skeleton={<SessionViewSkeleton />}
-      errorDescription={t("panel.error.load_description")}
-    >
+    <AsyncBoundary skeleton={<SessionViewSkeleton />}>
       <AgentTaskProvider taskId={metadata.id}>
         <SessionView shouldStartStream={isInitialDraft.current} />
       </AgentTaskProvider>
diff --git a/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetCreateForm.tsx b/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetCreateForm.tsx
index ae003f9..79c74c8 100644
--- a/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetCreateForm.tsx
+++ b/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetCreateForm.tsx
@@ -1,6 +1,6 @@
 import { useTranslation } from "react-i18next";
 import { toast } from "sonner";
-import { invalidateToolsetQueries, useCreateMcpToolset } from "@/api/toolset";
+import { invalidateToolsetQueries, useCreateToolset } from "@/api/toolset";
 import { FormShell, FormShellFooter } from "@/components/custom/form/FormShell";
 import { NameField } from "@/components/custom/form/fields";
 import { Button } from "@/components/ui/button";
@@ -18,7 +18,7 @@ type ToolsetCreateProps = {
 export function ToolsetCreateForm({ onConfirm }: ToolsetCreateProps) {
   const { t } = useTranslation("tabs-toolset");
 
-  const createMutation = useCreateMcpToolset({
+  const createMutation = useCreateToolset({
     mutation: {
       async onSuccess(newToolset) {
         await invalidateToolsetQueries();
@@ -26,12 +26,7 @@ export function ToolsetCreateForm({ onConfirm }: ToolsetCreateProps) {
           description: t("toast.create.success_description_with_name", { name: newToolset.name }),
         });
         onConfirm?.();
-      },
-      onError(error: Error) {
-        toast.error(t("toast.create.error_title"), {
-          description: error.message || t("toast.create.error_description"),
-        });
-      },
+      }
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetEditForm.tsx b/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetEditForm.tsx
index fdb12a1..dca4298 100644
--- a/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetEditForm.tsx
+++ b/src-frontend/src/features/Tabs/ToolsetPanel/ToolsetEditForm.tsx
@@ -29,11 +29,6 @@ export function ToolsetEditForm({ toolset, onConfirm }: ToolsetEditFormProps) {
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.update.error_title"), {
-          description: error.message || t("toast.update.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/ToolsetPanel/index.tsx b/src-frontend/src/features/Tabs/ToolsetPanel/index.tsx
index 4100ad8..5069a6c 100644
--- a/src-frontend/src/features/Tabs/ToolsetPanel/index.tsx
+++ b/src-frontend/src/features/Tabs/ToolsetPanel/index.tsx
@@ -1,6 +1,4 @@
-import { useTranslation } from "react-i18next";
 import { useGetToolsetSuspense } from "@/api/toolset";
-import { FailedToLoad } from "@/components/custom/FailedToLoad";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { ToolsetEditForm } from "@/features/Tabs/ToolsetPanel/ToolsetEditForm";
 import { useTabsStore } from "@/stores/tabs-store";
@@ -37,8 +35,6 @@ export function ToolsetPanel({
   tabId,
   metadata,
 }: TabPanelProps<ToolsetTabMetadata>) {
-  const { t } = useTranslation("tabs-toolset");
-
   if (metadata.mode === "create") {
     return (
       <ScrollArea className="h-full px-8">
@@ -48,14 +44,7 @@ export function ToolsetPanel({
   }
 
   return (
-    <TabPanelFrame
-      errorRender={({ resetErrorBoundary }) => (
-        <FailedToLoad
-          refetch={resetErrorBoundary}
-          description={t("panel.error.load_description")}
-        />
-      )}
-    >
+    <TabPanelFrame>
       <ToolsetEditPanel tabId={tabId} toolsetId={metadata.id} />
     </TabPanelFrame>
   );
diff --git a/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceCreateForm.tsx b/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceCreateForm.tsx
index 7cf464f..f3350fc 100644
--- a/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceCreateForm.tsx
+++ b/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceCreateForm.tsx
@@ -25,11 +25,6 @@ export function WorkspaceCreateForm({ onConfirm }: WorkspaceCreateFormProps) {
         });
         onConfirm?.();
       },
-      onError(error: Error) {
-        toast.error(t("toast.create.error_title"), {
-          description: error.message || t("toast.create.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceEditForm.tsx b/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceEditForm.tsx
index 23bd467..7abaab2 100644
--- a/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceEditForm.tsx
+++ b/src-frontend/src/features/Tabs/WorkspacePanel/WorkspaceEditForm.tsx
@@ -49,11 +49,6 @@ export function WorkspaceEditForm({
           await syncCurrentWorkspace();
         }
       },
-      onError(error: Error) {
-        toast.error(t("toast.update.error_title"), {
-          description: error.message || t("toast.update.error_description"),
-        });
-      },
     },
   });
 
diff --git a/src-frontend/src/features/Tabs/WorkspacePanel/fields/AgentMultiSelectField.tsx b/src-frontend/src/features/Tabs/WorkspacePanel/fields/AgentMultiSelectField.tsx
index 95a5bdb..bf8e3b7 100644
--- a/src-frontend/src/features/Tabs/WorkspacePanel/fields/AgentMultiSelectField.tsx
+++ b/src-frontend/src/features/Tabs/WorkspacePanel/fields/AgentMultiSelectField.tsx
@@ -121,7 +121,7 @@ export function AgentMultiSelectField() {
             <SelectDialogList>
               <SelectDialogEmpty>{t("form.usable_agents.empty")}</SelectDialogEmpty>
               <SelectDialogGroup>
-                <AsyncBoundary skeleton={<SelectDialogSkeleton />} errorDescription={t("form.usable_agents.load_error")}>
+                <AsyncBoundary skeleton={<SelectDialogSkeleton />}>
                   <AgentQueryList />
                 </AsyncBoundary>
               </SelectDialogGroup>
@@ -135,7 +135,7 @@ export function AgentMultiSelectField() {
         </SelectDialog>
       </FieldItem>
 
-      <AsyncBoundary errorDescription={t("form.usable_agents.load_error")}>
+      <AsyncBoundary>
         <AgentSelectedList selectedAgentIds={value} />
       </AsyncBoundary>
     </div>
diff --git a/src-frontend/src/features/Tabs/WorkspacePanel/fields/ToolMultiSelectField.tsx b/src-frontend/src/features/Tabs/WorkspacePanel/fields/ToolMultiSelectField.tsx
index 794492a..6a7f696 100644
--- a/src-frontend/src/features/Tabs/WorkspacePanel/fields/ToolMultiSelectField.tsx
+++ b/src-frontend/src/features/Tabs/WorkspacePanel/fields/ToolMultiSelectField.tsx
@@ -77,7 +77,7 @@ export function ToolMultiSelectField() {
         <ToolMultiSelectDialog value={selectedToolIds} onChange={onChange} />
       </FieldItem>
 
-      <AsyncBoundary errorDescription={t("form.usable_tools.load_error")}>
+      <AsyncBoundary>
         <ToolSelectedList selectedToolIds={selectedToolIds} />
       </AsyncBoundary>
     </div>
diff --git a/src-frontend/src/features/Tabs/WorkspacePanel/index.tsx b/src-frontend/src/features/Tabs/WorkspacePanel/index.tsx
index 442a18f..d8c814e 100644
--- a/src-frontend/src/features/Tabs/WorkspacePanel/index.tsx
+++ b/src-frontend/src/features/Tabs/WorkspacePanel/index.tsx
@@ -1,6 +1,4 @@
-import { useTranslation } from "react-i18next";
 import { useGetWorkspaceSuspense } from "@/api/workspace";
-import { FailedToLoad } from "@/components/custom/FailedToLoad";
 import { ScrollArea, ScrollBar } from "@/components/ui/scroll-area";
 import { useTabsStore } from "@/stores/tabs-store";
 import type { WorkspaceTabMetadata } from "@/types/tab";
@@ -34,8 +32,6 @@ export function WorkspacePanel({
   tabId,
   metadata,
 }: TabPanelProps<WorkspaceTabMetadata>) {
-  const { t } = useTranslation("tabs-workspace");
-
   if (metadata.mode === "create") {
     return (
       <ScrollArea className="h-full px-8">
@@ -46,14 +42,7 @@ export function WorkspacePanel({
   }
 
   return (
-    <TabPanelFrame
-      errorRender={({ resetErrorBoundary }) => (
-        <FailedToLoad
-          refetch={resetErrorBoundary}
-          description={t("panel.error.load_description")}
-        />
-      )}
-    >
+    <TabPanelFrame>
       <WorkspaceEditPanel tabId={tabId} workspaceId={metadata.id} />
     </TabPanelFrame>
   );
diff --git a/src-frontend/src/i18n/error-message.ts b/src-frontend/src/i18n/error-message.ts
new file mode 100644
index 0000000..3b555cc
--- /dev/null
+++ b/src-frontend/src/i18n/error-message.ts
@@ -0,0 +1,12 @@
+import { i18n } from "./index";
+import { ErrorCode } from "@/api/orval-mutator/custom-fetch";
+import { ERROR_NAMESPACE } from "./resources";
+
+export function getErrorMessage(errorCode: ErrorCode): string {
+  if (i18n.exists(errorCode, { ns: ERROR_NAMESPACE })) {
+    return i18n.t(errorCode, {
+      ns: ERROR_NAMESPACE
+    });
+  }
+  return i18n.t("UNEXPECTED_ERROR", { ns: ERROR_NAMESPACE });
+}
diff --git a/src-frontend/src/i18n/locales/en/components-custom.json b/src-frontend/src/i18n/locales/en/components-custom.json
new file mode 100644
index 0000000..ec23e08
--- /dev/null
+++ b/src-frontend/src/i18n/locales/en/components-custom.json
@@ -0,0 +1,6 @@
+{
+  "load_failed": {
+    "retry": "Retry",
+    "title": "Failed to load"
+  }
+}
diff --git a/src-frontend/src/i18n/locales/en/dialog.json b/src-frontend/src/i18n/locales/en/dialog.json
index 1def5e9..3da7622 100644
--- a/src-frontend/src/i18n/locales/en/dialog.json
+++ b/src-frontend/src/i18n/locales/en/dialog.json
@@ -11,7 +11,6 @@
         "no_model": "No models found",
         "no_provider": "No providers yet. Add an LLM provider first to use models."
       },
-      "load_error": "Failed to load model list. Please try again later.",
       "search_placeholder": "Search models...",
       "trigger": {
         "deleted": "Model has been deleted",
@@ -23,7 +22,6 @@
       "cancel": "Cancel",
       "confirm": "Confirm",
       "empty": "No matching tools found",
-      "load_error": "Failed to load tool list. Please try again later.",
       "search_placeholder": "Search tools...",
       "select_all": "Select all",
       "trigger": {
diff --git a/src-frontend/src/i18n/locales/en/error.json b/src-frontend/src/i18n/locales/en/error.json
new file mode 100644
index 0000000..c6666d2
--- /dev/null
+++ b/src-frontend/src/i18n/locales/en/error.json
@@ -0,0 +1,25 @@
+{
+  "AGENT_NOT_FOUND": "The agent was not found.",
+  "CANNOT_CREATE_BUILTIN_TOOLSET": "Built-in toolsets cannot be created.",
+  "MCP_AUTH_FAILED": "Authentication failed. Check your credentials and try again.",
+  "MCP_COMMAND_NOT_FOUND": "The requested command was not found.",
+  "MCP_CONNECTION_FAILED": "Connection failed. Please try again.",
+  "MCP_CONNECTION_TIMEOUT": "Connection timed out. Please try again.",
+  "MCP_PERMISSION_DENIED": "Permission denied. Please check access rights.",
+  "MCP_PROCESS_CRASHED": "The MCP process crashed. Please try again.",
+  "MCP_PROCESS_START_FAILED": "Failed to start the MCP process.",
+  "MCP_PROTOCOL_ERROR": "Protocol error. Please check the server configuration.",
+  "MODEL_NOT_FOUND": "The model was not found.",
+  "NETWORK_ERROR": "Network error. Check your connection and try again.",
+  "PATH_ACCESS_DENIED": "You do not have permission to access the path.",
+  "PATH_NOT_DIRECTORY": "The selected path is not a folder.",
+  "PATH_NOT_FOUND": "The selected path was not found.",
+  "PROVIDER_NOT_FOUND": "The provider was not found.",
+  "TASK_NOT_FOUND": "The task was not found.",
+  "TOOL_CALL_NOT_FOUND": "The requested operation was not found.",
+  "TOOL_NOT_FOUND": "The tool was not found.",
+  "TOOLSET_INTERNAL_KEY_ALREADY_EXISTS": "This toolset already exists.",
+  "TOOLSET_NOT_FOUND": "The toolset was not found.",
+  "UNEXPECTED_ERROR": "Something went wrong. Please try again.",
+  "WORKSPACE_NOT_FOUND": "The workspace was not found."
+}
diff --git a/src-frontend/src/i18n/locales/en/sidebar.json b/src-frontend/src/i18n/locales/en/sidebar.json
index c6a3437..cb49e22 100644
--- a/src-frontend/src/i18n/locales/en/sidebar.json
+++ b/src-frontend/src/i18n/locales/en/sidebar.json
@@ -8,7 +8,6 @@
       "title": "Agents"
     },
     "list": {
-      "error_load": "Failed to load agents. Please try again later.",
       "no_model": "No model"
     },
     "menu": {
@@ -20,8 +19,6 @@
       "edit_title_with_name": "Edit: {{name}}"
     },
     "toast": {
-      "delete_error_description": "Failed to delete the agent. Please try again later.",
-      "delete_error_title": "Delete failed",
       "delete_success_description": "Agent deleted successfully.",
       "delete_success_title": "Delete success"
     }
@@ -59,8 +56,7 @@
     "helper_model": {
       "flash_model": {
         "title": "Flash model"
-      },
-      "error_load": "Failed to load helper model settings. Please try again later."
+      }
     },
     "providers": {
       "actions": {
@@ -76,7 +72,6 @@
       "list": {
         "delete_provider_title": "Delete",
         "edit_provider_title": "Edit provider",
-        "error_load": "Failed to load providers. Please try again later.",
         "model_count_with_count_one": "",
         "model_count_with_count_other": ""
       },
@@ -85,8 +80,6 @@
         "edit_title_with_name": "Edit: {{name}}"
       },
       "toast": {
-        "delete_error_description": "Failed to delete the provider. Please try again later.",
-        "delete_error_title": "Delete failed",
         "delete_success_description": "Provider deleted successfully.",
         "delete_success_title": "Delete success"
       }
@@ -114,16 +107,11 @@
       "create_tooltip": "Create new task",
       "title": "Tasks"
     },
-    "list": {
-      "error_load": "Failed to load tasks. Please try again later."
-    },
     "menu": {
       "delete": "Delete",
       "rename": "Edit task name"
     },
     "toast": {
-      "delete_error_description": "Failed to delete the task. Please try again later.",
-      "delete_error_title": "Delete failed",
       "delete_success_description": "Task deleted successfully.",
       "delete_success_title": "Delete success",
       "rename_feature_description": "Rename feature is not implemented yet",
@@ -138,20 +126,21 @@
       "create_tooltip": "Connect to MCP server",
       "title": "Toolsets"
     },
-    "list": {
-      "error_load": "Failed to load toolsets. Please try again later."
-    },
     "menu": {
       "delete": "Delete",
       "edit": "Edit toolset"
     },
+    "status": {
+      "connected": "Connected",
+      "connecting": "Connecting",
+      "disconnected": "Disconnected",
+      "error": "Error"
+    },
     "tab": {
       "create_title": "Connect to MCP server",
       "edit_title_with_name": "Edit: {{name}}"
     },
     "toast": {
-      "delete_error_description": "Failed to delete the toolset. Please try again later.",
-      "delete_error_title": "Delete failed",
       "delete_success_description": "Toolset deleted successfully.",
       "delete_success_title": "Delete success"
     }
@@ -168,21 +157,16 @@
       "create_tooltip": "Create new workspace",
       "title": "Workspaces"
     },
-    "list": {
-      "error_load": "Failed to load workspaces. Please try again later."
-    },
     "menu": {
       "delete": "Delete",
       "edit": "Edit workspace",
-      "set_current": "Set as current"
+      "select": "Set as current"
     },
     "tab": {
       "create_title": "Create workspace",
       "edit_title_with_name": "Edit: {{name}}"
     },
     "toast": {
-      "delete_error_description": "Failed to delete the workspace. Please try again later.",
-      "delete_error_title": "Delete failed",
       "delete_success_description": "Workspace deleted successfully.",
       "delete_success_title": "Delete success"
     }
diff --git a/src-frontend/src/i18n/locales/en/tabs-agent.json b/src-frontend/src/i18n/locales/en/tabs-agent.json
index 91f7402..fde4e76 100644
--- a/src-frontend/src/i18n/locales/en/tabs-agent.json
+++ b/src-frontend/src/i18n/locales/en/tabs-agent.json
@@ -20,8 +20,7 @@
       "saving": "Saving..."
     },
     "usable_tools": {
-      "label": "Available tools",
-      "load_error": "Failed to load tool list. Please try again later."
+      "label": "Available tools"
     }
   },
   "icon_dialog": {
@@ -43,21 +42,12 @@
       "select": "Select icon"
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "Failed to load agent details. Please try again later."
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "Failed to create agent. Please try again later.",
-      "error_title": "Create failed",
       "success_description_with_name": "Agent {{name}} created successfully.",
       "success_title": "Create success"
     },
     "update": {
-      "error_description": "Failed to update agent. Please try again later.",
-      "error_title": "Update failed",
       "success_description_with_name": "Agent {{name}} updated successfully.",
       "success_title": "Update success"
     }
diff --git a/src-frontend/src/i18n/locales/en/tabs-provider.json b/src-frontend/src/i18n/locales/en/tabs-provider.json
index c91e87e..a4b8e88 100644
--- a/src-frontend/src/i18n/locales/en/tabs-provider.json
+++ b/src-frontend/src/i18n/locales/en/tabs-provider.json
@@ -59,25 +59,15 @@
       "cancel": "Cancel",
       "confirm": "Confirm",
       "empty": "No models found",
-      "error_load": "Failed to load model list. Please try again later.",
       "search_placeholder": "Search models..."
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "Failed to load provider details. Please try again later."
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "Failed to create provider. Please try again later.",
-      "error_title": "Create failed",
       "success_description_with_name": "Provider {{name}} created successfully.",
       "success_title": "Create success"
     },
     "update": {
-      "error_description": "Failed to update provider. Please try again later.",
-      "error_title": "Update failed",
       "success_description_with_name": "Provider {{name}} updated successfully.",
       "success_title": "Update success"
     }
diff --git a/src-frontend/src/i18n/locales/en/tabs-task.json b/src-frontend/src/i18n/locales/en/tabs-task.json
index 33ab790..9312ba2 100644
--- a/src-frontend/src/i18n/locales/en/tabs-task.json
+++ b/src-frontend/src/i18n/locales/en/tabs-task.json
@@ -16,10 +16,10 @@
       "title": "Task failed. Please retry."
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "Failed to load task. Please try again later."
-    }
+  "notification": {
+    "require_permission": "Dais wants to use {{toolName}}",
+    "require_response": "Dais is waiting for your response",
+    "task_done": "Dais has finished the task"
   },
   "prompt": {
     "agent": {
@@ -31,7 +31,6 @@
       "workspace_load_failed": "Failed to load workspace"
     },
     "context": {
-      "load_error": "Failed to load files.",
       "loading": "Loading...",
       "no_results": "No results found.",
       "search_placeholder": "Add files, folders, docs...",
@@ -45,11 +44,6 @@
   "task_progress": {
     "completed": "Task completed"
   },
-  "notification": {
-    "require_response": "Dais is waiting for your response",
-    "require_permission": "Dais wants to use {{toolName}}",
-    "task_done": "Dais has finished the task"
-  },
   "toast": {
     "task_failed": {
       "title": "Task failed"
@@ -82,4 +76,4 @@
       "title": "Task todos updated"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src-frontend/src/i18n/locales/en/tabs-toolset.json b/src-frontend/src/i18n/locales/en/tabs-toolset.json
index 8674852..99c7370 100644
--- a/src-frontend/src/i18n/locales/en/tabs-toolset.json
+++ b/src-frontend/src/i18n/locales/en/tabs-toolset.json
@@ -47,21 +47,12 @@
       "placeholder": "https://api.example.com"
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "Failed to load toolset details. Please try again later."
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "Failed to create toolset. Please try again later.",
-      "error_title": "Create failed",
       "success_description_with_name": "Toolset {{name}} created successfully.",
       "success_title": "Create success"
     },
     "update": {
-      "error_description": "Failed to update toolset. Please try again later.",
-      "error_title": "Update failed",
       "success_description_with_name": "Toolset {{name}} updated successfully.",
       "success_title": "Update success"
     }
diff --git a/src-frontend/src/i18n/locales/en/tabs-workspace.json b/src-frontend/src/i18n/locales/en/tabs-workspace.json
index aab4c85..76d1ef9 100644
--- a/src-frontend/src/i18n/locales/en/tabs-workspace.json
+++ b/src-frontend/src/i18n/locales/en/tabs-workspace.json
@@ -18,30 +18,19 @@
       "confirm": "Confirm",
       "empty": "No matching agents found",
       "label": "Available agents",
-      "load_error": "Failed to load agent list. Please try again later.",
       "search_placeholder": "Search agents...",
       "select": "Select"
     },
     "usable_tools": {
-      "label": "Available tools",
-      "load_error": "Failed to load tool list. Please try again later."
-    }
-  },
-  "panel": {
-    "error": {
-      "load_description": "Failed to load workspace details. Please try again later."
+      "label": "Available tools"
     }
   },
   "toast": {
     "create": {
-      "error_description": "Failed to create workspace. Please try again later.",
-      "error_title": "Create failed",
       "success_description_with_name": "Workspace \"{{name}}\" created successfully.",
       "success_title": "Create success"
     },
     "update": {
-      "error_description": "Failed to update workspace. Please try again later.",
-      "error_title": "Update failed",
       "success_description_with_name": "Workspace \"{{name}}\" updated successfully.",
       "success_title": "Update success"
     }
diff --git a/src-frontend/src/i18n/locales/zh_CN/components-custom.json b/src-frontend/src/i18n/locales/zh_CN/components-custom.json
new file mode 100644
index 0000000..b0c58c2
--- /dev/null
+++ b/src-frontend/src/i18n/locales/zh_CN/components-custom.json
@@ -0,0 +1,6 @@
+{
+  "load_failed": {
+    "retry": "重试",
+    "title": "加载失败"
+  }
+}
diff --git a/src-frontend/src/i18n/locales/zh_CN/dialog.json b/src-frontend/src/i18n/locales/zh_CN/dialog.json
index 52a3ff7..d761a71 100644
--- a/src-frontend/src/i18n/locales/zh_CN/dialog.json
+++ b/src-frontend/src/i18n/locales/zh_CN/dialog.json
@@ -11,7 +11,6 @@
         "no_model": "未找到模型",
         "no_provider": "暂无供应商，请先添加 LLM 供应商以使用模型。"
       },
-      "load_error": "无法加载模型列表，请稍后重试。",
       "search_placeholder": "搜索模型...",
       "trigger": {
         "deleted": "模型已被删除",
@@ -23,7 +22,6 @@
       "cancel": "取消",
       "confirm": "确定",
       "empty": "未找到匹配的工具",
-      "load_error": "无法加载工具列表，请稍后重试。",
       "search_placeholder": "搜索工具...",
       "select_all": "全选",
       "trigger": {
diff --git a/src-frontend/src/i18n/locales/zh_CN/error.json b/src-frontend/src/i18n/locales/zh_CN/error.json
new file mode 100644
index 0000000..60571d9
--- /dev/null
+++ b/src-frontend/src/i18n/locales/zh_CN/error.json
@@ -0,0 +1,25 @@
+{
+  "AGENT_NOT_FOUND": "未找到该代理。",
+  "CANNOT_CREATE_BUILTIN_TOOLSET": "无法创建内置工具集。",
+  "MCP_AUTH_FAILED": "认证失败，请检查凭据后重试。",
+  "MCP_COMMAND_NOT_FOUND": "未找到对应的命令。",
+  "MCP_CONNECTION_FAILED": "连接失败，请稍后重试。",
+  "MCP_CONNECTION_TIMEOUT": "连接超时，请稍后重试。",
+  "MCP_PERMISSION_DENIED": "权限不足，请检查访问权限。",
+  "MCP_PROCESS_CRASHED": "进程崩溃，请稍后重试。",
+  "MCP_PROCESS_START_FAILED": "进程启动失败，请稍后重试。",
+  "MCP_PROTOCOL_ERROR": "协议错误，请检查服务端配置。",
+  "MODEL_NOT_FOUND": "未找到该模型。",
+  "NETWORK_ERROR": "网络错误，请检查连接后重试。",
+  "PATH_ACCESS_DENIED": "没有权限访问该路径。",
+  "PATH_NOT_DIRECTORY": "该路径不是文件夹。",
+  "PATH_NOT_FOUND": "未找到指定路径。",
+  "PROVIDER_NOT_FOUND": "未找到该提供商。",
+  "TASK_NOT_FOUND": "未找到该任务。",
+  "TOOL_CALL_NOT_FOUND": "未找到对应的工具调用。",
+  "TOOL_NOT_FOUND": "未找到该工具。",
+  "TOOLSET_INTERNAL_KEY_ALREADY_EXISTS": "该工具集已存在。",
+  "TOOLSET_NOT_FOUND": "未找到该工具集。",
+  "UNEXPECTED_ERROR": "发生错误，请稍后重试。",
+  "WORKSPACE_NOT_FOUND": "未找到该工作区。"
+}
diff --git a/src-frontend/src/i18n/locales/zh_CN/sidebar.json b/src-frontend/src/i18n/locales/zh_CN/sidebar.json
index 1694d7b..e65640a 100644
--- a/src-frontend/src/i18n/locales/zh_CN/sidebar.json
+++ b/src-frontend/src/i18n/locales/zh_CN/sidebar.json
@@ -8,7 +8,6 @@
       "title": "Agents"
     },
     "list": {
-      "error_load": "无法加载 Agent 列表，请稍后重试。",
       "no_model": "无模型"
     },
     "menu": {
@@ -20,8 +19,6 @@
       "edit_title_with_name": "编辑：{{name}}"
     },
     "toast": {
-      "delete_error_description": "删除 Agent 时发生错误，请稍后重试。",
-      "delete_error_title": "删除失败",
       "delete_success_description": "已成功删除 Agent。",
       "delete_success_title": "删除成功"
     }
@@ -59,8 +56,7 @@
     "helper_model": {
       "flash_model": {
         "title": "快速模型"
-      },
-      "error_load": "无法加载助手模型设置，请稍后重试。"
+      }
     },
     "providers": {
       "actions": {
@@ -76,7 +72,6 @@
       "list": {
         "delete_provider_title": "删除",
         "edit_provider_title": "编辑服务提供商",
-        "error_load": "无法加载服务提供商列表，请稍后重试。",
         "model_count_with_count_one": "",
         "model_count_with_count_other": ""
       },
@@ -85,8 +80,6 @@
         "edit_title_with_name": "编辑：{{name}}"
       },
       "toast": {
-        "delete_error_description": "删除服务提供商时发生错误，请稍后重试。",
-        "delete_error_title": "删除失败",
         "delete_success_description": "已成功删除服务提供商。",
         "delete_success_title": "删除成功"
       }
@@ -114,16 +107,11 @@
       "create_tooltip": "创建任务",
       "title": "任务"
     },
-    "list": {
-      "error_load": "无法加载任务列表，请稍后重试。"
-    },
     "menu": {
       "delete": "删除",
       "rename": "编辑任务名称"
     },
     "toast": {
-      "delete_error_description": "删除任务时发生错误，请稍后重试。",
-      "delete_error_title": "删除失败",
       "delete_success_description": "已成功删除任务。",
       "delete_success_title": "删除成功",
       "rename_feature_description": "重命名功能待实现",
@@ -138,20 +126,21 @@
       "create_tooltip": "连接到 MCP 服务",
       "title": "工具集"
     },
-    "list": {
-      "error_load": "无法加载工具集列表，请稍后重试。"
-    },
     "menu": {
       "delete": "删除",
       "edit": "编辑工具集"
     },
+    "status": {
+      "connected": "已连接",
+      "connecting": "连接中",
+      "disconnected": "已断开",
+      "error": "错误"
+    },
     "tab": {
       "create_title": "连接到 MCP 服务",
       "edit_title_with_name": "编辑：{{name}}"
     },
     "toast": {
-      "delete_error_description": "删除工具集时发生错误，请稍后重试。",
-      "delete_error_title": "删除失败",
       "delete_success_description": "已成功删除工具集。",
       "delete_success_title": "删除成功"
     }
@@ -168,21 +157,16 @@
       "create_tooltip": "创建工作区",
       "title": "工作区"
     },
-    "list": {
-      "error_load": "无法加载工作区列表，请稍后重试。"
-    },
     "menu": {
       "delete": "删除",
       "edit": "编辑工作区",
-      "set_current": "设为当前工作区"
+      "select": "设为当前工作区"
     },
     "tab": {
       "create_title": "创建工作区",
       "edit_title_with_name": "编辑：{{name}}"
     },
     "toast": {
-      "delete_error_description": "删除工作区时发生错误，请稍后重试。",
-      "delete_error_title": "删除失败",
       "delete_success_description": "已成功删除工作区。",
       "delete_success_title": "删除成功"
     }
diff --git a/src-frontend/src/i18n/locales/zh_CN/tabs-agent.json b/src-frontend/src/i18n/locales/zh_CN/tabs-agent.json
index a83fadf..75b9549 100644
--- a/src-frontend/src/i18n/locales/zh_CN/tabs-agent.json
+++ b/src-frontend/src/i18n/locales/zh_CN/tabs-agent.json
@@ -20,8 +20,7 @@
       "saving": "保存中..."
     },
     "usable_tools": {
-      "label": "可用的工具",
-      "load_error": "无法加载工具列表，请稍后重试。"
+      "label": "可用的工具"
     }
   },
   "icon_dialog": {
@@ -43,21 +42,12 @@
       "select": "选择图标"
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "无法加载 Agent 信息，请稍后重试。"
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "创建 Agent 时发生错误，请稍后重试。",
-      "error_title": "创建失败",
       "success_description_with_name": "已成功创建 Agent {{name}}。",
       "success_title": "创建成功"
     },
     "update": {
-      "error_description": "更新 Agent 时发生错误，请稍后重试。",
-      "error_title": "更新失败",
       "success_description_with_name": "已成功更新 Agent {{name}}。",
       "success_title": "更新成功"
     }
diff --git a/src-frontend/src/i18n/locales/zh_CN/tabs-provider.json b/src-frontend/src/i18n/locales/zh_CN/tabs-provider.json
index 7b06a91..6308b51 100644
--- a/src-frontend/src/i18n/locales/zh_CN/tabs-provider.json
+++ b/src-frontend/src/i18n/locales/zh_CN/tabs-provider.json
@@ -59,25 +59,15 @@
       "cancel": "取消",
       "confirm": "确认",
       "empty": "未找到模型",
-      "error_load": "无法加载模型列表，请稍后重试。",
       "search_placeholder": "搜索模型..."
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "无法加载服务提供商信息，请稍后重试。"
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "创建服务提供商时发生错误，请稍后重试。",
-      "error_title": "创建失败",
       "success_description_with_name": "已成功创建服务提供商 {{name}}。",
       "success_title": "创建成功"
     },
     "update": {
-      "error_description": "更新服务提供商时发生错误，请稍后重试。",
-      "error_title": "更新失败",
       "success_description_with_name": "已成功更新服务提供商 {{name}}。",
       "success_title": "更新成功"
     }
diff --git a/src-frontend/src/i18n/locales/zh_CN/tabs-task.json b/src-frontend/src/i18n/locales/zh_CN/tabs-task.json
index bb32b60..89fb5e8 100644
--- a/src-frontend/src/i18n/locales/zh_CN/tabs-task.json
+++ b/src-frontend/src/i18n/locales/zh_CN/tabs-task.json
@@ -16,10 +16,10 @@
       "title": "任务出错，请重试"
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "无法加载任务，请稍后重试。"
-    }
+  "notification": {
+    "require_permission": "Dais 想要使用 {{toolName}}",
+    "require_response": "Dais 正在等待你的回复",
+    "task_done": "Dais 已完成任务"
   },
   "prompt": {
     "agent": {
@@ -31,7 +31,6 @@
       "workspace_load_failed": "工作区加载失败"
     },
     "context": {
-      "load_error": "加载文件失败。",
       "loading": "加载中...",
       "no_results": "未找到结果。",
       "search_placeholder": "添加文件、文件夹、文档...",
@@ -45,11 +44,6 @@
   "task_progress": {
     "completed": "任务已完成"
   },
-  "notification": {
-    "require_response": "Dais 正在等待你的回复",
-    "require_permission": "Dais 想要使用 {{toolName}}",
-    "task_done": "Dais 已完成任务"
-  },
   "toast": {
     "task_failed": {
       "title": "任务失败"
@@ -82,4 +76,4 @@
       "title": "已更新任务待办"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src-frontend/src/i18n/locales/zh_CN/tabs-toolset.json b/src-frontend/src/i18n/locales/zh_CN/tabs-toolset.json
index d2f5b7e..4ef79d0 100644
--- a/src-frontend/src/i18n/locales/zh_CN/tabs-toolset.json
+++ b/src-frontend/src/i18n/locales/zh_CN/tabs-toolset.json
@@ -36,9 +36,9 @@
     "type": {
       "label": "类型",
       "option": {
-        "built_in": "Built-in",
-        "mcp_local": "Local MCP",
-        "mcp_remote": "Remote MCP"
+        "built_in": "内置",
+        "mcp_local": "本地 MCP",
+        "mcp_remote": "远程 MCP"
       },
       "placeholder": "选择 Toolset 类型"
     },
@@ -47,21 +47,12 @@
       "placeholder": "https://api.example.com"
     }
   },
-  "panel": {
-    "error": {
-      "load_description": "无法加载 Toolset 信息，请稍后重试。"
-    }
-  },
   "toast": {
     "create": {
-      "error_description": "创建 Toolset 时发生错误，请稍后重试。",
-      "error_title": "创建失败",
       "success_description_with_name": "已成功创建 Toolset {{name}}。",
       "success_title": "创建成功"
     },
     "update": {
-      "error_description": "更新 Toolset 时发生错误，请稍后重试。",
-      "error_title": "更新失败",
       "success_description_with_name": "已成功更新 Toolset {{name}}。",
       "success_title": "更新成功"
     }
diff --git a/src-frontend/src/i18n/locales/zh_CN/tabs-workspace.json b/src-frontend/src/i18n/locales/zh_CN/tabs-workspace.json
index efdb332..5c3e2ff 100644
--- a/src-frontend/src/i18n/locales/zh_CN/tabs-workspace.json
+++ b/src-frontend/src/i18n/locales/zh_CN/tabs-workspace.json
@@ -18,30 +18,19 @@
       "confirm": "确定",
       "empty": "未找到匹配的 Agent",
       "label": "可用的 Agent",
-      "load_error": "无法加载 Agent 列表，请稍后重试。",
       "search_placeholder": "搜索 Agent...",
       "select": "选择"
     },
     "usable_tools": {
-      "label": "可用的工具",
-      "load_error": "无法加载工具列表，请稍后重试。"
-    }
-  },
-  "panel": {
-    "error": {
-      "load_description": "无法加载工作区信息，请稍后重试。"
+      "label": "可用的工具"
     }
   },
   "toast": {
     "create": {
-      "error_description": "创建工作区时发生错误，请稍后重试。",
-      "error_title": "创建失败",
       "success_description_with_name": "已成功创建工作区 \"{{name}}\"。",
       "success_title": "创建成功"
     },
     "update": {
-      "error_description": "更新工作区时发生错误，请稍后重试。",
-      "error_title": "更新失败",
       "success_description_with_name": "已成功更新工作区 \"{{name}}\"。",
       "success_title": "更新成功"
     }
diff --git a/src-frontend/src/i18n/resources.ts b/src-frontend/src/i18n/resources.ts
index 891529e..c44a6ac 100644
--- a/src-frontend/src/i18n/resources.ts
+++ b/src-frontend/src/i18n/resources.ts
@@ -9,6 +9,8 @@ import enTabsProvider from "./locales/en/tabs-provider.json";
 import enTabsTask from "./locales/en/tabs-task.json";
 import enTabsToolset from "./locales/en/tabs-toolset.json";
 import enTabsWorkspace from "./locales/en/tabs-workspace.json";
+import enError from "./locales/en/error.json";
+import enComponentsCustom from "./locales/en/components-custom.json";
 import zhCnDialog from "./locales/zh_CN/dialog.json";
 import zhCnForm from "./locales/zh_CN/form.json";
 import zhCnSideBar from "./locales/zh_CN/sidebar.json";
@@ -18,6 +20,8 @@ import zhCnTabsProvider from "./locales/zh_CN/tabs-provider.json";
 import zhCnTabsTask from "./locales/zh_CN/tabs-task.json";
 import zhCnTabsToolset from "./locales/zh_CN/tabs-toolset.json";
 import zhCnTabsWorkspace from "./locales/zh_CN/tabs-workspace.json";
+import zhCnError from "./locales/zh_CN/error.json";
+import zhCnComponentsCustom from "./locales/zh_CN/components-custom.json";
 
 export const DEFAULT_NAMESPACE = "common";
 export const SIDEBAR_NAMESPACE = "sidebar";
@@ -29,55 +33,11 @@ export const TABS_WORKSPACE_NAMESPACE = "tabs-workspace";
 export const TABS_TASK_NAMESPACE = "tabs-task";
 export const FORM_NAMESPACE = "form";
 export const DIALOG_NAMESPACE = "dialog";
+export const ERROR_NAMESPACE = "error";
+export const COMPONENTS_CUSTOM_NAMESPACE = "components-custom";
 export const FALLBACK_LANGUAGE: Language = "en";
 export const SUPPORTED_LANGUAGES = ["en", "zh_CN"] as const satisfies readonly Language[];
 
-
-const SIDEBAR_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enSideBar,
-  zh_CN: zhCnSideBar,
-};
-
-const TABS_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabs,
-  zh_CN: zhCnTabs,
-};
-
-const TABS_AGENT_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabsAgent,
-  zh_CN: zhCnTabsAgent,
-};
-
-const TABS_PROVIDER_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabsProvider,
-  zh_CN: zhCnTabsProvider,
-};
-
-const TABS_TOOLSET_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabsToolset,
-  zh_CN: zhCnTabsToolset,
-};
-
-const TABS_WORKSPACE_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabsWorkspace,
-  zh_CN: zhCnTabsWorkspace,
-};
-
-const TABS_TASK_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enTabsTask,
-  zh_CN: zhCnTabsTask,
-};
-
-const FORM_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enForm,
-  zh_CN: zhCnForm,
-};
-
-const DIALOG_TRANSLATIONS: Record<Language, ResourceLanguage> = {
-  en: enDialog,
-  zh_CN: zhCnDialog,
-};
-
 export const namespaces = [
   DEFAULT_NAMESPACE,
   SIDEBAR_NAMESPACE,
@@ -89,29 +49,34 @@ export const namespaces = [
   TABS_TASK_NAMESPACE,
   FORM_NAMESPACE,
   DIALOG_NAMESPACE,
+  ERROR_NAMESPACE,
 ];
 
 export const resources: Resource = {
   en: {
-    [SIDEBAR_NAMESPACE]: SIDEBAR_TRANSLATIONS.en,
-    [TABS_NAMESPACE]: TABS_TRANSLATIONS.en,
-    [TABS_AGENT_NAMESPACE]: TABS_AGENT_TRANSLATIONS.en,
-    [TABS_PROVIDER_NAMESPACE]: TABS_PROVIDER_TRANSLATIONS.en,
-    [TABS_TOOLSET_NAMESPACE]: TABS_TOOLSET_TRANSLATIONS.en,
-    [TABS_WORKSPACE_NAMESPACE]: TABS_WORKSPACE_TRANSLATIONS.en,
-    [TABS_TASK_NAMESPACE]: TABS_TASK_TRANSLATIONS.en,
-    [FORM_NAMESPACE]: FORM_TRANSLATIONS.en,
-    [DIALOG_NAMESPACE]: DIALOG_TRANSLATIONS.en,
+    [SIDEBAR_NAMESPACE]: enSideBar,
+    [TABS_NAMESPACE]: enTabs,
+    [TABS_AGENT_NAMESPACE]: enTabsAgent,
+    [TABS_PROVIDER_NAMESPACE]: enTabsProvider,
+    [TABS_TOOLSET_NAMESPACE]: enTabsToolset,
+    [TABS_WORKSPACE_NAMESPACE]: enTabsWorkspace,
+    [TABS_TASK_NAMESPACE]: enTabsTask,
+    [FORM_NAMESPACE]: enForm,
+    [DIALOG_NAMESPACE]: enDialog,
+    [COMPONENTS_CUSTOM_NAMESPACE]: enComponentsCustom,
+    [ERROR_NAMESPACE]: enError,
   },
   zh_CN: {
-    [SIDEBAR_NAMESPACE]: SIDEBAR_TRANSLATIONS.zh_CN,
-    [TABS_NAMESPACE]: TABS_TRANSLATIONS.zh_CN,
-    [TABS_AGENT_NAMESPACE]: TABS_AGENT_TRANSLATIONS.zh_CN,
-    [TABS_PROVIDER_NAMESPACE]: TABS_PROVIDER_TRANSLATIONS.zh_CN,
-    [TABS_TOOLSET_NAMESPACE]: TABS_TOOLSET_TRANSLATIONS.zh_CN,
-    [TABS_WORKSPACE_NAMESPACE]: TABS_WORKSPACE_TRANSLATIONS.zh_CN,
-    [TABS_TASK_NAMESPACE]: TABS_TASK_TRANSLATIONS.zh_CN,
-    [FORM_NAMESPACE]: FORM_TRANSLATIONS.zh_CN,
-    [DIALOG_NAMESPACE]: DIALOG_TRANSLATIONS.zh_CN,
+    [SIDEBAR_NAMESPACE]: zhCnSideBar,
+    [TABS_NAMESPACE]: zhCnTabs,
+    [TABS_AGENT_NAMESPACE]: zhCnTabsAgent,
+    [TABS_PROVIDER_NAMESPACE]: zhCnTabsProvider,
+    [TABS_TOOLSET_NAMESPACE]: zhCnTabsToolset,
+    [TABS_WORKSPACE_NAMESPACE]: zhCnTabsWorkspace,
+    [TABS_TASK_NAMESPACE]: zhCnTabsTask,
+    [FORM_NAMESPACE]: zhCnForm,
+    [DIALOG_NAMESPACE]: zhCnDialog,
+    [COMPONENTS_CUSTOM_NAMESPACE]: zhCnComponentsCustom,
+    [ERROR_NAMESPACE]: zhCnError,
   },
 };
diff --git a/src-frontend/src/query-client.ts b/src-frontend/src/query-client.ts
index 8c1ad3a..623fd68 100644
--- a/src-frontend/src/query-client.ts
+++ b/src-frontend/src/query-client.ts
@@ -1,4 +1,7 @@
+import { toast } from "sonner";
 import { QueryClient } from "@tanstack/react-query";
+import { FetchError } from "@/api/orval-mutator/custom-fetch";
+import { getErrorMessage } from "@/i18n/error-message";
 
 export default new QueryClient({
   defaultOptions: {
@@ -6,5 +9,15 @@ export default new QueryClient({
       staleTime: 5 * 60 * 1000,
       retry: 1,
     },
+    mutations: {
+      onError: (error) => {
+        console.error(error);
+        if (error instanceof FetchError) {
+          toast.error(getErrorMessage(error.errorCode), { duration: Number.POSITIVE_INFINITY });
+        } else {
+          toast.error(getErrorMessage("UNEXPECTED_ERROR"), { duration: Number.POSITIVE_INFINITY });
+        }
+      },
+    },
   },
 });
diff --git a/src-server/pyproject.toml b/src-server/pyproject.toml
index 516be15..fe8aae5 100644
--- a/src-server/pyproject.toml
+++ b/src-server/pyproject.toml
@@ -3,7 +3,7 @@ name = "dais-server"
 version = "0.1.0"
 requires-python = ">=3.14"
 dependencies = [
-    "dais-sdk==0.8.4",
+    "dais-sdk==0.8.7",
     "dais-shell==0.1.2",
 
     "alembic==1.18.4",
diff --git a/src-server/src/agent/tool/toolset_manager/mcp_toolset_manager.py b/src-server/src/agent/tool/toolset_manager/mcp_toolset_manager.py
index 0a90e1e..4fafac6 100644
--- a/src-server/src/agent/tool/toolset_manager/mcp_toolset_manager.py
+++ b/src-server/src/agent/tool/toolset_manager/mcp_toolset_manager.py
@@ -1,26 +1,35 @@
 import asyncio
-import threading
+from enum import Enum
 from typing import Sequence, override
 from loguru import logger
-from dais_sdk.tool import Toolset
+from dais_sdk.tool import Toolset, McpToolset as SdkMcpToolset
 from .types import ToolsetManager
 from ..toolset_wrapper import McpToolset
-from ....db import db_context
+from ....db import db_context, toolset_models
 
-_logger = logger.bind(name="McpToolsetManager")
+
+class McpToolsetManagerNotInitializedError(Exception):
+    def __init__(self):
+        super().__init__("MCP toolset manager not initialized")
+
+class McpToolsetManagerState(Enum):
+    CONNECTING = "connecting"
+    CONNECTED = "connected"
+    DISCONNECTING = "disconnecting"
+    DISCONNECTED = "disconnected"
 
 class McpToolsetManager(ToolsetManager):
+    _logger = logger.bind(name="McpToolsetManager")
+
     def __init__(self):
-        self._lock = threading.Lock()
-        self._connecting = False
-        self._connected = False
+        self._state = McpToolsetManagerState.DISCONNECTED
         self._toolset_map: dict[int, McpToolset] | None = None
 
     @property
     @override
     def toolsets(self) -> Sequence[Toolset]:
         if self._toolset_map is None:
-            raise ValueError("Toolset manager not initialized")
+            raise McpToolsetManagerNotInitializedError()
         return list(self._toolset_map.values())
 
     async def initialize(self):
@@ -28,69 +37,57 @@ async def initialize(self):
 
         async with db_context() as db_session:
             toolset_ents = await ToolsetService(db_session).get_all_mcp_toolsets()
-        with self._lock:
-            self._toolset_map = {toolset.id: McpToolset(toolset) for toolset in toolset_ents}
+        self._toolset_map = {toolset.id: McpToolset(toolset) for toolset in toolset_ents}
 
-    async def refresh_toolset_metadata(self):
-        from ....services import ToolsetService
+    def append(self, inner_toolset: SdkMcpToolset, toolset_ent: toolset_models.Toolset):
+        """
+        Append a newly connected MCP toolset to the manager.
+        """
+        if self._toolset_map is None:
+            raise McpToolsetManagerNotInitializedError()
 
+        new_toolset = McpToolset(toolset_ent, inner_toolset)
+        self._toolset_map[toolset_ent.id] = new_toolset
+
+    async def remove(self, toolset_id: int):
         if self._toolset_map is None:
-            raise ValueError("Toolset manager not initialized")
+            raise McpToolsetManagerNotInitializedError()
 
-        async with db_context() as db_session:
-            toolset_ents = await ToolsetService(db_session).get_all_mcp_toolsets()
+        toolset = self._toolset_map.pop(toolset_id, None)
+        if toolset is None:
+            self._logger.warning(f"Toolset {toolset_id} not found, skip disconnecting")
+            return
 
-        toolsets = []
-        toolset_connect_tasks = []
-        with self._lock:
-            for toolset in toolset_ents:
-                existing_toolset = self._toolset_map.get(toolset.id)
-                if existing_toolset is None:
-                    new_toolset = McpToolset(toolset)
-                    self._toolset_map[toolset.id] = new_toolset
-                    toolsets.append(new_toolset)
-                    toolset_connect_tasks.append(new_toolset.connect())
-                    continue
-                toolsets.append(existing_toolset)
-                existing_toolset.refresh_metadata(toolset.tools)
-
-        results = await asyncio.gather(*toolset_connect_tasks, return_exceptions=True)
-        for toolset, result in zip(toolsets, results):
-            if not isinstance(result, BaseException): continue
-            _logger.exception(f"Failed to connect to MCP server {toolset.name}")
-            toolset.error = result
+        try:
+            await toolset.disconnect()
+        except Exception as e:
+            self._logger.opt(exception=e).warning(f"Failed to disconnect from MCP server {toolset.name}")
 
     async def connect_mcp_servers(self):
         if self._toolset_map is None:
             raise ValueError("Toolset manager not initialized")
 
-        with self._lock:
-            if self._connected or self._connecting: return
-            self._connecting = True
+        if self._state != McpToolsetManagerState.DISCONNECTED: return
+        self._state = McpToolsetManagerState.CONNECTING
 
         toolsets = list(self._toolset_map.values())
         tasks = [toolset.connect() for toolset in toolsets]
         results = await asyncio.gather(*tasks, return_exceptions=True)
         for toolset, result in zip(toolsets, results):
             if not isinstance(result, BaseException): continue
-            _logger.exception(f"Failed to connect to MCP server {toolset.name}")
-            toolset.error = result
-
-        with self._lock:
-            self._connecting = False
-            self._connected = True
+            self._logger.exception(f"Failed to connect to MCP server {toolset.name}")
+        self._state = McpToolsetManagerState.CONNECTED
 
     async def disconnect_mcp_servers(self):
         if self._toolset_map is None:
             raise ValueError("Toolset manager not initialized")
 
-        with self._lock:
-            if not self._connected or self._connecting: return
-            self._connecting = False
-            self._connected = False
+        if self._state != McpToolsetManagerState.CONNECTED: return
+        self._state = McpToolsetManagerState.DISCONNECTING
 
         tasks = [toolset.disconnect() for toolset in self._toolset_map.values()]
         await asyncio.gather(*tasks, return_exceptions=True)
+        self._state = McpToolsetManagerState.DISCONNECTED
 
 __instance: McpToolsetManager | None = None
 
diff --git a/src-server/src/agent/tool/toolset_wrapper/mcp_toolset.py b/src-server/src/agent/tool/toolset_wrapper/mcp_toolset.py
index 02acf61..eb56611 100644
--- a/src-server/src/agent/tool/toolset_wrapper/mcp_toolset.py
+++ b/src-server/src/agent/tool/toolset_wrapper/mcp_toolset.py
@@ -1,38 +1,97 @@
+import asyncio
+import subprocess
+import anyio
+import httpx
+import mcp
 from dataclasses import replace
 from enum import Enum
 from typing import cast, override
 from dais_sdk.mcp_client import LocalServerParams, RemoteServerParams
 from dais_sdk.tool import Toolset, McpToolset as SdkMcpToolset, LocalMcpToolset, RemoteMcpToolset
 from dais_sdk.types import ToolDef
+from loguru import logger
 from ..types import ToolMetadata
 from ....db import db_context
 from ....db.models import toolset as toolset_models
 
 
+class McpToolsetNotConnectedError(Exception):
+    def __init__(self, toolset_name: str):
+        super().__init__(f"MCP toolset '{toolset_name}' not connected")
+
 class McpToolsetStatus(str, Enum):
     CONNECTING = "connecting"
     CONNECTED = "connected"
     DISCONNECTED = "disconnected"
     ERROR = "error"
 
-class McpToolset(Toolset):
-    def __init__(self, toolset_ent: toolset_models.Toolset):
-        match toolset_ent.type:
-            case toolset_models.ToolsetType.MCP_LOCAL:
-                assert isinstance(toolset_ent.params, LocalServerParams)
-                inner_toolset = LocalMcpToolset(toolset_ent.name, toolset_ent.params)
-            case toolset_models.ToolsetType.MCP_REMOTE:
-                assert isinstance(toolset_ent.params, RemoteServerParams)
-                inner_toolset = RemoteMcpToolset(toolset_ent.name, toolset_ent.params)
+class McpConnectErrorCode(str, Enum):
+    CONNECTION_TIMEOUT = "MCP_CONNECTION_TIMEOUT"
+
+    # remote
+    CONNECTION_FAILED = "MCP_CONNECTION_FAILED"
+    AUTH_FAILED = "MCP_AUTH_FAILED"
+    PROTOCOL_ERROR = "MCP_PROTOCOL_ERROR"
+
+    # local
+    COMMAND_NOT_FOUND = "MCP_COMMAND_NOT_FOUND"
+    PERMISSION_DENIED = "MCP_PERMISSION_DENIED"
+    PROCESS_START_FAILED = "MCP_PROCESS_START_FAILED"
+    PROCESS_CRASHED = "MCP_PROCESS_CRASHED"
+
+    @classmethod
+    def from_exception(cls, e: Exception) -> McpConnectErrorCode:
+        match e:
+            case asyncio.TimeoutError():
+                return cls.CONNECTION_TIMEOUT
+            case httpx.HTTPStatusError() as e if e.response.status_code == 401:
+                return cls.AUTH_FAILED
+            case mcp.McpError():
+                return cls.PROTOCOL_ERROR
+            case FileNotFoundError():
+                return cls.COMMAND_NOT_FOUND
+            case PermissionError():
+                return cls.PERMISSION_DENIED
+            case subprocess.SubprocessError():
+                return cls.PROCESS_START_FAILED
+            case BrokenPipeError() | anyio.EndOfStream():
+                return cls.PROCESS_CRASHED
             case _:
-                raise ValueError(f"Unsupported toolset type: {toolset_ent.type}")
+                return cls.CONNECTION_FAILED
+
+async def mcp_connect_wrapper(toolset: SdkMcpToolset) -> McpConnectErrorCode | None:
+    error_code = None
+    try:
+        await asyncio.wait_for(toolset.connect(), timeout=15)
+    except* Exception as eg:
+        e = eg.exceptions[0]
+        logger.exception(f"MCP server connect error: {type(e).__name__}", exc_info=e)
+        error_code = McpConnectErrorCode.from_exception(e)
+    return error_code
+
+class McpToolset(Toolset):
+    def __init__(self, toolset_ent: toolset_models.Toolset, inner_toolset: SdkMcpToolset | None = None):
+        if not inner_toolset:
+            match toolset_ent.type:
+                case toolset_models.ToolsetType.MCP_LOCAL:
+                    assert isinstance(toolset_ent.params, LocalServerParams)
+                    inner_toolset = LocalMcpToolset(toolset_ent.name, toolset_ent.params)
+                case toolset_models.ToolsetType.MCP_REMOTE:
+                    assert isinstance(toolset_ent.params, RemoteServerParams)
+                    inner_toolset = RemoteMcpToolset(toolset_ent.name, toolset_ent.params)
+                case _:
+                    raise ValueError(f"Unsupported toolset type: {toolset_ent.type}")
+
         self._inner_toolset = inner_toolset
         self._toolset_id = toolset_ent.id
-        self._status = McpToolsetStatus.CONNECTING
-        self._error: BaseException | None = None
+        self._status = McpToolsetStatus.DISCONNECTED
+        self._error: McpConnectErrorCode | None = None
         self._tool_map = {self._inner_toolset.format_tool_name(tool.internal_key): tool
                           for tool in toolset_ent.tools}
 
+        if self._inner_toolset.connected:
+            self._status = McpToolsetStatus.CONNECTED
+
     @property
     @override
     def name(self) -> str:
@@ -43,14 +102,9 @@ def status(self) -> McpToolsetStatus:
         return self._status
 
     @property
-    def error(self) -> BaseException | None:
+    def error(self) -> McpConnectErrorCode | None:
         return self._error
 
-    @error.setter
-    def error(self, error: BaseException):
-        self._status = McpToolsetStatus.ERROR
-        self._error = error
-
     async def _merge_tools(self, latest_tool_list: list[ToolDef]) -> list[toolset_models.Tool]:
         from ....services import ToolsetService
 
@@ -79,21 +133,28 @@ def get_tools(self) -> list[ToolDef]:
                                     needs_user_interaction=False)))
         return result
 
-    def refresh_metadata(self, tools: list[toolset_models.Tool]):
-        self._tool_map = {self._inner_toolset.format_tool_name(tool.internal_key): tool
-                          for tool in tools}
+    async def sync(self):
+        if self._status != McpToolsetStatus.CONNECTED:
+            raise McpToolsetNotConnectedError(self.name)
 
-    async def connect(self):
         inner_toolset = cast(SdkMcpToolset, self._inner_toolset)
-        await inner_toolset.connect()
-
         latest_tool_list = inner_toolset.get_tools(namespaced_tool_name=False)
         merged_tool_list = await self._merge_tools(latest_tool_list)
+        self._tool_map = {self._inner_toolset.format_tool_name(tool.internal_key): tool
+                          for tool in merged_tool_list}
 
-        self.refresh_metadata(merged_tool_list)
-        self._status = McpToolsetStatus.CONNECTED
+    async def connect(self):
+        inner_toolset = cast(SdkMcpToolset, self._inner_toolset)
+        self._status = McpToolsetStatus.CONNECTING
+        error_code = await mcp_connect_wrapper(inner_toolset)
+        if error_code is None:
+            self._status = McpToolsetStatus.CONNECTED
+            await self.sync()
+        else:
+            self._status = McpToolsetStatus.ERROR
+            self._error = error_code
 
     async def disconnect(self):
-        inner_toolset = cast(McpToolset, self._inner_toolset)
+        inner_toolset = cast(SdkMcpToolset, self._inner_toolset)
         await inner_toolset.disconnect()
         self._status = McpToolsetStatus.DISCONNECTED
diff --git a/src-server/src/api/__init__.py b/src-server/src/api/__init__.py
index 1d8244c..27180d9 100644
--- a/src-server/src/api/__init__.py
+++ b/src-server/src/api/__init__.py
@@ -19,12 +19,14 @@
 )
 from .exception_handlers import (
     ErrorResponseSchema,
+    handle_api_error,
     handle_service_error,
     handle_validation_error,
     handle_http_exception,
     handle_unexpected_exception,
 )
 from .lifespan import lifespan
+from .exceptions import ApiError
 from ..services.exceptions import ServiceError
 
 
@@ -51,6 +53,7 @@
 )
 
 app.add_exception_handler(ServiceError, handle_service_error)
+app.add_exception_handler(ApiError, handle_api_error)
 app.add_exception_handler(RequestValidationError, handle_validation_error)
 app.add_exception_handler(HTTPException, handle_http_exception)
 app.add_exception_handler(Exception, handle_unexpected_exception)
diff --git a/src-server/src/api/exception_handlers.py b/src-server/src/api/exception_handlers.py
index ba0c685..b317995 100644
--- a/src-server/src/api/exception_handlers.py
+++ b/src-server/src/api/exception_handlers.py
@@ -5,13 +5,9 @@
 from fastapi.exceptions import HTTPException, RequestValidationError
 from pydantic import BaseModel
 from loguru import logger
-from ..services.exceptions import ServiceError, ServiceErrorCode
+from .exceptions import ApiError
+from ..services.exceptions import ServiceError, ServiceStatusCode
 
-SERVICE_ERROR_STATUS_CODES: dict[ServiceErrorCode, int] = {
-    ServiceErrorCode.NOT_FOUND: status.HTTP_404_NOT_FOUND,
-    ServiceErrorCode.CONFLICT: status.HTTP_409_CONFLICT,
-    ServiceErrorCode.BAD_REQUEST: status.HTTP_400_BAD_REQUEST,
-}
 
 class ErrorResponseContent(TypedDict):
     error_code: str
@@ -46,15 +42,21 @@ async def wrapper(request: Request, exc: Exception) -> JSONResponse:
 @_specific_exception_handler(ServiceError)
 async def handle_service_error(_: Request, exc: ServiceError) -> JSONResponse:
     """Handle service layer errors and convert them to HTTP responses."""
-    status_code = SERVICE_ERROR_STATUS_CODES.get(exc.code, status.HTTP_500_INTERNAL_SERVER_ERROR)
+    status_code = ServiceStatusCode.status_code_map(exc.status_code)
     return JSONResponse(status_code=status_code,
-                        content=ErrorResponseContent(error_code=exc.code.value,
+                        content=ErrorResponseContent(error_code=exc.error_code.value,
                                                      message=exc.message))
 
+@_specific_exception_handler(ApiError)
+async def handle_api_error(_: Request, exc: ApiError) -> JSONResponse:
+    return JSONResponse(status_code=exc.status_code,
+                        content=ErrorResponseContent(error_code=exc.error_code.value,
+                                                     message=str(exc)))
+
 # pydantic schema validation error
 @_specific_exception_handler(RequestValidationError)
 async def handle_validation_error(_: Request, exc: RequestValidationError) -> JSONResponse:
-    _logger.error(exc)
+    _logger.warning(exc)
     return JSONResponse(status_code=status.HTTP_400_BAD_REQUEST,
                         content=ErrorResponseContent(error_code="VALIDATION_ERROR",
                                                      message="Invalid request parameters"))
@@ -66,7 +68,7 @@ async def handle_http_exception(_: Request, exc: HTTPException) -> JSONResponse:
                                                      message=exc.detail))
 
 async def handle_unexpected_exception(_: Request, exc: Exception) -> JSONResponse:
-    _logger.error(f"Unexpected server error: ", exc_info=exc)
+    _logger.error("Unexpected server error: ", exc_info=exc)
     return JSONResponse(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
                         content=ErrorResponseContent(error_code="UNKNOWN",
                                                      message="Unexpected server error"))
diff --git a/src-server/src/api/exceptions.py b/src-server/src/api/exceptions.py
new file mode 100644
index 0000000..eeff893
--- /dev/null
+++ b/src-server/src/api/exceptions.py
@@ -0,0 +1,18 @@
+from enum import Enum
+from ..agent.tool.toolset_wrapper.mcp_toolset import McpConnectErrorCode
+
+
+class ApiErrorCode(str, Enum):
+    TOOL_CALL_NOT_FOUND = "TOOL_CALL_NOT_FOUND"
+    CANNOT_CREATE_BUILTIN_TOOLSET = "CANNOT_CREATE_BUILTIN_TOOLSET"
+
+    PATH_NOT_FOUND = "PATH_NOT_FOUND"
+    PATH_NOT_DIRECTORY = "PATH_NOT_DIRECTORY"
+    PATH_ACCESS_DENIED = "PATH_ACCESS_DENIED"
+
+class ApiError(Exception):
+    """Base class for all API errors."""
+    def __init__(self, status_code: int, error_code: ApiErrorCode | McpConnectErrorCode, *args) -> None:
+        super().__init__(*args)
+        self.status_code = status_code
+        self.error_code = error_code
diff --git a/src-server/src/api/lifespan.py b/src-server/src/api/lifespan.py
index 94738c3..90c21ed 100644
--- a/src-server/src/api/lifespan.py
+++ b/src-server/src/api/lifespan.py
@@ -1,3 +1,4 @@
+import asyncio
 from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from typing import TypedDict
@@ -23,11 +24,16 @@ async def lifespan(_: FastAPI) -> AsyncIterator[AppState]:
 
     mcp_toolset_manager = use_mcp_toolset_manager()
     await mcp_toolset_manager.initialize()
-    await mcp_toolset_manager.connect_mcp_servers()
+    mcp_toolset_connect_task = asyncio.create_task(mcp_toolset_manager.connect_mcp_servers())
 
     try:
         yield AppState(sse_dispatcher=sse_dispatcher,
                        mcp_toolset_manager=mcp_toolset_manager)
+
+        mcp_toolset_connect_task.cancel()
+        await mcp_toolset_connect_task
+    except asyncio.CancelledError:
+        pass
     finally:
         await mcp_toolset_manager.disconnect_mcp_servers()
         await app_setting_manager.persist()
diff --git a/src-server/src/api/routes/task/context_file.py b/src-server/src/api/routes/task/context_file.py
index 58f32c8..8c2aa4c 100644
--- a/src-server/src/api/routes/task/context_file.py
+++ b/src-server/src/api/routes/task/context_file.py
@@ -1,10 +1,10 @@
 from functools import lru_cache
 from pathlib import Path
 from typing import Literal
-from fastapi import APIRouter, Query
+from fastapi import APIRouter, Query, status
 from pydantic import BaseModel
-from rapidfuzz import process, fuzz
-from ....services.exceptions import BadRequestError, NotFoundError
+from rapidfuzz import fuzz
+from ...exceptions import ApiError, ApiErrorCode
 from ....db import DbSessionDep
 from ....services.workspace import WorkspaceService
 from ....schemas import task as task_schemas
@@ -12,40 +12,31 @@
 
 context_file_router = APIRouter(tags=["context_file"])
 
-class ContextPathError(BadRequestError):
-    """Raised when the provided context path is invalid."""
-
+class ContextFileInternalError(ValueError):
     def __init__(self, message: str) -> None:
         super().__init__(message)
 
-class ContextDirectoryNotFoundError(NotFoundError):
-    """Raised when the requested context directory does not exist."""
-
-    def __init__(self, path: str) -> None:
-        super().__init__("Context directory", path)
-
-
 def _list_directory(workspace_root: Path, path: str) -> list[task_schemas.ContextFileItem]:
     normalized_path = path.strip() or "."
     requested_path = Path(normalized_path)
     if requested_path.is_absolute():
-        raise ContextPathError("Path must be a relative path")
+        raise ContextFileInternalError("Path must be a relative path")
 
     target_directory = (workspace_root / requested_path).resolve()
     try:
         target_directory.relative_to(workspace_root)
     except ValueError as error:
-        raise ContextPathError("Path is outside workspace directory") from error
+        raise ContextFileInternalError("Path is outside workspace directory") from error
 
     if not target_directory.exists():
-        raise ContextDirectoryNotFoundError(normalized_path)
+        raise ApiError(status.HTTP_404_NOT_FOUND, ApiErrorCode.PATH_NOT_FOUND, f"Path not found: {normalized_path}")
     if not target_directory.is_dir():
-        raise ContextPathError("Path is not a directory")
+        raise ApiError(status.HTTP_400_BAD_REQUEST, ApiErrorCode.PATH_NOT_DIRECTORY, "Path is not a directory")
 
     try:
         entries = list(target_directory.iterdir())
-    except PermissionError as error:
-        raise ContextPathError("Permission denied for target directory") from error
+    except PermissionError:
+        raise ApiError(status.HTTP_403_FORBIDDEN, ApiErrorCode.PATH_ACCESS_DENIED, "Permission denied for target directory")
 
     items: list[task_schemas.ContextFileItem] = []
     for entry in entries:
diff --git a/src-server/src/api/routes/task/stream/__init__.py b/src-server/src/api/routes/task/stream/__init__.py
index 48b9338..b548f12 100644
--- a/src-server/src/api/routes/task/stream/__init__.py
+++ b/src-server/src/api/routes/task/stream/__init__.py
@@ -1,9 +1,10 @@
 from typing import Literal
-from fastapi import APIRouter, Request, HTTPException, status
+from fastapi import APIRouter, Request, status
 from fastapi.sse import EventSourceResponse
 from dais_sdk.types import UserMessage
 from pydantic import BaseModel
-from .utils import agent_stream
+from .stream_connector import agent_stream
+from ....exceptions import ApiError, ApiErrorCode
 from .....agent.context import AgentContext
 from .....agent.task import AgentTask, ToolCallNotFoundError
 from .....agent.types import AgentEvent
@@ -72,7 +73,9 @@ async def tool_answer(task_id: int, body: ToolAnswerBody, request: Request):
     try:
         replace_event = task.set_tool_call_result(body.call_id, body.answer)
     except ToolCallNotFoundError as e:
-        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=e.call_id)
+        raise ApiError(status.HTTP_404_NOT_FOUND,
+                       ApiErrorCode.TOOL_CALL_NOT_FOUND,
+                       e.call_id)
 
     yield replace_event
     async for event in agent_stream(task, request):
@@ -92,6 +95,7 @@ async def tool_reviews(task_id: int, body: ToolReviewBody, request: Request):
         async for event in task.approve_tool_call(body.call_id, body.status == "approved"):
             yield event
     except ToolCallNotFoundError as e:
-        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=e.call_id)
+        raise ApiError(status.HTTP_404_NOT_FOUND, ApiErrorCode.TOOL_CALL_NOT_FOUND, e.call_id)
+
     async for event in agent_stream(task, request):
         yield event
diff --git a/src-server/src/api/routes/task/stream/utils.py b/src-server/src/api/routes/task/stream/stream_connector.py
similarity index 96%
rename from src-server/src/api/routes/task/stream/utils.py
rename to src-server/src/api/routes/task/stream/stream_connector.py
index 93740fe..8ee3812 100644
--- a/src-server/src/api/routes/task/stream/utils.py
+++ b/src-server/src/api/routes/task/stream/stream_connector.py
@@ -9,7 +9,7 @@
 )
 
 
-_logger = logger.bind(name="TaskStreamRoute")
+_logger = logger.bind(name="AgentStream")
 
 async def agent_stream(task: AgentTask, request: Request) -> AgentGenerator:
     pending_terminal_event = None
diff --git a/src-server/src/api/routes/toolset.py b/src-server/src/api/routes/toolset.py
index dfcc52d..54889ef 100644
--- a/src-server/src/api/routes/toolset.py
+++ b/src-server/src/api/routes/toolset.py
@@ -1,11 +1,16 @@
 from typing import Annotated, cast
+from dais_sdk.mcp_client import LocalServerParams, RemoteServerParams
+from dais_sdk.tool import LocalMcpToolset, RemoteMcpToolset
 from fastapi import APIRouter, Depends, Request, status
+from ..exceptions import ApiError, ApiErrorCode
 from ...agent.tool import McpToolset
+from ...agent.tool.toolset_wrapper.mcp_toolset import mcp_connect_wrapper
 from ...agent.tool.toolset_manager.mcp_toolset_manager import McpToolsetManager
-from ...db import DbSessionDep
+from ...db import DbSessionDep, toolset_models
 from ...services.toolset import ToolsetService
 from ...schemas import toolset as toolset_schemas
 
+
 toolset_router = APIRouter(tags=["toolset"])
 
 def get_mcp_toolset_manager(request: Request) -> McpToolsetManager:
@@ -25,23 +30,19 @@ async def get_toolsets_brief(
     result = []
     for toolset in built_in_toolsets:
         result.append(
-            toolset_schemas.ToolsetBrief(
-                id=toolset.id,
-                name=toolset.name,
-                type=toolset.type,
-                status="connected",
-            )
-        )
+            toolset_schemas.ToolsetBrief(id=toolset.id,
+                                         name=toolset.name,
+                                         type=toolset.type,
+                                         status="connected",
+                                         error_code=None))
     for toolset in cast(list[McpToolset], mcp_toolset_manager.toolsets):
         ent = mcp_toolset_map[toolset.name]
         result.append(
-            toolset_schemas.ToolsetBrief(
-                id=ent.id,
-                name=ent.name,
-                type=ent.type,
-                status=toolset.status,
-            )
-        )
+            toolset_schemas.ToolsetBrief(id=ent.id,
+                                         name=ent.name,
+                                         type=ent.type,
+                                         status=toolset.status,
+                                         error_code=toolset.error))
     return result
 
 @toolset_router.get("/", response_model=list[toolset_schemas.ToolsetRead])
@@ -56,15 +57,28 @@ async def get_toolset(toolset_id: int, db_session: DbSessionDep):
     return await ToolsetService(db_session).get_toolset_by_id(toolset_id)
 
 @toolset_router.post("/", status_code=status.HTTP_201_CREATED, response_model=toolset_schemas.ToolsetRead)
-async def create_mcp_toolset(
+async def create_toolset(
     body: toolset_schemas.ToolsetCreate,
     db_session: DbSessionDep,
     mcp_toolset_manager: McpToolsetManagerDep,
 ):
-    new_toolset = await ToolsetService(db_session).create_toolset(body)
-    if (body.type == toolset_schemas.ToolsetType.MCP_LOCAL or
-        body.type == toolset_schemas.ToolsetType.MCP_REMOTE):
-        await mcp_toolset_manager.refresh_toolset_metadata()
+    match body.type:
+        case toolset_models.ToolsetType.BUILT_IN:
+            raise ApiError(status.HTTP_400_BAD_REQUEST, ApiErrorCode.CANNOT_CREATE_BUILTIN_TOOLSET, "Cannot create built-in toolset")
+        case toolset_models.ToolsetType.MCP_LOCAL:
+            assert isinstance(body.params, LocalServerParams)
+            toolset = LocalMcpToolset(body.name, body.params)
+        case toolset_models.ToolsetType.MCP_REMOTE:
+            assert isinstance(body.params, RemoteServerParams)
+            toolset = RemoteMcpToolset(body.name, body.params)
+
+    mcp_connect_error = await mcp_connect_wrapper(toolset)
+    if mcp_connect_error is not None:
+        raise ApiError(status.HTTP_503_SERVICE_UNAVAILABLE, mcp_connect_error, "Failed to connect to MCP server")
+
+    tools = toolset.get_tools(namespaced_tool_name=False)
+    new_toolset = await ToolsetService(db_session).create_toolset(body, tools)
+    mcp_toolset_manager.append(toolset, new_toolset)
     return new_toolset
 
 @toolset_router.put("/{toolset_id}", response_model=toolset_schemas.ToolsetRead)
@@ -74,10 +88,24 @@ async def update_toolset(
     db_session: DbSessionDep,
     mcp_toolset_manager: McpToolsetManagerDep,
 ):
+    await mcp_toolset_manager.remove(toolset_id)
     updated_toolset = await ToolsetService(db_session).update_toolset(toolset_id, body)
-    if (updated_toolset.type == toolset_schemas.ToolsetType.MCP_LOCAL or
-        updated_toolset.type == toolset_schemas.ToolsetType.MCP_REMOTE):
-        await mcp_toolset_manager.refresh_toolset_metadata()
+
+    match body.type:
+        case toolset_models.ToolsetType.MCP_LOCAL:
+            assert isinstance(body.params, LocalServerParams)
+            toolset = LocalMcpToolset(updated_toolset.name, body.params)
+        case toolset_models.ToolsetType.MCP_REMOTE:
+            assert isinstance(body.params, RemoteServerParams)
+            toolset = RemoteMcpToolset(updated_toolset.name, body.params)
+        case _:
+            raise ApiError(status.HTTP_400_BAD_REQUEST, ApiErrorCode.CANNOT_CREATE_BUILTIN_TOOLSET, "Cannot create built-in toolset")
+
+    mcp_connect_error = await mcp_connect_wrapper(toolset)
+    if mcp_connect_error is not None:
+        raise ApiError(status.HTTP_503_SERVICE_UNAVAILABLE, mcp_connect_error, "Failed to connect to MCP server")
+
+    mcp_toolset_manager.append(toolset, updated_toolset)
     return updated_toolset
 
 @toolset_router.delete("/{toolset_id}", status_code=status.HTTP_204_NO_CONTENT)
@@ -87,4 +115,4 @@ async def delete_toolset(
     mcp_toolset_manager: McpToolsetManagerDep,
 ):
     await ToolsetService(db_session).delete_toolset(toolset_id)
-    await mcp_toolset_manager.refresh_toolset_metadata()
+    await mcp_toolset_manager.remove(toolset_id)
diff --git a/src-server/src/db/models/toolset.py b/src-server/src/db/models/toolset.py
index 9335f38..7ff6d8f 100644
--- a/src-server/src/db/models/toolset.py
+++ b/src-server/src/db/models/toolset.py
@@ -44,10 +44,6 @@ def toolset_id(self) -> int: return self._toolset_id
     _agents: Mapped[list[Agent]] = relationship(secondary=agent_tool_association_table,
                                                 back_populates="usable_tools")
 
-    @staticmethod
-    def from_mcp_tool(tool: McpTool) -> Tool:
-        return Tool(name=tool.name, description=tool.description, internal_key=tool.name)
-
 class Toolset(Base):
     __tablename__ = "toolsets"
     id: Mapped[int] = mapped_column(primary_key=True)
diff --git a/src-server/src/logger.py b/src-server/src/logger.py
new file mode 100644
index 0000000..4fd95b4
--- /dev/null
+++ b/src-server/src/logger.py
@@ -0,0 +1,45 @@
+import sys
+import logging
+from loguru import logger
+from .common import DATA_DIR
+
+class InterceptHandler(logging.Handler):
+    def emit(self, record: logging.LogRecord):
+        try:
+            level = logger.level(record.levelname).name
+        except ValueError:
+            level = record.levelno
+
+        # Find caller from where originated the logged message
+        frame, depth = sys._getframe(6), 6
+        while frame and (depth == 0 or frame.f_code.co_filename == logging.__file__):
+            frame = frame.f_back
+            depth += 1
+
+        logger.opt(depth=depth, exception=record.exc_info).log(
+            level, record.getMessage()
+        )
+
+def get_log_level(is_dev: bool):
+    return logging.getLevelNamesMapping().get(
+        "DEBUG" if is_dev else "INFO",
+        logging.DEBUG
+    )
+
+def setup_logging(log_level: int):
+    # intercept everything at the root logger
+    logging.root.handlers = [InterceptHandler()]
+    logging.root.setLevel(log_level)
+
+    # remove every other logger's handlers
+    # and propagate to root logger
+    for name in logging.root.manager.loggerDict.keys():
+        logging.getLogger(name).handlers = []
+        logging.getLogger(name).propagate = True
+
+    for noisy_logger in ("aiosqlite", "httpcore", "httpx", "mcp"):
+        logging.getLogger(noisy_logger).setLevel(logging.WARNING)
+
+    logger.remove()
+    logger.add(sys.stderr)
+    logger.add(DATA_DIR / "server.log", rotation="256 MB", mode="w")
diff --git a/src-server/src/main.py b/src-server/src/main.py
index 8c5850c..ed1cbf5 100644
--- a/src-server/src/main.py
+++ b/src-server/src/main.py
@@ -1,4 +1,5 @@
 import argparse
+import logging
 import uvicorn
 from typing import Callable
 from loguru import logger
@@ -6,8 +7,8 @@
 from . import IS_DEV
 from .api import app
 from .db import migrate_db
+from .logger import get_log_level, setup_logging
 from .parent_watchdog import ParentWatchdog
-from .common import DATA_DIR
 
 
 def prevent_port_occupancy(port: int):
@@ -38,11 +39,15 @@ def try_kill(proc: psutil.Process):
             continue
     time.sleep(1)
 
-def create_server(port: int) -> tuple[Server, Callable[[], None]]:
+def create_server(port: int, log_level: int) -> tuple[Server, Callable[[], None]]:
     def stop_server():
         server.should_exit = True
 
-    server_config = uvicorn.Config(app, host="127.0.0.1", port=port, workers=1)
+    server_config = uvicorn.Config(app,
+                                           host="127.0.0.1",
+                                           port=port,
+                                           workers=1,
+                                           log_level=log_level)
     server = uvicorn.Server(server_config)
     return server, stop_server
 
@@ -54,10 +59,11 @@ async def main():
     if IS_DEV:
         prevent_port_occupancy(args.port)
 
-    logger.add(DATA_DIR / "server.log", mode="w", enqueue=True)
     await migrate_db()
 
-    server, stop_server = create_server(args.port)
+    log_level = get_log_level(IS_DEV)
+    server, stop_server = create_server(args.port, log_level)
     ParentWatchdog(stop_server).start()
+    setup_logging(log_level)
+
     await server.serve()
-    await logger.complete()
diff --git a/src-server/src/schemas/extra.py b/src-server/src/schemas/extra.py
index e1278d8..5b12ad7 100644
--- a/src-server/src/schemas/extra.py
+++ b/src-server/src/schemas/extra.py
@@ -1,9 +1,16 @@
 from typing import TypeAliasType
 from dais_sdk.types import ToolSchema
 from ..agent.tool import get_builtin_tool_enum, get_builtin_tool_arg_schemas
+from ..agent.tool.toolset_wrapper.mcp_toolset import McpConnectErrorCode
 from ..agent.types.metadata import ToolMessageMetadata
+from ..api.exceptions import ApiErrorCode
+from ..services.exceptions import ServiceErrorCode
 
 EXTRA_SCHEMA_TYPES: list[type | TypeAliasType | ToolSchema] = [
+    ApiErrorCode,
+    ServiceErrorCode,
+    McpConnectErrorCode,
+
     ToolMessageMetadata,
     get_builtin_tool_enum(),
     *get_builtin_tool_arg_schemas(),
diff --git a/src-server/src/schemas/toolset.py b/src-server/src/schemas/toolset.py
index 859f315..150b337 100644
--- a/src-server/src/schemas/toolset.py
+++ b/src-server/src/schemas/toolset.py
@@ -3,6 +3,7 @@
 from . import DTOBase
 from ..db.models.toolset import ToolsetType
 from ..agent.tool import McpToolsetStatus
+from ..agent.tool.toolset_wrapper.mcp_toolset import McpConnectErrorCode
 
 class ToolBase(DTOBase):
     name: str
@@ -33,6 +34,8 @@ class ToolsetBrief(DTOBase):
     type: ToolsetType
     # "connected" for built-in toolsets, McpToolsetStatus for MCP toolsets
     status: Literal["connected"] | McpToolsetStatus
+    # None for built-in toolsets
+    error_code: McpConnectErrorCode | None
 
 class ToolsetRead(ToolsetBase):
     id: int
diff --git a/src-server/src/services/__init__.py b/src-server/src/services/__init__.py
index 9335b64..88c60d6 100644
--- a/src-server/src/services/__init__.py
+++ b/src-server/src/services/__init__.py
@@ -1,18 +1,7 @@
-from .agent import AgentService, AgentNotFoundError
-from .workspace import WorkspaceService, WorkspaceNotFoundError
-from .provider import ProviderService, ProviderNotFoundError
-from .llm_model import LlmModelService, ModelNotFoundError
-from .toolset import (
-    ToolsetService,
-    ToolsetNotFoundError,
-    ToolsetInternalKeyAlreadyExistsError,
-    ToolNotFoundError,
-    CannotCreateBuiltinToolsetError,
-)
-from .task import TaskService, TaskNotFoundError
-from .exceptions import (
-    ServiceError,
-    NotFoundError,
-    ConflictError,
-    BadRequestError,
-)
+from .agent import AgentService
+from .workspace import WorkspaceService
+from .provider import ProviderService
+from .llm_model import LlmModelService
+from .toolset import ToolsetService
+from .task import TaskService
+from .exceptions import ServiceError
\ No newline at end of file
diff --git a/src-server/src/services/agent.py b/src-server/src/services/agent.py
index edfcaf2..5f4db21 100644
--- a/src-server/src/services/agent.py
+++ b/src-server/src/services/agent.py
@@ -1,18 +1,15 @@
 from sqlalchemy import select
 from sqlalchemy.orm import selectinload
 from .service_base import ServiceBase
-from .exceptions import NotFoundError
+from .exceptions import NotFoundError, ServiceErrorCode
 from ..db.models import agent as agent_models
 from ..db.models import toolset as toolset_models
 from ..schemas import agent as agent_schemas
 
 
 class AgentNotFoundError(NotFoundError):
-    """Raised when an agent is not found."""
-
     def __init__(self, agent_id: int) -> None:
-        super().__init__("Agent", agent_id)
-
+        super().__init__(ServiceErrorCode.AGENT_NOT_FOUND, "Agent", agent_id)
 
 class AgentService(ServiceBase):
     def get_agents_query(self):
@@ -73,7 +70,5 @@ async def update_agent(self, id: int, data: agent_schemas.AgentUpdate) -> agent_
         return updated_agent
 
     async def delete_agent(self, id: int) -> None:
-        agent = await self._db_session.get(agent_models.Agent, id)
-        if not agent:
-            raise AgentNotFoundError(id)
+        agent = await self.get_agent_by_id(id)
         await self._db_session.delete(agent)
diff --git a/src-server/src/services/exceptions.py b/src-server/src/services/exceptions.py
index 359d35d..873d2f6 100644
--- a/src-server/src/services/exceptions.py
+++ b/src-server/src/services/exceptions.py
@@ -1,37 +1,60 @@
-"""Service layer error types.
-
-This module defines custom error types for the service layer.
-These errors should not inherit from framework-specific exception classes.
-"""
 from enum import Enum
 
-class ServiceErrorCode(str, Enum):
+
+class ServiceStatusCode(str, Enum):
     NOT_FOUND = "NOT_FOUND"
     CONFLICT = "CONFLICT"
     BAD_REQUEST = "BAD_REQUEST"
+    UNAVAILABLE = "UNAVAILABLE"
+
+    @staticmethod
+    def status_code_map(code: ServiceStatusCode) -> int:
+        from fastapi import status
+        return ({
+            ServiceStatusCode.NOT_FOUND: status.HTTP_404_NOT_FOUND,
+            ServiceStatusCode.CONFLICT: status.HTTP_409_CONFLICT,
+            ServiceStatusCode.BAD_REQUEST: status.HTTP_400_BAD_REQUEST,
+            ServiceStatusCode.UNAVAILABLE: status.HTTP_503_SERVICE_UNAVAILABLE,
+        }).get(code, status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+class ServiceErrorCode(str, Enum):
+    AGENT_NOT_FOUND = "AGENT_NOT_FOUND"
+
+    WORKSPACE_NOT_FOUND = "WORKSPACE_NOT_FOUND"
+
+    MODEL_NOT_FOUND = "MODEL_NOT_FOUND"
+
+    PROVIDER_NOT_FOUND = "PROVIDER_NOT_FOUND"
+
+    TASK_NOT_FOUND = "TASK_NOT_FOUND"
+
+    TOOLSET_NOT_FOUND = "TOOLSET_NOT_FOUND"
+    TOOLSET_INTERNAL_KEY_ALREADY_EXISTS = "TOOLSET_INTERNAL_KEY_ALREADY_EXISTS"
+
+    TOOL_NOT_FOUND = "TOOL_NOT_FOUND"
 
 class ServiceError(Exception):
-    """Base class for all service layer errors."""
-    def __init__(self, code: ServiceErrorCode, message: str) -> None:
+    def __init__(self, status_code: ServiceStatusCode, error_code: ServiceErrorCode, message: str) -> None:
         super().__init__(message)
-        self.code = code
+        self.status_code = status_code
+        self.error_code = error_code
         self.message = message
 
 class NotFoundError(ServiceError):
-    """Raised when a requested resource is not found."""
-
-    def __init__(self, resource_type: str, identifier: int | str) -> None:
+    def __init__(self, error_code: ServiceErrorCode, resource_type: str, identifier: int | str) -> None:
         message = f"{resource_type} '{identifier}' not found"
-        super().__init__(ServiceErrorCode.NOT_FOUND, message)
+        super().__init__(ServiceStatusCode.NOT_FOUND, error_code, message)
         self.resource_type = resource_type
         self.identifier = identifier
 
 class ConflictError(ServiceError):
-    """Raised when there is a conflict with the current state of the resource."""
-    def __init__(self, message: str) -> None:
-        super().__init__(ServiceErrorCode.CONFLICT, message)
+    def __init__(self, error_code: ServiceErrorCode, message: str) -> None:
+        super().__init__(ServiceStatusCode.CONFLICT, error_code, message)
 
 class BadRequestError(ServiceError):
-    """Raised when the request is invalid or cannot be processed."""
-    def __init__(self, message: str) -> None:
-        super().__init__(ServiceErrorCode.BAD_REQUEST, message)
+    def __init__(self, error_code: ServiceErrorCode, message: str) -> None:
+        super().__init__(ServiceStatusCode.BAD_REQUEST, error_code, message)
+
+class UnavailableError(ServiceError):
+    def __init__(self, error_code: ServiceErrorCode, message: str) -> None:
+        super().__init__(ServiceStatusCode.UNAVAILABLE, error_code, message)
diff --git a/src-server/src/services/llm_model.py b/src-server/src/services/llm_model.py
index fce0c00..08b43f9 100644
--- a/src-server/src/services/llm_model.py
+++ b/src-server/src/services/llm_model.py
@@ -1,15 +1,12 @@
 from sqlalchemy.orm import selectinload
 from .service_base import ServiceBase
-from .exceptions import NotFoundError
+from .exceptions import NotFoundError, ServiceErrorCode
 from ..db.models import provider as provider_models
 
 
 class ModelNotFoundError(NotFoundError):
-    """Raised when a model is not found."""
-
     def __init__(self, model_id: int) -> None:
-        super().__init__("Model", model_id)
-
+        super().__init__(ServiceErrorCode.MODEL_NOT_FOUND, "Model", model_id)
 
 class LlmModelService(ServiceBase):
     async def get_model_by_id(self, model_id: int) -> provider_models.LlmModel:
diff --git a/src-server/src/services/provider.py b/src-server/src/services/provider.py
index dac6772..7768784 100644
--- a/src-server/src/services/provider.py
+++ b/src-server/src/services/provider.py
@@ -2,19 +2,16 @@
 from sqlalchemy import select
 from sqlalchemy.orm import selectinload
 from .service_base import ServiceBase
-from .exceptions import NotFoundError
+from .exceptions import NotFoundError, ServiceErrorCode
 from ..db.models import provider as provider_models
 from ..schemas import provider as provider_schemas
 
-_logger = logger.bind(name="ProviderService")
 
+_logger = logger.bind(name="ProviderService")
 
 class ProviderNotFoundError(NotFoundError):
-    """Raised when a provider is not found."""
-
     def __init__(self, provider_id: int) -> None:
-        super().__init__("Provider", provider_id)
-
+        super().__init__(ServiceErrorCode.PROVIDER_NOT_FOUND, "Provider", provider_id)
 
 class ProviderService(ServiceBase):
     def get_providers_query(self):
@@ -128,7 +125,5 @@ def merge_models(
         return updated_provider
 
     async def delete_provider(self, id: int) -> None:
-        provider = await self._db_session.get(provider_models.Provider, id)
-        if not provider:
-            raise ProviderNotFoundError(id)
+        provider = await self.get_provider_by_id(id)
         await self._db_session.delete(provider)
diff --git a/src-server/src/services/task.py b/src-server/src/services/task.py
index dd6f9e2..20dd52c 100644
--- a/src-server/src/services/task.py
+++ b/src-server/src/services/task.py
@@ -1,17 +1,14 @@
 from sqlalchemy import select
 from sqlalchemy.orm import selectinload
 from .service_base import ServiceBase
-from .exceptions import NotFoundError
+from .exceptions import NotFoundError, ServiceErrorCode
 from ..db.models import task as task_models
 from ..schemas import task as task_schemas
 
 
 class TaskNotFoundError(NotFoundError):
-    """Raised when a task is not found."""
-
     def __init__(self, task_id: int) -> None:
-        super().__init__("Task", task_id)
-
+        super().__init__(ServiceErrorCode.TASK_NOT_FOUND, "Task", task_id)
 
 class TaskService(ServiceBase):
     def get_tasks_query(self, workspace_id: int):
@@ -61,7 +58,5 @@ async def update_task(self, id: int, data: task_schemas.TaskUpdate) -> task_mode
         return task
 
     async def delete_task(self, id: int) -> None:
-        task = await self._db_session.get(task_models.Task, id)
-        if not task:
-            raise TaskNotFoundError(id)
+        task = await self.get_task_by_id(id)
         await self._db_session.delete(task)
diff --git a/src-server/src/services/toolset.py b/src-server/src/services/toolset.py
index a5fc748..e8dbc02 100644
--- a/src-server/src/services/toolset.py
+++ b/src-server/src/services/toolset.py
@@ -1,40 +1,24 @@
 from typing import NamedTuple
+from dais_sdk.types import ToolDef
 from sqlalchemy import select
 from sqlalchemy.orm import selectinload
-from dais_sdk.mcp_client import LocalMcpClient, RemoteMcpClient, LocalServerParams, RemoteServerParams
 from .service_base import ServiceBase
-from .exceptions import NotFoundError, ConflictError, BadRequestError
+from .exceptions import NotFoundError, ConflictError, ServiceErrorCode
 from ..db.models import toolset as toolset_models
 from ..schemas import toolset as toolset_schemas
 
 
 class ToolsetNotFoundError(NotFoundError):
-    """Raised when a toolset is not found."""
-
     def __init__(self, toolset_identifier: int | str) -> None:
-        super().__init__("Toolset", toolset_identifier)
-
+        super().__init__(ServiceErrorCode.TOOLSET_NOT_FOUND, "Toolset", toolset_identifier)
 
 class ToolsetInternalKeyAlreadyExistsError(ConflictError):
-    """Raised when attempting to create a toolset with a name that already exists."""
-
     def __init__(self, name: str) -> None:
-        super().__init__(f"Toolset '{name}' already exists")
-
+        super().__init__(ServiceErrorCode.TOOLSET_INTERNAL_KEY_ALREADY_EXISTS, f"Toolset '{name}' already exists")
 
 class ToolNotFoundError(NotFoundError):
-    """Raised when a tool is not found."""
-
     def __init__(self, tool_id: int) -> None:
-        super().__init__("Tool", tool_id)
-
-
-class CannotCreateBuiltinToolsetError(BadRequestError):
-    """Raised when attempting to create a builtin toolset."""
-
-    def __init__(self) -> None:
-        super().__init__("Cannot create builtin toolset")
-
+        super().__init__(ServiceErrorCode.TOOL_NOT_FOUND, "Tool", tool_id)
 
 class ToolsetService(ServiceBase):
     class ToolLike(NamedTuple):
@@ -89,17 +73,7 @@ async def get_toolset_by_internal_key(self, internal_key: str) -> toolset_models
             raise ToolsetNotFoundError(internal_key)
         return toolset
 
-    async def create_toolset(self, data: toolset_schemas.ToolsetCreate) -> toolset_models.Toolset:
-        match data.type:
-            case toolset_models.ToolsetType.BUILT_IN:
-                raise CannotCreateBuiltinToolsetError()
-            case toolset_models.ToolsetType.MCP_LOCAL:
-                assert isinstance(data.params, LocalServerParams)
-                client = LocalMcpClient(data.name, data.params)
-            case toolset_models.ToolsetType.MCP_REMOTE:
-                assert isinstance(data.params, RemoteServerParams)
-                client = RemoteMcpClient(data.name, data.params)
-
+    async def create_toolset(self, data: toolset_schemas.ToolsetCreate, tools: list[ToolDef]) -> toolset_models.Toolset:
         try:
             await self.get_toolset_by_internal_key(data.name)
         except ToolsetNotFoundError:
@@ -107,16 +81,15 @@ async def create_toolset(self, data: toolset_schemas.ToolsetCreate) -> toolset_m
         else:
             raise ToolsetInternalKeyAlreadyExistsError(data.name)
 
-        await client.connect()
-        try:
-            tools = await client.list_tools()
-        finally:
-            await client.disconnect()
-
         new_toolset = toolset_models.Toolset(
-            **data.model_dump(),
+            **data.model_dump(exclude={"params"}),
+            params=data.params,
             internal_key=data.name,
-            tools=[toolset_models.Tool.from_mcp_tool(tool) for tool in tools],
+            tools=[toolset_models.Tool(
+                name=tool.name,
+                internal_key=tool.name,
+                description=tool.description,
+            ) for tool in tools],
         )
 
         self._db_session.add(new_toolset)
@@ -133,7 +106,10 @@ async def update_toolset(self, id: int, data: toolset_schemas.ToolsetUpdate) ->
             for tool_data in data.tools:
                 await self.update_tool(id, tool_data.id, tool_data)
 
-        update_data = data.model_dump(exclude={"tools"}, exclude_unset=True)
+        if data.params is not None:
+            toolset.params = data.params
+
+        update_data = data.model_dump(exclude={"params", "tools"}, exclude_unset=True)
         for key, value in update_data.items():
             if hasattr(toolset, key) and value is not None:
                 setattr(toolset, key, value)
diff --git a/src-server/src/services/workspace.py b/src-server/src/services/workspace.py
index 5e00d2f..26ca951 100644
--- a/src-server/src/services/workspace.py
+++ b/src-server/src/services/workspace.py
@@ -1,7 +1,7 @@
 from sqlalchemy import select
 from sqlalchemy.orm import selectinload
 from .service_base import ServiceBase
-from .exceptions import NotFoundError
+from .exceptions import NotFoundError, ServiceErrorCode
 from ..db.models import workspace as workspace_models
 from ..db.models import agent as agent_models
 from ..db.models import toolset as toolset_models
@@ -9,11 +9,8 @@
 
 
 class WorkspaceNotFoundError(NotFoundError):
-    """Raised when a workspace is not found."""
-
     def __init__(self, workspace_id: int) -> None:
-        super().__init__("Workspace", workspace_id)
-
+        super().__init__(ServiceErrorCode.WORKSPACE_NOT_FOUND, "Workspace", workspace_id)
 
 class WorkspaceService(ServiceBase):
     def get_workspaces_query(self):
@@ -66,8 +63,6 @@ async def create_workspace(self, data: workspace_schemas.WorkspaceCreate) -> wor
 
     async def update_workspace(self, id: int, data: workspace_schemas.WorkspaceUpdate) -> workspace_models.Workspace:
         workspace = await self.get_workspace_by_id(id)
-        if not workspace:
-            raise WorkspaceNotFoundError(id)
 
         update_data = data.model_dump(exclude_unset=True,
                                                       exclude={"usable_agent_ids", "usable_tool_ids"})
@@ -82,7 +77,5 @@ async def update_workspace(self, id: int, data: workspace_schemas.WorkspaceUpdat
         return updated_workspace
 
     async def delete_workspace(self, id: int) -> None:
-        workspace = await self._db_session.get(workspace_models.Workspace, id)
-        if not workspace:
-            raise WorkspaceNotFoundError(id)
+        workspace = await self.get_workspace_by_id(id)
         await self._db_session.delete(workspace)
diff --git a/src-server/uv.lock b/src-server/uv.lock
index bc8b5ea..d16ea2e 100644
--- a/src-server/uv.lock
+++ b/src-server/uv.lock
@@ -298,7 +298,7 @@ wheels = [
 
 [[package]]
 name = "dais-sdk"
-version = "0.8.4"
+version = "0.8.7"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "httpx" },
@@ -308,9 +308,9 @@ dependencies = [
     { name = "starlette" },
     { name = "uvicorn" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/d0/c4/e47d8531441b77a1cb9fcbabda9760ddc57ef5c25c99a522cf4693a49516/dais_sdk-0.8.4.tar.gz", hash = "sha256:d03170e3d3f8ae6b2a4b52f5bee5317d1c7dcddc70ff95bbd11fcedb42ed262b", size = 18193, upload-time = "2026-03-07T14:06:54.114Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/24/2f/b2a244ae9b4e2d5da2dec4a785fb500a2713dcc6682ebcca64a839683744/dais_sdk-0.8.7.tar.gz", hash = "sha256:976d312e75465998b3f002770790e0fe91433772cf66aa370a2ee285045ee198", size = 18196, upload-time = "2026-03-12T04:44:59.452Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/8b/60/e9e6bf992f1f4f6905e2e9a7fbb98e8f1d410661838dc4a64609af653436/dais_sdk-0.8.4-py3-none-any.whl", hash = "sha256:cd6059f3b5e85123568067464082fccb168982bb3f3f4868b12dda0788e9c08f", size = 26959, upload-time = "2026-03-07T14:06:52.593Z" },
+    { url = "https://files.pythonhosted.org/packages/4b/e9/65f77b5b7806536c779e2b1e1d3191b344be6cd6ce65847e51517896e0e2/dais_sdk-0.8.7-py3-none-any.whl", hash = "sha256:0b961b1a2f3efdd6e1c157bb849459f3d7bb49ca27eb272b25824b19fdac779f", size = 27010, upload-time = "2026-03-12T04:44:58.339Z" },
 ]
 
 [[package]]
@@ -358,7 +358,7 @@ requires-dist = [
     { name = "aiosqlite", specifier = "==0.22.1" },
     { name = "alembic", specifier = "==1.18.4" },
     { name = "binaryornot", specifier = "==0.4.4" },
-    { name = "dais-sdk", specifier = "==0.8.4" },
+    { name = "dais-sdk", specifier = "==0.8.7" },
     { name = "dais-shell", specifier = "==0.1.2" },
     { name = "fastapi", specifier = "==0.135.1" },
     { name = "fastapi-pagination", specifier = "==0.15.10" },