diff --git a/web/app/components/header/account-setting/sandbox-provider-page/config-modal.tsx b/web/app/components/header/account-setting/sandbox-provider-page/config-modal.tsx
index a518418eec..b77277517c 100644
--- a/web/app/components/header/account-setting/sandbox-provider-page/config-modal.tsx
+++ b/web/app/components/header/account-setting/sandbox-provider-page/config-modal.tsx
@@ -12,6 +12,7 @@ import Modal from '@/app/components/base/modal'
 import RadioUI from '@/app/components/base/radio/ui'
 import { useToastContext } from '@/app/components/base/toast'
 import {
+  useActivateSandboxProvider,
   useDeleteSandboxProviderConfig,
   useSaveSandboxProviderConfig,
 } from '@/service/use-sandbox-provider'
@@ -69,6 +70,7 @@ function ConfigModal({ provider, onClose }: ConfigModalProps) {
 
   const { mutateAsync: saveConfig, isPending: isSaving } = useSaveSandboxProviderConfig()
   const { mutateAsync: deleteConfig, isPending: isDeleting } = useDeleteSandboxProviderConfig()
+  const { mutateAsync: activateProvider, isPending: isActivating } = useActivateSandboxProvider()
 
   // Determine if mode selection should be shown (for providers that support it)
   const shouldShowModeSelection = PROVIDERS_WITH_MODE_SELECTION.includes(provider.provider_type)
@@ -102,10 +104,10 @@ function ConfigModal({ provider, onClose }: ConfigModalProps) {
   }, [provider.config_schema, provider.config, t])
 
   const handleSave = useCallback(async () => {
-    // For managed mode, delete user config to use system defaults
+    // For managed mode, activate system config (preserves user config for future use)
     if (shouldShowModeSelection && configMode === 'managed') {
       try {
-        await deleteConfig(provider.provider_type)
+        await activateProvider({ providerType: provider.provider_type, type: 'system' })
         notify({ type: 'success', message: t('api.saved', { ns: 'common' }) })
         onClose()
       }
@@ -127,6 +129,7 @@ function ConfigModal({ provider, onClose }: ConfigModalProps) {
       await saveConfig({
         providerType: provider.provider_type,
         config: formValues.values,
+        activate: true,
       })
       notify({ type: 'success', message: t('api.saved', { ns: 'common' }) })
       onClose()
@@ -134,7 +137,7 @@ function ConfigModal({ provider, onClose }: ConfigModalProps) {
     catch {
       // Error toast is handled by fetch layer
     }
-  }, [shouldShowModeSelection, configMode, saveConfig, deleteConfig, provider.provider_type, notify, t, onClose])
+  }, [shouldShowModeSelection, configMode, saveConfig, activateProvider, provider.provider_type, notify, t, onClose])
 
   const handleRevoke = useCallback(async () => {
     try {
@@ -154,7 +157,7 @@ function ConfigModal({ provider, onClose }: ConfigModalProps) {
   // Only show revoke button when in BYOK mode, tenant has custom config, and provider is not active
   // (active provider cannot be revoked to prevent "no sandbox provider" error)
   const showRevokeButton = provider.is_tenant_configured && !provider.is_active && (!shouldShowModeSelection || configMode === 'byok')
-  const isActionDisabled = isSaving || isDeleting
+  const isActionDisabled = isSaving || isDeleting || isActivating
   const showByokForm = !shouldShowModeSelection || configMode === 'byok'
 
   return (
diff --git a/web/app/components/header/account-setting/sandbox-provider-page/switch-modal.tsx b/web/app/components/header/account-setting/sandbox-provider-page/switch-modal.tsx
index c15049b2e2..a31c6f501d 100644
--- a/web/app/components/header/account-setting/sandbox-provider-page/switch-modal.tsx
+++ b/web/app/components/header/account-setting/sandbox-provider-page/switch-modal.tsx
@@ -23,16 +23,20 @@ const SwitchModal = ({
 
   const { mutateAsync: activateProvider, isPending } = useActivateSandboxProvider()
 
+  // Determine the type based on provider configuration
+  // If tenant has custom config, activate as 'user', otherwise as 'system'
+  const activationType: 'system' | 'user' = provider.is_tenant_configured ? 'user' : 'system'
+
   const handleConfirm = useCallback(async () => {
     try {
-      await activateProvider(provider.provider_type)
+      await activateProvider({ providerType: provider.provider_type, type: activationType })
       notify({ type: 'success', message: t('api.success', { ns: 'common' }) })
       onClose()
     }
     catch {
       // Error toast is handled by fetch layer
     }
-  }, [activateProvider, provider.provider_type, notify, t, onClose])
+  }, [activateProvider, provider.provider_type, activationType, notify, t, onClose])
 
   return (
     <Modal
diff --git a/web/contract/console/sandbox-provider.ts b/web/contract/console/sandbox-provider.ts
index 5f78e26150..a4a618f6bb 100644
--- a/web/contract/console/sandbox-provider.ts
+++ b/web/contract/console/sandbox-provider.ts
@@ -21,6 +21,7 @@ export const saveSandboxProviderConfigContract = base
     }
     body: {
       config: Record<string, string>
+      activate?: boolean
     }
   }>())
   .output(type<{ result: string }>())
@@ -46,5 +47,8 @@ export const activateSandboxProviderContract = base
     params: {
       providerType: string
     }
+    body: {
+      type: 'system' | 'user'
+    }
   }>())
   .output(type<{ result: string }>())
diff --git a/web/service/use-sandbox-provider.ts b/web/service/use-sandbox-provider.ts
index 975d3008c6..b038b80ed4 100644
--- a/web/service/use-sandbox-provider.ts
+++ b/web/service/use-sandbox-provider.ts
@@ -16,10 +16,10 @@ export const useSaveSandboxProviderConfig = () => {
   const queryClient = useQueryClient()
   return useMutation({
     mutationKey: consoleQuery.sandboxProvider.saveSandboxProviderConfig.mutationKey(),
-    mutationFn: ({ providerType, config }: { providerType: string, config: Record<string, string> }) => {
+    mutationFn: ({ providerType, config, activate }: { providerType: string, config: Record<string, string>, activate?: boolean }) => {
       return consoleClient.sandboxProvider.saveSandboxProviderConfig({
         params: { providerType },
-        body: { config },
+        body: { config, activate },
       })
     },
     onSuccess: () => {
@@ -47,9 +47,10 @@ export const useActivateSandboxProvider = () => {
   const queryClient = useQueryClient()
   return useMutation({
     mutationKey: consoleQuery.sandboxProvider.activateSandboxProvider.mutationKey(),
-    mutationFn: (providerType: string) => {
+    mutationFn: ({ providerType, type }: { providerType: string, type: 'system' | 'user' }) => {
       return consoleClient.sandboxProvider.activateSandboxProvider({
         params: { providerType },
+        body: { type },
       })
     },
     onSuccess: () => {