fix(grok): default client tool caching on for Free accounts

frontend/src/components/account/EditAccountModal.vue

@@ -2768,7 +2768,9 @@ const headerOverrideCapable = computed(
 // Grok OAuth 自定义上游地址（仅转发端点；OAuth 授权/令牌刷新不受影响）
 const grokOAuthCustomBaseUrlEnabled = ref(false)
 const grokOAuthBaseUrl = ref('')
-const grokClientToolCacheEnabled = ref(false)
+// Grok Free OAuth accounts use client-tool prompt caching by default. Keep an
+// explicit false in the account extra as the opt-out signal.
+const grokClientToolCacheEnabled = ref(true)
 
 const interceptWarmupRequests = ref(false)
 const autoPauseOnExpired = ref(false)
@@ -3424,10 +3426,14 @@ const syncFormFromAccount = (newAccount: Account | null) => {
   // Load Grok OAuth custom upstream URL state（存储的官方地址视同未定制）
   grokOAuthCustomBaseUrlEnabled.value = false
   grokOAuthBaseUrl.value = ''
+  const grokClientToolCacheSetting =
+    newAccount.platform === 'grok' && newAccount.type === 'oauth'
+      ? newAccount.extra?.[GROK_CLIENT_TOOL_CACHE_EXTRA_KEY]
+      : undefined
   grokClientToolCacheEnabled.value =
     newAccount.platform === 'grok' &&
     newAccount.type === 'oauth' &&
-    newAccount.extra?.[GROK_CLIENT_TOOL_CACHE_EXTRA_KEY] === true
+    (grokClientToolCacheSetting === undefined || grokClientToolCacheSetting === true)
   if (newAccount.platform === 'grok' && newAccount.type === 'oauth' && newAccount.credentials) {
     const grokCreds = newAccount.credentials as Record<string, unknown>
     if (isCustomGrokBaseUrl(grokCreds.base_url)) {
@@ -4318,11 +4324,9 @@ const handleSubmit = async () => {
       const newExtra: Record<string, unknown> = {
         ...((props.account.extra as Record<string, unknown>) || {})
       }
-      if (grokClientToolCacheEnabled.value) {
-        newExtra[GROK_CLIENT_TOOL_CACHE_EXTRA_KEY] = true
-      } else {
-        delete newExtra[GROK_CLIENT_TOOL_CACHE_EXTRA_KEY]
-      }
+      // Persist both states so a disabled account remains opted out when the
+      // backend applies the default-enabled policy to missing values.
+      newExtra[GROK_CLIENT_TOOL_CACHE_EXTRA_KEY] = grokClientToolCacheEnabled.value
       updatePayload.extra = newExtra
     }
 

frontend/src/components/account/__tests__/EditAccountModal.grokUpstream.spec.ts

@@ -264,18 +264,17 @@ describe('EditAccountModal Grok OAuth upstream config', () => {
 
     const payload = updateAccountMock.mock.calls[0]?.[1]
     expect(payload?.extra?.custom_setting).toBe('keep-me')
-    expect(payload?.extra).not.toHaveProperty('grok_client_tool_cache_enabled')
+    expect(payload?.extra?.grok_client_tool_cache_enabled).toBe(false)
   })
 
-  it('enables client-tool caching while preserving unrelated extra fields', async () => {
+  it('defaults client-tool caching on when the setting is missing and persists explicit true', async () => {
     const account = buildGrokOAuthAccount({}, { custom_setting: 'keep-me' })
     updateAccountMock.mockResolvedValue(account)
 
     const wrapper = mountModal(account)
     const toggle = wrapper.get('[data-testid="grok-client-tool-cache-toggle"]')
-    expect(toggle.attributes('aria-checked')).toBe('false')
+    expect(toggle.attributes('aria-checked')).toBe('true')
 
-    await toggle.trigger('click')
     await wrapper.get('form#edit-account-form').trigger('submit.prevent')
     await vi.waitFor(() => expect(updateAccountMock).toHaveBeenCalledTimes(1))
 
@@ -285,4 +284,43 @@ describe('EditAccountModal Grok OAuth upstream config', () => {
       custom_setting: 'keep-me'
     })
   })
+
+  it('keeps an explicit false opt-out when saving an untouched account', async () => {
+    const account = buildGrokOAuthAccount(
+      {},
+      {
+        grok_client_tool_cache_enabled: false,
+        custom_setting: 'keep-me'
+      }
+    )
+    updateAccountMock.mockResolvedValue(account)
+
+    const wrapper = mountModal(account)
+    const toggle = wrapper.get('[data-testid="grok-client-tool-cache-toggle"]')
+    expect(toggle.attributes('aria-checked')).toBe('false')
+
+    await wrapper.get('form#edit-account-form').trigger('submit.prevent')
+    await vi.waitFor(() => expect(updateAccountMock).toHaveBeenCalledTimes(1))
+
+    const payload = updateAccountMock.mock.calls[0]?.[1]
+    expect(payload?.extra).toMatchObject({
+      grok_client_tool_cache_enabled: false,
+      custom_setting: 'keep-me'
+    })
+  })
+
+  it('shows malformed cache settings as disabled so the UI matches the fail-closed backend', () => {
+    const account = buildGrokOAuthAccount(
+      {},
+      {
+        grok_client_tool_cache_enabled: 'true',
+        custom_setting: 'keep-me'
+      }
+    )
+
+    const wrapper = mountModal(account)
+    expect(
+      wrapper.get('[data-testid="grok-client-tool-cache-toggle"]').attributes('aria-checked')
+    ).toBe('false')
+  })
 })