diff --git a/frontend/src/api/admin/channelMonitor.ts b/frontend/src/api/admin/channelMonitor.ts
index f3353ebd45..bf9e1c88fb 100644
--- a/frontend/src/api/admin/channelMonitor.ts
+++ b/frontend/src/api/admin/channelMonitor.ts
@@ -134,7 +134,9 @@ export interface CreateParams {
   api_key: string
   /** 缺省 probe；antigravity 仅支持 quota */
   check_mode?: CheckMode
-  /** 配额模式必填：数据源账号（provider 需与账号平台一致） */
+  /** 配额模式必填：数据源账号（provider 需与账号平台一致）。
+   * update 语义：>0=换绑，0=解绑（切回 probe 模式时前端发 0 清空存量关联）；
+   * create 绝不发 0——后端会把 0 存成 &0 触发外键违约。 */
   account_id?: number | null
   primary_model: string
   extra_models?: string[]
@@ -148,7 +150,8 @@ export interface CreateParams {
   body_override?: Record<string, unknown> | null
 }
 
-// Update request: api_key 空串 = 不修改；clear_template=true 时把 template_id 置空
+// Update request: api_key 空串 = 不修改；clear_template=true 时把 template_id 置空；
+// account_id=0 显式解绑关联账号（null = 不动，见 CreateParams 注释）
 export type UpdateParams = Partial<CreateParams> & {
   clear_template?: boolean
 }
diff --git a/frontend/src/components/admin/monitor/MonitorFormDialog.vue b/frontend/src/components/admin/monitor/MonitorFormDialog.vue
index ea73b929ed..fb89f1a0ce 100644
--- a/frontend/src/components/admin/monitor/MonitorFormDialog.vue
+++ b/frontend/src/components/admin/monitor/MonitorFormDialog.vue
@@ -675,6 +675,14 @@ function selectProvider(provider: Provider) {
   if (provider === PROVIDER_ANTIGRAVITY && form.check_mode !== CHECK_MODE_QUOTA) {
     form.check_mode = CHECK_MODE_QUOTA
   }
+  // 对称还原：从 antigravity 切走时撤掉强制 quota，否则编辑存量 antigravity
+  // 监控换平台后仍停留在 quota（目标平台未必支持），update 会携带残留配置。
+  // 同步清掉 quota 占位模型（loadFromMonitor 回填的 'quota'），否则切回
+  // probe 后拿 'quota' 当探活模型（与离开 grok 清 DEFAULT_GROK_MODEL 同理）。
+  if (previousProvider === PROVIDER_ANTIGRAVITY && form.check_mode === CHECK_MODE_QUOTA) {
+    form.check_mode = CHECK_MODE_PROBE
+    if (form.primary_model.trim() === 'quota') form.primary_model = ''
+  }
   if (provider === PROVIDER_GROK) {
     if (!form.endpoint.trim()) form.endpoint = DEFAULT_GROK_ENDPOINT
     if (!form.primary_model.trim()) form.primary_model = DEFAULT_GROK_MODEL
@@ -849,6 +857,9 @@ async function handleSubmit() {
         req.clear_template = true
         delete req.template_id
       }
+      // account_id 同理：probe 模式不带账号，update 发 0 显式解绑存量关联
+      // （后端 0=清空、null=不动）。仅 update——create 发 0 会落 &0 触发 FK 违约。
+      if (!usesQuotaMode.value) req.account_id = 0
       await adminAPI.channelMonitor.update(target.id, req)
       appStore.showSuccess(t('admin.channelMonitor.updateSuccess'))
     } else {
diff --git a/frontend/src/composables/useChannelMonitorFormat.ts b/frontend/src/composables/useChannelMonitorFormat.ts
index 04fc0546f5..67c0f197f1 100644
--- a/frontend/src/composables/useChannelMonitorFormat.ts
+++ b/frontend/src/composables/useChannelMonitorFormat.ts
@@ -26,6 +26,9 @@ import {
   STATUS_DEGRADED,
   STATUS_FAILED,
   STATUS_ERROR,
+  CHECK_MODE_PROBE,
+  CHECK_MODE_QUOTA,
+  CHECK_MODE_QUOTA_PROBE,
 } from '@/constants/channelMonitor'
 
 const NEUTRAL_BADGE = 'bg-gray-100 text-gray-800 dark:bg-dark-700 dark:text-gray-300'
@@ -101,6 +104,22 @@ export function useChannelMonitorFormat() {
     }
   }
 
+  /**
+   * Tailwind class for the check-mode badge shown next to the provider badge
+   * in the admin monitor list. Quota-bearing modes = blue (数据源是账号配额),
+   * plain probe = neutral grey.
+   */
+  function checkModeBadgeClass(m: CheckMode | string): string {
+    switch (m) {
+      case CHECK_MODE_QUOTA:
+      case CHECK_MODE_QUOTA_PROBE:
+        return 'bg-blue-100 text-blue-700 dark:bg-blue-500/15 dark:text-blue-300'
+      case CHECK_MODE_PROBE:
+      default:
+        return NEUTRAL_BADGE
+    }
+  }
+
   /**
    * Tailwind class for a provider radio-button-style picker (active/inactive state).
    * Reuses the same emerald/orange/sky palette as providerBadgeClass to keep
@@ -182,6 +201,7 @@ export function useChannelMonitorFormat() {
     providerLabel,
     checkModeLabel,
     providerBadgeClass,
+    checkModeBadgeClass,
     providerPickerClass,
     formatLatency,
     formatPercent,
diff --git a/frontend/src/views/admin/ChannelMonitorView.vue b/frontend/src/views/admin/ChannelMonitorView.vue
index d1bb148e8d..ae154f7136 100644
--- a/frontend/src/views/admin/ChannelMonitorView.vue
+++ b/frontend/src/views/admin/ChannelMonitorView.vue
@@ -78,6 +78,10 @@
             <span class="inline-flex items-center rounded-md px-2 py-0.5 text-xs font-medium" :class="providerBadgeClass(row.provider)">
               {{ providerLabel(row.provider) }}
             </span>
+            <!-- 三种检测模式并列展示，quota 系配额数据源与纯探活一眼可分 -->
+            <span class="ml-1 inline-flex items-center rounded-md px-2 py-0.5 text-xs font-medium" :class="checkModeBadgeClass(row.check_mode)">
+              {{ checkModeLabel(row.check_mode) }}
+            </span>
           </template>
 
           <template #cell-primary_model="{ row }">
@@ -204,6 +208,8 @@ const adminMonitorTab = ref<'v2' | 'legacy'>(isChannelMonitorV1Mode() ? 'legacy'
 const {
   providerLabel,
   providerBadgeClass,
+  checkModeLabel,
+  checkModeBadgeClass,
   formatLatency,
   formatAvailability,
 } = useChannelMonitorFormat()
diff --git a/frontend/src/views/admin/__tests__/ChannelMonitorView.checkModeBadge.spec.ts b/frontend/src/views/admin/__tests__/ChannelMonitorView.checkModeBadge.spec.ts
new file mode 100644
index 0000000000..8a94bd65cf
--- /dev/null
+++ b/frontend/src/views/admin/__tests__/ChannelMonitorView.checkModeBadge.spec.ts
@@ -0,0 +1,159 @@
+import { defineComponent } from 'vue'
+import { flushPromises, mount } from '@vue/test-utils'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import type { ChannelMonitor } from '@/api/admin/channelMonitor'
+import ChannelMonitorView from '@/views/admin/ChannelMonitorView.vue'
+
+// P2-7(d)：provider 徽章旁并列 check_mode 徽章，三种检测模式一眼可分
+// （quota 系 = 账号配额数据源，probe = 纯探活）。
+
+const { listMonitors } = vi.hoisted(() => ({ listMonitors: vi.fn() }))
+
+vi.mock('@/utils/featureFlags', () => ({
+  isChannelMonitorV1Mode: () => true,
+  isChannelMonitorV2Mode: () => false,
+  getChannelMonitorMode: () => 'v1' as const,
+}))
+
+vi.mock('@/features/channel-monitor-v2/MonitorSettingsPanel.vue', () => ({
+  default: { name: 'MonitorSettingsPanel', template: '<div data-testid="v2-settings" />' },
+}))
+
+vi.mock('@/api/admin', () => ({
+  adminAPI: {
+    channelMonitor: {
+      list: listMonitors,
+      duplicate: vi.fn(),
+      update: vi.fn(),
+      runNow: vi.fn(),
+      del: vi.fn(),
+    },
+  },
+}))
+
+vi.mock('@/stores/app', () => ({
+  useAppStore: () => ({ showSuccess: vi.fn(), showError: vi.fn() }),
+}))
+
+vi.mock('vue-i18n', async () => {
+  const actual = await vi.importActual<typeof import('vue-i18n')>('vue-i18n')
+  return {
+    ...actual,
+    useI18n: () => ({ t: (key: string) => key }),
+  }
+})
+
+const AppLayoutStub = defineComponent({
+  template: '<main><slot /></main>',
+})
+
+const TablePageLayoutStub = defineComponent({
+  template: '<section><slot name="filters" /><slot name="table" /><slot name="pagination" /></section>',
+})
+
+// 渲染 cell-provider slot，徽章断言基于它。
+const DataTableStub = defineComponent({
+  props: {
+    data: { type: Array, default: () => [] },
+    columns: { type: Array, default: () => [] },
+    loading: { type: Boolean, default: false },
+  },
+  template: '<div><div v-for="row in data" :key="row.id" class="provider-cell"><slot name="cell-provider" :row="row" /></div></div>',
+})
+
+function makeMonitor(overrides: Partial<ChannelMonitor> = {}): ChannelMonitor {
+  return {
+    id: 42,
+    name: 'primary',
+    provider: 'openai',
+    api_mode: 'chat_completions',
+    endpoint: 'https://api.example.com',
+    api_key_masked: 'sk-t***',
+    primary_model: 'gpt-4o-mini',
+    extra_models: [],
+    group_name: '',
+    enabled: true,
+    interval_seconds: 60,
+    jitter_seconds: 0,
+    last_checked_at: null,
+    created_by: 1,
+    created_at: '2026-07-16T00:00:00Z',
+    updated_at: '2026-07-16T00:00:00Z',
+    primary_status: '',
+    primary_latency_ms: null,
+    availability_7d: 0,
+    extra_models_status: [],
+    template_id: null,
+    extra_headers: {},
+    body_override_mode: 'off',
+    body_override: null,
+    check_mode: 'probe',
+    account_id: null,
+    ...overrides,
+  }
+}
+
+function mountView() {
+  return mount(ChannelMonitorView, {
+    global: {
+      stubs: {
+        AppLayout: AppLayoutStub,
+        TablePageLayout: TablePageLayoutStub,
+        DataTable: DataTableStub,
+        MonitorFiltersBar: true,
+        Pagination: true,
+        ConfirmDialog: true,
+        EmptyState: true,
+        HelpTooltip: true,
+        Toggle: true,
+        MonitorFormDialog: true,
+        MonitorTemplateManagerDialog: true,
+        MonitorRunResultDialog: true,
+        MonitorPrimaryModelCell: true,
+      },
+    },
+  })
+}
+
+describe('ChannelMonitorView check-mode badge', () => {
+  beforeEach(() => {
+    localStorage.clear()
+    listMonitors.mockReset()
+  })
+
+  it.each([
+    ['quota', 'monitorCommon.checkMode.quota'],
+    ['quota_probe', 'monitorCommon.checkMode.quota_probe'],
+    ['probe', 'monitorCommon.checkMode.probe'],
+  ] as const)('renders the %s badge next to the provider badge', async (mode, label) => {
+    listMonitors.mockResolvedValue({
+      items: [makeMonitor({ check_mode: mode })],
+      total: 1,
+      page: 1,
+      page_size: 20,
+      pages: 1,
+    })
+    const wrapper = mountView()
+    await flushPromises()
+
+    const cell = wrapper.get('.provider-cell')
+    expect(cell.text()).toContain(label)
+    // provider 徽章仍在（不因并列展示被顶掉）。
+    expect(cell.text()).toContain('monitorCommon.providers.openai')
+
+    const badges = cell.findAll('span')
+    const modeBadge = badges.find(el => el.text() === label)
+    expect(modeBadge).toBeDefined()
+    // quota 系=蓝、probe=中性灰的配色区分。
+    const cls = modeBadge!.attributes('class')
+    if (mode === 'probe') {
+      expect(cls).toContain('bg-gray-100')
+      expect(cls).not.toContain('bg-blue-100')
+    } else {
+      expect(cls).toContain('bg-blue-100')
+      expect(cls).not.toContain('bg-gray-100')
+    }
+    wrapper.unmount()
+  })
+})
diff --git a/frontend/src/views/admin/__tests__/MonitorFormDialog.accountSelector.spec.ts b/frontend/src/views/admin/__tests__/MonitorFormDialog.accountSelector.spec.ts
index 9ff3fcd2b2..ba72d18f4e 100644
--- a/frontend/src/views/admin/__tests__/MonitorFormDialog.accountSelector.spec.ts
+++ b/frontend/src/views/admin/__tests__/MonitorFormDialog.accountSelector.spec.ts
@@ -308,4 +308,69 @@ describe('MonitorFormDialog linked account selector', () => {
     expect(accountTrigger(wrapper).text()).not.toContain('alpha')
     expect(accountTrigger(wrapper).text()).toContain('linkedAccountPlaceholder')
   })
+
+  // P2-7(b)：antigravity 强制的 quota 在切走时要对称还原，占位模型一并清掉。
+  it('restores probe mode and clears the quota placeholder when switching away from antigravity', async () => {
+    accountsGetById.mockRejectedValue(new Error('gone'))
+    const wrapper = mountDialog(makeMonitor({
+      provider: 'antigravity',
+      check_mode: 'quota',
+      account_id: 7,
+      endpoint: '',
+      primary_model: 'quota',
+    }))
+    await flushPromises()
+
+    await wrapper.get('[data-testid="monitor-provider-anthropic"]').trigger('click')
+    await flushPromises()
+
+    // 占位模型已被清空：probe 模式必填校验拦下提交，而不是拿 'quota' 探活。
+    await wrapper.get('#channel-monitor-form').trigger('submit')
+    await flushPromises()
+    expect(monitorUpdate).not.toHaveBeenCalled()
+
+    await wrapper.get('[data-testid="monitor-primary-model"]').setValue('claude-sonnet-4-5')
+    await wrapper.get('#channel-monitor-form').trigger('submit')
+    await flushPromises()
+    expect(monitorUpdate).toHaveBeenCalledWith(42, expect.objectContaining({
+      check_mode: 'probe',
+      primary_model: 'claude-sonnet-4-5',
+    }))
+  })
+
+  // P2-7(c)：update 切回 probe 显式发 account_id=0 解绑存量关联（null=不动）。
+  it('unbinds the linked account with account_id=0 when a quota monitor switches back to probe', async () => {
+    accountsGetById.mockRejectedValue(new Error('gone'))
+    const wrapper = mountDialog(makeMonitor({
+      provider: 'anthropic',
+      check_mode: 'quota',
+      account_id: 999,
+      endpoint: '',
+      primary_model: 'quota',
+    }))
+    await flushPromises()
+
+    await wrapper.get('[data-testid="monitor-check-mode-probe"]').trigger('click')
+    await wrapper.get('[data-testid="monitor-primary-model"]').setValue('claude-sonnet-4-5')
+    await wrapper.get('#channel-monitor-form').trigger('submit')
+    await flushPromises()
+
+    expect(monitorUpdate).toHaveBeenCalledWith(42, expect.objectContaining({ account_id: 0 }))
+  })
+
+  // P2-7(c)：create 绝不发 0（后端会把 0 存成 &0 触发外键违约），保持 null。
+  it('keeps account_id null when creating a probe monitor', async () => {
+    const wrapper = mountDialog()
+    await flushPromises()
+
+    await wrapper.findAll('input[type="text"]')[0].setValue('my monitor')
+    await wrapper.get('[data-testid="monitor-primary-model"]').setValue('claude-sonnet-4-5')
+    await wrapper.get('#channel-monitor-form').trigger('submit')
+    await flushPromises()
+
+    expect(monitorCreate).toHaveBeenCalledWith(expect.objectContaining({
+      check_mode: 'probe',
+      account_id: null,
+    }))
+  })
 })