diff --git a/frontend/src/i18n/__tests__/localesNoKeyCollision.spec.ts b/frontend/src/i18n/__tests__/localesNoKeyCollision.spec.ts
new file mode 100644
index 0000000000..6e89d10de9
--- /dev/null
+++ b/frontend/src/i18n/__tests__/localesNoKeyCollision.spec.ts
@@ -0,0 +1,82 @@
+import { describe, expect, it } from 'vitest'
+
+import enAdminAccounts from '../locales/en/admin/accounts'
+import enAdminChannels from '../locales/en/admin/channels'
+import enAdminOps from '../locales/en/admin/ops'
+import enAdminOverview from '../locales/en/admin/overview'
+import enAdminResources from '../locales/en/admin/resources'
+import enAdminSettings from '../locales/en/admin/settings'
+import enCommon from '../locales/en/common'
+import enDashboard from '../locales/en/dashboard'
+import enLanding from '../locales/en/landing'
+import enMisc from '../locales/en/misc'
+import zhAdminAccounts from '../locales/zh/admin/accounts'
+import zhAdminChannels from '../locales/zh/admin/channels'
+import zhAdminOps from '../locales/zh/admin/ops'
+import zhAdminOverview from '../locales/zh/admin/overview'
+import zhAdminResources from '../locales/zh/admin/resources'
+import zhAdminSettings from '../locales/zh/admin/settings'
+import zhCommon from '../locales/zh/common'
+import zhDashboard from '../locales/zh/dashboard'
+import zhLanding from '../locales/zh/landing'
+import zhMisc from '../locales/zh/misc'
+
+// locales/{zh,en}/index.ts 与 admin/index.ts 使用对象展开聚合各域模块，
+// 展开模块之间若出现同名顶层键会静默覆盖。本测试将该风险固化为显式失败。
+type Modules = Record<string, Record<string, unknown>>
+
+function collisions(modules: Modules): string[] {
+  const seen = new Map<string, string>()
+  const out: string[] = []
+  for (const [name, mod] of Object.entries(modules)) {
+    for (const key of Object.keys(mod)) {
+      const prev = seen.get(key)
+      if (prev) {
+        out.push(`"${key}" in both ${prev} and ${name}`)
+      } else {
+        seen.set(key, name)
+      }
+    }
+  }
+  return out
+}
+
+const roots: Record<string, Modules> = {
+  zh: { landing: zhLanding, common: zhCommon, dashboard: zhDashboard, misc: zhMisc },
+  en: { landing: enLanding, common: enCommon, dashboard: enDashboard, misc: enMisc }
+}
+
+const admins: Record<string, Modules> = {
+  zh: {
+    overview: zhAdminOverview,
+    channels: zhAdminChannels,
+    accounts: zhAdminAccounts,
+    resources: zhAdminResources,
+    ops: zhAdminOps,
+    settings: zhAdminSettings
+  },
+  en: {
+    overview: enAdminOverview,
+    channels: enAdminChannels,
+    accounts: enAdminAccounts,
+    resources: enAdminResources,
+    ops: enAdminOps,
+    settings: enAdminSettings
+  }
+}
+
+describe.each(Object.keys(roots))('locale %s spread assembly', (locale) => {
+  it('root modules have no overlapping top-level keys', () => {
+    expect(collisions(roots[locale])).toEqual([])
+  })
+
+  it('root modules do not shadow the explicit "admin" namespace', () => {
+    for (const [name, mod] of Object.entries(roots[locale])) {
+      expect(Object.keys(mod), `module ${name} must not define "admin"`).not.toContain('admin')
+    }
+  })
+
+  it('admin modules have no overlapping top-level keys', () => {
+    expect(collisions(admins[locale])).toEqual([])
+  })
+})