diff --git a/apps/desktop/src/main/__tests__/computer-use-host.test.ts b/apps/desktop/src/main/__tests__/computer-use-host.test.ts
index 51c89b636e..3fe5bd3a1e 100644
--- a/apps/desktop/src/main/__tests__/computer-use-host.test.ts
+++ b/apps/desktop/src/main/__tests__/computer-use-host.test.ts
@@ -36,7 +36,7 @@ describe('Computer Use host health', () => {
   it('does not report a binary-only executor as healthy before first use', () => {
     assert.deepEqual(computerUseServiceHealth('maka-cu', snapshot('idle')), {
       state: 'not_run',
-      reason: 'maka-cu 已可用，将在首次调用时启动。',
+      reason: 'cu_executor_lazy_start',
     });
   });
 
@@ -44,7 +44,7 @@ describe('Computer Use host health', () => {
     assert.equal(computerUseServiceHealth('maka-cu', snapshot('ready')).state, 'healthy');
     assert.equal(
       computerUseServiceHealth('maka-cu', snapshot('backing_off')).reason,
-      'maka-cu executor 正在启动或恢复。',
+      'cu_executor_recovering',
     );
     assert.equal(
       computerUseServiceHealth('maka-cu', snapshot('starting')).state,
@@ -52,11 +52,11 @@ describe('Computer Use host health', () => {
     );
     assert.deepEqual(computerUseServiceHealth('maka-cu', snapshot('unavailable')), {
       state: 'not_available',
-      reason: 'maka-cu executor 启动失败或已退出。',
+      reason: 'cu_executor_start_failed',
     });
     assert.deepEqual(computerUseServiceHealth('maka-cu', snapshot('disposed')), {
       state: 'not_available',
-      reason: 'maka-cu executor 已停止。',
+      reason: 'cu_executor_stopped',
     });
   });
 
diff --git a/apps/desktop/src/main/__tests__/github-copilot-local-credential.test.ts b/apps/desktop/src/main/__tests__/github-copilot-local-credential.test.ts
index a034d7cd1d..37d330c738 100644
--- a/apps/desktop/src/main/__tests__/github-copilot-local-credential.test.ts
+++ b/apps/desktop/src/main/__tests__/github-copilot-local-credential.test.ts
@@ -71,7 +71,7 @@ describe('importGitHubCopilotLocalCredential', () => {
     assert.equal(imported.result.ok, false);
     if (!imported.result.ok) {
       assert.equal(imported.result.reason, 'token_exchange_failed');
-      assert.match(imported.result.message, /不支持 classic PAT/);
+      assert.equal(imported.result.code, 'copilot_classic_pat_unsupported');
       assert.equal(imported.result.message.includes('ghp_classic_pat'), false);
     }
     assert.equal(imported.secret, undefined);
@@ -83,7 +83,7 @@ describe('importGitHubCopilotLocalCredential', () => {
     });
 
     assert.equal(imported.result.ok, false);
-    if (!imported.result.ok) assert.match(imported.result.message, /凭据类型不受支持/);
+    if (!imported.result.ok) assert.equal(imported.result.code, 'copilot_credential_type_unsupported');
     assert.equal(imported.secret, undefined);
   });
 
@@ -95,7 +95,7 @@ describe('importGitHubCopilotLocalCredential', () => {
     });
 
     assert.equal(imported.result.ok, false);
-    if (!imported.result.ok) assert.match(imported.result.message, /未找到可导入/);
+    if (!imported.result.ok) assert.equal(imported.result.code, 'copilot_local_credential_missing');
     assert.equal(imported.secret, undefined);
   });
 });
diff --git a/apps/desktop/src/main/__tests__/oauth-result-copy.test.ts b/apps/desktop/src/main/__tests__/oauth-result-copy.test.ts
new file mode 100644
index 0000000000..6e1c75e2d7
--- /dev/null
+++ b/apps/desktop/src/main/__tests__/oauth-result-copy.test.ts
@@ -0,0 +1,60 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import assert from "node:assert/strict";
+import test from "node:test";
+// Lives under main/__tests__ on purpose: desktop main tests run from dist via
+// `node --test "dist/main/**/*.test.js"`, and settings-provider-copy is a pure
+// copy module (no react), so it is safe to exercise from node. Same precedent
+// as permission-center-copy.test.ts.
+import {
+  connectionTestFailureMessage,
+  subscriptionResultMessage,
+} from "../../renderer/features/connection-settings/index.js";
+
+test("renders a coded Copilot import failure per locale, ignoring its machine message", () => {
+  const result = { code: "copilot_subscription_unavailable", message: "copilot_subscription_unavailable" };
+  assert.equal(subscriptionResultMessage(result, "fallback", "zh-CN"), "当前 GitHub 账号没有可用的 Copilot 订阅权限。");
+  assert.equal(subscriptionResultMessage(result, "fallback", "en"), "This GitHub account has no usable Copilot subscription.");
+});
+
+test("renders the typed experimental_disabled reason per locale", () => {
+  const result = { reason: "experimental_disabled", message: "enrollment is disabled for this provider" };
+  assert.equal(subscriptionResultMessage(result, "fallback", "zh-CN"), "本机未启用该账号登录方式；可改用导入兼容凭据，或由管理员启用后重试。");
+  assert.equal(subscriptionResultMessage(result, "fallback", "en"), "This sign-in is not enabled on this install. Import a compatible credential instead, or ask an operator to enable it.");
+});
+
+test("falls back to catalog copy for an unknown code instead of the raw message", () => {
+  const result = { code: "not_a_known_code", message: "内部错误" };
+  assert.equal(subscriptionResultMessage(result, "fallback", "en"), "fallback");
+  assert.equal(subscriptionResultMessage(result, "fallback", "zh-CN"), "fallback");
+});
+
+test("renders provider rate limits consistently from the stable status code", () => {
+  const result = { ok: false, statusCode: 429, errorClass: "provider_unavailable" } as const;
+  const troubleshooting = { auth: "auth", recheck: "recheck" };
+  assert.equal(
+    connectionTestFailureMessage(result, troubleshooting, "zh-CN"),
+    "当前账号或模型服务触发速率限制，请稍后重试。",
+  );
+  assert.equal(
+    connectionTestFailureMessage(result, troubleshooting, "en"),
+    "This account or model service is rate-limited. Try again later.",
+  );
+});
diff --git a/apps/desktop/src/main/__tests__/permission-center-copy.test.ts b/apps/desktop/src/main/__tests__/permission-center-copy.test.ts
index 318b15a877..f68a808474 100644
--- a/apps/desktop/src/main/__tests__/permission-center-copy.test.ts
+++ b/apps/desktop/src/main/__tests__/permission-center-copy.test.ts
@@ -25,3 +25,29 @@ test('presents a granted OS permission as a verified success', () => {
   assert.equal(getPermissionCenterCopy('zh-CN').osStates.granted.tone, 'success');
   assert.equal(getPermissionCenterCopy('en').osStates.granted.tone, 'success');
 });
+
+test('renders capability reason codes per locale', () => {
+  const zh = getPermissionCenterCopy('zh-CN');
+  const en = getPermissionCenterCopy('en');
+  assert.equal(zh.reasons['missing platform credentials'], '未配置平台凭据');
+  assert.equal(en.reasons['missing platform credentials'], 'Platform credentials are not configured');
+  assert.equal(zh.reasons.cu_executor_recovering, 'maka-cu executor 正在启动或恢复。');
+  assert.equal(en.reasons.cu_executor_recovering, 'The maka-cu executor is starting or recovering.');
+});
+
+test('composes the computer-use backend status from snapshot facts per locale', () => {
+  const zh = getPermissionCenterCopy('zh-CN');
+  const en = getPermissionCenterCopy('en');
+  assert.equal(
+    zh.cuBackendStatus(['辅助功能', '屏幕录制'], 'healthy'),
+    'maka-cu artifact 已通过本地完整性检查。等待辅助功能、屏幕录制权限。操作与截图 service 已就绪；按目标与动作类别授权后可操作本机应用。',
+  );
+  assert.equal(
+    zh.cuBackendStatus([], 'not_run'),
+    'maka-cu artifact 已通过本地完整性检查。service 将在首次调用时启动；按目标与动作类别授权后可操作本机应用。',
+  );
+  assert.equal(
+    en.cuBackendStatus(['Accessibility'], 'degraded'),
+    'The maka-cu artifact passed the local integrity check. Waiting for Accessibility permission. The maka-cu service is starting or recovering.',
+  );
+});
diff --git a/apps/desktop/src/main/__tests__/runtime-host-artifacts-ipc-main.test.ts b/apps/desktop/src/main/__tests__/runtime-host-artifacts-ipc-main.test.ts
index 6c452d5922..58f7ed0898 100644
--- a/apps/desktop/src/main/__tests__/runtime-host-artifacts-ipc-main.test.ts
+++ b/apps/desktop/src/main/__tests__/runtime-host-artifacts-ipc-main.test.ts
@@ -52,6 +52,7 @@ function attachmentReadHandler(
 ): Handler {
   const handlers = new Map<string, Handler>();
   registerRuntimeHostArtifactsIpc({
+    uiLocale: () => 'zh-CN' as const,
     ipcMain: {
       handle: (channel, handler) => handlers.set(channel, handler as Handler),
     },
@@ -121,6 +122,7 @@ test("Runtime Host Artifact IPC preserves previews and streams complete exports"
 
   try {
     registerRuntimeHostArtifactsIpc({
+    uiLocale: () => 'zh-CN' as const,
       ipcMain: {
         handle: (channel, handler) => handlers.set(channel, handler as Handler),
       },
diff --git a/apps/desktop/src/main/__tests__/runtime-host-memory-ipc-main.test.ts b/apps/desktop/src/main/__tests__/runtime-host-memory-ipc-main.test.ts
index 17391c12fc..fe7e199457 100644
--- a/apps/desktop/src/main/__tests__/runtime-host-memory-ipc-main.test.ts
+++ b/apps/desktop/src/main/__tests__/runtime-host-memory-ipc-main.test.ts
@@ -175,6 +175,7 @@ test('does not project or open remote Runtime Host file paths', async () => {
   assert.deepEqual(projected.backups.map(({ path }) => path), ['']);
   assert.deepEqual(opened, {
     ok: false,
+    code: 'remote_host_owned',
     message: 'Memory files are owned by the remote Runtime Host',
   });
 });
diff --git a/apps/desktop/src/main/__tests__/settings-memory-copy.test.ts b/apps/desktop/src/main/__tests__/settings-memory-copy.test.ts
new file mode 100644
index 0000000000..48dcb768df
--- /dev/null
+++ b/apps/desktop/src/main/__tests__/settings-memory-copy.test.ts
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  getMemorySettingsCopy,
+  memoryResultMessage,
+  type MemoryResultCode,
+} from '../../renderer/locales/settings-memory-copy.js';
+
+const rejectionCopy = {
+  invalid_content: ['MEMORY.md content is invalid. Check its format and try again.', 'MEMORY.md 内容无效，请检查格式后重试。'],
+  invalid_scope: ['The memory operation has an invalid scope.', '当前记忆操作的作用域无效。'],
+  not_found: ['The memory entry was not found.', '找不到对应的记忆条目。'],
+  not_pending: ['The memory entry is not pending review.', '对应的记忆条目不在待确认状态。'],
+  upload_not_found: ['The memory upload session does not exist or has expired.', '记忆上传会话不存在或已过期。'],
+  upload_incomplete: ['The memory content has not finished uploading.', '记忆内容尚未上传完整。'],
+  upload_conflict: ['Another memory upload is in progress. Try again.', '另一个记忆上传正在进行，请重试。'],
+} satisfies Partial<Record<MemoryResultCode, readonly [string, string]>>;
+
+test('renders Runtime Host memory rejection codes per locale', () => {
+  for (const [code, [en, zh]] of Object.entries(rejectionCopy)) {
+    assert.equal(memoryResultMessage({ code }, getMemorySettingsCopy('en'), 'fallback'), en);
+    assert.equal(memoryResultMessage({ code }, getMemorySettingsCopy('zh-CN'), 'fallback'), zh);
+  }
+});
+
+test('falls back for an unknown Runtime Host memory rejection code', () => {
+  assert.equal(
+    memoryResultMessage({ code: 'future_host_code' }, getMemorySettingsCopy('en'), 'fallback'),
+    'fallback',
+  );
+});
diff --git a/apps/desktop/src/main/browser-message-box.ts b/apps/desktop/src/main/browser-message-box.ts
index 7ab4302cd7..0c5519dc96 100644
--- a/apps/desktop/src/main/browser-message-box.ts
+++ b/apps/desktop/src/main/browser-message-box.ts
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+import type { UiCatalog } from '@maka/core/ui-locale';
 import { randomUUID } from 'node:crypto';
 import { readFileSync } from 'node:fs';
 import { join } from 'node:path';
@@ -348,7 +349,7 @@ export function buildBrowserMessageBoxHtml(
 
 function renderBrowserMessageBoxHtml(input: BrowserMessageBoxPresentation): string {
   const nonce = randomUUID().replaceAll('-', '');
-  const closeLabel = input.locale === 'zh-CN' ? '关闭' : input.locale === 'zh-TW' ? '關閉' : 'Close';
+  const closeLabel = CLOSE_LABEL[input.locale];
   const closeButton = `<button class="window-close" type="button" data-response="${input.cancelId}" aria-label="${closeLabel}">
     <svg viewBox="0 0 24 24" aria-hidden="true"><path d="M18 6 6 18M6 6l12 12" /></svg>
   </button>`;
@@ -638,3 +639,5 @@ function escapeHtml(value: string): string {
     return entities[character] ?? character;
   });
 }
+
+const CLOSE_LABEL = { 'zh-CN': '关闭', 'zh-TW': '關閉', en: 'Close' } satisfies UiCatalog<string>;
diff --git a/apps/desktop/src/main/capability-snapshot.ts b/apps/desktop/src/main/capability-snapshot.ts
index 8c430d9b00..4d54a92a78 100644
--- a/apps/desktop/src/main/capability-snapshot.ts
+++ b/apps/desktop/src/main/capability-snapshot.ts
@@ -27,6 +27,7 @@ import {
   type CapabilityFeatureSignal,
   type CapabilityMemoryAcceptanceSignal,
   type CapabilityPermissionRequirement,
+  type CapabilityReasonCode,
   type CapabilityRuntimeProbeSignal,
   type CapabilitySnapshot,
   type CapabilitySnapshotCollection,
@@ -80,7 +81,7 @@ export function buildCapabilitySnapshotCollection(input: {
       feature: {
         state: 'partial',
         source: 'runtime',
-        reason: 'Daily Review 已聚合本地任务 / 工具 / 模型活动；当前不包含屏幕与应用级录制',
+        reason: 'activity_recorder_partial',
       },
       requiredPermissions: [
         { id: 'screen_recording', required: false, status: permissions.screen_recording.status },
@@ -90,7 +91,7 @@ export function buildCapabilitySnapshotCollection(input: {
       runtimeProbe: {
         state: 'not_run',
         source: 'runtime_probe',
-        reason: '打开 Daily Review 可查看本地活动聚合结果',
+        reason: 'activity_recorder_probe_hint',
       },
     }),
     staticCapability({
@@ -100,7 +101,7 @@ export function buildCapabilitySnapshotCollection(input: {
       feature: {
         state: 'partial',
         source: 'runtime',
-        reason: '本地 MEMORY.md 已可见；自动抽取/写入仍需用户确认',
+        reason: 'memory_partial',
       },
       requiredPermissions: [],
       actionApproval: { state: 'not_required', source: 'not_applicable' },
@@ -108,7 +109,7 @@ export function buildCapabilitySnapshotCollection(input: {
       runtimeProbe: {
         state: 'not_run',
         source: 'runtime_probe',
-        reason: '透明本地记忆为文件读写能力，不做后台探测',
+        reason: 'memory_no_probe',
       },
     }),
     ...BOT_PROVIDERS.map((provider) =>
@@ -138,7 +139,7 @@ function computerUseCapability(
     feature: {
       state: artifactAvailable ? 'enabled' : 'not_available',
       source: 'runtime',
-      reason: computerUseCapabilityReason(input, permissions),
+      reason: input === undefined || input.backendId === 'none' ? 'cu_artifact_missing' : 'cu_backend_status',
     },
     requiredPermissions: [
       { id: 'accessibility', required: true, status: permissions.accessibility.status },
@@ -153,47 +154,11 @@ function computerUseCapability(
       state: input?.health.state ?? 'not_available',
       source: 'runtime_probe',
       lastCheckedAt: now,
-      reason: input?.health.reason ?? 'Computer Use 后端当前不可用。',
+      reason: input?.health.reason ?? 'cu_backend_unavailable',
     },
   });
 }
 
-function computerUseCapabilityReason(
-  input: {
-    backendId: CuBackendId | 'none';
-    health: ReturnType<typeof computerUseServiceHealth>;
-  } | undefined,
-  permissions: PermissionSnapshot['permissions'],
-): string {
-  if (input === undefined || input.backendId === 'none') {
-    return '未找到通过完整性检查的 Computer Use 执行器 artifact。';
-  }
-
-  const reasons = [`${input.backendId} artifact 已通过本地完整性检查。`];
-  const missingPermissions = [
-    ['辅助功能', permissions.accessibility.status],
-    ['屏幕录制', permissions.screen_recording.status],
-  ].filter((entry) => entry[1] !== 'granted').map((entry) => entry[0]);
-  if (missingPermissions.length > 0) {
-    reasons.push(`等待${missingPermissions.join('、')}权限。`);
-  }
-  switch (input.health.state) {
-    case 'not_available':
-      reasons.push(`${input.backendId} service 启动失败、已退出或已停止。`);
-      break;
-    case 'degraded':
-      reasons.push(`${input.backendId} service 正在启动或恢复。`);
-      break;
-    case 'healthy':
-      reasons.push('操作与截图 service 已就绪；按目标与动作类别授权后可操作本机应用。');
-      break;
-    case 'not_run':
-      reasons.push('service 将在首次调用时启动；按目标与动作类别授权后可操作本机应用。');
-      break;
-  }
-  return reasons.join('');
-}
-
 function staticCapability(input: {
   id: CapabilitySnapshot['id'];
   label: string;
@@ -243,7 +208,7 @@ function botCapability(
   };
   const configuration: CapabilityConfigurationSignal = hasConfig
     ? { state: 'present', source: 'settings' }
-    : { state: 'missing', source: 'settings', reason: '未配置平台凭据' };
+    : { state: 'missing', source: 'settings', reason: 'missing platform credentials' };
   const runtimeProbe = runtimeProbeFromBotReadiness(
     status.readiness,
     channel.readinessUpdatedAt,
@@ -274,7 +239,7 @@ function botCapability(
 }
 
 function accessibilitySnapshot(now: number, platform: NodeJS.Platform): OsPermissionSnapshot {
-  if (platform !== 'darwin') return unsupportedPermission('accessibility', now, '仅 macOS TCC 权限适用');
+  if (platform !== 'darwin') return unsupportedPermission('accessibility', now, 'macOS TCC only');
   try {
     const granted = systemPreferences.isTrustedAccessibilityClient(false);
     return {
@@ -282,12 +247,12 @@ function accessibilitySnapshot(now: number, platform: NodeJS.Platform): OsPermis
       status: granted ? 'granted' : 'not_determined',
       source: 'electron',
       checkedAt: now,
-      reason: granted ? undefined : 'macOS 不区分辅助功能权限是未授权还是未申请',
+      reason: granted ? undefined : 'accessibility_status_ambiguous',
       canOpenSettings: true,
       canRequest: false,
     };
-  } catch (error) {
-    return unknownPermission('accessibility', now, generalizedReason(error), true);
+  } catch {
+    return unknownPermission('accessibility', now, true);
   }
 }
 
@@ -298,11 +263,7 @@ function mediaPermissionSnapshot(
   platform: NodeJS.Platform,
 ): OsPermissionSnapshot {
   if (!supportsMediaPermissionProbe(id, platform)) {
-    return unsupportedPermission(
-      id,
-      now,
-      '屏幕录制权限状态仅能在 macOS 上读取',
-    );
+    return unsupportedPermission(id, now, 'screen_recording_status_mac_only');
   }
   try {
     const status = mapMediaAccessStatus(systemPreferences.getMediaAccessStatus(mediaType));
@@ -314,8 +275,8 @@ function mediaPermissionSnapshot(
       checkedAt: now,
       ...actions,
     };
-  } catch (error) {
-    return unknownPermission(id, now, generalizedReason(error), platform === 'darwin');
+  } catch {
+    return unknownPermission(id, now, platform === 'darwin');
   }
 }
 
@@ -328,9 +289,9 @@ function notificationSnapshot(now: number, platform: NodeJS.Platform): OsPermiss
     checkedAt: now,
     reason: supported
       ? platform === 'darwin'
-        ? 'Electron 无法可靠读取 macOS 通知授权状态，请在系统设置中确认'
-        : 'Electron 无法可靠读取当前系统的通知授权状态'
-      : 'Electron 通知能力不可用',
+        ? 'notifications_status_unreadable_macos'
+        : 'notifications_status_unreadable'
+      : 'notifications_unsupported',
     canOpenSettings: platform === 'darwin',
     // Showing a Notification is not an authorization API and does not report
     // whether macOS delivered or suppressed it. Never present that probe as a
@@ -340,19 +301,23 @@ function notificationSnapshot(now: number, platform: NodeJS.Platform): OsPermiss
 }
 
 function automationSnapshot(now: number, platform: NodeJS.Platform): OsPermissionSnapshot {
-  if (platform !== 'darwin') return unsupportedPermission('automation', now, '仅 macOS TCC 权限适用');
+  if (platform !== 'darwin') return unsupportedPermission('automation', now, 'macOS TCC only');
   return {
     id: 'automation',
     status: 'unknown',
     source: 'static',
     checkedAt: now,
-    reason: 'Electron 暂不支持读取逐 App 的 Apple Events 授权状态',
+    reason: 'no Electron API for per-target Apple Events TCC status',
     canOpenSettings: true,
     canRequest: false,
   };
 }
 
-function unsupportedPermission(id: OsPermissionId, now: number, reason: string): OsPermissionSnapshot {
+function unsupportedPermission(
+  id: OsPermissionId,
+  now: number,
+  reason: CapabilityReasonCode,
+): OsPermissionSnapshot {
   return {
     id,
     status: 'unsupported',
@@ -367,7 +332,6 @@ function unsupportedPermission(id: OsPermissionId, now: number, reason: string):
 function unknownPermission(
   id: OsPermissionId,
   now: number,
-  reason: string,
   canOpenSettings: boolean,
 ): OsPermissionSnapshot {
   return {
@@ -375,12 +339,8 @@ function unknownPermission(
     status: 'unknown',
     source: 'electron',
     checkedAt: now,
-    reason,
+    reason: 'permission_probe_failed',
     canOpenSettings,
     canRequest: false,
   };
 }
-
-function generalizedReason(error: unknown): string {
-  return error instanceof Error ? error.message : 'permission probe failed';
-}
diff --git a/apps/desktop/src/main/computer-use-host.ts b/apps/desktop/src/main/computer-use-host.ts
index 5b5c964b74..aefef19cec 100644
--- a/apps/desktop/src/main/computer-use-host.ts
+++ b/apps/desktop/src/main/computer-use-host.ts
@@ -34,6 +34,7 @@ import {
   selectComputerUseBackend,
   type SelectedComputerUseBackend,
 } from '@maka/computer-use';
+import type { CapabilityReasonCode } from '@maka/core/capabilities';
 import type { CuOverlayHook } from '@maka/runtime/computer-use-types';
 
 export interface ComputerUseHostState {
@@ -147,25 +148,22 @@ export function computerUseServiceHealth(
   state: MakaCuServiceSnapshot | undefined,
 ): {
   state: 'not_available' | 'not_run' | 'healthy' | 'degraded';
-  reason: string;
+  reason: CapabilityReasonCode;
 } {
   if (backendId === 'none' || !state) {
-    return {
-      state: 'not_available',
-      reason: '未找到通过完整性检查且可分发的 maka-cu executor。',
-    };
+    return { state: 'not_available', reason: 'cu_executor_undistributable' };
   }
   switch (state.state) {
     case 'disposed':
-      return { state: 'not_available', reason: 'maka-cu executor 已停止。' };
+      return { state: 'not_available', reason: 'cu_executor_stopped' };
     case 'unavailable':
-      return { state: 'not_available', reason: 'maka-cu executor 启动失败或已退出。' };
+      return { state: 'not_available', reason: 'cu_executor_start_failed' };
     case 'starting':
     case 'backing_off':
-      return { state: 'degraded', reason: 'maka-cu executor 正在启动或恢复。' };
+      return { state: 'degraded', reason: 'cu_executor_recovering' };
     case 'ready':
-      return { state: 'healthy', reason: 'maka-cu executor 已就绪。' };
+      return { state: 'healthy', reason: 'cu_executor_ready' };
     default:
-      return { state: 'not_run', reason: 'maka-cu 已可用，将在首次调用时启动。' };
+      return { state: 'not_run', reason: 'cu_executor_lazy_start' };
   }
 }
diff --git a/apps/desktop/src/main/main.ts b/apps/desktop/src/main/main.ts
index 565583503f..cad8498460 100644
--- a/apps/desktop/src/main/main.ts
+++ b/apps/desktop/src/main/main.ts
@@ -17,7 +17,7 @@
  * under the License.
  */
 
-import { resolveSystemUiLocale } from '@maka/core/ui-locale';
+import { resolveSystemUiLocale, type UiCatalog } from '@maka/core/ui-locale';
 import {
   DEV_LOSER_EXIT_CODE,
   developmentLaunchResultFile,
@@ -105,27 +105,14 @@ if (!app.requestSingleInstanceLock()) {
         .whenReady()
         .then(() => {
           const locale = resolveSystemUiLocale(app.getPreferredSystemLanguages());
-          const isSimplifiedChinese = locale === 'zh-CN';
-          const isTraditionalChinese = locale === 'zh-TW';
+          const copy = DEV_SINGLETON_COPY[locale];
           return showBrowserMessageBox(
             {
               type: 'warning',
-              title: isSimplifiedChinese
-                ? 'Maka Dev 已在运行'
-                : isTraditionalChinese
-                  ? 'Maka Dev 已在執行'
-                  : 'Maka Dev is already running',
-              message: isSimplifiedChinese
-                ? '另一个 Maka Dev 实例正在使用此开发配置。'
-                : isTraditionalChinese
-                  ? '另一個 Maka Dev 執行個體正在使用此開發設定。'
-                  : 'Another Maka Dev instance is using this development profile.',
-              detail: isSimplifiedChinese
-                ? `开发配置：${profilePath}\n\n请先退出正在运行的实例，然后重试。`
-                : isTraditionalChinese
-                  ? `開發設定：${profilePath}\n\n請先退出正在執行的執行個體，然後重試。`
-                  : `Development profile: ${profilePath}\n\nQuit the running instance, then retry.`,
-              buttons: [isSimplifiedChinese ? '退出' : isTraditionalChinese ? '退出' : 'Exit'],
+              title: copy.title,
+              message: copy.message,
+              detail: copy.detail(profilePath),
+              buttons: [copy.exit],
               defaultId: 0,
               cancelId: 0,
             },
@@ -246,3 +233,29 @@ if (!app.requestSingleInstanceLock()) {
       }
     });
 }
+
+const DEV_SINGLETON_COPY = {
+  'zh-CN': {
+    title: 'Maka Dev 已在运行',
+    message: '另一个 Maka Dev 实例正在使用此开发配置。',
+    detail: (profilePath: string) => `开发配置：${profilePath}\n\n请先退出正在运行的实例，然后重试。`,
+    exit: '退出',
+  },
+  'zh-TW': {
+    title: 'Maka Dev 已在執行',
+    message: '另一個 Maka Dev 執行個體正在使用此開發設定。',
+    detail: (profilePath: string) => `開發設定：${profilePath}\n\n請先退出正在執行的執行個體，然後重試。`,
+    exit: '退出',
+  },
+  en: {
+    title: 'Maka Dev is already running',
+    message: 'Another Maka Dev instance is using this development profile.',
+    detail: (profilePath: string) => `Development profile: ${profilePath}\n\nQuit the running instance, then retry.`,
+    exit: 'Exit',
+  },
+} satisfies UiCatalog<{
+  title: string;
+  message: string;
+  detail(profilePath: string): string;
+  exit: string;
+}>;
diff --git a/apps/desktop/src/main/oauth/github-copilot-local-credential.ts b/apps/desktop/src/main/oauth/github-copilot-local-credential.ts
index 2a39fed564..21bcc4854a 100644
--- a/apps/desktop/src/main/oauth/github-copilot-local-credential.ts
+++ b/apps/desktop/src/main/oauth/github-copilot-local-credential.ts
@@ -56,8 +56,8 @@ export async function importGitHubCopilotLocalCredential(
         result: {
           ok: false,
           reason: 'token_exchange_failed',
-          message:
-            'GitHub Copilot 不支持 classic PAT；请使用兼容 OAuth 登录或具有 Copilot Requests 权限的 fine-grained PAT。',
+          code: 'copilot_classic_pat_unsupported',
+          message: 'GitHub Copilot does not accept classic PATs.',
         },
       };
     }
@@ -66,7 +66,8 @@ export async function importGitHubCopilotLocalCredential(
         result: {
           ok: false,
           reason: 'token_exchange_failed',
-          message: '当前 GitHub 凭据类型不受支持；请使用兼容 OAuth 登录或 fine-grained PAT。',
+          code: 'copilot_credential_type_unsupported',
+          message: 'Unsupported GitHub credential type.',
         },
       };
     }
@@ -79,7 +80,8 @@ export async function importGitHubCopilotLocalCredential(
       result: {
         ok: false,
         reason: 'token_exchange_failed',
-        message: '未找到可导入的 GitHub 凭据；请先使用 gh 登录或配置兼容凭据。',
+        code: 'copilot_local_credential_missing',
+        message: 'No importable GitHub credential found.',
       },
     };
   }
diff --git a/apps/desktop/src/main/runtime-host-artifacts-ipc-main.ts b/apps/desktop/src/main/runtime-host-artifacts-ipc-main.ts
index 4032293ef4..b012daa815 100644
--- a/apps/desktop/src/main/runtime-host-artifacts-ipc-main.ts
+++ b/apps/desktop/src/main/runtime-host-artifacts-ipc-main.ts
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+import type { UiCatalog, UiLocale } from '@maka/core/ui-locale';
 import { randomUUID } from "node:crypto";
 import { open, mkdir, rename, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
@@ -36,6 +37,7 @@ import type { createMainWindowController } from "./main-window.js";
 import type { DesktopRuntimeHostClient } from "./runtime-host-client.js";
 
 interface RuntimeHostArtifactsIpcDeps {
+  uiLocale(): UiLocale;
   readonly ipcMain: ReconnectableReadIpcMain;
   readonly client: DesktopRuntimeHostClient;
   readonly mainWindowController: ReturnType<typeof createMainWindowController>;
@@ -130,7 +132,7 @@ export function registerRuntimeHostArtifactsIpc(
       if (!artifact) return { ok: false, reason: "not_found" };
       if (artifact.status === "deleted") return { ok: false, reason: "deleted" };
       const result = await deps.mainWindowController.showSaveDialog({
-        title: `另存为 ${artifact.name}`,
+        title: ARTIFACT_DIALOG_COPY[deps.uiLocale()].saveAs(artifact.name),
         defaultPath: artifact.name,
       });
       if (result.canceled || !result.filePath) {
@@ -250,3 +252,9 @@ async function materializeArtifact(
     throw error;
   }
 }
+
+const ARTIFACT_DIALOG_COPY = {
+  'zh-CN': { saveAs: (name: string) => `另存为 ${name}` },
+  'zh-TW': { saveAs: (name: string) => `另存為 ${name}` },
+  en: { saveAs: (name: string) => `Save ${name} as` },
+} satisfies UiCatalog<{ saveAs(name: string): string }>;
diff --git a/apps/desktop/src/main/runtime-host-boot.ts b/apps/desktop/src/main/runtime-host-boot.ts
index 7caee1cf13..d30e6e91aa 100644
--- a/apps/desktop/src/main/runtime-host-boot.ts
+++ b/apps/desktop/src/main/runtime-host-boot.ts
@@ -1064,6 +1064,8 @@ const startLocalRuntimeHostManager = () => startRuntimeHostDesktopManager(
               const chatId = requireScheduledTaskEffectString(input.chatId, "chatId");
               const title = requireScheduledTaskEffectString(input.title, "title");
               const body = typeof input.body === "string" ? input.body.trim() : "";
+              // Bot-channel notices follow the bot audience language, not the
+              // desktop UI locale; localization tracked under the locale issue.
               const text = [`【定时任务】${title}`, ...(body ? ["", body] : [])].join("\n");
               const sent = await botRegistry.sendMessage(platform, chatId, text);
               if (!sent) throw new Error("ScheduledTask bot channel is unavailable");
@@ -1496,6 +1498,7 @@ function registerHostClientIpc(
   });
   registerRuntimeHostRendererIpc({ ipcMain: scopedIpc, client });
   registerRuntimeHostArtifactsIpc({
+    uiLocale: () => desktopLocale.current(),
     ipcMain: scopedIpc,
     client,
     mainWindowController,
@@ -1532,6 +1535,7 @@ function registerHostClientIpc(
     module: runtimeHostSettings,
   });
   registerRuntimeHostConfigIpc({
+    uiLocale: () => desktopLocale.current(),
     ipcMain: scopedIpc,
     client,
     mainWindowController,
diff --git a/apps/desktop/src/main/runtime-host-config-ipc-main.ts b/apps/desktop/src/main/runtime-host-config-ipc-main.ts
index 073283c34b..a4458df2b7 100644
--- a/apps/desktop/src/main/runtime-host-config-ipc-main.ts
+++ b/apps/desktop/src/main/runtime-host-config-ipc-main.ts
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+import type { UiCatalog, UiLocale } from '@maka/core/ui-locale';
 import { readFile, writeFile } from 'node:fs/promises';
 import { isDeepStrictEqual } from 'node:util';
 import type { IpcMain } from 'electron';
@@ -67,6 +68,7 @@ import {
 } from '@maka/storage/config-transfer';
 
 interface RuntimeHostConfigIpcDeps {
+  uiLocale(): UiLocale;
   readonly ipcMain: Pick<IpcMain, 'handle'>;
   readonly client: DesktopRuntimeHostClient;
   readonly mainWindowController: ReturnType<typeof createMainWindowController>;
@@ -100,7 +102,7 @@ export function registerRuntimeHostConfigIpc(
       }
       const today = new Date().toISOString().slice(0, 10);
       const result = await deps.mainWindowController.showSaveDialog({
-        title: '导出 Maka 配置',
+        title: CONFIG_DIALOG_COPY[deps.uiLocale()].exportTitle,
         defaultPath: `maka-config-${today}.json`,
         filters: [{ name: 'Maka Config', extensions: ['json'] }],
       });
@@ -129,7 +131,7 @@ export function registerRuntimeHostConfigIpc(
     'config:import',
     async (_event, input: { strategy?: unknown } = {}) => {
       const result = await deps.mainWindowController.showOpenDialog({
-        title: '导入 Maka 配置',
+        title: CONFIG_DIALOG_COPY[deps.uiLocale()].importTitle,
         properties: ['openFile'],
         filters: [{ name: 'Maka Config', extensions: ['json'] }],
       });
@@ -656,3 +658,9 @@ function sanitizeCategories(value: unknown): ConfigCategory[] {
 function sanitizeStrategy(value: unknown): ConnectionConflictStrategy {
   return value === 'overwrite' ? 'overwrite' : 'skip';
 }
+
+const CONFIG_DIALOG_COPY = {
+  'zh-CN': { exportTitle: '导出 Maka 配置', importTitle: '导入 Maka 配置' },
+  'zh-TW': { exportTitle: '匯出 Maka 設定', importTitle: '匯入 Maka 設定' },
+  en: { exportTitle: 'Export Maka configuration', importTitle: 'Import Maka configuration' },
+} satisfies UiCatalog<{ exportTitle: string; importTitle: string }>;
diff --git a/apps/desktop/src/main/runtime-host-github-copilot-ipc-main.ts b/apps/desktop/src/main/runtime-host-github-copilot-ipc-main.ts
index d463637e23..45de4a1174 100644
--- a/apps/desktop/src/main/runtime-host-github-copilot-ipc-main.ts
+++ b/apps/desktop/src/main/runtime-host-github-copilot-ipc-main.ts
@@ -53,7 +53,7 @@ export function registerRuntimeHostGitHubCopilotIpc(deps: RuntimeHostGitHubCopil
   deps.ipcMain.handle('github-copilot:connect-existing-login', async () => {
     const imported = await importExistingLogin();
     if (!imported.result.ok) return imported.result;
-    if (!imported.secret) return storageFailure('GitHub Copilot login produced no credential');
+    if (!imported.secret) return storageFailure('copilot_import_no_credential');
 
     try {
       const before = await deps.client.loadConnectionCatalog();
@@ -69,23 +69,23 @@ export function registerRuntimeHostGitHubCopilotIpc(deps: RuntimeHostGitHubCopil
       });
       if (adopted.kind === 'rejected') {
         if (adopted.reason === 'superseded') {
-          return storageFailure('GitHub Copilot 账号在导入期间发生变化，请重试。');
+          return storageFailure('copilot_import_superseded');
         }
         return adopted.reason === 'model_unavailable'
-          ? actionFailure('当前 GitHub 账号没有可用的 Copilot 订阅权限。')
-          : actionFailure('当前 GitHub 凭据无法导入，请检查凭据后重试。');
+          ? actionFailure('copilot_subscription_unavailable')
+          : actionFailure('copilot_credential_import_rejected');
       }
       if (adopted.kind === 'failed') {
         return adopted.errorClass === 'auth'
-          ? actionFailure('当前 GitHub 账号没有可用的 Copilot 订阅权限。')
-          : actionFailure('暂时无法验证 GitHub Copilot 订阅状态，请稍后重试。');
+          ? actionFailure('copilot_subscription_unavailable')
+          : actionFailure('copilot_subscription_check_failed');
       }
 
       await selectAccountDefaultIfMissing(deps.client, adopted.connection.connectionId);
       deps.emitConnectionListChanged();
       return { ok: true as const };
     } catch {
-      return storageFailure('GitHub Copilot login could not be committed to Runtime Host');
+      return storageFailure('copilot_import_commit_failed');
     }
   });
 }
@@ -108,10 +108,10 @@ async function selectAccountDefaultIfMissing(
   }
 }
 
-function actionFailure(message: string) {
-  return { ok: false as const, reason: 'token_exchange_failed' as const, message };
+function actionFailure(code: string) {
+  return { ok: false as const, reason: 'token_exchange_failed' as const, code, message: code };
 }
 
-function storageFailure(message: string) {
-  return { ok: false as const, reason: 'storage_failed' as const, message };
+function storageFailure(code: string) {
+  return { ok: false as const, reason: 'storage_failed' as const, code, message: code };
 }
diff --git a/apps/desktop/src/main/runtime-host-memory-ipc-main.ts b/apps/desktop/src/main/runtime-host-memory-ipc-main.ts
index 1004f497e3..2474cfa9f7 100644
--- a/apps/desktop/src/main/runtime-host-memory-ipc-main.ts
+++ b/apps/desktop/src/main/runtime-host-memory-ipc-main.ts
@@ -54,6 +54,7 @@ type LocalMemoryMutationResult =
       readonly ok: false;
       readonly state: LocalMemoryState;
       readonly reason: string;
+      readonly code: string;
       readonly message: string;
     };
 
@@ -99,6 +100,7 @@ export function registerRuntimeHostMemoryIpc(
       return {
         ok: false as const,
         state,
+        code: "no_backup",
         message: "No Memory backup is available",
       };
     return restoreBackup(deps, backup.kind);
@@ -108,6 +110,7 @@ export function registerRuntimeHostMemoryIpc(
       return {
         ok: false as const,
         state: await getMemoryState(deps),
+        code: "invalid_backup_kind",
         message: "Invalid Memory backup kind",
       };
     }
@@ -140,12 +143,20 @@ export function registerRuntimeHostMemoryIpc(
           deps,
           BACKUP_FILES[state.latestBackup.kind],
         )
-      : { ok: false as const, message: "No Memory backup is available" };
+      : {
+          ok: false as const,
+          code: "no_backup",
+          message: "No Memory backup is available",
+        };
   });
   deps.ipcMain.handle("memory:openBackup", async (_event, kind: unknown) => {
     return isBackupKind(kind)
       ? openMemoryPath(deps, BACKUP_FILES[kind])
-      : { ok: false as const, message: "Invalid Memory backup kind" };
+      : {
+          ok: false as const,
+          code: "invalid_backup_kind",
+          message: "Invalid Memory backup kind",
+        };
   });
 }
 
@@ -479,13 +490,14 @@ async function restoreBackup(
   kind: MemoryBackupKind,
 ): Promise<
   | { ok: true; state: LocalMemoryState }
-  | { ok: false; state: LocalMemoryState; message: string }
+  | { ok: false; state: LocalMemoryState; code: string; message: string }
 > {
   const state = await deps.client.queryMemory({ kind: "state" });
   if (state.kind !== "state") {
     return {
       ok: false,
       state: await getMemoryState(deps),
+      code: "memory_unavailable",
       message: "Memory is unavailable",
     };
   }
@@ -494,6 +506,7 @@ async function restoreBackup(
     return {
       ok: false,
       state: await getMemoryState(deps),
+      code: "backup_not_found",
       message: "Memory backup not found",
     };
   }
@@ -505,7 +518,7 @@ async function restoreBackup(
   }));
   return result.ok
     ? { ok: true, state: result.state }
-    : { ok: false, state: result.state, message: result.message };
+    : { ok: false, state: result.state, code: result.code, message: result.message };
 }
 
 async function openMemoryPath(
@@ -514,10 +527,11 @@ async function openMemoryPath(
     "workspaceRoot" | "allowLocalPaths" | "openPath"
   >,
   fileName: string,
-): Promise<{ ok: true } | { ok: false; message: string }> {
+): Promise<{ ok: true } | { ok: false; code: string; message: string }> {
   if (deps.allowLocalPaths === false) {
     return {
       ok: false,
+      code: "remote_host_owned",
       message: "Memory files are owned by the remote Runtime Host",
     };
   }
@@ -529,15 +543,20 @@ async function openMemoryPath(
     if (!isPathInside(directory, path) || !(await lstat(path)).isFile()) {
       return {
         ok: false,
+        code: "not_regular_file",
         message: "Memory path is not an allowed regular file",
       };
     }
     const error = await deps.openPath(path);
     return error
-      ? { ok: false, message: "The system could not open the Memory file" }
+      ? {
+          ok: false,
+          code: "open_failed",
+          message: "The system could not open the Memory file",
+        }
       : { ok: true };
   } catch {
-    return { ok: false, message: "Memory file not found" };
+    return { ok: false, code: "file_not_found", message: "Memory file not found" };
   }
 }
 
@@ -600,6 +619,7 @@ async function mutationFailure(
     ok: false,
     state: await getMemoryState(deps),
     reason,
+    code: reason,
     message: memoryReasonMessage(reason),
   };
 }
diff --git a/apps/desktop/src/preload/bridge-contract.d.ts b/apps/desktop/src/preload/bridge-contract.d.ts
index 70b940e6b6..d7761c364f 100644
--- a/apps/desktop/src/preload/bridge-contract.d.ts
+++ b/apps/desktop/src/preload/bridge-contract.d.ts
@@ -1508,13 +1508,13 @@ export interface MakaBridge {
     getState(sessionId?: string, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState>;
     save(content: string, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState>;
     reset(host?: DesktopRuntimeHostRef): Promise<LocalMemoryState>;
-    restoreLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; message: string }>;
-    restoreBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; message: string }>;
+    restoreLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; code: string; message: string }>;
+    restoreBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; code: string; message: string }>;
     setEnabled(enabled: boolean, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState>;
     setAgentReadEnabled(enabled: boolean, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState>;
-    openFile(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }>;
-    openLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }>;
-    openBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }>;
+    openFile(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }>;
+    openLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }>;
+    openBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }>;
   };
   attachments: {
     pickDirectory(): Promise<{ ok: true; reference: import('@maka/core/events').DirectoryReference } | { ok: false; reason: 'cancelled' }>;
diff --git a/apps/desktop/src/preload/preload.ts b/apps/desktop/src/preload/preload.ts
index bcb2babbf9..225f1fcb46 100644
--- a/apps/desktop/src/preload/preload.ts
+++ b/apps/desktop/src/preload/preload.ts
@@ -2943,10 +2943,10 @@ const makaBridge = {
     reset(host?: DesktopRuntimeHostRef): Promise<LocalMemoryState> {
       return invokeSelectedRuntimeHost(host, 'memory:reset');
     },
-    restoreLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; message: string }> {
+    restoreLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; code: string; message: string }> {
       return invokeSelectedRuntimeHost(host, 'memory:restoreLatestBackup');
     },
-    restoreBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; message: string }> {
+    restoreBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true; state: LocalMemoryState } | { ok: false; state: LocalMemoryState; code: string; message: string }> {
       return invokeSelectedRuntimeHost(host, 'memory:restoreBackup', kind);
     },
     setEnabled(enabled: boolean, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState> {
@@ -2955,13 +2955,13 @@ const makaBridge = {
     setAgentReadEnabled(enabled: boolean, host?: DesktopRuntimeHostRef): Promise<LocalMemoryState> {
       return invokeSelectedRuntimeHost(host, 'memory:setAgentReadEnabled', enabled);
     },
-    openFile(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }> {
+    openFile(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }> {
       return invokeSelectedRuntimeHost(host, 'memory:openFile');
     },
-    openLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }> {
+    openLatestBackup(host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }> {
       return invokeSelectedRuntimeHost(host, 'memory:openLatestBackup');
     },
-    openBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; message: string }> {
+    openBackup(kind: 'save' | 'reset' | 'restore', host?: DesktopRuntimeHostRef): Promise<{ ok: true } | { ok: false; code: string; message: string }> {
       return invokeSelectedRuntimeHost(host, 'memory:openBackup', kind);
     },
   },
diff --git a/apps/desktop/src/renderer/features/connection-settings/index.ts b/apps/desktop/src/renderer/features/connection-settings/index.ts
index cf1c5ddb5f..109e3d3824 100644
--- a/apps/desktop/src/renderer/features/connection-settings/index.ts
+++ b/apps/desktop/src/renderer/features/connection-settings/index.ts
@@ -37,8 +37,7 @@ export {
   providerPanelActionErrorMessage,
 } from './provider-panel-shared.js';
 export { OnboardingStepForm } from './onboarding-step-form.js';
-export { getProviderSettingsCopy } from './settings-provider-copy.js';
-export { subscriptionResultMessage } from './subscription-result-message.js';
+export { getProviderSettingsCopy, subscriptionActionErrorMessage, subscriptionResultMessage } from './settings-provider-copy.js';
 export type { ProviderSettingsCopy } from './settings-provider-copy.js';
 export type {
   CredentialPresenceStatus,
diff --git a/apps/desktop/src/renderer/features/connection-settings/provider-panel-shared.ts b/apps/desktop/src/renderer/features/connection-settings/provider-panel-shared.ts
index b30f2d1a6f..f77888bfd1 100644
--- a/apps/desktop/src/renderer/features/connection-settings/provider-panel-shared.ts
+++ b/apps/desktop/src/renderer/features/connection-settings/provider-panel-shared.ts
@@ -25,7 +25,7 @@ import { cleanErrorMessage } from '../../application/contracts/connection-error-
 
 export type CredentialPresenceStatus = boolean | 'loading' | 'error';
 
-export function providerPanelActionErrorMessage(error: unknown, locale: UiLocale = 'zh-CN'): string {
+export function providerPanelActionErrorMessage(error: unknown, locale: UiLocale): string {
   const shared = getProviderSettingsCopy(locale).shared;
   // Electron wraps ipcMain.handle rejections as "Error invoking remote method
   // '<channel>': Error: <message>". Classify the original message, not the
@@ -34,8 +34,10 @@ export function providerPanelActionErrorMessage(error: unknown, locale: UiLocale
   const cleaned = redactSecrets(cleanErrorMessage(error)).trim();
   const known = (shared.lastTest as Readonly<Record<string, string>>)[cleaned.toLowerCase()];
   if (known) return known;
-  // Main-process handlers throw display-ready Chinese copy; keep it instead
-  // of flattening it into a coarser classification or the generic fallback.
+  // Main-process handlers still throw display-ready Chinese copy; keep it for
+  // zh only instead of flattening it into a coarser classification. en never
+  // sees raw CJK here — it falls through to the classifier and the fallback.
+  // Full removal waits on producer code-ification (locale roadmap W2b).
   if (locale === 'zh-CN' && /[\u3400-\u9fff]/.test(cleaned)) return cleaned;
   if (/connection_stale|Unable to delete Connection: connection_stale/i.test(cleaned)) {
     if (locale === 'zh-CN') return '连接状态已更新，请刷新列表后再删除。';
@@ -59,7 +61,7 @@ export interface ConnectionTestTroubleshootingCopy {
 export function connectionTestFailureFallback(
   result: ConnectionTestResult,
   copy: ConnectionTestTroubleshootingCopy,
-  locale: UiLocale = 'zh-CN',
+  locale: UiLocale,
 ): string {
   const shared = getProviderSettingsCopy(locale).shared;
   if (result.statusCode === 429) return shared.rateLimit;
@@ -77,14 +79,14 @@ export function connectionTestFailureFallback(
 export function connectionTestFailureMessage(
   result: ConnectionTestResult,
   copy: ConnectionTestTroubleshootingCopy,
-  locale: UiLocale = 'zh-CN',
+  locale: UiLocale,
 ): string {
   const fallback = connectionTestFailureFallback(result, copy, locale);
   if (!result.errorMessage) return fallback;
   return generalizedErrorMessageForLocale(new Error(result.errorMessage), fallback, locale);
 }
 
-export function connectionLastTestMessageDisplay(message: string | undefined, locale: UiLocale = 'zh-CN'): string | undefined {
+export function connectionLastTestMessageDisplay(message: string | undefined, locale: UiLocale): string | undefined {
   if (!message) return undefined;
   const trimmed = message.trim();
   if (!trimmed) return undefined;
diff --git a/apps/desktop/src/renderer/features/connection-settings/settings-provider-copy.ts b/apps/desktop/src/renderer/features/connection-settings/settings-provider-copy.ts
index da6a223f72..0a7774b502 100644
--- a/apps/desktop/src/renderer/features/connection-settings/settings-provider-copy.ts
+++ b/apps/desktop/src/renderer/features/connection-settings/settings-provider-copy.ts
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+import { generalizedErrorMessageForLocale, redactSecrets } from '@maka/core/redaction';
 import type { UiCatalog, UiLocale } from '@maka/core/ui-locale';
 
 type WidenCopy<T> = T extends string
@@ -249,6 +250,20 @@ const zhCopy = {
     loggedOut: '已退出登录', credentialsCleared: '本地凭据已清除。', logoutFailed: '退出失败', logoutFailedRetry: '退出登录失败，请稍后重试。',
     serviceUnavailable: '登录服务暂时不可用，请检查网络后重试。',
     logoutTitle: (name: string) => `退出 ${name} 登录？`,
+    loginConflict: '上一轮浏览器登录仍在进行或已切换，请再点一次登录，或稍后再试。',
+    browserPresentFailed: '无法打开系统浏览器完成登录，请检查是否拦截了弹窗后重试。',
+    resultCodes: {
+      copilot_classic_pat_unsupported: 'GitHub Copilot 不支持 classic PAT；请使用兼容 OAuth 登录或具有 Copilot Requests 权限的 fine-grained PAT。',
+      copilot_credential_type_unsupported: '当前 GitHub 凭据类型不受支持；请使用兼容 OAuth 登录或 fine-grained PAT。',
+      copilot_local_credential_missing: '未找到可导入的 GitHub 凭据；请先使用 gh 登录或配置兼容凭据。',
+      copilot_import_no_credential: 'GitHub Copilot 登录没有产生可用凭据。',
+      copilot_import_superseded: 'GitHub Copilot 账号在导入期间发生变化，请重试。',
+      copilot_subscription_unavailable: '当前 GitHub 账号没有可用的 Copilot 订阅权限。',
+      copilot_credential_import_rejected: '当前 GitHub 凭据无法导入，请检查凭据后重试。',
+      copilot_subscription_check_failed: '暂时无法验证 GitHub Copilot 订阅状态，请稍后重试。',
+      copilot_import_commit_failed: 'GitHub Copilot 登录未能写入 Runtime Host。',
+      experimental_disabled: '本机未启用该账号登录方式；可改用导入兼容凭据，或由管理员启用后重试。',
+    },
   },
   oauthSection: {
     signedIn: '已登录', codexDescription: '使用 ChatGPT Plus / Pro 账号添加连接。', xaiDescription: '使用 SuperGrok / X Premium 账号添加连接。',
@@ -417,6 +432,20 @@ const zhTwCopy = {
     logoutDescription: '將刪除本機儲存的訂閱憑據，之後需要重新登入才能繼續使用這些 OAuth 模型。', logout: '退出登入', cancel: '取消',
     loggedOut: '已退出登入', credentialsCleared: '本地憑據已清除。', logoutFailed: '退出失敗', logoutFailedRetry: '退出登入失敗，請稍後重試。',
     serviceUnavailable: '登入服務暫時不可用，請檢查網路後重試。',
+    loginConflict: '上一輪瀏覽器登入仍在進行或已切換，請再按一次登入，或稍後再試。',
+    browserPresentFailed: '無法開啟系統瀏覽器完成登入，請檢查是否封鎖了彈出式視窗後再試。',
+    resultCodes: {
+      copilot_classic_pat_unsupported: 'GitHub Copilot 不支援 classic PAT；請使用相容 OAuth 登入或具有 Copilot Requests 權限的 fine-grained PAT。',
+      copilot_credential_type_unsupported: '目前的 GitHub 憑據類型不受支援；請使用相容 OAuth 登入或 fine-grained PAT。',
+      copilot_local_credential_missing: '找不到可匯入的 GitHub 憑據；請先使用 gh 登入或設定相容憑據。',
+      copilot_import_no_credential: 'GitHub Copilot 登入沒有產生可用憑據。',
+      copilot_import_superseded: 'GitHub Copilot 帳號在匯入期間發生變化，請重試。',
+      copilot_subscription_unavailable: '目前的 GitHub 帳號沒有可用的 Copilot 訂閱權限。',
+      copilot_credential_import_rejected: '目前的 GitHub 憑據無法匯入，請檢查憑據後重試。',
+      copilot_subscription_check_failed: '暫時無法驗證 GitHub Copilot 訂閱狀態，請稍後重試。',
+      copilot_import_commit_failed: 'GitHub Copilot 登入未能寫入 Runtime Host。',
+      experimental_disabled: '本機未啟用該帳號登入方式；可改用匯入相容憑據，或由管理員啟用後重試。',
+    },
     logoutTitle: (name: string) => `退出 ${name} 登入？`,
   },
   oauthSection: {
@@ -588,6 +617,20 @@ const enCopy: ProviderSettingsCopy = {
     loggedOut: 'Signed out', credentialsCleared: 'Local credentials cleared.', logoutFailed: 'Sign-out failed', logoutFailedRetry: 'Sign-out failed. Try again later.',
     serviceUnavailable: 'The sign-in service is temporarily unavailable. Check the network and try again.',
     logoutTitle: (name: string) => `Sign out of ${name}?`,
+    loginConflict: 'A previous browser login is still running or was superseded. Try logging in again shortly.',
+    browserPresentFailed: 'Could not open the system browser for login. Check popup blockers and try again.',
+    resultCodes: {
+      copilot_classic_pat_unsupported: 'GitHub Copilot does not accept classic PATs. Use a compatible OAuth login or a fine-grained PAT with the Copilot Requests permission.',
+      copilot_credential_type_unsupported: 'This GitHub credential type is not supported. Use a compatible OAuth login or a fine-grained PAT.',
+      copilot_local_credential_missing: 'No importable GitHub credential was found. Sign in with gh or configure a compatible credential first.',
+      copilot_import_no_credential: 'The GitHub Copilot login produced no usable credential.',
+      copilot_import_superseded: 'The GitHub Copilot account changed during import. Try again.',
+      copilot_subscription_unavailable: 'This GitHub account has no usable Copilot subscription.',
+      copilot_credential_import_rejected: 'This GitHub credential could not be imported. Check it and try again.',
+      copilot_subscription_check_failed: 'Could not verify the GitHub Copilot subscription right now. Try again later.',
+      copilot_import_commit_failed: 'The GitHub Copilot login could not be committed to Runtime Host.',
+      experimental_disabled: 'This sign-in is not enabled on this install. Import a compatible credential instead, or ask an operator to enable it.',
+    },
   },
   oauthSection: {
     signedIn: 'Signed in', codexDescription: 'Use a ChatGPT Plus / Pro account to add a connection.', xaiDescription: 'Use a SuperGrok or X Premium account to add a connection.',
@@ -618,3 +661,38 @@ const PROVIDER_SETTINGS_COPY = {
 export function getProviderSettingsCopy(locale: UiLocale): ProviderSettingsCopy {
   return PROVIDER_SETTINGS_COPY[locale];
 }
+
+export function subscriptionActionErrorMessage(error: unknown, locale: UiLocale): string {
+  const message = error instanceof Error
+    ? error.message
+    : typeof error === 'string'
+      ? error
+      : '';
+  return subscriptionResultMessage(message, getProviderSettingsCopy(locale).oauthFlow.serviceUnavailable, locale);
+}
+
+export type SubscriptionResultInput =
+  // `code`/`reason` stay `string` on the wire: a newer host may send a code
+  // this client does not know yet, and the guard below maps only known codes.
+  | string
+  | undefined
+  | { readonly code?: string; readonly reason?: string; readonly message?: string };
+
+export function subscriptionResultMessage(input: SubscriptionResultInput, fallback: string, locale: UiLocale): string {
+  const { code, reason, message } = typeof input === 'object' && input !== null ? input : { message: input };
+  const copy = getProviderSettingsCopy(locale).oauthFlow;
+  // Catalog uses exact code keys; the index-signature view maps unknown wire
+  // codes (host version skew) to undefined without a cast.
+  const codes: Readonly<Record<string, string | undefined>> = copy.resultCodes;
+  const mapped = (code && codes[code]) || (reason && codes[reason]);
+  if (mapped) return mapped;
+  const raw = redactSecrets(message ?? '').trim();
+  if (!raw) return fallback;
+  // Stable Host messages, matched before the coarse keyword classifier turns
+  // "authorization" into a generic auth failure that does not tell the user what to do.
+  if (/enrollment is disabled for this provider/i.test(raw)) return copy.resultCodes.experimental_disabled;
+  if (/already in progress|superseded by a new attempt/i.test(raw)) return copy.loginConflict;
+  if (/did not present OAuth|no matching OAuth presentation/i.test(raw)) return copy.browserPresentFailed;
+  const classified = generalizedErrorMessageForLocale(new Error(raw), '', locale);
+  return classified || fallback;
+}
diff --git a/apps/desktop/src/renderer/features/connection-settings/subscription-result-message.ts b/apps/desktop/src/renderer/features/connection-settings/subscription-result-message.ts
deleted file mode 100644
index 125e073d68..0000000000
--- a/apps/desktop/src/renderer/features/connection-settings/subscription-result-message.ts
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-import { generalizedErrorMessageForLocale, redactSecrets } from '@maka/core/redaction';
-import type { UiLocale } from '@maka/core/ui-locale';
-
-export function subscriptionResultMessage(
-  message: string | undefined,
-  fallback: string,
-  locale: UiLocale = 'zh-CN',
-  reason?: string,
-): string {
-  const raw = redactSecrets(message ?? '').trim();
-  // The Host refuses an enrollment this install has not opted into and says so
-  // with a typed reason. Read the reason, not the English message: a reworded
-  // string or an added locale must not silently disable this branch. The
-  // message match stays only as a fallback for callers without a typed reason.
-  if (reason === 'experimental_disabled' || /enrollment is disabled for this provider/i.test(raw)) {
-    if (locale === 'zh-CN') return '本机未启用该账号登录方式；可改用导入兼容凭据，或由管理员启用后重试。';
-    if (locale === 'zh-TW') return '本機未啟用該帳號登入方式；可改用匯入相容憑據，或由管理員啟用後重試。';
-    return 'This sign-in is not enabled on this install. Import a compatible credential instead, or ask an operator to enable it.';
-  }
-  if (!raw) return fallback;
-  if (/already in progress|superseded by a new attempt/i.test(raw)) {
-    if (locale === 'zh-CN') return '上一轮浏览器登录仍在进行或已切换，请再点一次登录，或稍后再试。';
-    if (locale === 'zh-TW') return '上一輪瀏覽器登入仍在進行或已切換，請再按一次登入，或稍後再試。';
-    return 'A previous browser login is still running or was superseded. Try logging in again shortly.';
-  }
-  if (/did not present OAuth|no matching OAuth presentation/i.test(raw)) {
-    if (locale === 'zh-CN') return '无法打开系统浏览器完成登录，请检查是否拦截了弹窗后重试。';
-    if (locale === 'zh-TW') return '無法開啟系統瀏覽器完成登入，請檢查是否封鎖了彈出式視窗後再試。';
-    return 'Could not open the system browser for login. Check popup blockers and try again.';
-  }
-  const classified = generalizedErrorMessageForLocale(new Error(raw), '', locale);
-  if (classified) return classified;
-  return locale === 'zh-CN' || !/[\u4e00-\u9fff]/.test(raw) ? raw : fallback;
-}
diff --git a/apps/desktop/src/renderer/locales/permission-center-copy.ts b/apps/desktop/src/renderer/locales/permission-center-copy.ts
index 91df593854..92953a7a25 100644
--- a/apps/desktop/src/renderer/locales/permission-center-copy.ts
+++ b/apps/desktop/src/renderer/locales/permission-center-copy.ts
@@ -20,9 +20,11 @@
 import type { StatusSemantic } from '@maka/ui';
 import type {
   CapabilityReadinessState,
+  CapabilityReasonCode,
   CapabilitySnapshot,
   OsPermissionId,
   OsPermissionState,
+  RuntimeProbeState,
 } from '@maka/core/capabilities';
 
 import type { UiCatalog, UiLocale } from '@maka/core/ui-locale';
@@ -94,6 +96,11 @@ export type PermissionCenterCopy = {
   /** macOS drag-to-grant onboarding (accessibility / screen recording). */
   dragGrant: string;
   dragGranting: string;
+  reasons: Record<Exclude<CapabilityReasonCode, 'cu_backend_status'>, string>;
+  // Single-backend assumption: CU_BACKEND_IDS is ['maka-cu'], so the backend
+  // name stays a literal in copy. Revisit when a second backend lands.
+  cuBackendStatus(missingPermissionLabels: readonly string[], health: RuntimeProbeState): string;
+  reasonFallback: string;
 };
 
 const PERMISSION_CENTER_COPY = {
@@ -143,6 +150,40 @@ const PERMISSION_CENTER_COPY = {
     requiredPermissions: '所需系统权限', requiredPermissionsAria: (label) => `${label}所需系统权限列表`, guidance: '处理建议', guidanceAria: (label) => `${label}处理建议列表`,
     auditSection: '审计记录', noAudit: '暂无审计记录', auditAria: (label) => `${label}审计记录列表`,
     impact: '影响功能', opening: '打开中…', openSettings: '前往系统设置', requesting: '请求中…', request: '请求授权', dragGrant: '引导授权', dragGranting: '引导中…',
+    reasons: {
+      disabled: '该能力当前已关闭。',
+      'missing platform credentials': '未配置平台凭据',
+      'macOS TCC only': '仅 macOS TCC 权限适用',
+      'no Electron API for per-target Apple Events TCC status': 'Electron 暂不支持读取逐 App 的 Apple Events 授权状态',
+      cu_artifact_missing: '未找到通过完整性检查的 Computer Use 执行器 artifact。',
+      cu_backend_unavailable: 'Computer Use 后端当前不可用。',
+      cu_executor_undistributable: '未找到通过完整性检查且可分发的 maka-cu executor。',
+      cu_executor_stopped: 'maka-cu executor 已停止。',
+      cu_executor_start_failed: 'maka-cu executor 启动失败或已退出。',
+      cu_executor_recovering: 'maka-cu executor 正在启动或恢复。',
+      cu_executor_ready: 'maka-cu executor 已就绪。',
+      cu_executor_lazy_start: 'maka-cu 已可用，将在首次调用时启动。',
+      activity_recorder_partial: 'Daily Review 已聚合本地任务 / 工具 / 模型活动；当前不包含屏幕与应用级录制',
+      activity_recorder_probe_hint: '打开 Daily Review 可查看本地活动聚合结果',
+      memory_partial: '本地 MEMORY.md 已可见；自动抽取/写入仍需用户确认',
+      memory_no_probe: '透明本地记忆为文件读写能力，不做后台探测',
+      accessibility_status_ambiguous: 'macOS 不区分辅助功能权限是未授权还是未申请',
+      screen_recording_status_mac_only: '屏幕录制权限状态仅能在 macOS 上读取',
+      notifications_status_unreadable_macos: 'Electron 无法可靠读取 macOS 通知授权状态，请在系统设置中确认',
+      notifications_status_unreadable: 'Electron 无法可靠读取当前系统的通知授权状态',
+      notifications_unsupported: 'Electron 通知能力不可用',
+      permission_probe_failed: '权限探测失败',
+    },
+    cuBackendStatus: (missing, health) =>
+      'maka-cu artifact 已通过本地完整性检查。'
+      + (missing.length > 0 ? `等待${missing.join('、')}权限。` : '')
+      + ({
+        not_available: 'maka-cu service 启动失败、已退出或已停止。',
+        degraded: 'maka-cu service 正在启动或恢复。',
+        healthy: '操作与截图 service 已就绪；按目标与动作类别授权后可操作本机应用。',
+        not_run: 'service 将在首次调用时启动；按目标与动作类别授权后可操作本机应用。',
+      } satisfies Record<RuntimeProbeState, string>)[health],
+    reasonFallback: '状态详情请查看运行日志。',
   },
   'zh-TW': {
     readiness: {
@@ -190,6 +231,40 @@ const PERMISSION_CENTER_COPY = {
     requiredPermissions: '所需系統權限', requiredPermissionsAria: (label) => `${label}所需系統權限列表`, guidance: '處理建議', guidanceAria: (label) => `${label}處理建議列表`,
     auditSection: '審計記錄', noAudit: '暫無審計記錄', auditAria: (label) => `${label}審計記錄列表`,
     impact: '影響功能', opening: '開啟中…', openSettings: '前往系統設定', requesting: '請求中…', request: '請求授權', dragGrant: '引導授權', dragGranting: '引導中…',
+    reasons: {
+      disabled: '此能力目前已關閉。',
+      'missing platform credentials': '未設定平台憑據',
+      'macOS TCC only': '僅 macOS TCC 權限適用',
+      'no Electron API for per-target Apple Events TCC status': 'Electron 暫不支援讀取逐 App 的 Apple Events 授權狀態',
+      cu_artifact_missing: '找不到通過完整性檢查的 Computer Use 執行器 artifact。',
+      cu_backend_unavailable: 'Computer Use 後端目前無法使用。',
+      cu_executor_undistributable: '找不到通過完整性檢查且可分發的 maka-cu executor。',
+      cu_executor_stopped: 'maka-cu executor 已停止。',
+      cu_executor_start_failed: 'maka-cu executor 啟動失敗或已退出。',
+      cu_executor_recovering: 'maka-cu executor 正在啟動或恢復。',
+      cu_executor_ready: 'maka-cu executor 已就緒。',
+      cu_executor_lazy_start: 'maka-cu 已可用，將在首次呼叫時啟動。',
+      activity_recorder_partial: 'Daily Review 已彙整本機任務 / 工具 / 模型活動；目前不包含螢幕與應用程式層級錄製',
+      activity_recorder_probe_hint: '開啟 Daily Review 可檢視本機活動彙整結果',
+      memory_partial: '本機 MEMORY.md 已可見；自動擷取/寫入仍需使用者確認',
+      memory_no_probe: '透明本機記憶為檔案讀寫能力，不做背景探測',
+      accessibility_status_ambiguous: 'macOS 不區分輔助使用權限是未授權還是未申請',
+      screen_recording_status_mac_only: '螢幕錄製權限狀態僅能在 macOS 上讀取',
+      notifications_status_unreadable_macos: 'Electron 無法可靠讀取 macOS 通知授權狀態，請在系統設定中確認',
+      notifications_status_unreadable: 'Electron 無法可靠讀取目前系統的通知授權狀態',
+      notifications_unsupported: 'Electron 通知能力無法使用',
+      permission_probe_failed: '權限探測失敗',
+    },
+    cuBackendStatus: (missing, health) =>
+      'maka-cu artifact 已通過本機完整性檢查。'
+      + (missing.length > 0 ? `等待${missing.join('、')}權限。` : '')
+      + ({
+        not_available: 'maka-cu service 啟動失敗、已退出或已停止。',
+        degraded: 'maka-cu service 正在啟動或恢復。',
+        healthy: '操作與截圖 service 已就緒；依目標與動作類別授權後可操作本機應用程式。',
+        not_run: 'service 將在首次呼叫時啟動；依目標與動作類別授權後可操作本機應用程式。',
+      } satisfies Record<RuntimeProbeState, string>)[health],
+    reasonFallback: '狀態詳情請查看執行日誌。',
   },
   en: {
     readiness: {
@@ -237,6 +312,40 @@ const PERMISSION_CENTER_COPY = {
     requiredPermissions: 'Required system permissions', requiredPermissionsAria: (label) => `${label} required system permissions`, guidance: 'Suggested actions', guidanceAria: (label) => `${label} suggested actions`,
     auditSection: 'Audit records', noAudit: 'No audit records', auditAria: (label) => `${label} audit records`,
     impact: 'Affects', opening: 'Opening…', openSettings: 'Open System Settings', requesting: 'Requesting…', request: 'Request permission', dragGrant: 'Guide me', dragGranting: 'Opening…',
+    reasons: {
+      disabled: 'This capability is turned off.',
+      'missing platform credentials': 'Platform credentials are not configured',
+      'macOS TCC only': 'Only macOS TCC permissions apply',
+      'no Electron API for per-target Apple Events TCC status': 'Electron cannot read per-app Apple Events authorization status',
+      cu_artifact_missing: 'No Computer Use executor artifact passed the integrity check.',
+      cu_backend_unavailable: 'The Computer Use backend is currently unavailable.',
+      cu_executor_undistributable: 'No distributable maka-cu executor passed the integrity check.',
+      cu_executor_stopped: 'The maka-cu executor has stopped.',
+      cu_executor_start_failed: 'The maka-cu executor failed to start or has exited.',
+      cu_executor_recovering: 'The maka-cu executor is starting or recovering.',
+      cu_executor_ready: 'The maka-cu executor is ready.',
+      cu_executor_lazy_start: 'maka-cu is available and starts on first use.',
+      activity_recorder_partial: 'Daily Review aggregates local task, tool, and model activity; screen and app-level recording is not included.',
+      activity_recorder_probe_hint: 'Open Daily Review to see the local activity summary.',
+      memory_partial: 'The local MEMORY.md is visible; automatic extraction and writes still require confirmation.',
+      memory_no_probe: 'Transparent local memory is plain file access, so no background probe runs.',
+      accessibility_status_ambiguous: 'macOS does not distinguish denied from never-requested Accessibility permission',
+      screen_recording_status_mac_only: 'Screen Recording permission status can only be read on macOS',
+      notifications_status_unreadable_macos: 'Electron cannot reliably read macOS notification authorization; check System Settings',
+      notifications_status_unreadable: 'Electron cannot reliably read notification authorization on this system',
+      notifications_unsupported: 'Electron notifications are unavailable',
+      permission_probe_failed: 'Permission probe failed',
+    },
+    cuBackendStatus: (missing, health) =>
+      'The maka-cu artifact passed the local integrity check. '
+      + (missing.length > 0 ? `Waiting for ${missing.join(', ')} permission. ` : '')
+      + ({
+        not_available: 'The maka-cu service failed to start, exited, or was stopped.',
+        degraded: 'The maka-cu service is starting or recovering.',
+        healthy: 'The action and screenshot service is ready; grant by target and action category to operate local apps.',
+        not_run: 'The service starts on first use; grant by target and action category to operate local apps.',
+      } satisfies Record<RuntimeProbeState, string>)[health],
+    reasonFallback: 'See the runtime logs for details.',
   },
 } satisfies UiCatalog<PermissionCenterCopy>;
 
diff --git a/apps/desktop/src/renderer/locales/settings-data-copy.ts b/apps/desktop/src/renderer/locales/settings-data-copy.ts
index 9ad0c79a31..b8bce4bc15 100644
--- a/apps/desktop/src/renderer/locales/settings-data-copy.ts
+++ b/apps/desktop/src/renderer/locales/settings-data-copy.ts
@@ -28,7 +28,8 @@ export type DataSettingsCopy = {
   };
   loadFailed: string; openFailed(label: string): string; pathCopied: string; copyFailed: string; copyFailedDetail: string;
   historyCleared: string; historyClearedDetail: string; selectCategory: string; exported: string; exportedDetail(items: readonly string[]): string;
-  exportFailed: string; noCategories: string; tryAgain: string; imported: string; importFailed: string; invalidFile: string;
+  exportFailed: string; noCategories: string; tryAgain: string; imported: string; importFailed: string;
+  importFailures: Record<'not_json' | 'malformed' | 'unsupported_version', string>;
   rows: {
     workspace: string; workspaceDetail: string; loadValueFailed: string; loading: string;
     history: string; historyDetail: string;
@@ -55,7 +56,8 @@ const SETTINGS_DATA_COPY = {
     loadFailed: '载入数据目录失败', openFailed: (label) => `无法打开${label}`, pathCopied: '已复制工作区路径', copyFailed: '复制失败', copyFailedDetail: '剪贴板不可用或被系统拒绝。',
     historyCleared: '已清空输入历史', historyClearedDetail: '已发送的提示词记录已从本机移除。', selectCategory: '请至少选择一个类别',
     exported: '已导出配置', exportedDetail: (items) => `包含：${items.join('、')}`, exportFailed: '导出失败', noCategories: '未选择任何类别', tryAgain: '请稍后重试',
-    imported: '已导入配置', importFailed: '导入失败', invalidFile: '文件无效或版本不受支持。',
+    imported: '已导入配置', importFailed: '导入失败',
+    importFailures: { not_json: '文件不是有效的 JSON。', malformed: '配置文件结构无效。', unsupported_version: '配置文件版本不受支持。' },
     rows: {
       workspace: '工作区路径', workspaceDetail: '任务、设置、凭据和技能文件都存在这个目录下。', loadValueFailed: '载入失败', loading: '正在加载…',
       history: '输入历史', historyDetail: '上箭头 / 下箭头调出的已发送提示词记录，保存在本机、重启后仍在。清空后无法恢复。',
@@ -82,7 +84,8 @@ const SETTINGS_DATA_COPY = {
     loadFailed: '載入資料目錄失敗', openFailed: (label) => `無法開啟${label}`, pathCopied: '已複製工作區路徑', copyFailed: '複製失敗', copyFailedDetail: '剪貼簿不可用或被系統拒絕。',
     historyCleared: '已清空輸入歷史', historyClearedDetail: '已傳送的提示詞記錄已從本機移除。', selectCategory: '請至少選擇一個類別',
     exported: '已匯出設定', exportedDetail: (items) => `包含：${items.join('、')}`, exportFailed: '匯出失敗', noCategories: '未選擇任何類別', tryAgain: '請稍後重試',
-    imported: '已匯入設定', importFailed: '匯入失敗', invalidFile: '檔案無效或版本不受支援。',
+    imported: '已匯入設定', importFailed: '匯入失敗',
+    importFailures: { not_json: '檔案不是有效的 JSON。', malformed: '設定檔結構無效。', unsupported_version: '設定檔版本不受支援。' },
     rows: {
       workspace: '工作區路徑', workspaceDetail: '任務、設定、憑據和技能檔案都存在這個目錄下。', loadValueFailed: '載入失敗', loading: '正在載入…',
       history: '輸入歷史', historyDetail: '上箭頭 / 下箭頭調出的已傳送提示詞記錄，儲存在本機、重啟後仍在。清空後無法恢復。',
@@ -109,7 +112,8 @@ const SETTINGS_DATA_COPY = {
     loadFailed: 'Failed to load data directory', openFailed: (label) => `Could not open ${label}`, pathCopied: 'Workspace path copied', copyFailed: 'Copy failed', copyFailedDetail: 'The clipboard is unavailable or access was denied by the system.',
     historyCleared: 'Input history cleared', historyClearedDetail: 'Sent prompt history was removed from this device.', selectCategory: 'Select at least one category',
     exported: 'Configuration exported', exportedDetail: (items) => `Included: ${items.join(', ')}`, exportFailed: 'Export failed', noCategories: 'No categories selected', tryAgain: 'Try again later',
-    imported: 'Configuration imported', importFailed: 'Import failed', invalidFile: 'The file is invalid or its version is unsupported.',
+    imported: 'Configuration imported', importFailed: 'Import failed',
+    importFailures: { not_json: 'The file is not valid JSON.', malformed: 'The config bundle is malformed.', unsupported_version: 'The config file version is unsupported.' },
     rows: {
       workspace: 'Workspace path', workspaceDetail: 'Tasks, settings, credentials, and skill files are stored in this directory.', loadValueFailed: 'Failed to load', loading: 'Loading…',
       history: 'Input history', historyDetail: 'Previously sent prompts recalled with the Up and Down arrows are kept on this machine and persist across restarts. Clearing them cannot be undone.',
diff --git a/apps/desktop/src/renderer/locales/settings-memory-copy.ts b/apps/desktop/src/renderer/locales/settings-memory-copy.ts
index 39dfd21856..212dec2da7 100644
--- a/apps/desktop/src/renderer/locales/settings-memory-copy.ts
+++ b/apps/desktop/src/renderer/locales/settings-memory-copy.ts
@@ -45,9 +45,18 @@ type MemoryTextKey =
   | 'entryRestoreFailed' | 'promptCopied' | 'promptCopiedDetail'
   | 'restoreDraftAction' | 'archiveDraftAction' | 'restoreAction' | 'archiveAction';
 
+export type MemoryResultCode =
+  | 'no_backup' | 'invalid_backup_kind' | 'memory_unavailable' | 'backup_not_found'
+  | 'remote_host_owned' | 'not_regular_file' | 'open_failed' | 'file_not_found'
+  | 'disabled' | 'incognito_active' | 'safe_mode' | 'oversize'
+  | 'revision_conflict' | 'backup_revision_conflict' | 'invalid_state'
+  | 'invalid_content' | 'invalid_scope' | 'not_found' | 'not_pending'
+  | 'upload_not_found' | 'upload_incomplete' | 'upload_conflict';
+
 export type MemorySettingsCopy = {
   intlLocale: string;
   text: Record<MemoryTextKey, string>;
+  results: Record<MemoryResultCode, string>;
   origins: Record<NonNullable<LocalMemoryState['latestEntry']>['origin'], string>;
   entryStatuses: Record<LocalMemoryState['entries'][number]['status'], string>;
   backupKinds: Record<NonNullable<LocalMemoryState['latestBackup']>['kind'], string>;
@@ -92,19 +101,70 @@ const enText = {
 
 const SETTINGS_MEMORY_COPY = {
   'zh-CN': makeCopy('zh-CN', zhText, {
+    results: {
+      no_backup: '当前没有可用的 MEMORY.md 备份。', invalid_backup_kind: '备份类型无法识别。',
+      memory_unavailable: '本地记忆服务当前不可用。', backup_not_found: '找不到对应的备份文件。',
+      remote_host_owned: '记忆文件由远程 Runtime Host 管理，无法在本机打开。', not_regular_file: '记忆路径不是允许打开的常规文件。',
+      open_failed: '系统无法打开记忆文件。', file_not_found: '找不到记忆文件。',
+      disabled: '本地记忆已关闭。', incognito_active: '隐身模式下不可用。',
+      safe_mode: 'MEMORY.md 内容过大，已进入安全模式。', oversize: 'MEMORY.md 超出安全上限，请先删减旧内容。',
+      revision_conflict: '记忆内容刚被其他操作修改，请重试。', backup_revision_conflict: '备份内容刚被其他操作修改，请重试。',
+      invalid_state: 'Runtime Host 返回了无效的记忆状态。',
+      invalid_content: 'MEMORY.md 内容无效，请检查格式后重试。', invalid_scope: '当前记忆操作的作用域无效。',
+      not_found: '找不到对应的记忆条目。', not_pending: '对应的记忆条目不在待确认状态。',
+      upload_not_found: '记忆上传会话不存在或已过期。', upload_incomplete: '记忆内容尚未上传完整。',
+      upload_conflict: '另一个记忆上传正在进行，请重试。',
+    },
     origins: { manual: '手动记录', imported: '导入记录', extracted: '确认提取', unknown: '手写条目' }, entryStatuses: { draft: '草稿', review_required: '待确认', active: '生效', archived: '已归档', rejected: '已拒绝', unknown: '未识别' }, backupKinds: { reset: '重置前备份', restore: '恢复前备份', save: '保存前备份' }, memoryStatuses: { ok: '本地文件已就绪', disabled: '已关闭', safe_mode: '安全模式', incognito_blocked: '隐身禁用', error: '读取失败' }, promptBlocked: { disabled: '本地记忆已关闭。', incognito: '隐身模式下不会提供本地记忆。', safeMode: 'MEMORY.md 过大，当前不会提供。', agentRead: '模型上下文读取未开启。' }, backupOversize: '备份过大，无法预览条目', previewOversize: '草稿过大，条目预览已暂停；保存前请先删减 MEMORY.md 内容。', previewTruncationMarker: '[本地记忆已按长度截断]',
   }),
   'zh-TW': makeCopy('zh-TW', zhTwText, {
+    results: {
+      no_backup: '目前沒有可用的 MEMORY.md 備份。', invalid_backup_kind: '備份類型無法識別。',
+      memory_unavailable: '本機記憶服務目前無法使用。', backup_not_found: '找不到對應的備份檔案。',
+      remote_host_owned: '記憶檔案由遠端 Runtime Host 管理，無法在本機開啟。', not_regular_file: '記憶路徑不是允許開啟的一般檔案。',
+      open_failed: '系統無法開啟記憶檔案。', file_not_found: '找不到記憶檔案。',
+      disabled: '本機記憶已關閉。', incognito_active: '隱身模式下無法使用。',
+      safe_mode: 'MEMORY.md 內容過大，已進入安全模式。', oversize: 'MEMORY.md 超出安全上限，請先刪減舊內容。',
+      revision_conflict: '記憶內容剛被其他操作修改，請重試。', backup_revision_conflict: '備份內容剛被其他操作修改，請重試。',
+      invalid_state: 'Runtime Host 回傳了無效的記憶狀態。',
+      invalid_content: 'MEMORY.md 內容無效，請檢查格式後重試。', invalid_scope: '目前記憶操作的作用域無效。',
+      not_found: '找不到對應的記憶條目。', not_pending: '對應的記憶條目不在待確認狀態。',
+      upload_not_found: '記憶上傳工作階段不存在或已過期。', upload_incomplete: '記憶內容尚未上傳完整。',
+      upload_conflict: '另一個記憶上傳正在進行，請重試。',
+    },
     origins: { manual: '手動記錄', imported: '匯入記錄', extracted: '確認提取', unknown: '手寫條目' }, entryStatuses: { draft: '草稿', review_required: '待確認', active: '生效', archived: '已歸檔', rejected: '已拒絕', unknown: '未識別' }, backupKinds: { reset: '重置前備份', restore: '恢復前備份', save: '儲存前備份' }, memoryStatuses: { ok: '本地檔案已就緒', disabled: '已關閉', safe_mode: '安全模式', incognito_blocked: '隱身停用', error: '讀取失敗' }, promptBlocked: { disabled: '本地記憶已關閉。', incognito: '隱身模式下不會提供本地記憶。', safeMode: 'MEMORY.md 過大，目前不會提供。', agentRead: '模型上下文讀取未開啟。' }, backupOversize: '備份過大，無法預覽條目', previewOversize: '草稿過大，條目預覽已暫停；儲存前請先刪減 MEMORY.md 內容。', previewTruncationMarker: '[本地記憶已按長度截斷]',
   }),
   en: makeCopy('en-US', enText, {
+    results: {
+      no_backup: 'No MEMORY.md backup is available.', invalid_backup_kind: 'Unrecognized backup kind.',
+      memory_unavailable: 'Local memory is currently unavailable.', backup_not_found: 'The backup file was not found.',
+      remote_host_owned: 'Memory files are owned by the remote Runtime Host and cannot be opened locally.', not_regular_file: 'The memory path is not an allowed regular file.',
+      open_failed: 'The system could not open the memory file.', file_not_found: 'The memory file was not found.',
+      disabled: 'Local memory is disabled.', incognito_active: 'Unavailable in incognito mode.',
+      safe_mode: 'MEMORY.md is too large and entered safe mode.', oversize: 'MEMORY.md exceeds the safety limit. Remove older content first.',
+      revision_conflict: 'Memory was just changed by another operation. Try again.', backup_revision_conflict: 'The backup was just changed by another operation. Try again.',
+      invalid_state: 'The Runtime Host returned an invalid memory state.',
+      invalid_content: 'MEMORY.md content is invalid. Check its format and try again.', invalid_scope: 'The memory operation has an invalid scope.',
+      not_found: 'The memory entry was not found.', not_pending: 'The memory entry is not pending review.',
+      upload_not_found: 'The memory upload session does not exist or has expired.', upload_incomplete: 'The memory content has not finished uploading.',
+      upload_conflict: 'Another memory upload is in progress. Try again.',
+    },
     origins: { manual: 'Manual entry', imported: 'Imported entry', extracted: 'Confirmed extraction', unknown: 'Handwritten entry' }, entryStatuses: { draft: 'Draft', review_required: 'Needs review', active: 'Active', archived: 'Archived', rejected: 'Rejected', unknown: 'Unrecognized' }, backupKinds: { reset: 'Before reset', restore: 'Before restore', save: 'Before save' }, memoryStatuses: { ok: 'Local file ready', disabled: 'Off', safe_mode: 'Safe mode', incognito_blocked: 'Disabled in incognito', error: 'Read failed' }, promptBlocked: { disabled: 'Local memory is disabled.', incognito: 'Local memory is never added in incognito mode.', safeMode: 'MEMORY.md is too large and will not be added.', agentRead: 'Model context access is disabled.' }, backupOversize: 'Backup is too large to preview entries', previewOversize: 'The draft is too large, so entry preview is paused. Reduce MEMORY.md before saving.', previewTruncationMarker: '[Local memory truncated to the length limit]',
   }),
 } satisfies UiCatalog<MemorySettingsCopy>;
 
 export function getMemorySettingsCopy(locale: UiLocale): MemorySettingsCopy { return SETTINGS_MEMORY_COPY[locale]; }
 
-function makeCopy(intlLocale: string, text: Record<MemoryTextKey, string>, values: Pick<MemorySettingsCopy, 'origins' | 'entryStatuses' | 'backupKinds' | 'memoryStatuses' | 'promptBlocked' | 'backupOversize' | 'previewOversize' | 'previewTruncationMarker'>): MemorySettingsCopy {
+export function memoryResultMessage(
+  result: { code?: string },
+  copy: MemorySettingsCopy,
+  fallback: string,
+): string {
+  const results: Readonly<Record<string, string | undefined>> = copy.results;
+  return (result.code && results[result.code]) || fallback;
+}
+
+function makeCopy(intlLocale: string, text: Record<MemoryTextKey, string>, values: Pick<MemorySettingsCopy, 'results' | 'origins' | 'entryStatuses' | 'backupKinds' | 'memoryStatuses' | 'promptBlocked' | 'backupOversize' | 'previewOversize' | 'previewTruncationMarker'>): MemorySettingsCopy {
   const plural = (count: number, one: string, many: string) => `${count} ${count === 1 ? one : many}`;
   const isZh = intlLocale !== 'en-US';
   const isZhTw = intlLocale === 'zh-TW';
diff --git a/apps/desktop/src/renderer/locales/settings-test-result-copy.ts b/apps/desktop/src/renderer/locales/settings-test-result-copy.ts
index ee5ce9b90d..5e0f4f005e 100644
--- a/apps/desktop/src/renderer/locales/settings-test-result-copy.ts
+++ b/apps/desktop/src/renderer/locales/settings-test-result-copy.ts
@@ -163,9 +163,7 @@ export function settingsTestResultMessage(
     case "bot_connection_failed":
       return copy.bot.connectionFailed;
     default:
-      return locale === "en" && result.message.trim()
-        ? result.message
-        : copy.bot.connectionFailed;
+      return copy.bot.connectionFailed;
   }
 }
 
diff --git a/apps/desktop/src/renderer/settings/data-settings-page.tsx b/apps/desktop/src/renderer/settings/data-settings-page.tsx
index 7ab341d52d..ecf86f43e9 100644
--- a/apps/desktop/src/renderer/settings/data-settings-page.tsx
+++ b/apps/desktop/src/renderer/settings/data-settings-page.tsx
@@ -220,10 +220,7 @@ export function DataSettingsPage(props: {
       if (res.ok) {
         toast.success(copy.imported, summarizeImportResult(res.result, copy));
       } else if (res.reason !== 'canceled') {
-        const detail = res.message && (locale === 'zh-CN' || !/[\u3400-\u9fff]/u.test(res.message))
-          ? res.message
-          : copy.invalidFile;
-        toast.error(copy.importFailed, detail, undefined, diagnosticTarget);
+        toast.error(copy.importFailed, copy.importFailures[res.reason], undefined, diagnosticTarget);
       }
     } catch (error) {
       toast.error(
diff --git a/apps/desktop/src/renderer/settings/permission-center-page.tsx b/apps/desktop/src/renderer/settings/permission-center-page.tsx
index ec4c6517d7..e0cdf1bf2a 100644
--- a/apps/desktop/src/renderer/settings/permission-center-page.tsx
+++ b/apps/desktop/src/renderer/settings/permission-center-page.tsx
@@ -36,7 +36,11 @@ import type {
   PermissionSnapshot,
 } from '@maka/core/capabilities';
 import type { UiLocale } from '@maka/core/ui-locale';
-import { isDragGrantPermissionId, OS_PERMISSION_IDS } from '@maka/core/capabilities';
+import {
+  isCapabilityReasonCode,
+  isDragGrantPermissionId,
+  OS_PERMISSION_IDS,
+} from '@maka/core/capabilities';
 import {
   Banner,
   Button,
@@ -421,10 +425,10 @@ function CapabilityRow(props: {
   const { copy, locale } = props;
   const readinessCopy = copy.readiness[capability.readiness];
   const capabilityLabel = localizedCapabilityLabel(capability, locale);
-  const featureReason = localizedSnapshotText(capability.feature.reason, locale);
-  const configurationReason = localizedSnapshotText(capability.configuration.reason, locale);
-  const runtimeReason = localizedSnapshotText(capability.runtimeProbe.reason, locale);
-  const guidance = localizedCapabilityGuidance(capability, locale, copy);
+  const featureReason = capabilityReasonText(capability.feature.reason, capability, copy);
+  const configurationReason = capabilityReasonText(capability.configuration.reason, capability, copy);
+  const runtimeReason = capabilityReasonText(capability.runtimeProbe.reason, capability, copy);
+  const guidance = localizedCapabilityGuidance(capability, copy);
 
   const layers: Array<{ label: string; value: string; reason?: string }> = [
     {
@@ -589,7 +593,7 @@ function OsPermissionRow(props: {
   const purpose = permissionCopy?.purpose ?? '';
   const impact = permissionCopy?.impact ?? '';
   const stateCopy = props.copy.osStates[snapshot.status];
-  const reason = localizedSnapshotText(snapshot.reason, props.locale);
+  const reason = osPermissionReasonText(snapshot, props.copy);
 
   const showRequest = snapshot.canRequest && snapshot.status !== 'granted';
   const showOpenSettings = snapshot.canOpenSettings && snapshot.status !== 'granted';
@@ -704,17 +708,45 @@ function localizedCapabilityLabel(capability: CapabilitySnapshot, locale: UiLoca
   return capability.label;
 }
 
-function localizedSnapshotText(value: string | undefined, locale: UiLocale): string | undefined {
-  if (!value || (locale !== 'zh-CN' && /[\u3400-\u9fff]/u.test(value))) return undefined;
-  return value;
+function capabilityReasonText(
+  reason: string | undefined,
+  capability: CapabilitySnapshot,
+  copy: PermissionCenterCopy,
+): string | undefined {
+  if (!reason) return undefined;
+  if (reason === 'cu_backend_status') {
+    const missing = capability.osPermissions
+      .filter((permission) => permission.required && permission.status !== 'granted')
+      .map((permission) => copy.osPermissions[permission.id]?.label ?? permission.id);
+    return copy.cuBackendStatus(missing, capability.runtimeProbe.state);
+  }
+  if (isCapabilityReasonCode(reason) && reason !== 'cu_backend_status') {
+    return copy.reasons[reason];
+  }
+  // Bot capabilities pass bridge status reasons through as machine codes; the
+  // bot settings page owns their full copy, this summary shows the generic line.
+  return copy.reasonFallback;
 }
 
 function localizedCapabilityGuidance(
   capability: CapabilitySnapshot,
-  locale: UiLocale,
   copy: PermissionCenterCopy,
 ): readonly string[] {
-  return capability.guidance.filter((item) => locale === 'zh-CN' || !/[\u3400-\u9fff]/u.test(item));
+  return capability.guidance
+    .map((code) => capabilityReasonText(code, capability, copy))
+    .filter((item): item is string => Boolean(item));
+}
+
+function osPermissionReasonText(
+  snapshot: OsPermissionSnapshot,
+  copy: PermissionCenterCopy,
+): string | undefined {
+  const text = snapshot.reason
+    ? isCapabilityReasonCode(snapshot.reason) && snapshot.reason !== 'cu_backend_status'
+      ? copy.reasons[snapshot.reason]
+      : copy.reasonFallback
+    : undefined;
+  return text;
 }
 
 function featureTone(state: CapabilitySnapshot['feature']['state']): StatusSemantic {
diff --git a/apps/desktop/src/renderer/settings/provider-oauth-section.tsx b/apps/desktop/src/renderer/settings/provider-oauth-section.tsx
index 3f144ded6b..4bc1ac26a7 100644
--- a/apps/desktop/src/renderer/settings/provider-oauth-section.tsx
+++ b/apps/desktop/src/renderer/settings/provider-oauth-section.tsx
@@ -29,6 +29,7 @@ import {
 } from '@maka/ui';
 import {
   getProviderSettingsCopy,
+  subscriptionActionErrorMessage,
   subscriptionResultMessage,
   type ConnectionOAuthProviderBridge,
   type ConnectionsBridge,
@@ -36,7 +37,6 @@ import {
 } from '../features/connection-settings';
 import {
   useOAuthLoginFlow,
-  subscriptionActionErrorMessage,
   type OAuthAuthorizationFlowBridge,
   type OAuthConnectionIdentity,
   type SubscriptionSnapshot,
@@ -256,7 +256,7 @@ function GitHubCopilotLoginPanel(props: {
       if (!result.ok) {
         flow.reportError(
           copy.copilotActionFailed,
-          subscriptionResultMessage(result.message, copy.copilotActionFailed, locale, result.reason),
+          subscriptionResultMessage(result, copy.copilotActionFailed, locale),
         );
         return;
       }
diff --git a/apps/desktop/src/renderer/settings/use-memory-settings-controller.ts b/apps/desktop/src/renderer/settings/use-memory-settings-controller.ts
index 2bfa9a4732..cb08daac78 100644
--- a/apps/desktop/src/renderer/settings/use-memory-settings-controller.ts
+++ b/apps/desktop/src/renderer/settings/use-memory-settings-controller.ts
@@ -40,7 +40,7 @@ import {
 } from './memory-settings-labels';
 import { deriveMemorySettingsViewModel } from './memory-settings-view-model';
 import { useKeyedActionGuard } from './use-action-guard';
-import { getMemorySettingsCopy } from '../locales/settings-memory-copy';
+import { getMemorySettingsCopy, memoryResultMessage } from '../locales/settings-memory-copy';
 import { readScrollMotionBehavior } from '../scroll-motion-policy';
 import {
   useRuntimeHostSettingsErrorReporter,
@@ -287,7 +287,7 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
           } else {
             reportHostError(
               copy.text.restoreFailed,
-              memoryResultMessage(result.message, locale, copy.text.restoreFailed),
+              memoryResultMessage(result, copy, copy.text.restoreFailed),
             );
           }
         });
@@ -324,7 +324,7 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
           } else {
             reportHostError(
               copy.text.restoreFailed,
-              memoryResultMessage(result.message, locale, copy.text.restoreFailed),
+              memoryResultMessage(result, copy, copy.text.restoreFailed),
             );
           }
         });
@@ -345,7 +345,7 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
         if (!result.ok) {
           reportHostError(
             copy.text.openFailed,
-            memoryResultMessage(result.message, locale, copy.text.openFailed),
+            memoryResultMessage(result, copy, copy.text.openFailed),
           );
         }
       } catch (error) {
@@ -364,7 +364,7 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
         if (!result.ok) {
           reportHostError(
             copy.text.openPreviousFailed,
-            memoryResultMessage(result.message, locale, copy.text.openPreviousFailed),
+            memoryResultMessage(result, copy, copy.text.openPreviousFailed),
           );
         }
       } catch (error) {
@@ -386,7 +386,7 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
         if (!result.ok) {
           reportHostError(
             copy.openBackupFailed(localMemoryBackupKindLabel(backup.kind, copy)),
-            memoryResultMessage(result.message, locale, copy.text.openFailed),
+            memoryResultMessage(result, copy, copy.text.openFailed),
           );
         }
       } catch (error) {
@@ -687,7 +687,3 @@ export function useMemoryDocumentController(props: MemoryDocumentControllerProps
     copyLocalMemoryPromptPreview,
   };
 }
-
-function memoryResultMessage(message: string, locale: UiLocale, fallback: string): string {
-  return locale === 'zh-CN' || !/[\u3400-\u9fff]/u.test(message) ? message : fallback;
-}
diff --git a/apps/desktop/src/renderer/settings/use-oauth-login-flow.ts b/apps/desktop/src/renderer/settings/use-oauth-login-flow.ts
index f237429d4d..d399135b6f 100644
--- a/apps/desktop/src/renderer/settings/use-oauth-login-flow.ts
+++ b/apps/desktop/src/renderer/settings/use-oauth-login-flow.ts
@@ -25,7 +25,7 @@ import {
   useUiLocale,
 } from '@maka/ui';
 import { createOneShotActionGuard, teardownPendingAuthorization } from './oauth-login-flow-guard';
-import { getProviderSettingsCopy, subscriptionResultMessage } from '../features/connection-settings';
+import { getProviderSettingsCopy, subscriptionActionErrorMessage, subscriptionResultMessage } from '../features/connection-settings';
 import { useRuntimeHostSettingsErrorReporter } from './runtime-host-settings-target.js';
 
 // Shared browser-assisted OAuth login-flow controller (device-code polling).
@@ -210,7 +210,7 @@ export function useOAuthLoginFlow(params: OAuthLoginFlowParams): OAuthLoginFlowC
       const payload = await authorizationBridge.getAuthUrl();
       if ('ok' in payload) {
         if (!oauthLoginFlowMountedRef.current) return;
-        const failureMessage = payload.ok ? copy.retry : subscriptionResultMessage(payload.message, copy.startFailedRetry, locale, payload.reason);
+        const failureMessage = payload.ok ? copy.retry : subscriptionResultMessage(payload, copy.startFailedRetry, locale);
         reportHostError(copy.startFailed, failureMessage);
         setErrorMessage(failureMessage);
         return;
@@ -226,7 +226,7 @@ export function useOAuthLoginFlow(params: OAuthLoginFlowParams): OAuthLoginFlowC
       const opened = await authorizationBridge.openAuthUrl(payload.authRequestId);
       if (!oauthLoginFlowMountedRef.current) return;
       if (!opened.ok) {
-        const message = subscriptionResultMessage(opened.message, copy.openFailedRetry, locale, opened.reason);
+        const message = subscriptionResultMessage(opened, copy.openFailedRetry, locale);
         reportHostError(copy.openFailed, message);
         setErrorMessage(message);
         void authorizationBridge.cancelAuthorization(payload.authRequestId);
@@ -249,7 +249,7 @@ export function useOAuthLoginFlow(params: OAuthLoginFlowParams): OAuthLoginFlowC
         if (!oauthLoginFlowMountedRef.current) return;
         if (params.onLoginSuccess) await params.onLoginSuccess(result.connection);
       } else {
-        const message = subscriptionResultMessage(result.message, copy.incompleteRetry, locale, result.reason);
+        const message = subscriptionResultMessage(result, copy.incompleteRetry, locale);
         reportHostError(copy.incomplete, message);
         setErrorMessage(message);
       }
@@ -293,7 +293,7 @@ export function useOAuthLoginFlow(params: OAuthLoginFlowParams): OAuthLoginFlowC
       } else {
         reportHostError(
           copy.logoutFailed,
-          subscriptionResultMessage(result.message, copy.logoutFailedRetry, locale),
+          subscriptionResultMessage(result, copy.logoutFailedRetry, locale),
         );
       }
     } catch (error) {
@@ -327,12 +327,3 @@ export function useOAuthLoginFlow(params: OAuthLoginFlowParams): OAuthLoginFlowC
     refresh,
   };
 }
-
-export function subscriptionActionErrorMessage(error: unknown, locale: UiLocale = 'zh-CN'): string {
-  const message = error instanceof Error
-    ? error.message
-    : typeof error === 'string'
-      ? error
-      : '';
-  return subscriptionResultMessage(message, getProviderSettingsCopy(locale).oauthFlow.serviceUnavailable, locale);
-}
diff --git a/packages/core/src/capabilities.ts b/packages/core/src/capabilities.ts
index bdc33a1fd1..fbd355e39d 100644
--- a/packages/core/src/capabilities.ts
+++ b/packages/core/src/capabilities.ts
@@ -103,6 +103,47 @@ export type CapabilityId =
   | 'memory_write'
   | `bot:${BotProvider}`;
 
+/**
+ * Stable machine codes for capability and OS-permission reasons. Producers
+ * emit these instead of locale-bound prose; presenters own the code→copy map
+ * per locale. Bot capabilities pass their bridge status reasons through as-is
+ * (`rate-limited`, `gateway-closed-4004`, …), so signal `reason` fields stay
+ * `string` — this union types the desktop producers and the presenter maps.
+ */
+export const CAPABILITY_REASON_CODES = [
+  'disabled',
+  'missing platform credentials',
+  'macOS TCC only',
+  'no Electron API for per-target Apple Events TCC status',
+  'cu_artifact_missing',
+  'cu_backend_status',
+  'cu_backend_unavailable',
+  'cu_executor_undistributable',
+  'cu_executor_stopped',
+  'cu_executor_start_failed',
+  'cu_executor_recovering',
+  'cu_executor_ready',
+  'cu_executor_lazy_start',
+  'activity_recorder_partial',
+  'activity_recorder_probe_hint',
+  'memory_partial',
+  'memory_no_probe',
+  'accessibility_status_ambiguous',
+  'screen_recording_status_mac_only',
+  'notifications_status_unreadable_macos',
+  'notifications_status_unreadable',
+  'notifications_unsupported',
+  'permission_probe_failed',
+] as const;
+
+export type CapabilityReasonCode = (typeof CAPABILITY_REASON_CODES)[number];
+
+export function isCapabilityReasonCode(value: unknown): value is CapabilityReasonCode {
+  return (
+    typeof value === 'string' && (CAPABILITY_REASON_CODES as readonly string[]).includes(value)
+  );
+}
+
 export interface OsPermissionSnapshot {
   id: OsPermissionId;
   status: OsPermissionState;
diff --git a/packages/core/src/health.ts b/packages/core/src/health.ts
index e88582cc56..dca5eb3a7b 100644
--- a/packages/core/src/health.ts
+++ b/packages/core/src/health.ts
@@ -366,6 +366,11 @@ function capabilityDetail(capability: CapabilitySnapshot): string | undefined {
 function userVisibleCapabilityReason(reason: string | undefined): string | undefined {
   const raw = reason?.trim();
   if (!raw) return undefined;
+  // Locale anchor contract: this module is the zh source of truth and
+  // settings-health-copy maps en from these exact strings (see
+  // englishSignalMessage/englishSignalDetail). New codes below intentionally
+  // add zh branches only — en keeps the generic line there until #4524
+  // code-ifies the health presenter. Do not reword without updating both.
   switch (raw) {
     case 'disabled':
       return '该能力当前已关闭。';
@@ -375,8 +380,34 @@ function userVisibleCapabilityReason(reason: string | undefined): string | undef
       return '仅 macOS 系统权限可探测。';
     case 'no Electron API for per-target Apple Events TCC status':
       return '系统未提供可直接读取的授权状态。';
+    case 'cu_artifact_missing':
+      return '未找到通过完整性检查的 Computer Use 执行器 artifact。';
+    case 'cu_backend_status':
+      return 'maka-cu artifact 已通过本地完整性检查。';
+    case 'cu_backend_unavailable':
+      return 'Computer Use 后端当前不可用。';
+    case 'cu_executor_undistributable':
+      return '未找到通过完整性检查且可分发的 maka-cu executor。';
+    case 'cu_executor_stopped':
+      return 'maka-cu executor 已停止。';
+    case 'cu_executor_start_failed':
+      return 'maka-cu executor 启动失败或已退出。';
+    case 'cu_executor_recovering':
+      return 'maka-cu executor 正在启动或恢复。';
+    case 'cu_executor_ready':
+      return 'maka-cu executor 已就绪。';
+    case 'cu_executor_lazy_start':
+      return 'maka-cu 已可用，将在首次调用时启动。';
+    case 'activity_recorder_partial':
+      return 'Daily Review 已聚合本地任务 / 工具 / 模型活动；当前不包含屏幕与应用级录制';
+    case 'activity_recorder_probe_hint':
+      return '打开 Daily Review 可查看本地活动聚合结果';
+    case 'memory_partial':
+      return '本地 MEMORY.md 已可见；自动抽取/写入仍需用户确认';
+    case 'memory_no_probe':
+      return '透明本地记忆为文件读写能力，不做后台探测';
     default:
-      return /[\u3400-\u9fff]/.test(raw) ? raw : '状态详情请见对应设置页。';
+      return '状态详情请见对应设置页。';
   }
 }
 
diff --git a/packages/core/src/oauth-subscription.ts b/packages/core/src/oauth-subscription.ts
index c8f271b92d..9459597cce 100644
--- a/packages/core/src/oauth-subscription.ts
+++ b/packages/core/src/oauth-subscription.ts
@@ -38,7 +38,13 @@
  */
 export type SubscriptionActionResult =
   | { ok: true }
-  | { ok: false; reason: SubscriptionActionFailureReason; message: string };
+  | {
+      ok: false;
+      reason: SubscriptionActionFailureReason;
+      /** Stable machine code the presenter maps to per-locale copy. */
+      code?: string;
+      message: string;
+    };
 
 export type SubscriptionActionFailureReason =
   | 'authorization_pending' // no startAuthorization called yet
diff --git a/packages/runtime/src/test-connection.ts b/packages/runtime/src/test-connection.ts
index 3c95c80fe4..875bea65cc 100644
--- a/packages/runtime/src/test-connection.ts
+++ b/packages/runtime/src/test-connection.ts
@@ -508,8 +508,6 @@ async function httpFailure(r: ConnectionEffectResponse, t0: number): Promise<Con
     await r.cancel();
     return {
       ok: false,
-      errorMessage:
-        'OAuth 已登录，但当前账号或 provider 正在 rate limit。请稍后重试，或先切换到其它可用模型。',
       statusCode,
       errorClass: 'provider_unavailable',
       latencyMs: Date.now() - t0,