diff --git a/apps/web/src/components/SettingsSections.test.tsx b/apps/web/src/components/SettingsSections.test.tsx
index 30dfdc13..8674d9ea 100644
--- a/apps/web/src/components/SettingsSections.test.tsx
+++ b/apps/web/src/components/SettingsSections.test.tsx
@@ -72,7 +72,9 @@ it("lists audit events with tombstone labels and pages by the Server cursor", as
       expect.anything(),
     );
     expect(view.container.querySelectorAll(".audit-list li")).toHaveLength(3);
-    expect(view.container.textContent).toContain("unknown kind");
+    // An unknown type shows its category in Chinese, never the internal code.
+    expect(view.container.textContent).toContain("其他事件");
+    expect(view.container.textContent).not.toContain("unknown kind");
     expect(view.container.textContent).not.toContain("显示更早的记录");
   } finally {
     await view.unmount();
@@ -202,3 +204,39 @@ it.each([
     await view.unmount();
   }
 });
+
+it("names every audit event in Chinese, falling back to its category for an unknown type", async () => {
+  const event = (id: string, type: string, category: string) => ({
+    id,
+    type,
+    category,
+    createdAt: "2026-10-10T00:00:00.000Z",
+    details: {},
+  });
+  vi.stubGlobal(
+    "fetch",
+    vi.fn().mockResolvedValue(
+      respond({
+        events: [
+          event("a", "AUTH_LOGIN_SUCCEEDED", "authentication"),
+          event("b", "MODEL_CONNECTION_CREATED", "settings"),
+          event("c", "AUTOMATION_PAUSED", "other"),
+          event("d", "AUTH_PASSKEY_ENROLLED", "authentication"),
+        ],
+      }),
+    ),
+  );
+  const view = await renderComponent(<AuditLogSettings />);
+  try {
+    await interact(() => undefined);
+    const titles = Array.from(view.container.querySelectorAll("strong")).map(
+      (item) => item.textContent,
+    );
+    expect(titles).toEqual(
+      expect.arrayContaining(["登录成功", "添加模型服务", "暂停例行任务", "登录事件"]),
+    );
+    expect(view.container.textContent).not.toMatch(/auth|passkey|automation/iu);
+  } finally {
+    await view.unmount();
+  }
+});
diff --git a/apps/web/src/components/SettingsSections.tsx b/apps/web/src/components/SettingsSections.tsx
index e55355f2..8a4b1fbb 100644
--- a/apps/web/src/components/SettingsSections.tsx
+++ b/apps/web/src/components/SettingsSections.tsx
@@ -93,7 +93,36 @@ export function ApprovalPolicySettings() {
   );
 }
 
+// Every event type the Server writes (apps/server/src) has a label; an unknown type falls back to
+// its category, so the Owner never sees an internal code such as "auth login succeeded".
 const auditLabels: Record<string, string> = {
+  AUTH_LOGIN_SUCCEEDED: "登录成功",
+  AUTH_LOGIN_FAILED: "登录失败",
+  AUTH_LOGOUT: "退出登录",
+  OWNER_PASSWORD_CHANGED: "修改密码",
+  OWNER_SESSIONS_REVOKED: "退出其他设备",
+  SETTINGS_OWNER_UPDATED: "更改偏好设置",
+  SETTINGS_APPROVAL_UPDATED: "更改审批规则",
+  SETTINGS_STORAGE_UPDATED: "更改存储设置",
+  SETTINGS_TRASH_AUTO_PURGE_RUN: "自动清空回收站",
+  MODEL_CONNECTION_CREATED: "添加模型服务",
+  MODEL_CONNECTION_UPDATED: "更新模型服务",
+  MODEL_CONNECTION_DELETED: "删除模型服务",
+  EMPLOYEE_MODEL_UPDATED: "更改 Bot 模型",
+  EMPLOYEE_APPEARANCE_UPDATED: "更新 Bot 头像",
+  BOT_GREETING_STARTED: "Bot 开始打招呼",
+  BOT_GREETING_FAILED: "Bot 打招呼失败",
+  AUTOMATION_CREATED: "创建例行任务",
+  AUTOMATION_PAUSED: "暂停例行任务",
+  AUTOMATION_RESUMED: "恢复例行任务",
+  AUTOMATION_DELETED: "删除例行任务",
+  AUTOMATION_OCCURRENCE: "执行例行任务",
+  CHANNEL_ATTACHMENT_PURGED: "清理频道附件",
+  BROWSER_COMMAND: "浏览器操作",
+  BROWSER_CONTROL_STATE: "切换浏览器控制",
+  BROWSER_HOST_BOUND: "绑定浏览器主机",
+  BROWSER_TRANSPORT_ADMITTED: "允许浏览器连接",
+  BROWSER_TRANSPORT_CLAIMED: "接管浏览器连接",
   CHANNEL_CREATED: "创建频道",
   CHANNEL_RENAMED: "重命名频道",
   CHANNEL_DELETED: "删除频道",
@@ -132,7 +161,7 @@ function auditTitle(event: AuditEvent) {
       event.details.primaryBotId == null ? "未设置" : (event.details.to ?? "未知 Bot");
     return `更改主 Bot：${previous} → ${current}`;
   }
-  const label = auditLabels[event.type] ?? event.type.replaceAll("_", " ").toLocaleLowerCase();
+  const label = auditLabels[event.type] ?? `${auditCategoryLabels[event.category ?? "other"]}事件`;
   const from = event.details.from;
   const to = event.details.to;
   if (typeof from === "string" && typeof to === "string") return `${label}：${from} → ${to}`;
diff --git a/apps/web/src/components/Sidebar.css b/apps/web/src/components/Sidebar.css
index 07fa020f..c7801181 100644
--- a/apps/web/src/components/Sidebar.css
+++ b/apps/web/src/components/Sidebar.css
@@ -190,6 +190,50 @@
 }
 /* 主 Bot leads the list as a raised card (PrimaryBot artboard); the hover and selection rules
    below still apply. */
+/* Upgraded workspaces without a 主 Bot get a dismissible nudge where the crowned card would be. */
+.sb .sb-primary-hint {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr) auto;
+  align-items: start;
+  gap: 10px;
+  margin: 0 0 6px;
+  padding: 10px 10px 10px 12px;
+  border-radius: var(--ob-radius-row);
+  box-shadow: inset 0 0 0 1px var(--ob-divider);
+  color: var(--ob-text-secondary);
+}
+.sb .sb-primary-hint .ob-crown-glyph {
+  margin-top: 3px;
+}
+.sb .sb-primary-hint span {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  min-width: 0;
+}
+.sb .sb-primary-hint strong {
+  color: var(--ob-text);
+  font-size: 14px;
+  font-weight: 600;
+}
+.sb .sb-primary-hint small {
+  font-size: 12px;
+  line-height: 1.45;
+}
+.sb .sb-primary-hint button {
+  display: grid;
+  width: 22px;
+  height: 22px;
+  place-items: center;
+  border: 0;
+  border-radius: 6px;
+  background: transparent;
+  color: inherit;
+  cursor: pointer;
+}
+.sb .sb-primary-hint button:hover {
+  background: var(--ob-fill-hover);
+}
 .sb .sb-primary {
   padding-bottom: 2px;
 }
diff --git a/apps/web/src/components/Sidebar.test.tsx b/apps/web/src/components/Sidebar.test.tsx
index 75fb9c42..b88ea935 100644
--- a/apps/web/src/components/Sidebar.test.tsx
+++ b/apps/web/src/components/Sidebar.test.tsx
@@ -345,3 +345,46 @@ it("leads with the crowned 主 Bot and offers 设为主 Bot to the others", asyn
     await view.unmount();
   }
 });
+
+it("nudges an upgraded workspace without a 主 Bot until one is chosen or the hint is dismissed", async () => {
+  window.localStorage.removeItem("openbot.sidebar.primaryHintDismissed");
+  const props = {
+    bots,
+    channels,
+    runs: [],
+    ownerName: "Owner",
+    onSelectChannel: vi.fn(),
+    onSelectBot: vi.fn(),
+    onCreateBot: vi.fn(),
+    onCreateChannel: vi.fn(),
+    onSetPrimaryBot: vi.fn(async () => undefined),
+  };
+  const hint = (root: HTMLElement) => root.querySelector(".sb-primary-hint");
+  const none = await renderComponent(<Sidebar {...props} primaryBotId={null} />);
+  try {
+    expect(hint(none.container)?.textContent).toContain("选一个主 Bot");
+    await interact(() =>
+      none.container.querySelector<HTMLButtonElement>('[aria-label="不再提示"]')?.click(),
+    );
+    expect(hint(none.container)).toBeNull();
+  } finally {
+    await none.unmount();
+  }
+  // Dismissal is remembered on this device.
+  const again = await renderComponent(<Sidebar {...props} primaryBotId={null} />);
+  try {
+    expect(hint(again.container)).toBeNull();
+  } finally {
+    await again.unmount();
+  }
+  window.localStorage.removeItem("openbot.sidebar.primaryHintDismissed");
+  // A chosen 主 Bot, an older Server (undefined) or no Bots never show the hint.
+  for (const extra of [{ primaryBotId: "reviewer" }, { primaryBotId: undefined }, { bots: [] }]) {
+    const view = await renderComponent(<Sidebar {...props} primaryBotId={null} {...extra} />);
+    try {
+      expect(hint(view.container)).toBeNull();
+    } finally {
+      await view.unmount();
+    }
+  }
+});
diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index 2542fed5..8d5b6d72 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -77,6 +77,15 @@ interface SidebarProps {
 }
 
 /** The shared sidebar of the design contract (docs/design/desktop-ui-2026-10/Sidebar.dc.html). */
+const primaryHintKey = "openbot.sidebar.primaryHintDismissed";
+function readPrimaryHintDismissed() {
+  try {
+    return window.localStorage.getItem(primaryHintKey) === "1";
+  } catch {
+    return false;
+  }
+}
+
 export function Sidebar({
   creatingBot,
   onWork,
@@ -177,6 +186,22 @@ export function Sidebar({
   const primaryEntry = primaryBotId
     ? entries.find((entry) => entry.key === `bot:${primaryBotId}`)
     : undefined;
+  // A workspace upgraded from before 主 Bot existed has none; nudge once, per device, until the
+  // Owner picks one or dismisses it. The Server never elects one silently during an upgrade.
+  const [primaryHintDismissed, setPrimaryHintDismissed] = useState(readPrimaryHintDismissed);
+  const suggestPrimary =
+    primaryBotId === null &&
+    bots.length > 0 &&
+    onSetPrimaryBot !== undefined &&
+    !primaryHintDismissed;
+  function dismissPrimaryHint() {
+    setPrimaryHintDismissed(true);
+    try {
+      window.localStorage.setItem(primaryHintKey, "1");
+    } catch {
+      // Storage can be unavailable (private window); the hint then hides for this session only.
+    }
+  }
   const sections = arrangeSidebar(
     primaryEntry ? entries.filter((entry) => entry !== primaryEntry) : entries,
     organization,
@@ -440,6 +465,17 @@ export function Sidebar({
       <>
         {primaryEntry ? (
           <div className="sb-section sb-primary">{renderRow(primaryEntry, "", true)}</div>
+        ) : suggestPrimary ? (
+          <div className="sb-primary-hint" role="note">
+            <CrownGlyph />
+            <span>
+              <strong>选一个主 Bot</strong>
+              <small>没有 @ 人的消息会先交给它。右键任意 Bot，选「设为主 Bot」。</small>
+            </span>
+            <button type="button" aria-label="不再提示" onClick={dismissPrimaryHint}>
+              <ClearGlyph />
+            </button>
+          </div>
         ) : null}
         {sections.map((section) => (
           <div className="sb-section" key={section.group?.id ?? "ungrouped"}>