fix(webui): polish session titles and status

webui/src/tests/nanobot-client.test.ts

@@ -233,9 +233,13 @@ describe("NanobotClient", () => {
     client.connect();
     lastSocket().fakeOpen();
 
-    lastSocket().fakeMessage({ event: "session_updated", chat_id: "chat-title" });
+    lastSocket().fakeMessage({
+      event: "session_updated",
+      chat_id: "chat-title",
+      scope: "metadata",
+    });
 
-    expect(globalHandler).toHaveBeenCalledWith("chat-title");
+    expect(globalHandler).toHaveBeenCalledWith("chat-title", "metadata");
     expect(chatHandler).not.toHaveBeenCalled();
   });
 

webui/src/tests/thread-shell.test.tsx

@@ -8,7 +8,7 @@ import type { UIMessage } from "@/lib/types";
 function makeClient() {
   const errorHandlers = new Set<(err: { kind: string }) => void>();
   const chatHandlers = new Map<string, Set<(ev: import("@/lib/types").InboundEvent) => void>>();
-  const sessionUpdateHandlers = new Set<(chatId: string) => void>();
+  const sessionUpdateHandlers = new Set<(chatId: string, scope?: string) => void>();
   const goalStateByChatId = new Map<string, import("@/lib/types").GoalStateWsPayload>();
   return {
     status: "open" as const,
@@ -34,7 +34,7 @@ function makeClient() {
         errorHandlers.delete(handler);
       };
     },
-    onSessionUpdate: (handler: (chatId: string) => void) => {
+    onSessionUpdate: (handler: (chatId: string, scope?: string) => void) => {
       sessionUpdateHandlers.add(handler);
       return () => {
         sessionUpdateHandlers.delete(handler);
@@ -49,8 +49,8 @@ function makeClient() {
       }
       for (const h of chatHandlers.get(chatId) ?? []) h(ev);
     },
-    _emitSessionUpdate(chatId: string) {
-      for (const h of sessionUpdateHandlers) h(chatId);
+    _emitSessionUpdate(chatId: string, scope?: string) {
+      for (const h of sessionUpdateHandlers) h(chatId, scope);
     },
     sendMessage: vi.fn(),
     newChat: vi.fn(),
@@ -651,6 +651,52 @@ describe("ThreadShell", () => {
     expect(historyCalls).toBe(1);
   });
 
+  it("does not refetch thread history for metadata-only session updates", async () => {
+    const client = makeClient();
+    let historyCalls = 0;
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async (input: RequestInfo | URL) => {
+        const url = String(input);
+        if (url.includes("websocket%3Achat-a/webui-thread")) {
+          historyCalls += 1;
+          return httpJson(
+            transcriptFromSimpleMessages([
+              { role: "user", content: "question" },
+              { role: "assistant", content: "answer" },
+            ]),
+          );
+        }
+        return {
+          ok: false,
+          status: 404,
+          json: async () => ({}),
+        };
+      }),
+    );
+
+    render(
+      wrap(
+        client,
+        <ThreadShell
+          session={session("chat-a")}
+          title="Chat chat-a"
+          onToggleSidebar={() => {}}
+          onNewChat={() => {}}
+        />,
+      ),
+    );
+
+    await waitFor(() => expect(screen.getByText("answer")).toBeInTheDocument());
+    expect(historyCalls).toBe(1);
+
+    await act(async () => {
+      client._emitSessionUpdate("chat-a", "metadata");
+    });
+
+    expect(historyCalls).toBe(1);
+  });
+
   it("scrolls to the bottom after loading a session from the blank new-chat page", async () => {
     const client = makeClient();
     const scrollIntoView = vi.fn();

webui/src/tests/useSessions.test.tsx

@@ -2,7 +2,7 @@ import { act, renderHook, waitFor } from "@testing-library/react";
 import type { ReactNode } from "react";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
-import { useSessionHistory, useSessions } from "@/hooks/useSessions";
+import { sessionTitle, useSessionHistory, useSessions } from "@/hooks/useSessions";
 import * as api from "@/lib/api";
 import { ClientProvider } from "@/providers/ClientProvider";
 
@@ -17,7 +17,7 @@ vi.mock("@/lib/api", async (importOriginal) => {
 });
 
 function fakeClient() {
-  const sessionUpdateHandlers = new Set<(chatId: string) => void>();
+  const sessionUpdateHandlers = new Set<(chatId: string, scope?: string) => void>();
   return {
     status: "open" as const,
     defaultChatId: null as string | null,
@@ -25,12 +25,12 @@ function fakeClient() {
     onError: () => () => {},
     onChat: () => () => {},
     getRunStartedAt: () => null,
-    onSessionUpdate: (handler: (chatId: string) => void) => {
+    onSessionUpdate: (handler: (chatId: string, scope?: string) => void) => {
       sessionUpdateHandlers.add(handler);
       return () => sessionUpdateHandlers.delete(handler);
     },
-    emitSessionUpdate: (chatId: string) => {
-      for (const handler of sessionUpdateHandlers) handler(chatId);
+    emitSessionUpdate: (chatId: string, scope?: string) => {
+      for (const handler of sessionUpdateHandlers) handler(chatId, scope);
     },
     sendMessage: vi.fn(),
     newChat: vi.fn(),
@@ -61,6 +61,28 @@ describe("useSessions", () => {
     vi.mocked(api.fetchWebuiThread).mockReset();
   });
 
+  it("does not use low-information greetings as fallback session titles", () => {
+    expect(sessionTitle({
+      key: "websocket:chat-hi",
+      channel: "websocket",
+      chatId: "chat-hi",
+      createdAt: "2026-04-16T10:00:00Z",
+      updatedAt: "2026-04-16T10:00:00Z",
+      title: "",
+      preview: "hi",
+    })).toBe("New chat");
+
+    expect(sessionTitle({
+      key: "websocket:chat-work",
+      channel: "websocket",
+      chatId: "chat-work",
+      createdAt: "2026-04-16T10:00:00Z",
+      updatedAt: "2026-04-16T10:00:00Z",
+      title: "",
+      preview: "帮我优化 WebUI 性能",
+    })).toBe("帮我优化 WebUI 性能");
+  });
+
   it("removes a session from the local list after delete succeeds", async () => {
     vi.mocked(api.listSessions).mockResolvedValue([
       {