diff --git a/webui/src/App.tsx b/webui/src/App.tsx
index 7033f6e30..1b50e0ce6 100644
--- a/webui/src/App.tsx
+++ b/webui/src/App.tsx
@@ -64,6 +64,7 @@ import {
 import { projectNameFromPath, scopeWithAccessMode } from "@/lib/workspace";
 import {
   createTemporaryChatSession,
+  deriveTemporaryChatTitle,
 } from "@/lib/temporary-chat";
 
 type BootState =
@@ -2069,7 +2070,7 @@ function Shell({
   }, []);
 
   const headerTitle = temporaryChatActive
-    ? t("temporaryChat.title")
+    ? deriveTemporaryChatTitle(activeSession?.preview, t("temporaryChat.title"))
     : activeSession
     ? sidebarState.title_overrides[activeSession.key] ||
       activeSession.title ||
diff --git a/webui/src/components/ChatList.tsx b/webui/src/components/ChatList.tsx
index f71a4e32a..e4abc146f 100644
--- a/webui/src/components/ChatList.tsx
+++ b/webui/src/components/ChatList.tsx
@@ -44,6 +44,7 @@ import {
   type ChatGroupLabels,
 } from "@/lib/chat-groups";
 import { clearDraggedSession, writeDraggedSession } from "@/lib/session-drag";
+import { deriveTemporaryChatTitle } from "@/lib/temporary-chat";
 import { cn } from "@/lib/utils";
 import type { ChatSummary, SidebarDensity, SidebarSortMode } from "@/lib/types";
 
@@ -537,7 +538,7 @@ function TemporaryChatSection({
       <ul className="space-y-0.5">
         {sessions.map((session) => {
           const active = session.key === activeKey;
-          const title = deriveTitle(session.preview, t("temporaryChat.title"));
+          const title = deriveTemporaryChatTitle(session.preview, t("temporaryChat.title"));
           return (
             <li key={session.key} className="min-w-0">
               <div
diff --git a/webui/src/lib/temporary-chat.ts b/webui/src/lib/temporary-chat.ts
index 969ae2f10..faa71550f 100644
--- a/webui/src/lib/temporary-chat.ts
+++ b/webui/src/lib/temporary-chat.ts
@@ -2,6 +2,15 @@ import type { ChatSummary } from "./types";
 
 const WEBSOCKET_SESSION_KEY_PREFIX = "websocket:";
 
+export function deriveTemporaryChatTitle(
+  firstMessage: string | undefined,
+  fallback: string,
+): string {
+  const oneLine = firstMessage?.replace(/\s+/g, " ").trim() ?? "";
+  if (!oneLine) return fallback;
+  return oneLine.length > 60 ? `${oneLine.slice(0, 57)}…` : oneLine;
+}
+
 export function createTemporaryChatSession(chatId: string): ChatSummary {
   const now = new Date().toISOString();
   return {
diff --git a/webui/src/tests/app-layout.test.tsx b/webui/src/tests/app-layout.test.tsx
index 0b37c16d2..96071dd2c 100644
--- a/webui/src/tests/app-layout.test.tsx
+++ b/webui/src/tests/app-layout.test.tsx
@@ -466,7 +466,10 @@ describe("App layout", () => {
       name: "first private message",
     }));
     await waitFor(() => expect(window.location.hash).toBe(firstHash));
-    expect(screen.getByText("Temporary chat")).toBeInTheDocument();
+    expect(within(screen.getByTestId("thread-header")).getByText(
+      "first private message",
+    )).toBeInTheDocument();
+    await waitFor(() => expect(document.title).toBe("first private message · nanobot"));
     expect(screen.queryByRole("button", { name: "Temporary chat" })).not.toBeInTheDocument();
 
     fireEvent.click(within(sidebar).getByRole("button", {
diff --git a/webui/src/tests/chat-list.test.tsx b/webui/src/tests/chat-list.test.tsx
index 97e2cccd1..fa2e3cb79 100644
--- a/webui/src/tests/chat-list.test.tsx
+++ b/webui/src/tests/chat-list.test.tsx
@@ -156,7 +156,7 @@ describe("ChatList", () => {
     const temporarySession = session({
       key: "temporary:temporary-one",
       chatId: "temporary-one",
-      preview: "Private planning",
+      preview: "hi",
     });
     const onSelect = vi.fn();
     const onClose = vi.fn();
@@ -176,11 +176,11 @@ describe("ChatList", () => {
     );
 
     const section = screen.getByRole("region", { name: "Temporary chats" });
-    fireEvent.click(within(section).getByRole("button", { name: "Private planning" }));
+    fireEvent.click(within(section).getByRole("button", { name: "hi" }));
     expect(onSelect).toHaveBeenCalledWith("temporary:temporary-one");
 
     fireEvent.click(within(section).getByRole("button", {
-      name: "Close temporary chat: Private planning",
+      name: "Close temporary chat: hi",
     }));
     expect(onClose).toHaveBeenCalledWith("temporary:temporary-one");
   });