fix(webui): sync model badge after preset switch

Co-authored-by: Cursor <cursoragent@cursor.com>

nanobot/channels/websocket.py

@@ -1471,6 +1471,9 @@ class WebSocketChannel(BaseChannel):
             payload["kind"] = "tool_hint"
         elif msg.metadata.get("_progress"):
             payload["kind"] = "progress"
+        webui_model_name = msg.metadata.get("_webui_model_name")
+        if isinstance(webui_model_name, str) and webui_model_name.strip():
+            payload["model_name"] = webui_model_name.strip()
         raw = json.dumps(payload, ensure_ascii=False)
         for connection in conns:
             await self._safe_send_to(connection, raw, label=" ")

nanobot/command/builtin.py

@@ -225,7 +225,7 @@ async def cmd_model(ctx: CommandContext) -> OutboundMessage:
             channel=ctx.msg.channel,
             chat_id=ctx.msg.chat_id,
             content=_model_command_status(loop),
-            metadata=metadata,
+            metadata={**metadata, "_webui_model_name": loop.model},
         )
 
     parts = args.split()
@@ -264,7 +264,7 @@ async def cmd_model(ctx: CommandContext) -> OutboundMessage:
         channel=ctx.msg.channel,
         chat_id=ctx.msg.chat_id,
         content="\n".join(lines),
-        metadata=metadata,
+        metadata={**metadata, "_webui_model_name": loop.model},
     )
 
 

tests/channels/test_websocket_channel.py

@@ -229,6 +229,26 @@ async def test_send_delivers_json_message_with_media_and_reply() -> None:
     assert payload["buttons"] == [["Yes", "No"]]
 
 
+@pytest.mark.asyncio
+async def test_send_includes_webui_model_name_metadata() -> None:
+    bus = MagicMock()
+    channel = WebSocketChannel({"enabled": True, "allowFrom": ["*"]}, bus)
+    mock_ws = AsyncMock()
+    channel._attach(mock_ws, "chat-1")
+
+    await channel.send(
+        OutboundMessage(
+            channel="websocket",
+            chat_id="chat-1",
+            content="switched",
+            metadata={"_webui_model_name": "openai/gpt-4.1"},
+        )
+    )
+
+    payload = json.loads(mock_ws.send.call_args[0][0])
+    assert payload["model_name"] == "openai/gpt-4.1"
+
+
 @pytest.mark.asyncio
 async def test_send_stages_external_media_as_signed_url(monkeypatch, tmp_path) -> None:
     bus = MagicMock()

tests/command/test_model_command.py

@@ -64,7 +64,8 @@ async def test_model_command_lists_current_and_available_presets(tmp_path) -> No
     assert "Active preset: `(none)`" in out.content
     assert "`default`" in out.content
     assert "`fast`" in out.content
-    assert out.metadata == {"render_as": "text"}
+    assert out.metadata["render_as"] == "text"
+    assert out.metadata["_webui_model_name"] == "base-model"
 
 
 @pytest.mark.asyncio
@@ -75,6 +76,7 @@ async def test_model_command_switches_preset(tmp_path) -> None:
 
     assert "Switched model preset to `fast`." in out.content
     assert "Model: `openai/gpt-4.1`" in out.content
+    assert out.metadata["_webui_model_name"] == "openai/gpt-4.1"
     assert loop.model_preset == "fast"
     assert loop.model == "openai/gpt-4.1"
     assert loop.subagents.model == "openai/gpt-4.1"
@@ -90,6 +92,7 @@ async def test_model_command_switches_back_to_default(tmp_path) -> None:
     out = await cmd_model(_ctx(loop, "/model default", args="default"))
 
     assert "Switched model preset to `default`." in out.content
+    assert out.metadata["_webui_model_name"] == "base-model"
     assert loop.model_preset == "default"
     assert loop.model == "base-model"
     assert loop.context_window_tokens == 1000

webui/src/App.tsx

@@ -492,6 +492,7 @@ function Shell({ onModelNameChange, onLogout }: { onModelNameChange: (modelName:
             onNewChat={onNewChat}
             onCreateChat={onCreateChat}
             onTurnEnd={onTurnEnd}
+            onModelNameChange={onModelNameChange}
             theme={theme}
             onToggleTheme={toggle}
             hideSidebarToggleOnDesktop={desktopSidebarOpen}

webui/src/components/thread/ThreadShell.tsx

@@ -32,6 +32,7 @@ interface ThreadShellProps {
   onNewChat?: () => void;
   onCreateChat?: () => Promise<string | null>;
   onTurnEnd?: () => void;
+  onModelNameChange?: (modelName: string | null) => void;
   theme?: "light" | "dark";
   onToggleTheme?: () => void;
   hideSidebarToggleOnDesktop?: boolean;
@@ -75,6 +76,7 @@ export function ThreadShell({
   onToggleSidebar,
   onCreateChat,
   onTurnEnd,
+  onModelNameChange,
   theme = "light",
   onToggleTheme = () => {},
   hideSidebarToggleOnDesktop = false,
@@ -103,7 +105,7 @@ export function ThreadShell({
     setMessages,
     streamError,
     dismissStreamError,
-  } = useNanobotStream(chatId, initial, hasPendingToolCalls, onTurnEnd);
+  } = useNanobotStream(chatId, initial, hasPendingToolCalls, onTurnEnd, onModelNameChange);
   const showHeroComposer = messages.length === 0 && !loading;
   const pendingAsk = useMemo(() => {
     for (let index = messages.length - 1; index >= 0; index -= 1) {

webui/src/hooks/useNanobotStream.ts

@@ -44,6 +44,7 @@ export function useNanobotStream(
   initialMessages: UIMessage[] = [],
   hasPendingToolCalls = false,
   onTurnEnd?: () => void,
+  onModelNameChange?: (modelName: string | null) => void,
 ): {
   messages: UIMessage[];
   isStreaming: boolean;
@@ -181,6 +182,9 @@ export function useNanobotStream(
       }
 
       if (ev.event === "message") {
+        if (ev.model_name !== undefined) {
+          onModelNameChange?.(ev.model_name || null);
+        }
         if (
           suppressStreamUntilTurnEndRef.current &&
           (ev.kind === "tool_hint" || ev.kind === "progress")

webui/src/lib/types.ts

@@ -147,6 +147,8 @@ export type InboundEvent =
       /** Present when the frame is an agent breadcrumb (e.g. tool hint,
        * generic progress line) rather than a conversational reply. */
       kind?: "tool_hint" | "progress";
+      /** Runtime model name after commands like `/model fast` update it. */
+      model_name?: string | null;
     }
   | {
       event: "delta";

webui/src/tests/useNanobotStream.test.tsx

@@ -134,6 +134,28 @@ describe("useNanobotStream", () => {
     ]);
   });
 
+  it("reports runtime model name updates from message frames", () => {
+    const fake = fakeClient();
+    const onModelNameChange = vi.fn();
+    renderHook(
+      () => useNanobotStream("chat-model", EMPTY_MESSAGES, false, undefined, onModelNameChange),
+      {
+        wrapper: wrap(fake.client),
+      },
+    );
+
+    act(() => {
+      fake.emit("chat-model", {
+        event: "message",
+        chat_id: "chat-model",
+        text: "Switched model preset to `fast`.",
+        model_name: "openai/gpt-4.1",
+      });
+    });
+
+    expect(onModelNameChange).toHaveBeenCalledWith("openai/gpt-4.1");
+  });
+
   it("suppresses redundant stream confirmation after assistant media", () => {
     const fake = fakeClient();
     const { result } = renderHook(() => useNanobotStream("chat-img-result", EMPTY_MESSAGES), {