Studio: fix duplicate response model labels and hover

studio/frontend/src/components/assistant-ui/message-response-details-sheet.tsx

@@ -288,7 +288,7 @@ export const MessageResponseModelBadge: FC<{ className?: string }> = ({
   return (
     <span
       className={cn(
-        "aui-response-model-badge inline-flex min-h-5 max-w-full items-center text-muted-foreground/80 text-xs font-medium leading-5 opacity-0 transition-opacity duration-150 group-hover/assistant-message:opacity-100 group-focus-within/assistant-message:opacity-100",
+        "aui-response-model-badge pointer-events-none relative inline-flex min-h-5 max-w-full cursor-text select-text items-center text-muted-foreground/80 text-xs font-medium leading-5 opacity-0 transition-opacity duration-150 after:absolute after:inset-x-0 after:top-full after:h-1 after:content-[''] hover:opacity-100 group-hover/assistant-message:pointer-events-auto group-hover/assistant-message:opacity-100 group-focus-within/assistant-message:pointer-events-auto group-focus-within/assistant-message:opacity-100",
         className,
       )}
       title={providerLabel ? `${modelLabel} - ${providerLabel}` : modelLabel}

studio/frontend/src/components/assistant-ui/reasoning.tsx

@@ -6,7 +6,6 @@
 /* eslint-disable react-refresh/only-export-components */
 
 import { MarkdownText } from "@/components/assistant-ui/markdown-text";
-import { MessageResponseModelBadge } from "@/components/assistant-ui/message-response-details-sheet";
 import {
   Collapsible,
   CollapsibleContent,
@@ -393,15 +392,12 @@ const ReasoningGroupImpl: ReasoningGroupComponent = ({
     >
       <div className="flex min-w-0 items-center gap-2">
         <ReasoningTrigger
-          className="min-w-0 flex-none"
+          className="min-w-0 flex-1"
           active={isReasoningStreaming}
           // Prefer server timing when available.
           duration={persistedDuration || duration}
         />
-        <span className="hidden min-w-0 max-w-[12rem] group-hover/assistant-message:inline-flex group-focus-within/assistant-message:inline-flex sm:max-w-[16rem]">
-          <MessageResponseModelBadge className="min-w-0" />
-        </span>
-        <div className="ml-auto flex w-16 shrink-0 justify-end">
+        <div className="flex w-16 shrink-0 justify-end">
           {isOpen && !isReasoningStreaming && (
             <ReasoningCopyButton startIndex={startIndex} endIndex={endIndex} />
           )}

studio/frontend/src/components/assistant-ui/thread.tsx

@@ -3569,9 +3569,6 @@ const AssistantMessage: FC = () => {
   const aui = useAui();
   const messageId = useAuiState(({ message }) => message.id);
   const messageContent = useAuiState(({ message }) => message.content);
-  const hasReasoningParts = useAuiState(({ message }) =>
-    message.parts.some((part) => part.type === "reasoning"),
-  );
   const incognito = useChatRuntimeStore((s) => s.incognito);
 
   // Use global store for editing state to ensure a single source of truth
@@ -3657,11 +3654,9 @@ const AssistantMessage: FC = () => {
           </div>
         ) : (
           <>
-            {!hasReasoningParts ? (
-              <div className="pointer-events-none relative h-0 min-w-0">
-                <MessageResponseModelBadge className="absolute -top-6 left-0 max-w-[min(22rem,100%)]" />
-              </div>
-            ) : null}
+            <div className="pointer-events-none relative h-0 min-w-0">
+              <MessageResponseModelBadge className="absolute -top-6 left-0 max-w-[min(22rem,100%)]" />
+            </div>
             <GeneratingIndicator />
             <CancelledIndicator />
             <DiffusionCanvas />

tests/studio/test_chat_response_details_ui_contract.py

@@ -44,7 +44,7 @@ def test_response_details_sheet_uses_unsloth_sheet_and_key_sections():
         assert f'label="{field}"' in src
 
 
-def test_response_model_chip_is_user_configurable_and_rendered_in_metadata_rows():
+def test_response_model_badge_is_user_configurable_and_rendered_once_per_message():
     prefs_src = CHAT_PREFS_TS.read_text()
     chat_tab_src = CHAT_TAB_TSX.read_text()
     thread_src = THREAD_TSX.read_text()
@@ -55,17 +55,24 @@ def test_response_model_chip_is_user_configurable_and_rendered_in_metadata_rows(
     assert "showResponseModel: saved?.showResponseModel ?? false" in prefs_src
     assert "Show response model" in chat_tab_src
     assert "setShowResponseModel" in chat_tab_src
-    assert "aui-response-model-badge inline-flex min-h-5" in DETAILS_TSX.read_text()
-    assert "leading-5" in DETAILS_TSX.read_text()
-    assert "group-hover/assistant-message:opacity-100" in DETAILS_TSX.read_text()
-    assert "MessageResponseModelBadge" in thread_src
-    assert "hasReasoningParts" in thread_src
+    details_src = DETAILS_TSX.read_text()
+    assert (
+        "aui-response-model-badge pointer-events-none relative inline-flex min-h-5" in details_src
+    )
+    assert "cursor-text select-text" in details_src
+    assert "leading-5" in details_src
+    assert "after:top-full after:h-1" in details_src
+    assert "hover:opacity-100" in details_src
+    assert "group-hover/assistant-message:opacity-100" in details_src
+    # Pointer events gated behind hover/focus so the hidden badge stays inert when idle.
+    assert "group-hover/assistant-message:pointer-events-auto" in details_src
+    assert "group-focus-within/assistant-message:pointer-events-auto" in details_src
+    assert thread_src.count("<MessageResponseModelBadge") == 1
+    assert "hasReasoningParts" not in thread_src
     assert "group/assistant-message aui-assistant-message-root" in thread_src
     assert "pointer-events-none relative h-0" in thread_src
-    assert "MessageResponseModelBadge" in reasoning_src
-    assert 'className="min-w-0 flex-none"' in reasoning_src
-    assert "hidden min-w-0 max-w-[12rem]" in reasoning_src
-    assert "group-hover/assistant-message:inline-flex" in reasoning_src
+    assert "MessageResponseModelBadge" not in reasoning_src
+    assert 'className="min-w-0 flex-1"' in reasoning_src
 
 
 def test_response_details_metadata_is_persisted_without_backend_schema_change():