feat(studio): coding agent chat polish

services/studio/src/nmp/studio/coding_agents.py

@@ -7,6 +7,7 @@
 import json
 import logging
 import os
+import re
 import shutil
 import uuid
 from collections.abc import AsyncIterator, Awaitable, Mapping
@@ -104,6 +105,7 @@ class HistorySessionResponse(BaseModel):
 
     session_id: str
     mtime: float
+    title: str | None = None
     first_prompt: str
     message_count: int
     token_count: int
@@ -131,6 +133,7 @@ class SessionHistoryResponse(BaseModel):
 class HistorySummary:
     """Aggregated metadata from a Claude session history file."""
 
+    title: str | None = None
     first_prompt: str | None = None
     message_count: int = 0
     token_count: int = 0
@@ -323,6 +326,7 @@ def _build_studio_system_prompt(
         f"Start the summary block on its own line with {STUDIO_MESSAGE_SUMMARY_START} and end it on its own line with {STUDIO_MESSAGE_SUMMARY_END}.",
         "Inside the summary block, use exactly these fields on separate lines:",
         f"{STUDIO_MESSAGE_SUMMARY_START}",
+        "title: <meaningful 3-7 word title naming the user's overall task; keep it stable across messages unless the topic clearly changes>",
         "worked_for: <elapsed time if you know it, otherwise unknown>",
         "summary: <concise Markdown, at most 60 words, describing the user-visible result and current state>",
         "details_label: worked for <same elapsed time or unknown>",
@@ -440,6 +444,24 @@ def _append_tool_call(summary: HistorySummary, tool_name: str) -> None:
     record_tool_name(summary.chat_artifacts, tool_name)
 
 
+def _studio_message_title(text: str) -> str | None:
+    summary_start = text.find(STUDIO_MESSAGE_SUMMARY_START)
+    if summary_start < 0:
+        return None
+
+    summary_end = text.find(STUDIO_MESSAGE_SUMMARY_END, summary_start)
+    block = text[summary_start + len(STUDIO_MESSAGE_SUMMARY_START) : summary_end if summary_end >= 0 else None]
+    match = re.search(
+        r"(?:^|\s)title:\s*(.+?)(?=\s+(?:worked_for|summary|details_label):\s*|$)",
+        block,
+        flags=re.IGNORECASE | re.DOTALL,
+    )
+    if not match:
+        return None
+
+    return _trimmed_string(" ".join(match.group(1).split()))
+
+
 def _record_assistant_tool_calls(
     summary: HistorySummary,
     message: dict[str, Any],
@@ -452,6 +474,7 @@ def _record_assistant_tool_calls(
         if part.get("type") == "text":
             text = string_value(part.get("text"))
             if text:
+                summary.title = _studio_message_title(text) or summary.title
                 record_spec_text_artifacts(summary.chat_artifacts, text)
             continue
         if part.get("type") != "tool_use":
@@ -595,6 +618,7 @@ def list_history_sessions() -> list[HistorySessionResponse]:
             HistorySessionResponse(
                 session_id=history_file.stem,
                 mtime=mtime,
+                title=summary.title,
                 first_prompt=summary.first_prompt or "",
                 message_count=summary.message_count,
                 token_count=summary.token_count,

services/studio/tests/unit/test_coding_agents.py

@@ -320,6 +320,7 @@ def test_list_and_get_history_sessions(
         {
             "session_id": session_id,
             "mtime": history.stat().st_mtime,
+            "title": None,
             "first_prompt": "first prompt",
             "message_count": 1,
             "token_count": 30,
@@ -695,6 +696,7 @@ def test_build_studio_system_prompt_includes_message_summary_contract():
     assert "Required message-summary behavior:" in prompt
     assert coding_agents.STUDIO_MESSAGE_SUMMARY_START in prompt
     assert coding_agents.STUDIO_MESSAGE_SUMMARY_END in prompt
+    assert "title: <meaningful 3-7 word title" in prompt
     assert "worked_for: <elapsed time if you know it, otherwise unknown>" in prompt
     assert "summary: <concise Markdown" in prompt
     assert "details_label: worked for <same elapsed time or unknown>" in prompt
@@ -712,6 +714,43 @@ def test_build_studio_system_prompt_includes_message_summary_contract():
     assert "Do not omit the summary block because the message is short." in prompt
 
 
+def test_history_summary_reads_model_generated_session_title(tmp_path: Path):
+    history = tmp_path / "session.jsonl"
+    history.write_text(
+        "\n".join(
+            [
+                json.dumps({"type": "user", "message": {"content": "A long initial request"}}),
+                json.dumps(
+                    {
+                        "type": "assistant",
+                        "message": {
+                            "content": [
+                                {
+                                    "type": "text",
+                                    "text": "\n".join(
+                                        [
+                                            coding_agents.STUDIO_MESSAGE_SUMMARY_START,
+                                            "title: Create Spam Detector Agent",
+                                            "worked_for: unknown",
+                                            "summary: Created the requested agent.",
+                                            "details_label: worked for unknown",
+                                            coding_agents.STUDIO_MESSAGE_SUMMARY_END,
+                                        ]
+                                    ),
+                                }
+                            ]
+                        },
+                    }
+                ),
+            ]
+        )
+    )
+
+    summary = coding_agents._summarize_history_session(history)
+
+    assert summary.title == "Create Spam Detector Agent"
+
+
 def test_studio_link_destinations_cover_registered_workspace_routes():
     repo_root = Path(__file__).resolve().parents[4]
     routes_index = (repo_root / "web/packages/studio/src/routes/index.tsx").read_text()

web/packages/common/src/components/AssistantChat/AssistantChatMessageContent.tsx

@@ -6,21 +6,46 @@ import type { MessageRenderProps } from '@nemo/common/src/components/AssistantCh
 import { MessageContent } from '@nemo/common/src/components/Chat/MessageContent';
 import { Banner } from '@nvidia/foundations-react-core';
 
+interface AssistantChatMessageContentProps extends MessageRenderProps {
+  contentSurfaceClassName?: string;
+}
+
 export const AssistantChatMessageContent = ({
+  contentSurfaceClassName,
   messageContentProps,
   toolCallPartComponent,
-}: MessageRenderProps) => (
+}: AssistantChatMessageContentProps) => (
   <>
     <MessagePrimitive.Parts
       components={{
-        Text: ({ text }) => <MessageContent content={text} {...messageContentProps} />,
-        Image: ({ image, filename }) => (
-          <img
-            src={image}
-            alt={filename ?? 'Attached image'}
-            className="mt-density-xs max-h-64 w-auto rounded-lg border border-base object-contain"
-          />
-        ),
+        Text: ({ text }) => {
+          if (!text.trim()) return null;
+
+          const content = <MessageContent content={text} {...messageContentProps} />;
+          return contentSurfaceClassName ? (
+            <div className={contentSurfaceClassName} data-testid="assistant-chat-message-surface">
+              {content}
+            </div>
+          ) : (
+            content
+          );
+        },
+        Image: ({ image, filename }) => {
+          const content = (
+            <img
+              src={image}
+              alt={filename ?? 'Attached image'}
+              className="mt-density-xs max-h-64 w-auto rounded-lg border border-base object-contain"
+            />
+          );
+          return contentSurfaceClassName ? (
+            <div className={contentSurfaceClassName} data-testid="assistant-chat-message-surface">
+              {content}
+            </div>
+          ) : (
+            content
+          );
+        },
         tools: { Fallback: toolCallPartComponent },
       }}
     />

web/packages/common/src/components/AssistantChat/AssistantMessage.tsx

@@ -17,6 +17,9 @@ import type { MessageRenderProps } from '@nemo/common/src/components/AssistantCh
 import { Skeleton, Tooltip } from '@nvidia/foundations-react-core';
 import { RefreshCw } from 'lucide-react';
 
+const ASSISTANT_MESSAGE_SURFACE_CLASS =
+  'w-full max-w-full rounded-lg border border-base border-l-4 border-l-[var(--border-color-brand)] bg-surface-base px-density-lg py-density-md shadow ring-1 ring-black/5 dark:ring-white/10';
+
 export const AssistantMessage = ({
   hideAssistantMessageActions,
   messageContentProps,
@@ -26,33 +29,23 @@ export const AssistantMessage = ({
   hideAssistantMessageActions?: boolean;
   showRunningIndicator?: boolean;
 }) => {
-  const isToolOnlyMessage = useAuiState((state) => {
-    const { parts } = state.message;
-    return parts.length > 0 && parts.every((part) => part.type === 'tool-call');
-  });
+  const hasRenderableContent = useAuiState((state) =>
+    state.message.parts.some((part) => part.type !== 'text' || part.text.trim().length > 0)
+  );
 
   return (
     <MessagePrimitive.Root
       data-testid="assistant-chat-message"
       data-testspeaker="assistant"
       className="group/message flex w-full flex-col items-start gap-density-xs whitespace-normal"
     >
-      {isToolOnlyMessage ? (
+      {hasRenderableContent ? (
         <AssistantChatMessageContent
+          contentSurfaceClassName={ASSISTANT_MESSAGE_SURFACE_CLASS}
           messageContentProps={messageContentProps}
           toolCallPartComponent={toolCallPartComponent}
         />
-      ) : (
-        <div
-          className="w-full max-w-full rounded-lg border border-base border-l-4 border-l-[var(--border-color-brand)] bg-surface-base px-density-lg py-density-md shadow ring-1 ring-black/5 dark:ring-white/10"
-          data-testid="assistant-chat-message-surface"
-        >
-          <AssistantChatMessageContent
-            messageContentProps={messageContentProps}
-            toolCallPartComponent={toolCallPartComponent}
-          />
-        </div>
-      )}
+      ) : null}
       {showRunningIndicator ? (
         <MessagePrimitive.If last>
           <ThreadPrimitive.If running>

web/packages/common/src/components/AssistantChat/index.test.tsx

@@ -112,18 +112,20 @@ const renderAssistantChat = (element: ReactElement) =>
 
 const StaticAssistantChatThread = ({
   hideAssistantMessageActions,
+  isRunning = false,
   messages: initialMessages = defaultStaticMessages,
   toolCallPartComponent,
 }: {
   hideAssistantMessageActions?: boolean;
+  isRunning?: boolean;
   messages?: readonly ThreadMessageLike[];
   toolCallPartComponent?: ToolCallMessagePartComponent;
 }) => {
   const [messages, setMessages] = useState<readonly ThreadMessageLike[]>(initialMessages);
   const runtime = useExternalStoreRuntime<ThreadMessageLike>({
     messages,
     setMessages,
-    isRunning: false,
+    isRunning,
     onNew: async () => undefined,
     onEdit: async () => undefined,
     onReload: async () => undefined,
@@ -295,6 +297,112 @@ describe('AssistantChat', () => {
     ).not.toBeInTheDocument();
   });
 
+  it('renders streamed text and tool-call parts as separate message blocks', () => {
+    renderAssistantChat(
+      <StaticAssistantChatThread
+        hideAssistantMessageActions
+        messages={[
+          {
+            role: 'assistant',
+            content: [
+              { type: 'text', text: 'I will inspect the repository.' },
+              {
+                type: 'tool-call',
+                toolCallId: 'toolu_read',
+                toolName: 'Read',
+                args: { file_path: 'README.md' },
+              },
+              { type: 'text', text: 'I found the relevant file.' },
+            ],
+            status: { type: 'running' },
+          },
+        ]}
+        toolCallPartComponent={({ toolName }) => (
+          <div data-testid="assistant-chat-tool-pill">{toolName}</div>
+        )}
+      />
+    );
+
+    const assistantMessage = screen.getByTestId('assistant-chat-message');
+    const messageSurfaces = within(assistantMessage).getAllByTestId(
+      'assistant-chat-message-surface'
+    );
+    const toolCall = within(assistantMessage).getByTestId('assistant-chat-tool-pill');
+
+    expect(messageSurfaces).toHaveLength(2);
+    expect(messageSurfaces[0]).toHaveTextContent('I will inspect the repository.');
+    expect(messageSurfaces[1]).toHaveTextContent('I found the relevant file.');
+    expect(toolCall).toHaveTextContent('Read');
+    for (const messageSurface of messageSurfaces) {
+      expect(
+        within(messageSurface).queryByTestId('assistant-chat-tool-pill')
+      ).not.toBeInTheDocument();
+    }
+  });
+
+  it('shows the running skeleton without an empty assistant response surface', () => {
+    renderAssistantChat(
+      <StaticAssistantChatThread
+        hideAssistantMessageActions
+        isRunning
+        messages={[
+          {
+            role: 'assistant',
+            content: [{ type: 'text', text: '' }],
+            status: { type: 'running' },
+          },
+        ]}
+      />
+    );
+
+    const assistantMessage = screen.getByTestId('assistant-chat-message');
+
+    expect(
+      within(assistantMessage).queryByTestId('assistant-chat-message-surface')
+    ).not.toBeInTheDocument();
+    expect(
+      within(assistantMessage).getByTestId('assistant-chat-running-indicator')
+    ).toBeInTheDocument();
+    expect(within(assistantMessage).getByTestId('assistant-chat-skeleton')).toBeInTheDocument();
+  });
+
+  it('hides an empty text surface while a tool is running', () => {
+    renderAssistantChat(
+      <StaticAssistantChatThread
+        hideAssistantMessageActions
+        isRunning
+        messages={[
+          {
+            role: 'assistant',
+            content: [
+              { type: 'text', text: '  \n' },
+              {
+                type: 'tool-call',
+                toolCallId: 'toolu_read',
+                toolName: 'Read',
+                args: { file_path: 'README.md' },
+              },
+            ],
+            status: { type: 'running' },
+          },
+        ]}
+        toolCallPartComponent={({ toolName }) => (
+          <div data-testid="assistant-chat-tool-pill">{toolName}</div>
+        )}
+      />
+    );
+
+    const assistantMessage = screen.getByTestId('assistant-chat-message');
+
+    expect(within(assistantMessage).getByTestId('assistant-chat-tool-pill')).toHaveTextContent(
+      'Read'
+    );
+    expect(
+      within(assistantMessage).queryByTestId('assistant-chat-message-surface')
+    ).not.toBeInTheDocument();
+    expect(within(assistantMessage).getByTestId('assistant-chat-skeleton')).toBeInTheDocument();
+  });
+
   it('offers an enabled add-image affordance for a vision model when enabled', () => {
     renderAssistantChat(
       <AssistantChat model="test-vision-model" workspace="default" enableImageAttachments />

web/packages/studio/src/index.css

@@ -88,24 +88,3 @@ body {
 .nv-radio-group-item[data-disabled] {
   cursor: not-allowed;
 }
-
-@keyframes claude-code-tool-call-running-color {
-  0%,
-  100% {
-    color: var(--text-color-subtle);
-  }
-
-  50% {
-    color: var(--text-color-brand);
-  }
-}
-
-.claude-code-tool-call-running {
-  color: var(--text-color-brand);
-}
-
-@media (prefers-reduced-motion: no-preference) {
-  .claude-code-tool-call-running {
-    animation: claude-code-tool-call-running-color 1.6s ease-in-out infinite;
-  }
-}