fix(ai-chat): stop duplicating the assistant name in the typing indicator

While a multi-step agent turn is "thinking between tool steps", the
assistant identity name (e.g. the role name) was rendered twice, stacked:
once by the assistant message row (MessageItem) and once by the standalone
TypingIndicator below it. The indicator's name label only makes sense when
it stands in for a not-yet-started assistant row; between steps the row
above already shows the same name.

Render the indicator's dimmed name label only when it is standalone (no
assistant row at the tail yet); otherwise show just the "Thinking…" dots.

- typing-indicator.tsx: optional showName prop (default true); the name
  label renders only when showName !== false
- message-list.tsx: exported typingIndicatorShowsName(messages) helper;
  pass showName to the indicator at the render site
- typing-indicator-shows-name.test.ts: unit-cover the four cases

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/client/src/features/ai-chat/components/message-list.tsx

@@ -77,6 +77,17 @@ export function showTypingIndicator(messages: UIMessage[], isStreaming: boolean)
   return true;
 }
 
+/**
+ * Whether the standalone typing indicator should render its own assistant-name
+ * label. True only when it stands in for a not-yet-started assistant row (it IS
+ * the nascent bubble). False once an assistant row exists at the tail, because
+ * that row's MessageItem already shows the same name — avoids a duplicate label.
+ */
+export function typingIndicatorShowsName(messages: UIMessage[]): boolean {
+  const last = messages[messages.length - 1];
+  return !(last && last.role === "assistant");
+}
+
 /**
  * Scrollable transcript. Auto-scrolls to the newest message as it streams in,
  * but only while the user is pinned to the bottom — if they scrolled up to read
@@ -173,7 +184,7 @@ export default function MessageList({
             assistantName={assistantName}
           />
         ))}
-        {typing && <TypingIndicator assistantName={assistantName} />}
+        {typing && <TypingIndicator assistantName={assistantName} showName={typingIndicatorShowsName(messages)} />}
       </Stack>
     </ScrollArea>
   );

apps/client/src/features/ai-chat/components/typing-indicator-shows-name.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from "vitest";
+import type { UIMessage } from "@ai-sdk/react";
+import { typingIndicatorShowsName } from "@/features/ai-chat/components/message-list.tsx";
+
+/**
+ * Pure-helper tests for whether the standalone "Thinking…" indicator renders its
+ * own dimmed assistant-name label. It should only show the name while it stands
+ * in for a not-yet-started assistant row; once an assistant row exists at the
+ * tail, that row's MessageItem already shows the same name, so the indicator
+ * must show only the dots to avoid a duplicate stacked label.
+ */
+const msg = (
+  role: "user" | "assistant",
+  parts: UIMessage["parts"],
+): UIMessage => ({ id: Math.random().toString(), role, parts }) as UIMessage;
+
+describe("typingIndicatorShowsName", () => {
+  it("shows the name with no messages yet (standalone, just submitted)", () => {
+    expect(typingIndicatorShowsName([])).toBe(true);
+  });
+
+  it("shows the name when the last message is still the user's", () => {
+    expect(
+      typingIndicatorShowsName([msg("user", [{ type: "text", text: "q" }])]),
+    ).toBe(true);
+  });
+
+  it("hides the name when an assistant row exists at the tail", () => {
+    expect(
+      typingIndicatorShowsName([msg("assistant", [{ type: "text", text: "" }])]),
+    ).toBe(false);
+  });
+
+  it("hides the name when the assistant row's last part is a tool", () => {
+    const doneTool = { type: "tool-getPage", state: "output-available" } as unknown as UIMessage["parts"][number];
+    expect(
+      typingIndicatorShowsName([msg("assistant", [doneTool])]),
+    ).toBe(false);
+  });
+});

apps/client/src/features/ai-chat/components/typing-indicator.tsx

@@ -10,6 +10,12 @@ interface TypingIndicatorProps {
    * (agent role) name.
    */
   assistantName?: string;
+  /**
+   * Whether to render the dimmed assistant-name label. Defaults to true
+   * (standalone behavior preserved). Set false between agent steps where the
+   * assistant row above already shows the same name, to avoid a duplicate label.
+   */
+  showName?: boolean;
 }
 
 /**
@@ -24,15 +30,17 @@ interface TypingIndicatorProps {
  * typing line is always the generic "Thinking…" (it never includes the
  * role/identity name).
  */
-export default function TypingIndicator({ assistantName }: TypingIndicatorProps) {
+export default function TypingIndicator({ assistantName, showName = true }: TypingIndicatorProps) {
   const { t } = useTranslation();
   const name = resolveAssistantName(assistantName);
 
   return (
     <Box className={classes.messageRow}>
-      <Text size="xs" c="dimmed" mb={4}>
-        {name ?? t("AI agent")}
-      </Text>
+      {showName !== false && (
+        <Text size="xs" c="dimmed" mb={4}>
+          {name ?? t("AI agent")}
+        </Text>
+      )}
       <Group gap={8} align="center">
         <span className={classes.typingDots} aria-hidden="true">
           <span />