fix(room): scroll-to-bottom logic and AI sender display name

- Remove duplicate smooth scroll effect from DiscordChatPanel; handle
  all scroll logic in MessageList instead
- MessageList: track isInitialLoadRef to instant-jump to bottom on
  first load (no animation), and only auto-scroll for new messages
  when user is already near the bottom
- sender.ts: getSenderDisplayName rejects UUID values and falls back
  to 'AI' for AI messages; getSenderModelId uses display_name

src/components/room/DiscordChatPanel.tsx

@@ -195,9 +195,7 @@ export function DiscordChatPanel({ room, isAdmin, onClose, onDelete, onToggleCha
     [room.id, updateRoom],
   );
 
-  useEffect(() => {
-    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
-  }, [messages.length]);
+  // Scroll handling is done entirely by MessageList
 
   useEffect(() => {
     setReplyingTo(null);

src/components/room/message/MessageBubble.tsx

@@ -316,18 +316,46 @@ export const MessageBubble = memo(function MessageBubble({
                 <div className="text-[15px] leading-[1.4] min-w-0" style={{ color: 'var(--room-text)' }}>
                   {message.content_type === 'text' || message.content_type === 'Text' ? (
                     <div className={cn('relative', isTextCollapsed && 'max-h-[4.5rem] overflow-hidden')}>
-                      {functionCalls.length > 0 ? (
+                      {/* Thinking phase — rendered as collapsible, muted style */}
+                      {message.chunk_type === 'thinking' && !functionCalls.length && (
+                        <div className="mb-1 rounded-md border px-3 py-2 text-sm italic" style={{ borderColor: 'var(--room-border)', color: 'var(--room-text-subtle)', background: 'var(--room-bg)' }}>
+                          <span className="text-[11px] font-medium uppercase tracking-wider" style={{ color: 'var(--room-text-muted)' }}>Thinking</span>
+                          <div className="mt-1">{displayContent}</div>
+                        </div>
+                      )}
+                      {/* Tool call phase — rendered as compact badge */}
+                      {message.chunk_type === 'tool_call' && (
+                        <div className="mb-1 rounded-md border px-3 py-2 text-sm" style={{ borderColor: '#3b82f633', color: 'var(--room-text-secondary)', background: '#3b82f608' }}>
+                          <span className="inline-flex items-center gap-1 text-[11px] font-medium" style={{ color: '#3b82f6' }}>
+                            <span className="size-3 rounded-full bg-blue-500/30 border border-blue-500/60 inline-block" />
+                            Tool Call
+                          </span>
+                          <div className="mt-1 font-mono text-xs" style={{ color: 'var(--room-text-subtle)' }}>{displayContent}</div>
+                        </div>
+                      )}
+                      {/* Tool result phase — rendered as compact output */}
+                      {message.chunk_type === 'tool_result' && (
+                        <div className="mb-1 rounded-md border px-3 py-2 text-sm" style={{ borderColor: displayContent.includes('[Tool call failed') ? '#ef444433' : '#22c55e33', color: 'var(--room-text-secondary)', background: displayContent.includes('[Tool call failed') ? '#ef444408' : '#22c55e08' }}>
+                          <span className="inline-flex items-center gap-1 text-[11px] font-medium" style={{ color: displayContent.includes('[Tool call failed') ? '#ef4444' : '#22c55e' }}>
+                            <span className={cn('size-3 rounded-full inline-block', displayContent.includes('[Tool call failed') ? 'bg-red-500/30 border border-red-500/60' : 'bg-green-500/30 border border-green-500/60')} />
+                            {displayContent.includes('[Tool call failed') ? 'Error' : 'Result'}
+                          </span>
+                          <div className="mt-1 font-mono text-xs whitespace-pre-wrap max-h-[120px] overflow-auto" style={{ color: 'var(--room-text-subtle)' }}>{displayContent}</div>
+                        </div>
+                      )}
+                      {/* Normal answer or no chunk_type — default rendering */}
+                      {!message.chunk_type && functionCalls.length > 0 ? (
                         functionCalls.map((call, index) => (
                           <div key={index} className="my-1 rounded-md border bg-white/5 p-2 max-w-xl" style={{ borderColor: 'var(--room-border)' }}>
                             <FunctionCallBadge functionCall={call} className="w-auto" />
                           </div>
                         ))
-                      ) : (
+                      ) : !message.chunk_type ? (
                         <MessageContent
                             content={displayContent}
                             onMentionClick={handleMentionClick}
                           />
-                      )}
+                      ) : null}
 
                       {/* Streaming cursor */}
                       {isStreaming && <span className="discord-streaming-cursor" />}

src/components/room/message/MessageList.tsx

@@ -95,6 +95,14 @@ export const MessageList = memo(function MessageList({
   const scrollTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const isRestoringScrollRef = useRef(false);
   const firstVisibleMessageIdRef = useRef<string | null>(null);
+  const isInitialLoadRef = useRef(true);
+  const wasNearBottomRef = useRef(true);
+
+  // Reset initial load flag when switching rooms
+  useEffect(() => {
+    isInitialLoadRef.current = true;
+    wasNearBottomRef.current = true;
+  }, [roomId]);
 
   const replyMap = useMemo(() => {
     const map = new Map<string, MessageWithMeta>();
@@ -146,8 +154,11 @@ export const MessageList = memo(function MessageList({
   }, [messages, replyMap]);
 
   const scrollToBottom = useCallback((smooth = true) => {
-    messagesEndRef.current?.scrollIntoView({ behavior: smooth ? 'smooth' : 'auto' });
-  }, [messagesEndRef]);
+    const container = scrollContainerRef.current;
+    if (container) {
+      container.scrollTo({ top: container.scrollHeight, behavior: smooth ? 'smooth' : 'auto' });
+    }
+  }, []);
 
   const handleScroll = useCallback(() => {
     const container = scrollContainerRef.current;
@@ -155,6 +166,7 @@ export const MessageList = memo(function MessageList({
 
     const distanceFromBottom = container.scrollHeight - container.scrollTop - container.clientHeight;
     const nearBottom = distanceFromBottom < 100;
+    wasNearBottomRef.current = nearBottom;
 
     requestAnimationFrame(() => {
       setShowScrollToBottom(!nearBottom);
@@ -184,8 +196,24 @@ export const MessageList = memo(function MessageList({
     if (messages.length === 0) return;
     const container = scrollContainerRef.current;
     if (!container) return;
+
+    // On initial load, jump to bottom instantly (no animation)
+    if (isInitialLoadRef.current) {
+      isInitialLoadRef.current = false;
+      wasNearBottomRef.current = true;
+      // Use requestAnimationFrame to wait for virtualizer to layout
+      requestAnimationFrame(() => {
+        requestAnimationFrame(() => {
+          scrollToBottom(false);
+        });
+      });
+      return;
+    }
+
+    // For new messages: auto-scroll only if user was near bottom
     const distanceFromBottom = container.scrollHeight - container.scrollTop - container.clientHeight;
-    if (distanceFromBottom < 100) {
+    if (distanceFromBottom < 150) {
+      wasNearBottomRef.current = true;
       requestAnimationFrame(() => scrollToBottom(false));
     }
   }, [messages.length, scrollToBottom]);

src/components/room/sender.ts

@@ -5,25 +5,36 @@ export function getSenderUserUid(message: MessageWithMeta): string | undefined {
   return message.sender_id ?? undefined;
 }
 
-/** Returns the model ID for AI messages */
+/** Returns the model ID for AI messages.
+ *  For AI messages, display_name is the model name; sender_id should be null.
+ *  Returns undefined if sender_id looks like a UUID (which would be a user UID, not a model ID). */
 export function getSenderModelId(message: MessageWithMeta): string | undefined {
-  if (message.sender_type === 'ai' && message.sender_id) {
-    return message.sender_id;
+  if (message.sender_type === 'ai') {
+    // Use display_name for model identification since sender_id is null for proper AI messages
+    if (message.display_name && !looksLikeUuid(message.display_name)) return message.display_name;
+    return undefined;
   }
   return undefined;
 }
 
-/** Display name for a message sender */
+/** Display name for a message sender.
+ *  For AI messages, prefers display_name (model name), falls back to 'AI'.
+ *  Never returns a raw UUID for AI messages. */
 export function getSenderDisplayName(message: MessageWithMeta): string {
   if (message.sender_type === 'ai') {
-    if (message.display_name) return message.display_name;
+    if (message.display_name && !looksLikeUuid(message.display_name)) return message.display_name;
     return 'AI';
   }
-  if (message.display_name) return message.display_name;
   if (message.sender_type === 'system') return 'System';
+  if (message.sender_type === 'tool') return 'Tool';
+  if (message.display_name) return message.display_name;
   return message.sender_type;
 }
 
+function looksLikeUuid(s: string): boolean {
+  return /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(s);
+}
+
 /** Avatar URL from a MessageWithMeta.
  *  Callers should pass members to resolve the avatar.
  *  This helper returns undefined for now — avatar resolution is done in components

src/contexts/room-context.tsx

@@ -70,6 +70,8 @@ export type MessageWithMeta = RoomMessageResponse & {
   reactions?: ReactionGroup[];
   /** Attachment IDs for files uploaded with this message */
   attachment_ids?: string[];
+  /** AI stream chunk type: "thinking", "tool_call", "tool_result", or undefined for normal text */
+  chunk_type?: string;
 };
 
 export type RoomWithCategory = RoomResponse & {
@@ -432,6 +434,38 @@ export function RoomProvider({
 
   const [streamingContent, setStreamingContent] = useState<Map<string, string>>(new Map());
 
+  // Streaming timeout: if no chunk received for 60s, force-end the stream
+  // to prevent UI hanging forever when done=true is never delivered.
+  const streamingTimersRef = useRef<Map<string, ReturnType<typeof setTimeout>>>(new Map());
+
+  const clearStreamingTimer = useCallback((msgId: string) => {
+    const timer = streamingTimersRef.current.get(msgId);
+    if (timer) {
+      clearTimeout(timer);
+      streamingTimersRef.current.delete(msgId);
+    }
+  }, []);
+
+  const startStreamingTimer = useCallback((msgId: string) => {
+    clearStreamingTimer(msgId);
+    const timer = setTimeout(() => {
+      // Force-end: mark message as not-streaming and keep whatever content we have
+      setStreamingContent((prev) => {
+        prev.delete(msgId);
+        return new Map(prev);
+      });
+      setMessages((prev) =>
+        prev.map((m) =>
+          m.id === msgId && m.is_streaming
+            ? { ...m, is_streaming: false, content: m.content || '[Stream timed out — no completion signal received]' }
+            : m,
+        ),
+      );
+      streamingTimersRef.current.delete(msgId);
+    }, 60000);
+    streamingTimersRef.current.set(msgId, timer);
+  }, []);
+
   // Project repos for @repository: mention suggestions
   const [projectRepos, setProjectRepos] = useState<ProjectRepositoryItem[]>([]);
   const [reposLoading, setReposLoading] = useState(false);
@@ -509,8 +543,10 @@ export function RoomProvider({
             ]);
           }
         },
-    onAiStreamChunk: (chunk: { done: boolean; message_id: string; room_id: string; content: string; display_name?: string }) => {
+    onAiStreamChunk: (chunk: { done: boolean; message_id: string; room_id: string; content: string; display_name?: string; chunk_type?: string }) => {
       if (chunk.done) {
+        // Clear the timeout timer since stream completed normally
+        clearStreamingTimer(chunk.message_id);
         // When done: clear streaming content, set is_streaming=false, and
         // update seq so the subsequent RoomMessage event deduplicates correctly.
         setStreamingContent((prev) => {
@@ -520,11 +556,13 @@ export function RoomProvider({
         setMessages((prev) =>
           prev.map((m) =>
             m.id === chunk.message_id
-              ? { ...m, content: chunk.content, display_content: chunk.content, is_streaming: false }
+              ? { ...m, content: chunk.content, display_content: chunk.content, is_streaming: false, chunk_type: chunk.chunk_type }
               : m,
           ),
         );
       } else {
+        // Reset the timeout timer on each chunk — stream is still alive
+        startStreamingTimer(chunk.message_id);
         // Single atomic update: accumulate in streamingContent AND update message.
         // Backend sends CUMULATIVE content (text_accumulated.clone()), not delta.
         // Use deduplication to only add the new delta portion.
@@ -559,6 +597,7 @@ export function RoomProvider({
               content_type: 'text',
               send_at: new Date().toISOString(),
               is_streaming: true,
+              chunk_type: chunk.chunk_type,
             };
             return [...msgs, newMsg];
           });
@@ -715,6 +754,11 @@ export function RoomProvider({
     return () => {
       client.disconnect();  // Intentional disconnect on unmount — no reconnect
       wsClientRef.current = null;
+      // Clear all streaming timeout timers
+      for (const timer of streamingTimersRef.current.values()) {
+        clearTimeout(timer);
+      }
+      streamingTimersRef.current.clear();
     };
   }, []);  // ← empty deps: create once on mount
 

src/lib/room-ws-client.ts

@@ -29,6 +29,7 @@ import type {
   UserInfo,
   RoomReactionUpdatedPayload,
   UserPresencePayload,
+  NotificationCreatedPayload,
 } from './ws-protocol';
 
 export type {
@@ -53,10 +54,10 @@ export type {
   UserInfo,
   RoomReactionUpdatedPayload,
   UserPresencePayload,
+  NotificationCreatedPayload,
 };
 
 export interface WsTokenResponse {
-  token: string;
   expires_in_seconds: number;
 }
 
@@ -84,6 +85,8 @@ export interface RoomWsCallbacks {
   onError?: (error: Error) => void;
   /** Called each time the client sends a heartbeat ping */
   onHeartbeat?: () => void;
+  /** Called when a new notification is pushed from the server via WebSocket */
+  onNotification?: (payload: import('./ws-protocol').NotificationCreatedPayload) => void;
 }
 
 export class RoomWsClient {
@@ -133,6 +136,11 @@ export class RoomWsClient {
     this.wsToken = token;
   }
 
+  /** Update callbacks (e.g. to register onNotification after construction). */
+  updateCallbacks(callbacks: Partial<RoomWsCallbacks>): void {
+    Object.assign(this.callbacks, callbacks);
+  }
+
   getWsToken(): string | null {
     return this.wsToken;
   }
@@ -1059,6 +1067,11 @@ export class RoomWsClient {
           user_id: (event.data as { user_id?: string })?.user_id ?? '',
         });
         break;
+      case 'notification_created':
+        this.callbacks.onNotification?.(
+          event.data as import('./ws-protocol').NotificationCreatedPayload,
+        );
+        break;
       default:
         // Unknown event type - ignore silently
         break;

src/lib/room.ts

@@ -37,6 +37,7 @@ export type AiStreamChunkPayload = {
   content: string;
   done: boolean;
   error?: string | null;
+  chunk_type?: string | null;
 };
 
 export type RoomWsStatus = 'idle' | 'connecting' | 'open' | 'closing' | 'closed' | 'error';

src/lib/ws-protocol.ts

@@ -170,8 +170,16 @@ export type WsEventPayload =
   | { type: 'user_presence'; data: UserPresencePayload }
   | { type: 'typing_start'; data: TypingStartPayload }
   | { type: 'typing_stop'; data: TypingStopPayload }
+  | { type: 'notification_created'; data: NotificationCreatedPayload }
   | { type: string; data: unknown }; // catch-all for unknown events
 
+/** Payload for real-time notification push via WebSocket. */
+export interface NotificationCreatedPayload {
+  notification: NotificationData;
+  /** URL to navigate to for this notification (e.g. /project/x/issues/42) */
+  deep_link_url?: string;
+}
+
 export interface RoomMessagePayload {
   id: string;
   room_id: string;
@@ -205,6 +213,8 @@ export interface AiStreamChunkPayload {
   error?: string;
   /** Human-readable AI model name for display (e.g. "Claude 3.5 Sonnet"). */
   display_name?: string;
+  /** What kind of content: "thinking", "answer", "tool_call", "tool_result". */
+  chunk_type?: string;
 }
 
 export interface RoomResponse {