Sort chat recents by last activity (#6844)

* show chat by by last activity

* Update chat thread updated_at logic and enhance sidebar chat item handling

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: Lee Jackson <130007945+Imagineer99@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

studio/frontend/src/features/chat/hooks/use-chat-sidebar-items.ts

@@ -27,16 +27,21 @@ export interface SidebarItem {
   id: string;
   title: string;
   createdAt: number;
+  updatedAt: number;
   isFork?: boolean;
   projectId?: string | null;
 }
 
+function lastActivityAt(thread: ThreadRecord): number {
+  return thread.updatedAt ?? thread.createdAt;
+}
+
 export function groupThreads(
   threads: ThreadRecord[],
   archived = false,
 ): SidebarItem[] {
   const items: SidebarItem[] = [];
-  const seenPairs = new Set<string>();
+  const pairItems = new Map<string, SidebarItem>();
 
   for (const t of threads) {
     // Coerce archived to a boolean before comparing. Legacy threads (from the
@@ -48,30 +53,35 @@ export function groupThreads(
       continue;
     }
     if (t.pairId) {
-      if (seenPairs.has(t.pairId)) {
+      const existing = pairItems.get(t.pairId);
+      if (existing) {
+        existing.updatedAt = Math.max(existing.updatedAt, lastActivityAt(t));
         continue;
       }
-      seenPairs.add(t.pairId);
-      items.push({
+      const item: SidebarItem = {
         type: "compare",
         id: t.pairId,
         title: t.title,
         createdAt: t.createdAt,
+        updatedAt: lastActivityAt(t),
         projectId: t.projectId ?? null,
-      });
+      };
+      pairItems.set(t.pairId, item);
+      items.push(item);
     } else if (!t.pairId) {
       items.push({
         type: "single",
         id: t.id,
         title: t.title,
         createdAt: t.createdAt,
+        updatedAt: lastActivityAt(t),
         isFork: Boolean(t.forkedFromThreadId),
         projectId: t.projectId ?? null,
       });
     }
   }
 
-  return items.sort((a, b) => b.createdAt - a.createdAt);
+  return items.sort((a, b) => b.updatedAt - a.updatedAt);
 }
 
 // Streaming fires CHAT_HISTORY_UPDATED_EVENT per chunk. Debounce so each quiet
@@ -84,6 +94,7 @@ export function useChatSidebarItems(options?: {
   requireMessages?: boolean;
 }) {
   const [allThreads, setAllThreads] = useState<ThreadRecord[]>([]);
+  const [loaded, setLoaded] = useState(false);
   const enabled = options?.enabled ?? true;
   const requireMessages = options?.requireMessages ?? true;
 
@@ -111,6 +122,7 @@ export function useChatSidebarItems(options?: {
         // were in flight, or if the effect was torn down.
         if (cancelled || seq !== requestSeq) return;
         setAllThreads(threads);
+        setLoaded(true);
       } catch (error) {
         if (isExpectedBackgroundChatStorageError(error)) {
           return;
@@ -144,7 +156,7 @@ export function useChatSidebarItems(options?: {
   const archivedItems = groupThreads(allThreads ?? [], true);
   const canCompare = useChatRuntimeStore((s) => Boolean(s.params.checkpoint));
 
-  return { items, archivedItems, canCompare };
+  return { items, archivedItems, canCompare, loaded };
 }
 
 function cancelIfRunning(threadId: string): void {

studio/frontend/src/features/chat/types.ts

@@ -36,6 +36,7 @@ export interface ThreadRecord {
   projectId?: string | null;
   archived: boolean;
   createdAt: number;
+  updatedAt?: number;
   /**
    * OpenAI shell tool container id from a prior response. When set, the
    * next turn reuses it via `environment.type="container_reference"` so

studio/frontend/src/features/chat/utils/chat-history-storage.ts

@@ -590,7 +590,10 @@ export async function listStoredChatThreads(
   }
   return Array.from(byId.values())
     .filter((thread) => matchesThreadListArgs(thread, args))
-    .sort((a, b) => b.createdAt - a.createdAt);
+    .sort(
+      (a, b) =>
+        (b.updatedAt ?? b.createdAt) - (a.updatedAt ?? a.createdAt),
+    );
 }
 
 export async function listStoredChatThreadsWithMessages(