Expose last message timestamp on sessions (#9961)

Co-authored-by: Douwe M Osinga <douwe@sidewalklabs.com>

ui/desktop/openapi.json

@@ -8124,6 +8124,11 @@
           "id": {
             "type": "string"
           },
+          "last_message_at": {
+            "type": "string",
+            "format": "date-time",
+            "nullable": true
+          },
           "last_message_snippet": {
             "type": "string",
             "nullable": true

ui/desktop/src/acp/sessions.ts

@@ -14,6 +14,7 @@ import type { Recipe } from '../recipe';
 interface GooseSessionInfoMeta {
   messageCount?: number;
   createdAt?: string;
+  lastMessageAt?: string;
   archivedAt?: string;
   projectId?: string;
   providerId?: string;
@@ -30,6 +31,7 @@ export interface SessionListItem {
   workingDir: string;
   updatedAt: string;
   messageCount: number;
+  lastMessageAt?: string;
   createdAt: string;
   archivedAt?: string;
   projectId?: string;
@@ -94,6 +96,7 @@ export function sessionInfoToSession(s: SessionInfo, loadMeta: LoadSessionMeta =
     working_dir: loadMeta.workingDir ?? s.cwd,
     created_at: createdAt,
     updated_at: updatedAt,
+    last_message_at: meta.lastMessageAt,
     message_count: meta.messageCount ?? 0,
     extension_data: {},
     archived_at: meta.archivedAt,
@@ -116,6 +119,7 @@ function sessionInfoToListItem(s: SessionInfo): SessionListItem {
     workingDir: s.cwd,
     updatedAt: s.updatedAt ?? '',
     messageCount: meta.messageCount ?? 0,
+    lastMessageAt: meta.lastMessageAt,
     createdAt: meta.createdAt ?? s.updatedAt ?? '',
     archivedAt: meta.archivedAt,
     projectId: meta.projectId,

ui/desktop/src/api/types.gen.ts

@@ -1414,6 +1414,7 @@ export type Session = {
     extension_data: ExtensionData;
     goose_mode?: GooseMode;
     id: string;
+    last_message_at?: string | null;
     last_message_snippet?: string | null;
     message_count: number;
     model_config?: ModelConfig | null;

ui/desktop/src/components/sessions/SessionListView.tsx

@@ -21,7 +21,7 @@ import { ScrollArea } from '../ui/scroll-area';
 import { formatMessageTimestamp } from '../../utils/timeUtils';
 import { SearchView } from '../conversation/SearchView';
 import { MainPanelLayout } from '../Layout/MainPanelLayout';
-import { groupSessionsByDate, type DateGroup } from '../../utils/dateUtils';
+import { groupSessionsByDate, sessionActivityAt, type DateGroup } from '../../utils/dateUtils';
 import { errorMessage } from '../../utils/conversionUtils';
 import { Skeleton } from '../ui/skeleton';
 import { toast } from 'react-toastify';
@@ -734,7 +734,9 @@ const SessionListView: React.FC<SessionListViewProps> = React.memo(
             <div className="flex-1 mt-2">
               <div className="flex items-center text-text-secondary text-xs">
                 <Calendar className="w-3 h-3 mr-1 flex-shrink-0" />
-                <span>{formatMessageTimestamp(Date.parse(session.updatedAt) / 1000)}</span>
+                <span>
+                  {formatMessageTimestamp(Date.parse(sessionActivityAt(session)) / 1000)}
+                </span>
               </div>
               <div className="flex items-center text-text-secondary text-xs">
                 <Folder className="w-3 h-3 mr-1 flex-shrink-0" />

ui/desktop/src/hooks/useNavigationSessions.ts

@@ -31,6 +31,7 @@ export function sessionToListItem(s: Session): SessionListItem {
     workingDir: s.working_dir,
     updatedAt: s.updated_at,
     messageCount: s.message_count,
+    lastMessageAt: s.last_message_at ?? undefined,
     createdAt: s.created_at,
     archivedAt: s.archived_at ?? undefined,
     projectId: s.project_id ?? undefined,

ui/desktop/src/utils/dateUtils.ts

@@ -6,6 +6,10 @@ export interface DateGroup {
   date: Date;
 }
 
+export function sessionActivityAt(session: SessionListItem): string {
+  return session.lastMessageAt ?? session.updatedAt;
+}
+
 export function groupSessionsByDate(sessions: SessionListItem[]): DateGroup[] {
   const today = new Date();
   today.setHours(0, 0, 0, 0);
@@ -16,7 +20,7 @@ export function groupSessionsByDate(sessions: SessionListItem[]): DateGroup[] {
   const groups: { [key: string]: DateGroup } = {};
 
   sessions.forEach((session) => {
-    const sessionDate = new Date(session.updatedAt);
+    const sessionDate = new Date(sessionActivityAt(session));
     const sessionDateStart = new Date(sessionDate);
     sessionDateStart.setHours(0, 0, 0, 0);