feat(v2): 390 memory layout and section update time (TASK-690 slice 2)

backend/__tests__/service/agent-memory-editor.test.js

@@ -138,4 +138,31 @@ describe('owner memory editor', () => {
     expect(memory.sections.long_term.content).toBe('Old note');
     expect(memory.content).toBe('Old note');
   });
+
+  it('index sections carry the section update time and no per-note time', async () => {
+    await AgentMemory.updateOne({ agentName: 'editor-agent', instanceId: 'machine-1' }, { $set: {
+      'sections.long_term.content': '## Rules\nNever merge without a GATE line.\n## Overview\nReviews PRs.',
+      'sections.daily': [{ date: '2026-10-28', content: '#401 approved' }],
+    } });
+    const index = await request(app).get('/api/agent-memory/editor-agent/machine-1')
+      .set('Authorization', `Bearer ${token(owner)}`);
+    expect(index.status).toBe(200);
+    const longTerm = index.body.sections.find((s) => s.key === 'long_term');
+    const daily = index.body.sections.find((s) => s.key === 'daily');
+    expect(longTerm.updatedAt).toBe(new Date('2026-01-01').toISOString());
+    expect(daily.updatedAt).toBeNull();
+    for (const note of [...longTerm.notes, ...daily.notes]) {
+      expect(Object.keys(note).sort()).toEqual(['header', 'snippet']);
+    }
+  });
+
+  it('index returns a null section update time when the section has none', async () => {
+    await AgentMemory.updateOne({ agentName: 'editor-agent', instanceId: 'machine-1' }, {
+      $set: { 'sections.long_term.content': '## Rules\nNever merge.' },
+      $unset: { 'sections.long_term.updatedAt': '' },
+    });
+    const index = await request(app).get('/api/agent-memory/editor-agent/machine-1')
+      .set('Authorization', `Bearer ${token(owner)}`);
+    expect(index.body.sections.find((s) => s.key === 'long_term').updatedAt).toBeNull();
+  });
 });

backend/routes/agentMemoryView.ts

@@ -55,6 +55,12 @@ const snip = (s: unknown): string => {
   const t = String(s ?? '').replace(/\s+/g, ' ').trim();
   return t.length > SNIPPET ? `${t.slice(0, SNIPPET)}…` : t;
 };
+// Section last-write time as ISO, or null when the stored value is absent or unparseable.
+const isoOrNull = (v: unknown): string | null => {
+  if (v == null || v === '') return null;
+  const d = new Date(v as string | number | Date);
+  return Number.isNaN(d.getTime()) ? null : d.toISOString();
+};
 
 // Sections that are internal housekeeping, never shown as "memory". Shared with
 // the service so the public profile's durable/bookkeeping split and this
@@ -278,7 +284,7 @@ router.get('/:agentName/:instanceId?', auth, async (req: AuthReq, res: Res) => {
       .select('sections')
       .lean();
 
-    const sections: Array<{ key: string; label: string; kind: string; notes: unknown[] }> = [];
+    const sections: Array<{ key: string; label: string; kind: string; updatedAt: string | null; notes: unknown[] }> = [];
     let totalEntries = 0;
     const raw = ((record as Record<string, unknown>)?.sections || {}) as Record<string, unknown>;
 
@@ -291,7 +297,7 @@ router.get('/:agentName/:instanceId?', auth, async (req: AuthReq, res: Res) => {
           .reverse()
           .map((d: Record<string, unknown>) => ({ header: String(d.date || ''), snippet: snip(d.content) }))
           .filter((n) => n.header || n.snippet);
-        if (notes.length) { sections.push({ key, label: 'Daily journal', kind: 'log', notes }); totalEntries += notes.length; }
+        if (notes.length) { sections.push({ key, label: 'Daily journal', kind: 'log', updatedAt: null, notes }); totalEntries += notes.length; }
       } else if (key === 'cycles' && value && typeof value === 'object') {
         const entries = Array.isArray((value as Record<string, unknown>).entries)
           ? ((value as Record<string, unknown>).entries as Array<Record<string, unknown>>)
@@ -300,12 +306,13 @@ router.get('/:agentName/:instanceId?', auth, async (req: AuthReq, res: Res) => {
           header: e.ts ? String(e.ts).slice(0, 10) : 'cycle',
           snippet: snip(e.content),
         }));
-        if (notes.length) { sections.push({ key, label: 'Heartbeat cycles', kind: 'log', notes }); totalEntries += notes.length; }
+        if (notes.length) { sections.push({ key, label: 'Heartbeat cycles', kind: 'log', updatedAt: null, notes }); totalEntries += notes.length; }
       } else if (value && typeof value === 'object' && 'content' in (value as Record<string, unknown>)) {
         // long_term (and any future doc-shaped section) → index its headers.
         const notes = indexMarkdown(String((value as Record<string, unknown>).content || ''));
         const label = key === 'long_term' ? 'Long-term memory' : key.replace(/_/g, ' ');
-        if (notes.length) { sections.push({ key, label, kind: 'doc', notes }); totalEntries += notes.length; }
+        const updatedAt = isoOrNull((value as Record<string, unknown>).updatedAt);
+        if (notes.length) { sections.push({ key, label, kind: 'doc', updatedAt, notes }); totalEntries += notes.length; }
       }
     }
 

frontend/src/i18n/locales/en.json

@@ -1954,6 +1954,7 @@
       "viewTag": "{{role}} view · private",
       "indexSummary_one": "{{notes}} notes across {{count}} section{{updated}}. Visible to you; hidden from the public profile.",
       "indexSummary_other": "{{notes}} notes across {{count}} sections{{updated}}. Visible to you; hidden from the public profile.",
+      "sectionUpdated": "Section updated {{when}}",
       "lastSavedClause": " · last saved to {{section}} {{time}}",
       "more": "+{{count}} more",
       "entriesRemembered": "entries remembered",

frontend/src/i18n/locales/zh-CN.json

@@ -1945,6 +1945,7 @@
       "viewTag": "{{role}}视图 · 私有",
       "indexSummary_one": "{{notes}}条笔记，分布在{{count}}个板块{{updated}}。仅你可见；对公开资料页隐藏。",
       "indexSummary_other": "{{notes}}条笔记，分布在{{count}}个板块{{updated}}。仅你可见；对公开资料页隐藏。",
+      "sectionUpdated": "板块更新于{{when}}",
       "lastSavedClause": " · 最后保存至 {{section}}，{{time}}",
       "more": "还有{{count}}条",
       "entriesRemembered": "条已记住的条目",

frontend/src/v2/__tests__/V2AgentMemory.test.tsx

@@ -45,6 +45,13 @@ describe('groupSections', () => {
     const groups = groupSections([section('brand_new_key')]);
     expect(headersOf(groups, 'how')).toEqual(['brand_new_key 0']);
   });
+
+  it('carries the section update time onto its group sections and splits it with long_term', () => {
+    const at = '2026-10-30T12:00:00.000Z';
+    const groups = groupSections([{ ...named('long_term', ['Rules', 'Overview']), updatedAt: at }]);
+    expect(groups.find((g) => g.id === 'rules').sections[0].updatedAt).toBe(at);
+    expect(groups.find((g) => g.id === 'how').sections[0].updatedAt).toBe(at);
+  });
 });
 
 describe('V2AgentMemory', () => {
@@ -84,6 +91,27 @@ describe('V2AgentMemory', () => {
     expect(screen.queryByRole('heading', { name: /Journal/ })).toBeNull();
   });
 
+  it('shows the section update time once per group and never on a note', async () => {
+    axios.get.mockResolvedValue({ data: {
+      viewerRole: 'owner', totalEntries: 3,
+      sections: [
+        { ...named('long_term', ['Rules', 'Host notes']), updatedAt: '2026-10-30T12:00:00.000Z' },
+        section('daily', 1),
+      ],
+    } });
+    render(
+      <MemoryRouter initialEntries={['/v2/agents/maya-claude/default/memory']}>
+        <Routes>
+          <Route path="/v2/agents/:agentName/:instanceId/memory" element={<V2AgentMemory />} />
+        </Routes>
+      </MemoryRouter>,
+    );
+    await waitFor(() => expect(screen.getByRole('heading', { name: /Journal/ })).toBeInTheDocument());
+    // Rules and How I work each carry the long_term time; Journal has none.
+    expect(document.querySelectorAll('.v2-agent-memory__gmeta')).toHaveLength(2);
+    expect(document.querySelectorAll('.v2-agent-memory__mnote .v2-agent-memory__gmeta')).toHaveLength(0);
+  });
+
   it('shows a denied notice instead of the index when the viewer is not owner or admin', async () => {
     axios.get.mockRejectedValue(new Error('403'));
     render(

frontend/src/v2/agents/V2AgentMemory.tsx

@@ -3,11 +3,12 @@ import { Link, useParams } from 'react-router-dom';
 import { useTranslation } from 'react-i18next';
 import axios from '../../utils/axiosConfig';
 import V2PageHead from '../components/V2PageHead';
+import { localizeRelativeTime } from '../utils/localizeRelativeTime';
 import './v2-agent-settings.css';
 
 // Owner/admin memory index, as served by GET /api/agent-memory/:agentName/:instanceId.
 interface MemoryNote { header: string; snippet: string }
-interface MemorySection { key: string; label: string; kind: string; notes: MemoryNote[] }
+interface MemorySection { key: string; label: string; kind: string; updatedAt?: string | null; notes: MemoryNote[] }
 interface MemoryIndex { viewerRole: 'owner' | 'admin'; totalEntries: number; sections: MemorySection[] }
 
 // Which backend sections land in which group. Journal is the dated log. Soul
@@ -21,7 +22,7 @@ export const MEMORY_GROUPS = [
 ] as const;
 
 type GroupId = typeof MEMORY_GROUPS[number]['id'];
-interface GroupedSection { key: string; label: string; notes: MemoryNote[] }
+interface GroupedSection { key: string; label: string; updatedAt: string | null; notes: MemoryNote[] }
 
 const JOURNAL_KEYS = new Set(['daily', 'cycles']);
 // A long_term heading whose first word names a rule goes under Rules.
@@ -35,7 +36,7 @@ export const splitLongTerm = (section: MemorySection): Record<'rules' | 'how', G
   const rules = section.notes.filter((n) => RULE_HEADING.test(n.header));
   const how = section.notes.filter((n) => !RULE_HEADING.test(n.header));
   const make = (notes: MemoryNote[]): GroupedSection | null => (
-    notes.length ? { key: section.key, label: section.label, notes } : null
+    notes.length ? { key: section.key, label: section.label, updatedAt: section.updatedAt ?? null, notes } : null
   );
   return { rules: make(rules), how: make(how) };
 };
@@ -44,7 +45,7 @@ export const groupSections = (sections: MemorySection[]) => {
   const byGroup: Record<GroupId, GroupedSection[]> = { rules: [], how: [], journal: [] };
   // Soul first, so it leads Rules.
   const soul = sections.find((s) => s.key === 'soul');
-  if (soul) byGroup.rules.push({ key: soul.key, label: soul.label, notes: soul.notes });
+  if (soul) byGroup.rules.push({ key: soul.key, label: soul.label, updatedAt: soul.updatedAt ?? null, notes: soul.notes });
   for (const s of sections) {
     if (s.key === 'soul') continue;
     if (s.key === 'long_term') {
@@ -53,7 +54,7 @@ export const groupSections = (sections: MemorySection[]) => {
       if (split.how) byGroup.how.push(split.how);
       continue;
     }
-    byGroup[sectionGroup(s.key)].push({ key: s.key, label: s.label, notes: s.notes });
+    byGroup[sectionGroup(s.key)].push({ key: s.key, label: s.label, updatedAt: s.updatedAt ?? null, notes: s.notes });
   }
   return MEMORY_GROUPS.map((g) => ({
     id: g.id,
@@ -63,15 +64,16 @@ export const groupSections = (sections: MemorySection[]) => {
 };
 
 // Frame icons (docs/design/artboards/d215, #s-memory): stroke-only, 1.8 weight.
-const ICON_PATHS: Record<'pin' | 'brain' | 'cal' | 'search' | 'info', React.ReactNode> = {
+const ICON_PATHS: Record<'pin' | 'brain' | 'cal' | 'search' | 'info' | 'chev', React.ReactNode> = {
+  chev: <path d="m6 9 6 6 6-6" />,
   pin: <path d="M12 17v5M8 3h8l-1 6 3 4H6l3-4z" />,
   brain: <path d="M9 4a3 3 0 0 0-3 3 3 3 0 0 0-2 5 3 3 0 0 0 2 5 3 3 0 0 0 6 1V5a2 2 0 0 0-3-1zM15 4a3 3 0 0 1 3 3 3 3 0 0 1 2 5 3 3 0 0 1-2 5 3 3 0 0 1-6 1" />,
   cal: <><rect x="3" y="5" width="18" height="16" rx="2.5" /><path d="M3 10h18M8 3v4M16 3v4" /></>,
   search: <><circle cx="11" cy="11" r="7" /><path d="m20 20-3.5-3.5" /></>,
   info: <><circle cx="12" cy="12" r="9" /><path d="M12 16v-4M12 8h.01" /></>,
 };
-const MemIcon: React.FC<{ name: keyof typeof ICON_PATHS; size?: number }> = ({ name, size = 16 }) => (
-  <svg className="v2-agent-memory__icon" viewBox="0 0 24 24" width={size} height={size} aria-hidden="true"
+const MemIcon: React.FC<{ name: keyof typeof ICON_PATHS; size?: number; className?: string }> = ({ name, size = 16, className }) => (
+  <svg className={`v2-agent-memory__icon${className ? ` ${className}` : ''}`} viewBox="0 0 24 24" width={size} height={size} aria-hidden="true"
     fill="none" stroke="currentColor" strokeWidth={1.8} strokeLinecap="round" strokeLinejoin="round">
     {ICON_PATHS[name]}
   </svg>
@@ -159,32 +161,44 @@ const V2AgentMemory: React.FC = () => {
               </label>
             </aside>
             <div className="v2-agent-memory__body">
-              {groups.filter((g) => g.sections.length > 0).map((group) => (
-                <section key={group.id} className="v2-agent-memory__group" aria-labelledby={`memory-group-${group.id}`}>
-                  <h2 id={`memory-group-${group.id}`} className="v2-agent-memory__gtitle">
-                    <MemIcon name={GROUP_ICON[group.id]} size={13} />
-                    {group.label}
-                  </h2>
-                  <ul className="v2-agent-memory__list">
-                    {group.sections.flatMap((sec) => sec.notes).map((n, i) => (
-                      group.id === 'journal' ? (
-                        <li key={i} className="v2-agent-memory__jday">
-                          <span className="v2-agent-memory__jdate">{n.header}</span>
-                          <span>{n.snippet}</span>
-                        </li>
-                      ) : (
-                        <li key={i} className="v2-agent-memory__mnote">
-                          <MemIcon name={GROUP_ICON[group.id]} />
-                          <div>
-                            <div className="v2-agent-memory__tx">{n.header}</div>
-                            {n.snippet && <div className="v2-agent-memory__snip">{n.snippet}</div>}
-                          </div>
-                        </li>
-                      )
-                    ))}
-                  </ul>
-                </section>
-              ))}
+              {groups.filter((g) => g.sections.length > 0).map((group) => {
+                // One time per group: the newest section update in it. Never per note.
+                const updated = group.sections.map((s) => s.updatedAt).filter(Boolean).sort().pop() ?? null;
+                return (
+                  <details key={group.id} id={`memory-group-${group.id}`} className="v2-agent-memory__group" open>
+                    <summary className="v2-agent-memory__gtitle">
+                      <span role="heading" aria-level={2} className="v2-agent-memory__gheading">
+                        <MemIcon name={GROUP_ICON[group.id]} size={13} />
+                        {group.label}
+                      </span>
+                      {updated && (
+                        <span className="v2-agent-memory__gmeta">
+                          {t('agentProfile.memory.sectionUpdated', { defaultValue: 'Section updated {{when}}', when: localizeRelativeTime(updated, t) })}
+                        </span>
+                      )}
+                      <MemIcon name="chev" size={13} className="v2-agent-memory__chev" />
+                    </summary>
+                    <ul className="v2-agent-memory__list">
+                      {group.sections.flatMap((sec) => sec.notes).map((n, i) => (
+                        group.id === 'journal' ? (
+                          <li key={i} className="v2-agent-memory__jday">
+                            <span className="v2-agent-memory__jdate">{n.header}</span>
+                            <span>{n.snippet}</span>
+                          </li>
+                        ) : (
+                          <li key={i} className="v2-agent-memory__mnote">
+                            <MemIcon name={GROUP_ICON[group.id]} />
+                            <div>
+                              <div className="v2-agent-memory__tx">{n.header}</div>
+                              {n.snippet && <div className="v2-agent-memory__snip">{n.snippet}</div>}
+                            </div>
+                          </li>
+                        )
+                      ))}
+                    </ul>
+                  </details>
+                );
+              })}
             </div>
           </div>
         );

frontend/src/v2/agents/v2-agent-settings.css

@@ -148,8 +148,23 @@
 .v2-agent-memory__search:focus-within { box-shadow: var(--v2-focus-ring); }
 .v2-agent-memory__body { display: grid; min-width: 0; }
 .v2-agent-memory__group { margin-bottom: 18px; }
-.v2-agent-memory__gtitle { display: flex; align-items: center; gap: 8px; margin: 0 4px 8px; font: 500 11.5px/1 var(--v2-font-mono); color: var(--v2-text-tertiary); }
+.v2-agent-memory__gtitle { display: flex; align-items: center; gap: 8px; margin: 0 4px 8px; font: 500 11.5px/1 var(--v2-font-mono); color: var(--v2-text-tertiary); list-style: none; }
+.v2-agent-memory__gtitle::-webkit-details-marker { display: none; }
+.v2-agent-memory__gheading { display: inline-flex; align-items: center; gap: 8px; }
 .v2-agent-memory__gtitle .v2-agent-memory__icon { width: 13px; height: 13px; }
+.v2-agent-memory__gmeta { margin-left: auto; font-weight: 400; font-size: 11px; }
+/* Desktop: the groups are not collapsible, so the summary is a plain title. */
+.v2-agent-memory__chev { display: none; }
+@media (min-width: 768px) {
+  .v2-agent-memory__gtitle { pointer-events: none; }
+}
+/* Phone: search above the groups, group list hidden, groups collapsible. */
+@media (max-width: 767px) {
+  .v2-agent-memory__nav ul { display: none; }
+  .v2-agent-memory__gtitle { cursor: pointer; pointer-events: auto; }
+  .v2-agent-memory__chev { display: inline-block; margin-left: 4px; transition: transform 0.15s; }
+  .v2-agent-memory__group[open] > .v2-agent-memory__gtitle .v2-agent-memory__chev { transform: rotate(180deg); }
+}
 .v2-agent-memory__list { list-style: none; margin: 0; padding: 0; border-radius: 12px; border: 1px solid var(--v2-border-soft); background: var(--v2-surface); overflow: hidden; }
 .v2-agent-memory__list > li { border-top: 1px solid var(--v2-border-soft); }
 .v2-agent-memory__list > li:first-child { border-top: 0; }