diff --git a/apps/web/app/dashboard/notes/note-list.tsx b/apps/web/app/dashboard/notes/note-list.tsx
index 7d99b18..216e9ba 100644
--- a/apps/web/app/dashboard/notes/note-list.tsx
+++ b/apps/web/app/dashboard/notes/note-list.tsx
@@ -23,6 +23,9 @@ type NoteTask = {
   status: string
   note: string
   summaryUpdatedAt: string | null
+  taskUpdatedAt: string
+  taskUpdatedByName: string | null
+  taskUpdatedByType: string
   assigned: {
     id: string
     name: string
@@ -89,13 +92,19 @@ export function NoteList({ companyId, reviewReader, initialNotes }: NoteListProp
                   </div>
                   <div className="flex flex-wrap items-center gap-2">
                     <Badge variant="outline">{formatStatus(task.status)}</Badge>
-                    {task.summaryUpdatedAt ? (
-                      <Badge variant="secondary">{formatDate(task.summaryUpdatedAt)}</Badge>
-                    ) : null}
+                    <Badge variant="secondary">
+                      Summary {formatNullableDate(task.summaryUpdatedAt)}
+                    </Badge>
                   </div>
                 </div>
               </CardHeader>
               <CardContent className="space-y-3">
+                <SummaryAuditContext
+                  summaryUpdatedAt={task.summaryUpdatedAt}
+                  taskUpdatedAt={task.taskUpdatedAt}
+                  taskUpdatedByName={task.taskUpdatedByName}
+                  taskUpdatedByType={task.taskUpdatedByType}
+                />
                 <ExpandableNote text={task.note} />
                 <div className="flex flex-wrap gap-2">
                   <Button asChild type="button" variant="outline" size="sm">
@@ -148,6 +157,39 @@ export function NoteList({ companyId, reviewReader, initialNotes }: NoteListProp
   )
 }
 
+function SummaryAuditContext({
+  summaryUpdatedAt,
+  taskUpdatedAt,
+  taskUpdatedByName,
+  taskUpdatedByType,
+}: {
+  summaryUpdatedAt: string | null
+  taskUpdatedAt: string
+  taskUpdatedByName: string | null
+  taskUpdatedByType: string
+}) {
+  const actorLabel = taskUpdatedByName ?? fallbackActorLabel(taskUpdatedByType)
+
+  return (
+    <div className="rounded-2xl border bg-muted/40 px-3 py-2 text-xs text-muted-foreground">
+      <p>
+        Summary updated: {formatNullableDate(summaryUpdatedAt)} · Last task update by {actorLabel} ({taskUpdatedByType || "unknown"}) at {formatDate(taskUpdatedAt)}
+      </p>
+    </div>
+  )
+}
+
+function formatNullableDate(value: string | null) {
+  return value ? formatDate(value) : "unknown"
+}
+
+function fallbackActorLabel(actorType: string) {
+  if (actorType === "agent") return "Unknown agent"
+  if (actorType === "user") return "Unknown user"
+  if (actorType === "system") return "System"
+  return "Unknown actor"
+}
+
 function ExpandableNote({ text }: { text: string }) {
   const [expanded, setExpanded] = useState(false)
   const compact = text.length > 320 || text.includes("\n")
diff --git a/apps/web/app/dashboard/notes/page.tsx b/apps/web/app/dashboard/notes/page.tsx
index 9501b7b..b1613cc 100644
--- a/apps/web/app/dashboard/notes/page.tsx
+++ b/apps/web/app/dashboard/notes/page.tsx
@@ -44,6 +44,9 @@ export default async function NotesPage({ searchParams }: NotesPageProps) {
       status: true,
       note: true,
       summaryUpdatedAt: true,
+      taskUpdatedAt: true,
+      taskUpdatedByName: true,
+      taskUpdatedByType: true,
       assigned: {
         select: {
           id: true,
@@ -98,6 +101,9 @@ export default async function NotesPage({ searchParams }: NotesPageProps) {
               status: task.status,
               note: task.note ?? "",
               summaryUpdatedAt: task.summaryUpdatedAt?.toISOString() ?? null,
+              taskUpdatedAt: task.taskUpdatedAt.toISOString(),
+              taskUpdatedByName: task.taskUpdatedByName,
+              taskUpdatedByType: task.taskUpdatedByType,
               assigned: task.assigned,
               project: task.project,
             }))}
diff --git a/apps/web/lib/api/openapi.ts b/apps/web/lib/api/openapi.ts
index c9fd27b..6613f81 100644
--- a/apps/web/lib/api/openapi.ts
+++ b/apps/web/lib/api/openapi.ts
@@ -240,11 +240,20 @@ export function createOpenApiDocument() {
               summaryUpdatedAt: {
                 type: ["string", "null"],
                 format: "date-time",
-                description: "When note/summary was last explicitly changed.",
+                description:
+                  "Stored freshness timestamp for note/summary content. It is set when a non-empty note changes, cleared when the note is cleared, and remains null/unchanged otherwise; it does not fall back to taskUpdatedAt.",
+              },
+              taskUpdatedAt: {
+                type: "string",
+                format: "date-time",
+                description:
+                  "Latest task mutation timestamp, including note/summary changes. Use with taskUpdatedBy* to audit who changed the task while summaryUpdatedAt tracks summary freshness.",
               },
-              taskUpdatedAt: { type: "string", format: "date-time" },
               taskUpdatedById: { type: ["string", "null"], format: "uuid" },
-              taskUpdatedByName: { type: ["string", "null"] },
+              taskUpdatedByName: {
+                type: ["string", "null"],
+                description: "Display name for the latest task updater when available.",
+              },
               taskUpdatedByType: { type: "string" },
               blockingReason: { type: ["string", "null"] },
               archivedAt: { type: ["string", "null"], format: "date-time" },