diff --git a/apps/web/app/dashboard/notes/actions.ts b/apps/web/app/dashboard/notes/actions.ts
index 429ffb6..94fcc77 100644
--- a/apps/web/app/dashboard/notes/actions.ts
+++ b/apps/web/app/dashboard/notes/actions.ts
@@ -31,8 +31,6 @@ export async function markDoneTaskSummaryReadAction(
     },
     select: {
       id: true,
-      summaryUpdatedAt: true,
-      taskUpdatedAt: true,
       project: { select: { companyId: true } },
     },
   })
@@ -49,30 +47,21 @@ export async function markDoneTaskSummaryReadAction(
 
   const readAt = new Date()
 
-  await prisma.$transaction(async (tx) => {
-    if (!task.summaryUpdatedAt) {
-      await tx.task.update({
-        where: { id: task.id },
-        data: { summaryUpdatedAt: task.taskUpdatedAt },
-      })
-    }
-
-    await tx.taskReadMarker.upsert({
-      where: {
-        taskId_agentId_status: {
-          taskId: task.id,
-          agentId: reviewReader.id,
-          status: Status.done,
-        },
-      },
-      create: {
+  await prisma.taskReadMarker.upsert({
+    where: {
+      taskId_agentId_status: {
         taskId: task.id,
         agentId: reviewReader.id,
         status: Status.done,
-        readAt,
       },
-      update: { readAt },
-    })
+    },
+    create: {
+      taskId: task.id,
+      agentId: reviewReader.id,
+      status: Status.done,
+      readAt,
+    },
+    update: { readAt },
   })
 
   await invalidateCompanyCache(task.project.companyId)
diff --git a/apps/web/app/dashboard/notes/page.tsx b/apps/web/app/dashboard/notes/page.tsx
index 608f6a3..9501b7b 100644
--- a/apps/web/app/dashboard/notes/page.tsx
+++ b/apps/web/app/dashboard/notes/page.tsx
@@ -10,6 +10,7 @@ import {
 } from "@/components/ui/card"
 import { findReviewReader, getReviewReaderLabel } from "@/lib/api/review-reader"
 import { getDashboardContext } from "@/lib/dashboard/companies"
+import { isDoneSummaryUnread } from "@/lib/dashboard/note-read-state"
 import { prisma } from "@/lib/prisma"
 
 import { NoteList } from "./note-list"
@@ -43,7 +44,6 @@ export default async function NotesPage({ searchParams }: NotesPageProps) {
       status: true,
       note: true,
       summaryUpdatedAt: true,
-      taskUpdatedAt: true,
       assigned: {
         select: {
           id: true,
@@ -70,9 +70,7 @@ export default async function NotesPage({ searchParams }: NotesPageProps) {
   const unreadNotes = notes.filter((task) => {
     const readAt = task.readMarkers[0]?.readAt
 
-    const summaryUpdatedAt = task.summaryUpdatedAt ?? task.taskUpdatedAt
-
-    return !readAt || readAt < summaryUpdatedAt
+    return isDoneSummaryUnread({ readAt, summaryUpdatedAt: task.summaryUpdatedAt })
   })
 
   return (
@@ -99,7 +97,7 @@ export default async function NotesPage({ searchParams }: NotesPageProps) {
               name: task.name,
               status: task.status,
               note: task.note ?? "",
-              summaryUpdatedAt: (task.summaryUpdatedAt ?? task.taskUpdatedAt).toISOString(),
+              summaryUpdatedAt: task.summaryUpdatedAt?.toISOString() ?? null,
               assigned: task.assigned,
               project: task.project,
             }))}
diff --git a/apps/web/lib/dashboard/note-read-state.test.ts b/apps/web/lib/dashboard/note-read-state.test.ts
new file mode 100644
index 0000000..6976347
--- /dev/null
+++ b/apps/web/lib/dashboard/note-read-state.test.ts
@@ -0,0 +1,35 @@
+import assert from "node:assert/strict"
+import { describe, it } from "node:test"
+
+import { isDoneSummaryUnread } from "./note-read-state"
+
+describe("dashboard done summary read state", () => {
+  it("treats noted done tasks with unknown summary freshness as unread", () => {
+    assert.equal(
+      isDoneSummaryUnread({
+        readAt: new Date("2026-05-15T12:00:00.000Z"),
+        summaryUpdatedAt: null,
+      }),
+      true
+    )
+  })
+
+  it("compares read markers only against stored summary freshness", () => {
+    const summaryUpdatedAt = new Date("2026-05-15T12:00:00.000Z")
+
+    assert.equal(
+      isDoneSummaryUnread({
+        readAt: new Date("2026-05-15T11:59:59.000Z"),
+        summaryUpdatedAt,
+      }),
+      true
+    )
+    assert.equal(
+      isDoneSummaryUnread({
+        readAt: new Date("2026-05-15T12:00:00.000Z"),
+        summaryUpdatedAt,
+      }),
+      false
+    )
+  })
+})
diff --git a/apps/web/lib/dashboard/note-read-state.ts b/apps/web/lib/dashboard/note-read-state.ts
new file mode 100644
index 0000000..4e494f9
--- /dev/null
+++ b/apps/web/lib/dashboard/note-read-state.ts
@@ -0,0 +1,9 @@
+export function isDoneSummaryUnread({
+  readAt,
+  summaryUpdatedAt,
+}: {
+  readAt?: Date | null
+  summaryUpdatedAt?: Date | null
+}) {
+  return !readAt || !summaryUpdatedAt || readAt < summaryUpdatedAt
+}
diff --git a/package.json b/package.json
index 6db889d..ab26a34 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "prisma:studio": "prisma studio",
     "typecheck": "corepack pnpm prisma:generate && corepack pnpm --filter @agentbridge/web typecheck && corepack pnpm --filter agentbridge-ai typecheck",
     "typecheck:web": "corepack pnpm prisma:generate && corepack pnpm --filter @agentbridge/web typecheck",
-    "test:api": "tsx --tsconfig apps/web/tsconfig.json --test apps/web/lib/api/*.test.ts",
+    "test:api": "tsx --tsconfig apps/web/tsconfig.json --test apps/web/lib/api/*.test.ts apps/web/lib/dashboard/*.test.ts",
     "test:task-freshness": "tsx --tsconfig apps/web/tsconfig.json --test apps/web/lib/api/task-freshness.test.ts",
     "cli:dev": "corepack pnpm --filter agentbridge-ai dev",
     "cli:build": "corepack pnpm --filter agentbridge-ai build",