diff --git a/docs/IMPLEMENTATION_MASTERPLAN.md b/docs/IMPLEMENTATION_MASTERPLAN.md
index 41567ecbb..c265e516a 100644
--- a/docs/IMPLEMENTATION_MASTERPLAN.md
+++ b/docs/IMPLEMENTATION_MASTERPLAN.md
@@ -2,6 +2,8 @@
 
 Last Updated: 2026-09-10
 
+Board-object proposal overlay continuation (#2808): complete the contextual preview path with a shared board-owned marker provider and one read-only checked preview panel. Cards and columns in both renderers consume presentation markers; the saved board model is unchanged. Original/pinned revision identity and short server-relative freshness are checked before display, and Review retains all decisions. General before/after board simulation and provider quality acceptance are not implied by this projection.
+
 Private audio continuation (#2808): retain an original recording first, add manual written representations separately, then explicitly confirm into private memory. The vertical uses native source assets, bounded SQLite chunks, owner-scoped playback, idempotent upload retry, version conflicts and account portability/erasure. All four experiences share the question UI; automated transcription, real-device qualification and the wider source/attention work remain separate. This is a prototype delivery path with executable evidence, not a provider or release acceptance decision.
 
 Original-source Companion continuation (#2808): explicit per-asset source selection builds on native private-memory preservation. Bounded owner-scoped source queries, expected revisions and content hashes connect historical originals to chat receipts without implicit retrieval. All four experiences share the same picker and source contract. Execution evidence belongs to the continuation PR; hosted qualification and the wider overhaul remain separate.
diff --git a/docs/STATUS.md b/docs/STATUS.md
index 6d0810c8a..d6b87d43f 100644
--- a/docs/STATUS.md
+++ b/docs/STATUS.md
@@ -1,6 +1,8 @@
 # Taskdeck Status (Source of Truth)
 
-Last Updated: 2026-09-09
+Last Updated: 2026-09-10
+
+Board proposal preview continuation (#2808): Chat and both Review layouts link to a checked read-only overlay on the existing board. Effective revision, proposal status/update time and board identity must match before projecting operation targets; execution parameter IDs take precedence over display IDs. Existing cards/columns are marked across Classic, Studio, Companion and Unified, while creation/hidden objects remain in the diff. Board refresh failures, changes, route/account transitions and bounded expiry retract markers. The surface adds no approval, Apply or board mutation. Component and real-API Chromium checks prove projection, non-mutation, Review navigation and mobile rendering; the wider overhaul remains open.
 
 Original-source Companion continuation (#2808):
 
diff --git a/docs/product/WORKSPACE_OVERHAUL.md b/docs/product/WORKSPACE_OVERHAUL.md
index ce6fe7ee0..c8e35c082 100644
--- a/docs/product/WORKSPACE_OVERHAUL.md
+++ b/docs/product/WORKSPACE_OVERHAUL.md
@@ -1,6 +1,8 @@
 # Switchable workspace overhaul
 
-Last Updated: 2026-09-09
+Last Updated: 2026-09-10
+
+**Preview on board** opens a read-only proposal layer from Chat or Review. Choose **Refresh board preview** to check the current proposal revision and highlight saved cards/columns affected by its operations in either board renderer. The checked diff also describes new or hidden objects. The board continues to show saved data; **Open Review** returns to that exact proposal for approval and explicit Apply. Closing the preview, changing board data, losing access or reaching the short freshness limit removes its markers. This reduces the need to mentally match proposal changes to board objects while preserving review-first trust.
 
 Companion's source picker also offers individual preserved originals beside each private memory.
 Open **Choose original sources**, inspect the saved excerpt, then select the exact answer or evidence
diff --git a/docs/product/WORKSPACE_OVERHAUL_VALIDATION.md b/docs/product/WORKSPACE_OVERHAUL_VALIDATION.md
index 7f58dc2fb..bad7213c5 100644
--- a/docs/product/WORKSPACE_OVERHAUL_VALIDATION.md
+++ b/docs/product/WORKSPACE_OVERHAUL_VALIDATION.md
@@ -1,11 +1,18 @@
 # Workspace overhaul validation and follow-through
 
+## Board-object proposal overlays (2026-09-10)
+
+`BoardProposalPreview.spec.ts` covers matched effective revisions, approved pins, mismatched board/revision/status/update receipts, parameter-ID precedence, immutable board inputs, permission/board refresh failure, stale in-flight results, logout, same-user token refresh, server-clock expiry and both card renderers. Existing Chat preview and Board view regressions also pass. Full frontend: 6,368 passed and three existing skips; subsequent projection/access changes have 49 focused passing tests plus typecheck. Exact final evidence is retained with the continuation PR.
+
+`board-proposal-overlays.spec.ts` creates a real update/reorder/create proposal and checks both board renderers across all four experiences. It proves visible markers, saved titles, explicit close, unchanged saved cards/columns, no browser mutation requests, Review-to-board navigation, access refusal and 375 px/no serious-critical axe findings. The final journey passed in 15.8 seconds. Initial fixture failures omitted required operation parameters, requested an unsupported column action, and captured column card counts before seeding the card; each was corrected without relaxing product assertions. New objects remain described by the checked diff rather than simulated board state. No actual board Apply, production deployment or provider-quality acceptance is claimed.
+
 ## Audio review repairs (2026-09-10)
 
 Audio drafts now bind to the board, card, question and revision present when file selection or microphone acquisition starts. Editing that question retains the local file for replay/download but prevents uploading it under new question evidence. A new draft receives the current binding. Two regressions cover edits before upload and while recording.
 
 Production CSPs permit only same-origin and local `blob:` media; nginx and its AWS template permit same-origin microphone requests while continuing to deny camera and geolocation. API header checks, proxy policy contracts and Chromium probes exercise these exact policy strings. The probes load a local WAV and inspect effective microphone policy; they do not claim real microphone hardware acceptance. The retained-original library browser journey also passes.
 
+
 ## Original-source context continuation (2026-09-09)
 
 `ChatOriginalContextApiTests.cs` extends the context API suite with original-only dispatch, exact
diff --git a/frontend/taskdeck-web/src/components/board/BoardProposalPreview.vue b/frontend/taskdeck-web/src/components/board/BoardProposalPreview.vue
new file mode 100644
index 000000000..e0e28bfb5
--- /dev/null
+++ b/frontend/taskdeck-web/src/components/board/BoardProposalPreview.vue
@@ -0,0 +1,113 @@
+<script setup lang="ts">
+import { onScopeDispose, ref, watch } from 'vue'
+import { RouterLink } from 'vue-router'
+import { automationApi } from '../../api/automationApi'
+import { useSessionStore } from '../../store/sessionStore'
+import { getErrorDisplay } from '../../composables/useErrorMapper'
+import type { BoardProposalMarkers } from '../../composables/useBoardProposalMarker'
+import { normalizeProposalStatus } from '../../utils/automation'
+import type { BoardDetail, Card } from '../../types/board'
+import type { Proposal, ProposalPreview } from '../../types/automation'
+
+const props = withDefaults(defineProps<{ proposalId: string; board: BoardDetail; cards: Card[]; available?: boolean }>(), { available: true })
+const emit = defineEmits<{ markers: [value: BoardProposalMarkers]; close: [] }>()
+const session = useSessionStore()
+const preview = ref<ProposalPreview | null>(null)
+const proposal = ref<Proposal | null>(null)
+const loading = ref(false)
+const error = ref('')
+let generation = 0
+let timer: ReturnType<typeof setTimeout> | undefined
+const sameId = (a: string | null, b: string | null) => a?.toLowerCase() === b?.toLowerCase()
+function clear() {
+  generation++; clearTimeout(timer); preview.value = null; proposal.value = null
+  loading.value = false; error.value = ''; emit('markers', {})
+}
+function invalidate() {
+  clear(); error.value = 'The board or session changed. Refresh to check this proposal again.'
+}
+watch([() => props.proposalId, () => props.available, () => session.userId, () => !!session.token], invalidate, { flush: 'sync' })
+watch([() => props.board, () => props.cards], invalidate, { deep: true, flush: 'sync' })
+
+async function load() {
+  clear()
+  if (!props.available) return
+  const request = generation
+  const startedAt = performance.now()
+  loading.value = true
+  try {
+    const [receipt, detail] = await Promise.all([
+      automationApi.getProposalPreview(props.proposalId), automationApi.getProposal(props.proposalId),
+    ])
+    if (request !== generation) return
+    const status = normalizeProposalStatus(detail.status)
+    const effectiveId = status === 'Approved' ? detail.approvedRevisionId : detail.latestRevisionId
+    if (!sameId(receipt.proposalId, props.proposalId) || !sameId(detail.id, props.proposalId)
+      || !sameId(receipt.boardId, props.board.id) || !sameId(detail.boardId, props.board.id)
+      || !sameId(receipt.effectiveRevisionId, effectiveId)
+      || Date.parse(receipt.proposalUpdatedAt) !== Date.parse(detail.updatedAt)
+      || normalizeProposalStatus(receipt.status) !== status
+      || !['PendingReview', 'Approved'].includes(status))
+      throw new Error('The proposal changed while loading. Refresh to check its latest revision.')
+    const lifetime = Math.min(30000, Date.parse(receipt.expiresAt) - Date.parse(receipt.checkedAt)) - (performance.now() - startedAt)
+    if (!Number.isFinite(lifetime) || lifetime <= 0) throw new Error('This proposal preview has expired. Open Review for its history.')
+    const existing = new Set([
+      ...props.cards.filter(card => sameId(card.boardId, props.board.id)).map(card => `card:${card.id.toLowerCase()}`),
+      ...props.board.columns.map(column => `column:${column.id.toLowerCase()}`),
+    ])
+    const markers: Record<string, string> = {}
+    for (const operation of detail.operations) {
+      const kind = operation.targetType.toLowerCase()
+      let parameters: Record<string, unknown> = {}
+      try { const parsed: unknown = JSON.parse(operation.parameters); if (parsed && typeof parsed === 'object' && !Array.isArray(parsed)) parameters = parsed as Record<string, unknown> } catch { /* The checked diff remains available if a target cannot be projected. */ }
+      // Execution uses parameter IDs. A display targetId must never override them.
+      const parameterId = Object.entries(parameters).find(([name]) => name.toLowerCase() === `${kind}id`)?.[1]
+      const id = typeof parameterId === 'string' ? parameterId : operation.targetId
+      const key = `${kind}:${id?.toLowerCase()}`
+      if (operation.actionType.toLowerCase() !== 'create' && existing.has(key)) markers[key] = 'Proposed change'
+      if (kind === 'card' && ['create', 'move'].includes(operation.actionType.toLowerCase()) && typeof parameters.columnId === 'string') {
+        const destination = `column:${parameters.columnId.toLowerCase()}`
+        if (existing.has(destination)) markers[destination] = 'Proposed change'
+      }
+    }
+    proposal.value = detail; preview.value = receipt; emit('markers', markers)
+    timer = setTimeout(() => { clear(); error.value = 'Refresh the preview to check the latest changes.' }, lifetime)
+  } catch (cause) {
+    if (request === generation) error.value = getErrorDisplay(cause, 'Preview unavailable. Open Review to inspect this proposal.').message
+  } finally { if (request === generation) loading.value = false }
+}
+onScopeDispose(clear)
+</script>
+
+<template>
+  <section class="board-proposal-preview" aria-label="Board proposal preview">
+    <div class="board-proposal-preview__actions">
+      <h2>Proposed board changes</h2>
+      <button type="button" :disabled="loading || !available" @click="load">{{ loading ? 'Checking proposal…' : 'Refresh board preview' }}</button>
+      <RouterLink :to="{ path: '/workspace/review', query: { boardId: board.id }, hash: `#proposal-${proposalId}` }">Open Review</RouterLink>
+      <button type="button" @click="emit('close')">Close preview</button>
+    </div>
+    <p v-if="error" role="status">{{ error }}</p>
+    <template v-if="preview && proposal">
+      <p>{{ normalizeProposalStatus(preview.status) }} · {{ preview.effectiveRevisionNumber === null ? 'Original proposal' : `Revision ${preview.effectiveRevisionNumber}` }} · checked {{ new Date(preview.checkedAt).toLocaleTimeString() }}</p>
+      <p>{{ proposal.presentation?.plainSummary || proposal.summary }}</p>
+      <details open><summary>Changes to inspect</summary><pre>{{ preview.diff }}</pre></details>
+      <p>Existing targets are marked “Proposed change”. New items, hidden cards and targets without a board object appear in the summary above. The board still shows its saved state. Approval and Apply remain in Review.</p>
+    </template>
+    <p v-else-if="!loading && !error">Check the proposal to reveal its diff and mark the affected board objects.</p>
+  </section>
+</template>
+
+<style scoped>
+.board-proposal-preview { margin: 1rem; padding: 1rem; border: 2px dashed var(--td-border-default); border-radius: .75rem; background: var(--td-surface-primary); color: var(--td-text-primary); }
+.board-proposal-preview__actions { display: flex; flex-wrap: wrap; align-items: center; gap: .75rem; }
+h2 { font-size: 1rem; font-weight: 650; margin-right: auto; }
+button, a { padding: .5rem; border: 1px solid var(--td-border-default); border-radius: .3rem; }
+p { font-size: .85rem; margin-top: .5rem; line-height: 1.5; }
+pre { white-space: pre-wrap; overflow-wrap: anywhere; max-height: 16rem; overflow: auto; font-size: .8rem; }
+</style>
+
+<style>
+[data-proposal-change] { outline: 2px dashed var(--td-text-secondary); outline-offset: -2px; }
+.td-proposal-marker { display: block; padding: .3rem .6rem; font-size: .75rem; font-weight: 650; color: var(--td-text-primary); background: var(--td-surface-secondary); border-bottom: 1px dashed var(--td-border-default); }
+</style>
diff --git a/frontend/taskdeck-web/src/components/board/CardItem.vue b/frontend/taskdeck-web/src/components/board/CardItem.vue
index 20d677221..815b239c1 100644
--- a/frontend/taskdeck-web/src/components/board/CardItem.vue
+++ b/frontend/taskdeck-web/src/components/board/CardItem.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import { ref } from 'vue'
+import { useBoardProposalMarker } from '../../composables/useBoardProposalMarker'
 import type { Card, Column } from '../../types/board'
 import { formatCalendarDate, isCalendarDateOverdue } from '../../utils/dueDates'
 
@@ -17,6 +18,7 @@ const emit = defineEmits<{
 }>()
 
 const isDragging = ref(false)
+const proposalMarker = useBoardProposalMarker('card', () => props.card.id)
 const showMoveMenu = ref(false)
 
 function toggleMoveMenu(event: Event) {
@@ -120,6 +122,7 @@ function isOverdue(dateString: string | null): boolean {
   <div
     draggable="false"
     :data-card-id="card.id"
+    :data-proposal-change="proposalMarker ? true : undefined"
     role="option"
     :class="[
       'td-board-card group relative cursor-pointer',
@@ -135,6 +138,7 @@ function isOverdue(dateString: string | null): boolean {
     @dragend="handleDragEnd"
   >
     <!-- Ember leading-edge indicator -->
+    <span v-if="proposalMarker" class="td-proposal-marker">{{ proposalMarker }}</span>
     <span class="td-board-card__indicator" aria-hidden="true" />
 
     <!-- Card action bar: drag handle + move menu trigger -->
diff --git a/frontend/taskdeck-web/src/components/board/ColumnLane.vue b/frontend/taskdeck-web/src/components/board/ColumnLane.vue
index a84e34151..2716aa396 100644
--- a/frontend/taskdeck-web/src/components/board/ColumnLane.vue
+++ b/frontend/taskdeck-web/src/components/board/ColumnLane.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import { ref, computed, nextTick } from 'vue'
+import { useBoardProposalMarker } from '../../composables/useBoardProposalMarker'
 import { useBoardStore } from '../../store/boardStore'
 import { useToastStore } from '../../store/toastStore'
 import { getErrorDisplay } from '../../composables/useErrorMapper'
@@ -185,12 +186,14 @@ function handleCardDragOver(event: DragEvent) {
     event.dataTransfer.dropEffect = 'move'
   }
 }
+const proposalMarker = useBoardProposalMarker('column', () => props.column.id)
 </script>
 
 <template>
   <!-- eslint-disable-next-line vuejs-accessibility/no-static-element-interactions -- drag-and-drop column drop zone; group role + drag events are intentional for kanban DnD -->
   <div
     :data-column-id="column.id"
+    :data-proposal-change="proposalMarker ? true : undefined"
     role="group"
     :aria-label="`${column.name} column`"
     :class="[
@@ -202,6 +205,7 @@ function handleCardDragOver(event: DragEvent) {
     @drop="handleDrop"
   >
     <!-- Column Header -->
+    <span v-if="proposalMarker" class="td-proposal-marker">{{ proposalMarker }}</span>
     <div class="td-column-lane__header">
       <div class="td-column-lane__header-row">
         <h3 class="td-column-lane__title"><span class="td-column-lane__title-dot"></span>{{ column.name }}</h3>
diff --git a/frontend/taskdeck-web/src/components/chat/ChatProposalPreview.vue b/frontend/taskdeck-web/src/components/chat/ChatProposalPreview.vue
index 2d01db9a7..e0c7767f9 100644
--- a/frontend/taskdeck-web/src/components/chat/ChatProposalPreview.vue
+++ b/frontend/taskdeck-web/src/components/chat/ChatProposalPreview.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import { onScopeDispose, ref, watch } from 'vue'
+import { RouterLink } from 'vue-router'
 import { automationApi } from '../../api/automationApi'
 import { useSessionStore } from '../../store/sessionStore'
 import { getErrorDisplay } from '../../composables/useErrorMapper'
@@ -48,6 +49,7 @@ onScopeDispose(clear)
     <template v-if="preview">
       <p>{{ normalizeProposalStatus(preview.status) }} · {{ preview.effectiveRevisionNumber === null ? 'Original proposal' : `Revision ${preview.effectiveRevisionNumber}` }} · checked {{ new Date(preview.checkedAt).toLocaleTimeString() }}</p>
       <pre>{{ preview.diff }}</pre>
+      <RouterLink v-if="boardId" :to="{ path: `/workspace/boards/${boardId}`, query: { proposalId } }">Preview on board</RouterLink>
       <p>This is a checked preview, not an applied change. Open Review to inspect, approve and explicitly apply. Review checks the proposal again.</p>
     </template>
   </section>
diff --git a/frontend/taskdeck-web/src/components/review/ReviewProposalDetails.vue b/frontend/taskdeck-web/src/components/review/ReviewProposalDetails.vue
index 34eb76523..851344702 100644
--- a/frontend/taskdeck-web/src/components/review/ReviewProposalDetails.vue
+++ b/frontend/taskdeck-web/src/components/review/ReviewProposalDetails.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import { computed, ref } from 'vue'
+import { normalizeProposalStatus } from '../../utils/automation'
 import type { Proposal, ProposalAffectedEntity } from '../../types/automation'
 
 const props = withDefaults(defineProps<{
@@ -167,6 +168,13 @@ const fullCorrelationId = computed(() => props.proposal.correlationId?.trim() ??
             >
               Review Link
             </router-link>
+            <router-link
+              v-if="proposal.boardId && !props.readOnly && ['PendingReview', 'Approved'].includes(normalizeProposalStatus(proposal.status))"
+              class="td-review-card__links-dropdown-item"
+              role="menuitem"
+              :to="{ path: `/workspace/boards/${proposal.boardId}`, query: { proposalId: proposal.id } }"
+              @mousedown.prevent
+            >Preview on board</router-link>
             <button
               v-if="proposal.boardId && !props.readOnly"
               class="td-review-card__links-dropdown-item"
diff --git a/frontend/taskdeck-web/src/composables/useBoardProposalMarker.ts b/frontend/taskdeck-web/src/composables/useBoardProposalMarker.ts
new file mode 100644
index 000000000..0beeddebf
--- /dev/null
+++ b/frontend/taskdeck-web/src/composables/useBoardProposalMarker.ts
@@ -0,0 +1,10 @@
+import { computed, inject, type InjectionKey, type Ref } from 'vue'
+
+export type BoardProposalMarkers = Readonly<Record<string, string>>
+export const BOARD_PROPOSAL_MARKERS: InjectionKey<Readonly<Ref<BoardProposalMarkers>>> = Symbol('board-proposal-markers')
+
+/** Presentation only: a missing provider is the ordinary, unmodified board. */
+export function useBoardProposalMarker(kind: 'card' | 'column', id: () => string) {
+  const markers = inject(BOARD_PROPOSAL_MARKERS, undefined)
+  return computed(() => markers?.value[`${kind}:${id().toLowerCase()}`])
+}
diff --git a/frontend/taskdeck-web/src/tests/components/board/BoardProposalPreview.spec.ts b/frontend/taskdeck-web/src/tests/components/board/BoardProposalPreview.spec.ts
new file mode 100644
index 000000000..fa05a5475
--- /dev/null
+++ b/frontend/taskdeck-web/src/tests/components/board/BoardProposalPreview.spec.ts
@@ -0,0 +1,114 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { flushPromises, mount } from '@vue/test-utils'
+import { createPinia, setActivePinia } from 'pinia'
+import { computed, defineComponent, provide, ref } from 'vue'
+import BoardProposalPreview from '../../../components/board/BoardProposalPreview.vue'
+import CardItem from '../../../components/board/CardItem.vue'
+import PaperBoardCard from '../../../views/paper/PaperBoardCard.vue'
+import { BOARD_PROPOSAL_MARKERS, type BoardProposalMarkers } from '../../../composables/useBoardProposalMarker'
+import { useSessionStore } from '../../../store/sessionStore'
+import type { BoardDetail, Card } from '../../../types/board'
+import type { Proposal, ProposalPreview } from '../../../types/automation'
+
+const api = vi.hoisted(() => ({ preview: vi.fn(), detail: vi.fn() }))
+vi.mock('../../../api/automationApi', () => ({ automationApi: { getProposalPreview: api.preview, getProposal: api.detail } }))
+const at = new Date().toISOString()
+const board: BoardDetail = { id: 'b1', name: 'Board', description: null, isArchived: false, createdAt: at, updatedAt: at, columns: [{ id: 'c1', boardId: 'b1', name: 'Next', position: 0, wipLimit: null, cardCount: 1, createdAt: at, updatedAt: at }] }
+const card: Card = { id: 'a1', boardId: 'b1', columnId: 'c1', title: 'Saved title', description: '', dueDate: null, isBlocked: false, blockReason: null, position: 0, labels: [], createdAt: at, updatedAt: at }
+const receipt = (): ProposalPreview => ({ proposalId: 'p1', boardId: 'b1', status: 'PendingReview', effectiveRevisionId: 'r2', effectiveRevisionNumber: 2, proposalUpdatedAt: at, expiresAt: new Date(Date.now() + 60000).toISOString(), checkedAt: new Date().toISOString(), diff: 'Update Saved title → Proposed title <script>unsafe</script>' })
+const detail = (): Proposal => ({ id: 'p1', boardId: 'b1', status: 'PendingReview', latestRevisionId: 'r2', approvedRevisionId: null, updatedAt: at, summary: 'Rename a card and column; create another card', operations: [
+  { targetType: 'Card', targetId: 'wrong-display-target', actionType: 'update', parameters: '{"CardId":"A1"}' },
+  { targetType: 'Column', targetId: 'c1', actionType: 'update' },
+  { targetType: 'Card', targetId: null, actionType: 'create' },
+  { targetType: 'Card', targetId: 'not-on-board', actionType: 'delete' },
+] } as Proposal)
+function setup() {
+  const pinia = createPinia(); setActivePinia(pinia)
+  const session = useSessionStore(); session.userId = 'user'; session.token = 'token'
+  const wrapper = mount(BoardProposalPreview, { props: { proposalId: 'p1', board: structuredClone(board), cards: [structuredClone(card)] }, global: { plugins: [pinia], stubs: { RouterLink: true } } })
+  const load = async () => { await wrapper.get('button').trigger('click'); await flushPromises() }
+  return { wrapper, load, session }
+}
+describe('board proposal preview', () => {
+  beforeEach(() => { vi.clearAllMocks(); api.preview.mockResolvedValue(receipt()); api.detail.mockResolvedValue(detail()) })
+  afterEach(() => { vi.useRealTimers(); vi.restoreAllMocks() })
+  it('explicitly checks one matching revision, marks existing targets and never writes board state', async () => {
+    const { wrapper, load } = setup()
+    expect(api.preview).not.toHaveBeenCalled()
+    await load()
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({ 'card:a1': 'Proposed change', 'column:c1': 'Proposed change' })
+    expect(wrapper.get('pre').text()).toContain('<script>unsafe</script>')
+    expect(wrapper.find('script').exists()).toBe(false)
+    expect(wrapper.props('cards')).toEqual([card])
+    expect(wrapper.props('board')).toEqual(board)
+    expect(wrapper.findAll('button').map(button => button.text())).toEqual(['Refresh board preview', 'Close preview'])
+    expect(wrapper.getComponent({ name: 'RouterLink' }).props('to')).toEqual({ path: '/workspace/review', query: { boardId: 'b1' }, hash: '#proposal-p1' })
+    wrapper.unmount()
+  })
+  it.each(['board', 'revision', 'updated', 'status'])('rejects mismatched %s receipts', async mismatch => {
+    const value = detail()
+    if (mismatch === 'board') value.boardId = 'other'
+    if (mismatch === 'revision') value.latestRevisionId = 'r3'
+    if (mismatch === 'updated') value.updatedAt = new Date(Date.parse(at) + 1000).toISOString()
+    if (mismatch === 'status') value.status = 'Applied'
+    api.detail.mockResolvedValue(value)
+    const { wrapper, load } = setup(); await load()
+    expect(wrapper.find('pre').exists()).toBe(false)
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({})
+    wrapper.unmount()
+  })
+  it('uses the approved pin instead of a newer pending revision', async () => {
+    api.preview.mockResolvedValue({ ...receipt(), status: 'Approved' })
+    api.detail.mockResolvedValue({ ...detail(), status: 'Approved', latestRevisionId: 'r3', approvedRevisionId: 'r2' })
+    const { wrapper, load } = setup(); await load()
+    expect(wrapper.find('pre').exists()).toBe(true); wrapper.unmount()
+  })
+  it('retracts when board access or refresh fails and waits for board recovery', async () => {
+    const { wrapper, load } = setup(); await load()
+    await wrapper.setProps({ available: false })
+    expect(wrapper.find('pre').exists()).toBe(false)
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({})
+    expect(wrapper.get('button').attributes('disabled')).toBeDefined()
+    await wrapper.setProps({ available: true }); await load()
+    expect(wrapper.find('pre').exists()).toBe(true)
+    wrapper.unmount()
+  })
+  it('retracts on board changes, permission failure, logout and stale in-flight responses', async () => {
+    const { wrapper, load, session } = setup(); await load()
+    await wrapper.setProps({ cards: [{ ...card, title: 'Externally changed' }] })
+    expect(wrapper.find('pre').exists()).toBe(false)
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({})
+    api.preview.mockRejectedValueOnce({ response: { status: 403 } }); await load()
+    expect(wrapper.find('pre').exists()).toBe(false)
+    let resolve!: (value: ProposalPreview) => void
+    api.preview.mockReturnValue(new Promise<ProposalPreview>(done => { resolve = done }))
+    await wrapper.get('button').trigger('click')
+    session.token = null; resolve(receipt()); await flushPromises()
+    expect(wrapper.find('pre').exists()).toBe(false)
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({})
+    wrapper.unmount()
+  })
+  it('retains a same-user token refresh, expires on server time and clears markers on unmount', async () => {
+    vi.useFakeTimers()
+    const now = Date.now() + 3600000
+    api.preview.mockResolvedValue({ ...receipt(), checkedAt: new Date(now).toISOString(), expiresAt: new Date(now + 5000).toISOString() })
+    const { wrapper, load, session } = setup(); await load()
+    session.token = 'refreshed'; await flushPromises()
+    expect(wrapper.find('pre').exists()).toBe(true)
+    await vi.advanceTimersByTimeAsync(5000)
+    expect(wrapper.find('pre').exists()).toBe(false)
+    expect(wrapper.emitted('markers')?.at(-1)?.[0]).toEqual({})
+    wrapper.unmount()
+  })
+  it.each([CardItem, PaperBoardCard])('reactively labels saved cards in both renderers', async component => {
+    const markers = ref<BoardProposalMarkers>({ 'card:a1': 'Proposed change' })
+    const Host = defineComponent({ components: { Target: component }, setup() { provide(BOARD_PROPOSAL_MARKERS, computed(() => markers.value)); return { card } }, template: '<Target :card="card" />' })
+    const wrapper = mount(Host)
+    expect(wrapper.get('[data-card-id="a1"]').attributes('data-proposal-change')).toBe('true')
+    expect(wrapper.text()).toContain('Saved title')
+    expect(wrapper.text()).toContain('Proposed change')
+    markers.value = {}; await flushPromises()
+    expect(wrapper.find('[data-proposal-change]').exists()).toBe(false)
+    wrapper.unmount()
+  })
+})
diff --git a/frontend/taskdeck-web/src/tests/components/chat/ChatProposalPreview.spec.ts b/frontend/taskdeck-web/src/tests/components/chat/ChatProposalPreview.spec.ts
index 68d02a181..1fd8463d7 100644
--- a/frontend/taskdeck-web/src/tests/components/chat/ChatProposalPreview.spec.ts
+++ b/frontend/taskdeck-web/src/tests/components/chat/ChatProposalPreview.spec.ts
@@ -9,7 +9,7 @@ vi.mock('../../../api/automationApi', () => ({ automationApi: { getProposalPrevi
 const snapshot = (): ProposalPreview => ({ proposalId: 'p1', boardId: 'b1', status: 'PendingReview', effectiveRevisionId: 'r2', effectiveRevisionNumber: 2, proposalUpdatedAt: new Date().toISOString(), expiresAt: new Date(Date.now() + 60000).toISOString(), checkedAt: new Date().toISOString(), diff: 'Update card: revised title <script>unsafe</script>' })
 function setup() {
   const pinia = createPinia(); setActivePinia(pinia)
-  return { session: useSessionStore(), wrapper: mount(ChatProposalPreview, { props: { proposalId: 'p1', boardId: 'b1' }, global: { plugins: [pinia] } }) }
+  return { session: useSessionStore(), wrapper: mount(ChatProposalPreview, { props: { proposalId: 'p1', boardId: 'b1' }, global: { plugins: [pinia], stubs: { RouterLink: true } } }) }
 }
 describe('contextual proposal preview', () => {
   beforeEach(() => { vi.clearAllMocks(); api.preview.mockResolvedValue(snapshot()) })
diff --git a/frontend/taskdeck-web/src/views/BoardView.vue b/frontend/taskdeck-web/src/views/BoardView.vue
index 53cf56dc1..ca5c3d55b 100644
--- a/frontend/taskdeck-web/src/views/BoardView.vue
+++ b/frontend/taskdeck-web/src/views/BoardView.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { onBeforeUnmount, onMounted, ref, computed, watch } from 'vue'
+import { onBeforeUnmount, onMounted, ref, computed, watch, provide, readonly } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 import { useBoardStore } from '../store/boardStore'
 import { useSessionStore } from '../store/sessionStore'
@@ -13,6 +13,8 @@ import { usePerformanceMark } from '../composables/usePerformanceMark'
 import BoardToolbar from '../components/board/BoardToolbar.vue'
 import BoardActionRail from '../components/board/BoardActionRail.vue'
 import BoardCanvas from '../components/board/BoardCanvas.vue'
+import BoardProposalPreview from '../components/board/BoardProposalPreview.vue'
+import { BOARD_PROPOSAL_MARKERS, type BoardProposalMarkers } from '../composables/useBoardProposalMarker'
 import BoardDialogHost from '../components/board/BoardDialogHost.vue'
 import FilterPanel from '../components/board/FilterPanel.vue'
 import WorkspaceHelpCallout from '../components/workspace/WorkspaceHelpCallout.vue'
@@ -72,6 +74,16 @@ function normalizePresenceMembers(members: BoardPresenceMember[]): BoardPresence
 }
 
 const boardId = ref(route.params.id as string)
+const previewProposalId = computed(() => typeof route.query?.proposalId === 'string' ? route.query.proposalId : null)
+const proposalMarkers = ref<BoardProposalMarkers>({})
+provide(BOARD_PROPOSAL_MARKERS, readonly(proposalMarkers))
+watch([boardId, previewProposalId], () => { proposalMarkers.value = {} }, { flush: 'sync' })
+function closeProposalPreview() {
+  proposalMarkers.value = {}
+  const query = { ...route.query }
+  delete query.proposalId
+  void router.replace({ query })
+}
 const boardLoadRetryInFlight = ref(false)
 const boardLoadError = ref<string | null>(null)
 const routedBoard = computed(() => boardStore.currentBoard?.id === boardId.value
@@ -523,6 +535,15 @@ useKeyboardShortcuts([
 </script>
 
 <template>
+  <BoardProposalPreview
+    v-if="previewProposalId && routedBoard"
+    :proposal-id="previewProposalId"
+    :board="routedBoard"
+    :cards="boardStore.currentBoardCards"
+    :available="!boardLoadError && !boardStore.error"
+    @markers="proposalMarkers = $event"
+    @close="closeProposalPreview"
+  />
   <PaperBoardView
     v-if="paperOn"
     :selected-card-id="selectedCardId"
diff --git a/frontend/taskdeck-web/src/views/paper/PaperBoardCard.vue b/frontend/taskdeck-web/src/views/paper/PaperBoardCard.vue
index a38a9441b..1f8892673 100644
--- a/frontend/taskdeck-web/src/views/paper/PaperBoardCard.vue
+++ b/frontend/taskdeck-web/src/views/paper/PaperBoardCard.vue
@@ -1,6 +1,7 @@
 <script setup lang="ts">
 /* eslint-disable vuejs-accessibility/no-static-element-interactions -- the article and aria-hidden drag glyph are pointer drag boundaries; named-button activation and board keyboard movement remain separate */
 import { computed, ref } from 'vue'
+import { useBoardProposalMarker } from '../../composables/useBoardProposalMarker'
 import type { WorkspacePresentation } from '../../store/workspaceLayoutStore'
 import type { Card, Label } from '../../types/board'
 import { formatCalendarDate, isCalendarDateOverdue } from '../../utils/dueDates'
@@ -159,6 +160,7 @@ function onDragEnd() {
 function onDragHandleMouseDown() {
   window.getSelection()?.removeAllRanges()
 }
+const proposalMarker = useBoardProposalMarker('card', () => props.card.id)
 </script>
 
 <template>
@@ -169,6 +171,7 @@ function onDragHandleMouseDown() {
       selected ? 'paper-board-card--selected' : '',
     ]"
     :data-card-id="card.id"
+    :data-proposal-change="proposalMarker ? true : undefined"
     :data-variant="variant"
     :data-tone="tone || undefined"
     :data-presentation="presentation"
@@ -176,6 +179,7 @@ function onDragHandleMouseDown() {
     @dragstart="onDragStart"
     @dragend="onDragEnd"
   >
+    <span v-if="proposalMarker" class="td-proposal-marker">{{ proposalMarker }}</span>
     <button
       type="button"
       class="paper-board-card__open"
diff --git a/frontend/taskdeck-web/src/views/paper/PaperBoardColumn.vue b/frontend/taskdeck-web/src/views/paper/PaperBoardColumn.vue
index 6930f87be..fe9903cbd 100644
--- a/frontend/taskdeck-web/src/views/paper/PaperBoardColumn.vue
+++ b/frontend/taskdeck-web/src/views/paper/PaperBoardColumn.vue
@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { useBoardProposalMarker } from '../../composables/useBoardProposalMarker'
 import { computed } from 'vue'
 import { useI18n } from 'vue-i18n'
 import type { Card, Column } from '../../types/board'
@@ -175,6 +176,7 @@ function onCardDrop(card: Card, e: DragEvent) {
 function onCardDragOver(card: Card, e: DragEvent) {
   emit('card-dragover', card, e)
 }
+const proposalMarker = useBoardProposalMarker('column', () => props.column.id)
 </script>
 
 <template>
@@ -186,12 +188,14 @@ function onCardDragOver(card: Card, e: DragEvent) {
       'paper-board-column--selected': selected,
     }"
     :data-column-id="column.id"
+    :data-proposal-change="proposalMarker ? true : undefined"
     :data-collapsed="collapsed"
     role="group"
     :aria-label="`Column ${column.name}`"
     :aria-current="selected ? 'true' : undefined"
   >
     <header class="paper-board-column__header">
+      <span v-if="proposalMarker" class="td-proposal-marker">{{ proposalMarker }}</span>
       <div
         class="paper-board-column__heading"
         data-action="drag-column-handle"
diff --git a/frontend/taskdeck-web/src/views/paper/PaperReviewView.vue b/frontend/taskdeck-web/src/views/paper/PaperReviewView.vue
index 075a622f6..0d7def15c 100644
--- a/frontend/taskdeck-web/src/views/paper/PaperReviewView.vue
+++ b/frontend/taskdeck-web/src/views/paper/PaperReviewView.vue
@@ -2876,6 +2876,11 @@ async function onClearBoardScope() {
       >
         {{ revisionReviewUnavailableNote }}
       </p>
+      <router-link
+        v-if="activeProposal.boardId && !isArchivedHistory && ['PendingReview', 'Approved'].includes(normalizeProposalStatus(activeProposal.status))"
+        class="tk-meta"
+        :to="{ path: `/workspace/boards/${activeProposal.boardId}`, query: { proposalId: activeProposal.id } }"
+      >Preview on board</router-link>
       <ReviewMain
         ref="reviewMainRef"
         :key="activeProposal.id"
diff --git a/frontend/taskdeck-web/tests/e2e/board-proposal-overlays.spec.ts b/frontend/taskdeck-web/tests/e2e/board-proposal-overlays.spec.ts
new file mode 100644
index 000000000..e8a8f1e24
--- /dev/null
+++ b/frontend/taskdeck-web/tests/e2e/board-proposal-overlays.spec.ts
@@ -0,0 +1,61 @@
+import { expect, test } from '@playwright/test'
+import AxeBuilder from '@axe-core/playwright'
+import { API_BASE_URL, registerAndAttachSession } from './support/authSession'
+import { createBoardWithColumn } from './support/boardHelpers'
+import { assertOk } from './support/httpAsserts'
+
+test('a checked proposal highlights saved objects across board experiences without applying it', async ({ page, request }) => {
+  test.setTimeout(120000)
+  const auth = await registerAndAttachSession(page, request, 'board-preview')
+  const headers = { Authorization: `Bearer ${auth.token}` }
+  const seed = String(Date.now())
+  const boardId = await createBoardWithColumn(request, auth, seed, { boardNamePrefix: 'Proposal overlays', columnNamePrefix: 'Next' })
+  const board = await (await request.get(`${API_BASE_URL}/boards/${boardId}`, { headers })).json()
+  const columnId = board.columns[0].id
+  const createdCard = await request.post(`${API_BASE_URL}/boards/${boardId}/cards`, { headers, data: { boardId, columnId, title: 'Saved before preview' } })
+  await assertOk(createdCard, 'seed saved card'); const card = await createdCard.json()
+  const savedBoard = await (await request.get(`${API_BASE_URL}/boards/${boardId}`, { headers })).json()
+  const created = await request.post(`${API_BASE_URL}/automation/proposals`, { headers, data: {
+    sourceType: 1, requestedByUserId: auth.user.id, boardId, summary: 'Rename a card, position its column and propose a new card', riskLevel: 1, correlationId: `overlay-${seed}`,
+    operations: [
+      { sequence: 0, actionType: 'update', targetType: 'card', targetId: card.id, parameters: JSON.stringify({ cardId: card.id, title: 'Proposed new title' }), idempotencyKey: `overlay-${seed}-0` },
+      { sequence: 1, actionType: 'reorder', targetType: 'column', targetId: columnId, parameters: JSON.stringify({ columnId, position: 0 }), idempotencyKey: `overlay-${seed}-1` },
+      { sequence: 2, actionType: 'create', targetType: 'card', parameters: JSON.stringify({ boardId, columnId, title: 'New proposed card' }), idempotencyKey: `overlay-${seed}-2` },
+    ],
+  } })
+  await assertOk(created, 'seed proposal'); const proposal = await created.json()
+  const writes: string[] = []
+  page.on('request', req => { if (req.method() !== 'GET' && /\/api\/(boards|automation\/proposals)/.test(req.url())) writes.push(req.url()) })
+  const panel = page.getByRole('region', { name: 'Board proposal preview', exact: true })
+  for (const [experience, theme] of [['classic', 'off'], ['studio', 'grove'], ['companion', 'grove'], ['unified', 'grove']]) {
+    await page.goto(`/workspace/boards/${boardId}`)
+    await page.evaluate(value => {
+      localStorage.setItem('td.workspace.layout.v1', JSON.stringify({ experience: value[0], presentation: 'studio' }))
+      localStorage.setItem('td.paper.mode.v2', value[1]!)
+    }, [experience, theme])
+    await page.goto(`/workspace/boards/${boardId}?proposalId=${proposal.id}`)
+    await expect(page.locator(`[data-card-id="${card.id}"]`)).toBeVisible()
+    await panel.getByRole('button', { name: 'Refresh board preview', exact: true }).click()
+    await expect(panel.locator('pre')).toContainText('Proposed new title')
+    await expect(panel.locator('pre')).toContainText('New proposed card')
+    await expect(page.locator(`[data-card-id="${card.id}"]`)).toHaveAttribute('data-proposal-change', 'true')
+    await expect(page.locator(`[data-column-id="${columnId}"]`)).toHaveAttribute('data-proposal-change', 'true')
+    await expect(page.locator(`[data-card-id="${card.id}"]`)).toContainText('Saved before preview')
+  }
+  await page.setViewportSize({ width: 375, height: 812 })
+  expect(await page.evaluate(() => document.documentElement.scrollWidth)).toBeLessThanOrEqual(375)
+  expect((await new AxeBuilder({ page }).include('[aria-label="Board proposal preview"]').analyze()).violations.filter(item => ['serious', 'critical'].includes(item.impact ?? ''))).toEqual([])
+  await page.screenshot({ path: 'test-results/board-proposal-overlays-mobile.png', fullPage: true })
+  await panel.getByRole('button', { name: 'Close preview', exact: true }).click()
+  await expect(page.locator('[data-proposal-change]')).toHaveCount(0)
+  expect(writes).toEqual([])
+  expect(await (await request.get(`${API_BASE_URL}/boards/${boardId}/cards`, { headers })).json()).toEqual([card])
+  expect((await (await request.get(`${API_BASE_URL}/boards/${boardId}`, { headers })).json()).columns).toEqual(savedBoard.columns)
+  await page.goto(`/workspace/review?boardId=${boardId}`)
+  await page.getByRole('link', { name: 'Preview on board', exact: true }).click()
+  await expect(panel).toBeVisible()
+  await page.route(`**/automation/proposals/${proposal.id}/preview`, route => route.fulfill({ status: 403, contentType: 'application/json', body: JSON.stringify({ message: 'Synthetic revoked access' }) }))
+  await panel.getByRole('button', { name: 'Refresh board preview', exact: true }).click()
+  await expect(panel.getByRole('status')).toBeVisible()
+  await expect(page.locator('[data-proposal-change]')).toHaveCount(0)
+})