From ad090b688ece68c148a8311c58a343db6370a1ce Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Thu, 27 Aug 2026 13:44:39 +0200
Subject: [PATCH 1/5] Add activity timeline UI

---
 CHANGELOG.md                                  |   1 +
 .../activity/components/ActivityTimeline.vue  | 155 ++++
 .../components/ActivityTimelineActor.vue      |  40 +
 .../components/ActivityTimelineChangeList.vue |  89 +++
 .../ActivityTimelineChangeValue.vue           |  66 ++
 .../components/ActivityTimelineChanges.vue    |  83 +++
 .../components/ActivityTimelineComment.vue    | 315 ++++++++
 .../components/ActivityTimelineEvent.vue      | 152 ++++
 .../composables/useActivityTimeline.ts        | 163 ++++
 .../elements/components/ElementChips.vue      |   3 +
 .../components/ElementDetailsTabs.vue         | 113 +++
 .../elements/components/ElementEditScreen.vue |  97 +--
 .../elements/components/ElementEditor.vue     |  54 +-
 .../composables/useElementAutosave.ts         |   1 -
 .../composables/useElementEditor.test.ts      |  15 +
 .../elements/composables/useElementEditor.ts  |  14 +-
 .../js/modules/forms/MarkdownControl.vue      |  16 +-
 .../settings/composables/useSettingsSave.ts   |   1 +
 resources/js/pages/content/Activity.vue       |  22 +
 routes/actions.php                            |  10 +
 routes/cp.php                                 |   6 +
 src/Activity/ActivityComments.php             |  45 +-
 src/Activity/ActivityTimelinePresenter.php    | 174 +++++
 src/Activity/DraftActivity.php                |  10 +
 src/Activity/ElementWriteActivity.php         |  10 +-
 src/Activity/EntryActivity.php                |  54 +-
 src/Activity/EventTypes/CommentCreated.php    |   7 +-
 src/Activity/EventTypes/CommentDeleted.php    |   9 +
 src/Activity/EventTypes/CommentEdited.php     |   7 +-
 src/Activity/EventTypes/CommentEvent.php      |  12 +
 src/Activity/StructuralElementActivity.php    |   2 +-
 src/Element/Drafts.php                        |  40 +-
 .../Elements/ActivityCommentsController.php   | 125 ++++
 .../ActivityMentionSuggestionsController.php  |  62 ++
 .../Elements/ActivityTimelineController.php   |  47 ++
 .../Elements/ElementActivityController.php    |  43 ++
 src/Http/Requests/ActivityCommentRequest.php  |  27 +
 .../ActivityMentionSuggestionsRequest.php     |  18 +
 src/Http/Requests/ActivityRequest.php         |  38 +
 src/Http/Requests/ActivityTimelineRequest.php |  17 +
 src/Http/ViewModels/AssetEditViewModel.php    |   8 +
 src/Http/ViewModels/ElementEditViewModel.php  |  12 +
 src/Http/ViewModels/EntryEditViewModel.php    |  23 +
 src/Support/Facades/Drafts.php                |   1 +
 tests/Feature/Activity/EntryActivityTest.php  | 110 +++
 .../StructuralElementActivityTest.php         |  41 ++
 .../Assets/EditAssetControllerTest.php        |   2 +
 .../ActivityTimelineControllerTest.php        | 694 ++++++++++++++++++
 .../Entries/EditEntryControllerTest.php       |   6 +
 workbench/database/seeders/DatabaseSeeder.php | 214 +++++-
 50 files changed, 3112 insertions(+), 162 deletions(-)
 create mode 100644 resources/js/modules/activity/components/ActivityTimeline.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineActor.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineChangeList.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineChangeValue.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineChanges.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineComment.vue
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineEvent.vue
 create mode 100644 resources/js/modules/activity/composables/useActivityTimeline.ts
 create mode 100644 resources/js/modules/elements/components/ElementDetailsTabs.vue
 create mode 100644 resources/js/pages/content/Activity.vue
 create mode 100644 src/Activity/ActivityTimelinePresenter.php
 create mode 100644 src/Http/Controllers/Elements/ActivityCommentsController.php
 create mode 100644 src/Http/Controllers/Elements/ActivityMentionSuggestionsController.php
 create mode 100644 src/Http/Controllers/Elements/ActivityTimelineController.php
 create mode 100644 src/Http/Requests/ActivityCommentRequest.php
 create mode 100644 src/Http/Requests/ActivityMentionSuggestionsRequest.php
 create mode 100644 src/Http/Requests/ActivityRequest.php
 create mode 100644 src/Http/Requests/ActivityTimelineRequest.php
 create mode 100644 tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 55eded4334d..380791fc554 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - Fixed a bug where validating filesystem attributes could resolve `CraftCms\Cms\Filesystem\Filesystems\Filesystem::getRootUrl()`. ([#19535](https://github.com/craftcms/cms/pull/19535))
 - Fixed `CraftCms\Cms\Support\Env::parse()` to preserve unknown aliases rather than throw an exception. ([#19535](https://github.com/craftcms/cms/pull/19535))
 - Fixed a bug where nested Content Block fields’ content could be lost during a batched resave that included revisions. ([#19543](https://github.com/craftcms/cms/issues/19543))
+- Added Markdown comments to element activity timelines, with support for editing, removing, structured user mentions, and email notifications.
 
 ## 6.0.0-alpha.18 - 2026-09-01
 
diff --git a/resources/js/modules/activity/components/ActivityTimeline.vue b/resources/js/modules/activity/components/ActivityTimeline.vue
new file mode 100644
index 00000000000..c486f9f3669
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimeline.vue
@@ -0,0 +1,155 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import {ref} from 'vue';
+  import CpLink from '@/common/components/CpLink.vue';
+  import ActivityTimelineComment from './ActivityTimelineComment.vue';
+  import ActivityTimelineEvent from './ActivityTimelineEvent.vue';
+  import {
+    type ActivityEvent,
+    useActivityTimeline,
+    type ActivityTimelineProps,
+  } from '@/modules/activity/composables/useActivityTimeline';
+
+  const props = defineProps<ActivityTimelineProps>();
+  const timeline = ref<HTMLElement | null>(null);
+  const {addOrUpdateEvent, dayGroups, events, load, scrollToEnd, status} =
+    useActivityTimeline(props, timeline);
+
+  async function commentCreated(event: ActivityEvent): Promise<void> {
+    addOrUpdateEvent(event);
+    await scrollToEnd();
+  }
+</script>
+
+<template>
+  <div class="activity-timeline">
+    <div ref="timeline" class="activity-timeline__scroll" scroll-region>
+      <div
+        v-if="status === 'loading'"
+        class="activity-timeline__status"
+        role="status"
+      >
+        <craft-spinner />
+        <span class="visually-hidden">{{ t('Loading activity') }}</span>
+      </div>
+
+      <div
+        v-else-if="status === 'error'"
+        class="activity-timeline__status"
+        role="alert"
+      >
+        <p>{{ t('Couldn’t load activity.') }}</p>
+        <craft-button
+          type="button"
+          size="small"
+          variant="outline"
+          data-activity-retry
+          @click="load"
+        >
+          {{ t('Retry') }}
+        </craft-button>
+      </div>
+
+      <p
+        v-else-if="status === 'loaded' && events.length === 0"
+        class="activity-timeline__status"
+      >
+        {{ t('No activity has been recorded yet.') }}
+      </p>
+
+      <div v-else-if="status === 'loaded'" class="activity-timeline__rail">
+        <div v-if="pageUrl" class="activity-timeline__full-link">
+          <CpLink :href="pageUrl">
+            {{ t('View all activity') }}
+            <craft-icon name="circle-arrow-right" />
+          </CpLink>
+        </div>
+
+        <section
+          v-for="group in dayGroups"
+          :key="group.key"
+          :data-activity-day="group.key"
+        >
+          <h4 class="activity-timeline__day">{{ group.label }}</h4>
+          <ActivityTimelineEvent
+            v-for="(event, index) in group.events"
+            :key="event.id"
+            :event="event"
+            :element-type="elementType"
+            :element-id="elementId"
+            :site-id="siteId"
+            :last="index === group.events.length - 1"
+            @updated="addOrUpdateEvent"
+          />
+        </section>
+      </div>
+    </div>
+
+    <div
+      v-if="status === 'loaded'"
+      class="activity-timeline__composer"
+      data-activity-comment-composer
+    >
+      <ActivityTimelineComment
+        :element-type="elementType"
+        :element-id="elementId"
+        :site-id="siteId"
+        @created="commentCreated"
+      />
+    </div>
+  </div>
+</template>
+
+<style scoped>
+  .activity-timeline {
+    display: flex;
+    flex-direction: column;
+    max-height: 60vh;
+  }
+
+  .activity-timeline__scroll {
+    min-height: 8rem;
+    overflow-y: auto;
+  }
+
+  .activity-timeline__status {
+    display: grid;
+    justify-items: center;
+    gap: var(--c-spacing-sm);
+    padding: var(--c-spacing-xl) var(--c-spacing-md);
+    text-align: center;
+    color: var(--c-text-quiet);
+  }
+
+  .activity-timeline__status p {
+    margin: 0;
+  }
+
+  .activity-timeline__rail,
+  .activity-timeline__composer {
+    padding: var(--c-spacing-md);
+  }
+
+  .activity-timeline__full-link {
+    display: flex;
+    align-items: center;
+    margin-block-end: var(--c-spacing-md);
+  }
+
+  .activity-timeline__day {
+    margin-block: var(--c-spacing-lg) var(--c-spacing-xs);
+    color: var(--c-text-quiet);
+    font-size: var(--c-text-xs);
+    font-weight: 600;
+  }
+
+  section:first-of-type .activity-timeline__day {
+    margin-block-start: 0;
+  }
+
+  .activity-timeline__composer {
+    flex: none;
+    border-block-start: 1px solid var(--c-color-neutral-border-quiet);
+    background: var(--c-bg);
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineActor.vue b/resources/js/modules/activity/components/ActivityTimelineActor.vue
new file mode 100644
index 00000000000..f81151b8e8b
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineActor.vue
@@ -0,0 +1,40 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import {computed} from 'vue';
+  import type {ActivityTarget} from '@/modules/activity/composables/useActivityTimeline';
+
+  const props = defineProps<{
+    actor: ActivityTarget;
+    impersonator: ActivityTarget | null;
+  }>();
+
+  const identities = computed(() => [
+    ...(props.impersonator
+      ? [{role: 'impersonator', target: props.impersonator}]
+      : []),
+    {role: 'actor', target: props.actor},
+  ]);
+</script>
+
+<template>
+  <template v-for="(identity, index) in identities" :key="identity.role">
+    <span v-if="index" class="activity-timeline__as">{{ t('as') }}</span>
+    <a
+      v-if="identity.target.url"
+      :href="identity.target.url"
+      class="font-semibold"
+    >
+      {{ identity.target.label }}
+    </a>
+    <span v-else class="font-semibold">
+      {{ identity.target.label }}
+      <span v-if="identity.target.deleted">({{ t('deleted') }})</span>
+    </span>
+  </template>
+</template>
+
+<style scoped>
+  .activity-timeline__as {
+    margin-inline: 0.25em;
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineChangeList.vue b/resources/js/modules/activity/components/ActivityTimelineChangeList.vue
new file mode 100644
index 00000000000..b67fe3a68ae
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineChangeList.vue
@@ -0,0 +1,89 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import ActivityTimelineChangeValue from './ActivityTimelineChangeValue.vue';
+  import type {ActivityChange} from '@/modules/activity/composables/useActivityTimeline';
+
+  defineProps<{
+    changes: ActivityChange[];
+  }>();
+</script>
+
+<template>
+  <ul class="activity-timeline__change-list">
+    <li
+      v-for="(change, index) in changes"
+      :key="index"
+      class="activity-timeline__change"
+    >
+      <strong class="activity-timeline__change-label">
+        {{ change.label }}
+      </strong>
+      <dl class="activity-timeline__change-comparison">
+        <div>
+          <dt>{{ t('Before') }}</dt>
+          <dd><ActivityTimelineChangeValue :value="change.old" /></dd>
+        </div>
+        <div>
+          <dt>{{ t('After') }}</dt>
+          <dd><ActivityTimelineChangeValue :value="change.new" /></dd>
+        </div>
+      </dl>
+    </li>
+  </ul>
+</template>
+
+<style scoped>
+  .activity-timeline__change-list {
+    container-type: inline-size;
+    margin: 0;
+    padding: 0;
+    list-style: none;
+  }
+
+  .activity-timeline__change {
+    padding-block: var(--c-spacing-sm);
+    border-block-start: 1px solid var(--c-color-neutral-border-quiet);
+  }
+
+  .activity-timeline__change:first-child {
+    border-block-start: 0;
+  }
+
+  .activity-timeline__change-label,
+  .activity-timeline__change-comparison dd {
+    overflow-wrap: anywhere;
+  }
+
+  .activity-timeline__change-comparison {
+    display: grid;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    gap: var(--c-spacing-sm);
+    margin-block: var(--c-spacing-xs) 0;
+  }
+
+  .activity-timeline__change-comparison div {
+    min-width: 0;
+  }
+
+  .activity-timeline__change-comparison dt {
+    color: var(--c-text-quiet);
+    font-size: var(--c-text-xs);
+    font-weight: 600;
+  }
+
+  .activity-timeline__change-comparison dd {
+    margin: var(--c-spacing-xs) 0 0;
+  }
+
+  @container (min-width: 32rem) {
+    .activity-timeline__change {
+      display: grid;
+      grid-template-columns: minmax(8rem, 1fr) minmax(0, 2fr);
+      gap: var(--c-spacing-md);
+    }
+
+    .activity-timeline__change-comparison {
+      margin-block-start: 0;
+    }
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineChangeValue.vue b/resources/js/modules/activity/components/ActivityTimelineChangeValue.vue
new file mode 100644
index 00000000000..97a91fca46e
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineChangeValue.vue
@@ -0,0 +1,66 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import {computed} from 'vue';
+  import ElementChips from '@/modules/elements/components/ElementChips.vue';
+  import {useSelectable} from '@/common/composables/useSelectable';
+
+  interface ElementReference {
+    elementType: string;
+    id: number;
+    label: string;
+    siteId: number | null;
+  }
+
+  const props = defineProps<{value: unknown}>();
+  const selection = useSelectable<number>({ids: [], enabled: false});
+  const elements = computed(() =>
+    Array.isArray(props.value) && props.value.every(isElementReference)
+      ? props.value
+      : null
+  );
+
+  function isElementReference(value: unknown): value is ElementReference {
+    return (
+      typeof value === 'object' &&
+      value !== null &&
+      'elementType' in value &&
+      'id' in value &&
+      'label' in value
+    );
+  }
+
+  function valueText(value: unknown): string {
+    if (value === null || (Array.isArray(value) && value.length === 0)) {
+      return t('None');
+    }
+
+    if (typeof value === 'boolean') {
+      return value ? t('Yes') : t('No');
+    }
+
+    if (typeof value === 'string' || typeof value === 'number') {
+      return String(value);
+    }
+
+    return JSON.stringify(value) ?? '';
+  }
+</script>
+
+<template>
+  <ElementChips
+    v-if="elements !== null && elements.length > 0"
+    :data="elements"
+    :selection="selection"
+    inline
+    read-only
+  />
+  <span v-else class="activity-timeline-change-value__text">
+    {{ valueText(value) }}
+  </span>
+</template>
+
+<style scoped>
+  .activity-timeline-change-value__text {
+    white-space: pre-wrap;
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineChanges.vue b/resources/js/modules/activity/components/ActivityTimelineChanges.vue
new file mode 100644
index 00000000000..045780cf7cb
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineChanges.vue
@@ -0,0 +1,83 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import {computed, shallowRef} from 'vue';
+  import Modal from '@/common/components/Modal.vue';
+  import ActivityTimelineChangeList from './ActivityTimelineChangeList.vue';
+  import type {ActivityChange} from '@/modules/activity/composables/useActivityTimeline';
+
+  const props = defineProps<{
+    changes: ActivityChange[];
+  }>();
+
+  const modalActive = shallowRef(false);
+  const showInline = computed(
+    () =>
+      props.changes.length <= 3 && JSON.stringify(props.changes).length <= 400
+  );
+
+  function changeCountLabel(count: number): string {
+    return t('{count, plural, =1{1 change} other{# changes}}', {count});
+  }
+</script>
+
+<template>
+  <craft-card class="activity-timeline__changes">
+    <details v-if="showInline" open>
+      <summary>{{ changeCountLabel(changes.length) }}</summary>
+      <ActivityTimelineChangeList
+        class="activity-timeline__change-list"
+        :changes="changes"
+      />
+    </details>
+
+    <div v-else class="activity-timeline__changes-summary">
+      <span>{{ changeCountLabel(changes.length) }}</span>
+      <craft-button
+        type="button"
+        size="small"
+        variant="outline"
+        @click="modalActive = true"
+      >
+        {{ t('Expand') }}
+      </craft-button>
+    </div>
+  </craft-card>
+
+  <Teleport to="body">
+    <Modal :is-active="modalActive" width="2xl" @close="modalActive = false">
+      <craft-pane :label="changeCountLabel(changes.length)">
+        <craft-button
+          slot="header-actions"
+          type="button"
+          icon="x"
+          :aria-label="t('Close')"
+          variant="plain"
+          size="small"
+          @click="modalActive = false"
+        />
+        <ActivityTimelineChangeList :changes="changes" />
+      </craft-pane>
+    </Modal>
+  </Teleport>
+</template>
+
+<style scoped>
+  .activity-timeline__changes {
+    margin-block-start: var(--c-spacing-sm);
+  }
+
+  .activity-timeline__changes details > summary {
+    cursor: pointer;
+  }
+
+  .activity-timeline__change-list {
+    margin-block-start: var(--c-spacing-sm);
+  }
+
+  .activity-timeline__changes-summary {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: var(--c-spacing-sm);
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineComment.vue b/resources/js/modules/activity/components/ActivityTimelineComment.vue
new file mode 100644
index 00000000000..8b837f594a1
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineComment.vue
@@ -0,0 +1,315 @@
+<script setup lang="ts">
+  import {actionClient, t} from '@craftcms/ui';
+  import {computed, shallowRef} from 'vue';
+  import {
+    destroy,
+    store,
+    update,
+  } from '@actions/Elements/ActivityCommentsController';
+  import ActivityMentionSuggestionsController from '@actions/Elements/ActivityMentionSuggestionsController';
+  import ActionMenu from '@/common/components/ActionMenu.vue';
+  import type {ActionItem} from '@/common/types';
+  import type {ActivityEvent} from '@/modules/activity/composables/useActivityTimeline';
+  import ActivityTimelineActor from './ActivityTimelineActor.vue';
+  import '../../markdown-field/markdown-field';
+
+  interface ActivityCommentResponse {
+    event: ActivityEvent;
+  }
+
+  const props = defineProps<{
+    event?: ActivityEvent;
+    elementType: string;
+    elementId: number | null;
+    siteId: number | null;
+  }>();
+
+  const emit = defineEmits<{
+    created: [event: ActivityEvent];
+    updated: [event: ActivityEvent];
+  }>();
+
+  const editing = shallowRef(false);
+  const draft = shallowRef('');
+  const mutating = shallowRef(false);
+  const error = shallowRef(false);
+  const creating = computed(() => props.event === undefined);
+  const comment = computed(() => props.event?.comment);
+  const commentActions = computed<ActionItem[]>(() => [
+    ...(comment.value?.canEdit
+      ? [{label: t('Edit'), icon: 'pencil', onClick: startEditing}]
+      : []),
+    ...(comment.value?.canDelete
+      ? [
+          {
+            label: t('Remove'),
+            icon: 'trash',
+            variant: 'danger',
+            disabled: mutating.value,
+            onClick: deleteComment,
+          },
+        ]
+      : []),
+  ]);
+  const editorId = computed(() =>
+    creating.value
+      ? 'activity-comment-draft'
+      : `activity-comment-${props.event!.id}`
+  );
+  const toolbarButtons = [
+    'bold',
+    'italic',
+    'code',
+    'h3',
+    'quote',
+    'unordered-list',
+    'ordered-list',
+    'check-list',
+    'link',
+  ];
+
+  function requestData() {
+    return {
+      elementType: props.elementType,
+      elementId: props.elementId,
+      siteId: props.siteId,
+    };
+  }
+
+  const mentionTriggers = computed(() => [
+    {
+      trigger: '@',
+      boundary: 'whitespace' as const,
+      label: t('Users'),
+      source: ActivityMentionSuggestionsController.url(undefined, {
+        query: requestData(),
+      }),
+      limit: 10,
+    },
+  ]);
+
+  function sentenceFragment(text: string | null): string {
+    return text === null
+      ? ''
+      : text.charAt(0).toLocaleLowerCase() + text.slice(1);
+  }
+
+  function startEditing(): void {
+    editing.value = true;
+    draft.value = comment.value!.markdown ?? '';
+    error.value = false;
+  }
+
+  function cancelEditing(): void {
+    editing.value = false;
+    draft.value = '';
+    error.value = false;
+  }
+
+  async function saveComment(): Promise<void> {
+    if (draft.value.trim() === '') {
+      return;
+    }
+
+    mutating.value = true;
+    error.value = false;
+
+    try {
+      const event = props.event;
+      const {data} =
+        event === undefined
+          ? await actionClient.post<ActivityCommentResponse>(store.url(), {
+              ...requestData(),
+              markdown: draft.value,
+            })
+          : await actionClient.patch<ActivityCommentResponse>(update.url(), {
+              ...requestData(),
+              commentId: event.id,
+              markdown: draft.value,
+            });
+
+      if (event === undefined) {
+        draft.value = '';
+        emit('created', data.event);
+      } else {
+        emit('updated', data.event);
+        cancelEditing();
+      }
+    } catch {
+      error.value = true;
+    } finally {
+      mutating.value = false;
+    }
+  }
+
+  async function deleteComment(): Promise<void> {
+    if (!window.confirm(t('Remove this comment?'))) {
+      return;
+    }
+
+    mutating.value = true;
+    error.value = false;
+
+    try {
+      const {data} = await actionClient.delete<ActivityCommentResponse>(
+        destroy.url(),
+        {
+          data: {
+            ...requestData(),
+            commentId: props.event!.id,
+          },
+        }
+      );
+
+      emit('updated', data.event);
+      cancelEditing();
+    } catch {
+      error.value = true;
+    } finally {
+      mutating.value = false;
+    }
+  }
+</script>
+
+<template>
+  <div
+    v-if="creating || editing"
+    :data-activity-comment="editing ? '' : undefined"
+    :data-activity-comment-draft="creating ? '' : undefined"
+  >
+    <div
+      class="activity-timeline__comment-editor"
+      :class="{'activity-timeline__comment-edit': !creating}"
+    >
+      <label class="visually-hidden" :for="editorId">
+        {{ creating ? t('Add a comment') : t('Edit comment') }}
+      </label>
+      <craft-markdown-field
+        :id="editorId"
+        class="markdown-field"
+        :rows="creating ? 3 : 4"
+        :placeholder="creating ? t('Add a comment…') : undefined"
+        sanitize-html
+        show-toolbar
+        .toolbarButtons="toolbarButtons"
+        .value="draft"
+        @input="draft = ($event.target as HTMLTextAreaElement).value"
+      />
+      <craft-text-expander :for="editorId" .triggers="mentionTriggers" />
+      <div class="activity-timeline__comment-actions">
+        <p v-if="error" class="error" role="alert">
+          {{
+            creating
+              ? t('Couldn’t post comment.')
+              : t('Couldn’t update comment.')
+          }}
+        </p>
+        <button
+          v-if="!creating"
+          type="button"
+          class="btn small"
+          @click="cancelEditing"
+        >
+          {{ t('Cancel') }}
+        </button>
+        <button
+          type="button"
+          class="btn submit"
+          :class="{small: !creating}"
+          :disabled="draft.trim() === '' || mutating"
+          @click="saveComment"
+        >
+          {{ creating ? t('Comment') : t('Save') }}
+        </button>
+      </div>
+    </div>
+  </div>
+
+  <craft-card
+    v-else-if="event && comment && !comment.deleted"
+    class="activity-timeline__comment"
+    data-activity-comment
+  >
+    <div slot="label" class="activity-timeline__comment-heading">
+      <ActivityTimelineActor
+        :actor="event.actor"
+        :impersonator="event.impersonator"
+      />
+      <span
+        v-if="event?.description.html"
+        class="activity-timeline__comment-description"
+        v-html="event.description.html"
+      />
+      <span v-else class="activity-timeline__comment-description">
+        {{ sentenceFragment(event?.description.text ?? null) }}
+      </span>
+    </div>
+
+    <ActionMenu
+      v-if="commentActions.length"
+      slot="actions"
+      :actions="commentActions"
+      :label="t('Comment actions')"
+    />
+
+    <div class="activity-timeline__comment-body" v-html="comment.html" />
+
+    <p v-if="error" class="error" role="alert">
+      {{ t('Couldn’t update comment.') }}
+    </p>
+
+    <div v-if="event" slot="footer" class="activity-timeline__comment-footer">
+      <span v-if="comment.edited">{{ t('Edited') }}</span>
+      <time
+        :datetime="event.occurredAt"
+        :title="event.formattedOccurredAt.full"
+      >
+        {{ event.formattedOccurredAt.time }}
+      </time>
+    </div>
+  </craft-card>
+</template>
+
+<style scoped>
+  .activity-timeline__comment-description {
+    margin-inline-start: 0.25em;
+  }
+
+  .activity-timeline__comment-footer {
+    display: flex;
+    width: 100%;
+    color: var(--c-text-quiet);
+    font-size: var(--c-text-xs);
+  }
+
+  .activity-timeline__comment-footer time {
+    margin-inline-start: auto;
+    white-space: nowrap;
+  }
+
+  .activity-timeline__comment-actions {
+    display: flex;
+    align-items: center;
+    gap: var(--c-spacing-xs);
+  }
+
+  .activity-timeline__comment-body :deep(> :last-child),
+  .activity-timeline__comment .error {
+    margin: 0;
+  }
+
+  .activity-timeline__comment-editor craft-markdown-field {
+    contain: inline-size;
+    display: block;
+    width: 100%;
+  }
+
+  .activity-timeline__comment-editor .activity-timeline__comment-actions {
+    justify-content: flex-end;
+    margin-block-start: var(--c-spacing-xs);
+  }
+
+  .activity-timeline__comment-actions .error {
+    margin-inline-end: auto;
+  }
+</style>
diff --git a/resources/js/modules/activity/components/ActivityTimelineEvent.vue b/resources/js/modules/activity/components/ActivityTimelineEvent.vue
new file mode 100644
index 00000000000..731bef1ba75
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineEvent.vue
@@ -0,0 +1,152 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import type {ActivityEvent} from '@/modules/activity/composables/useActivityTimeline';
+  import ActivityTimelineActor from './ActivityTimelineActor.vue';
+  import ActivityTimelineChanges from './ActivityTimelineChanges.vue';
+  import ActivityTimelineComment from './ActivityTimelineComment.vue';
+
+  defineProps<{
+    event: ActivityEvent;
+    elementType: string;
+    elementId: number | null;
+    siteId: number | null;
+    last: boolean;
+  }>();
+
+  const emit = defineEmits<{
+    updated: [event: ActivityEvent];
+  }>();
+
+  function sentenceFragment(text: string | null): string {
+    return text === null
+      ? ''
+      : text.charAt(0).toLocaleLowerCase() + text.slice(1);
+  }
+</script>
+
+<template>
+  <article
+    :data-activity-event="event.id"
+    class="activity-timeline__event"
+    :class="{'activity-timeline__event--last': last}"
+  >
+    <span class="activity-timeline__marker" aria-hidden="true">
+      <craft-icon :name="event.icon ?? 'wave-pulse'" />
+    </span>
+
+    <div class="activity-timeline__content">
+      <div
+        v-if="!event.comment || event.comment.deleted"
+        class="activity-timeline__heading"
+      >
+        <div class="activity-timeline__summary">
+          <ActivityTimelineActor
+            :actor="event.actor"
+            :impersonator="event.impersonator"
+          />
+
+          <span
+            v-if="event.description.html"
+            class="activity-timeline__description"
+            v-html="event.description.html"
+          />
+          <span v-else class="activity-timeline__description">
+            {{ sentenceFragment(event.description.text) }}
+          </span>
+        </div>
+      </div>
+
+      <div
+        v-if="event.source.label !== 'Craft'"
+        class="activity-timeline__source"
+      >
+        {{ event.source.label }}
+      </div>
+
+      <ActivityTimelineComment
+        v-if="event.comment"
+        :event="event"
+        :element-type="elementType"
+        :element-id="elementId"
+        :site-id="siteId"
+        @updated="emit('updated', $event)"
+      />
+
+      <ActivityTimelineChanges
+        v-else-if="event.changes.length"
+        :changes="event.changes"
+      />
+
+      <div
+        v-if="!event.comment || event.comment.deleted"
+        class="activity-timeline__event-footer"
+      >
+        <time
+          :datetime="event.occurredAt"
+          :title="event.formattedOccurredAt.full"
+        >
+          {{ event.formattedOccurredAt.time }}
+        </time>
+      </div>
+    </div>
+  </article>
+</template>
+
+<style scoped>
+  .activity-timeline__event {
+    position: relative;
+    display: grid;
+    grid-template-columns: 1.75rem minmax(0, 1fr);
+    gap: var(--c-spacing-sm);
+    padding-block: var(--c-spacing-sm);
+  }
+
+  .activity-timeline__event::after {
+    position: absolute;
+    inset-block: 2.5rem 0;
+    inset-inline-start: 0.85rem;
+    width: 1px;
+    background: var(--c-color-neutral-border-quiet);
+    content: '';
+  }
+
+  .activity-timeline__event--last::after {
+    display: none;
+  }
+
+  .activity-timeline__marker {
+    z-index: 1;
+    display: grid;
+    width: 1.75rem;
+    height: 1.75rem;
+    place-items: center;
+    border: 1px solid var(--c-color-neutral-border-normal);
+    border-radius: 50%;
+    background: var(--c-color-neutral-fill-quiet);
+  }
+
+  .activity-timeline__content,
+  .activity-timeline__summary {
+    min-width: 0;
+  }
+
+  .activity-timeline__heading {
+    min-width: 0;
+  }
+
+  .activity-timeline__description {
+    margin-inline-start: 0.25em;
+  }
+
+  .activity-timeline__source,
+  .activity-timeline__event-footer {
+    color: var(--c-text-quiet);
+    font-size: var(--c-text-xs);
+  }
+
+  .activity-timeline__event-footer {
+    display: flex;
+    justify-content: flex-end;
+    margin-block-start: var(--c-spacing-xs);
+  }
+</style>
diff --git a/resources/js/modules/activity/composables/useActivityTimeline.ts b/resources/js/modules/activity/composables/useActivityTimeline.ts
new file mode 100644
index 00000000000..4bde8b8a003
--- /dev/null
+++ b/resources/js/modules/activity/composables/useActivityTimeline.ts
@@ -0,0 +1,163 @@
+import {actionClient} from '@craftcms/ui';
+import {computed, nextTick, ref, watch, type Ref} from 'vue';
+
+export interface ActivityTarget {
+  label: string;
+  url: string | null;
+  deleted: boolean;
+}
+
+export interface ActivityChange {
+  label: string;
+  old: unknown;
+  new: unknown;
+}
+
+export interface ActivityComment {
+  html: string | null;
+  markdown: string | null;
+  edited: boolean;
+  deleted: boolean;
+  canEdit: boolean;
+  canDelete: boolean;
+}
+
+export interface ActivityEvent {
+  id: string;
+  icon: string | null;
+  occurredAt: string;
+  formattedOccurredAt: {
+    date: string;
+    dateLabel: string;
+    time: string;
+    full: string;
+  };
+  actor: ActivityTarget;
+  impersonator: ActivityTarget | null;
+  source: {label: string};
+  description: {text: string | null; html: string | null};
+  changes: ActivityChange[];
+  comment?: ActivityComment | null;
+}
+
+interface ActivityTimelineResponse {
+  events: ActivityEvent[];
+}
+
+export interface ActivityTimelineProps {
+  active: boolean;
+  url: string;
+  elementType: string;
+  elementId: number | null;
+  siteId: number | null;
+  pageUrl?: string | null;
+  refreshToken?: number;
+}
+
+export function useActivityTimeline(
+  props: ActivityTimelineProps,
+  timeline: Ref<HTMLElement | null>
+) {
+  const events = ref<ActivityEvent[]>([]);
+  const status = ref<'idle' | 'loading' | 'loaded' | 'error'>('idle');
+
+  function requestData() {
+    return {
+      elementType: props.elementType,
+      elementId: props.elementId,
+      siteId: props.siteId,
+    };
+  }
+
+  async function load(): Promise<void> {
+    if (props.elementId === null) {
+      return;
+    }
+
+    const refreshing = status.value === 'loaded';
+
+    if (!refreshing) {
+      status.value = 'loading';
+    }
+
+    try {
+      const {data} = await actionClient.post<ActivityTimelineResponse>(
+        props.url,
+        requestData()
+      );
+
+      events.value = data.events;
+      status.value = 'loaded';
+      await scrollToEnd();
+    } catch {
+      if (!refreshing) {
+        status.value = 'error';
+      }
+    }
+  }
+
+  function addOrUpdateEvent(event: ActivityEvent): void {
+    const index = events.value.findIndex(({id}) => id === event.id);
+
+    if (index === -1) {
+      events.value.push(event);
+
+      return;
+    }
+
+    events.value[index] = event;
+  }
+
+  async function scrollToEnd(): Promise<void> {
+    await nextTick();
+
+    if (timeline.value !== null) {
+      timeline.value.scrollTop = timeline.value.scrollHeight;
+    }
+  }
+
+  watch(
+    () => props.active,
+    (active) => {
+      if (active && status.value === 'idle') {
+        void load();
+      }
+    },
+    {immediate: true}
+  );
+
+  watch(
+    () => props.refreshToken,
+    () => {
+      if (status.value === 'loaded') {
+        void load();
+      }
+    }
+  );
+
+  const dayGroups = computed(() => {
+    const groups = new Map<string, {label: string; events: ActivityEvent[]}>();
+
+    for (const event of events.value) {
+      const key = event.formattedOccurredAt.date;
+      const group = groups.get(key) ?? {
+        label: event.formattedOccurredAt.dateLabel,
+        events: [],
+      };
+
+      group.events.push(event);
+      groups.set(key, group);
+    }
+
+    return [...groups.entries()].map(([key, group]) => ({key, ...group}));
+  });
+
+  return {
+    addOrUpdateEvent,
+    dayGroups,
+    events,
+    load,
+    scrollToEnd,
+    status,
+  };
+}
diff --git a/resources/js/modules/elements/components/ElementChips.vue b/resources/js/modules/elements/components/ElementChips.vue
index fd2afa51a46..ed471e98935 100644
--- a/resources/js/modules/elements/components/ElementChips.vue
+++ b/resources/js/modules/elements/components/ElementChips.vue
@@ -233,6 +233,9 @@
 
 <style scoped lang="scss">
   .element-chips {
+    margin: 0;
+    padding: 0;
+    list-style: none;
     display: grid;
     gap: var(--c-spacing-xs);
     align-items: start;
diff --git a/resources/js/modules/elements/components/ElementDetailsTabs.vue b/resources/js/modules/elements/components/ElementDetailsTabs.vue
new file mode 100644
index 00000000000..79ef51e47b9
--- /dev/null
+++ b/resources/js/modules/elements/components/ElementDetailsTabs.vue
@@ -0,0 +1,113 @@
+<script setup lang="ts">
+  import {t} from '@craftcms/ui';
+  import {ref} from 'vue';
+  import ActivityTimeline from '@/modules/activity/components/ActivityTimeline.vue';
+  import RevisionsList from '@/modules/elements/components/RevisionsList.vue';
+  import type {ElementEditPayload} from '@/modules/elements/composables/useElementEditor';
+
+  defineProps<{
+    payload: ElementEditPayload;
+    activityTimelineVersion: number;
+    pane?: boolean;
+  }>();
+
+  const activityTabOpen = ref(false);
+
+  function onSelectedChanged(event: Event): void {
+    activityTabOpen.value =
+      (event.target as {selectedIndex?: number} | null)?.selectedIndex === 1;
+  }
+</script>
+
+<template>
+  <craft-tabs
+    size="small"
+    placement="inline-end"
+    collapsible
+    @selected-changed="onSelectedChanged"
+  >
+    <craft-tab slot="tab">
+      <craft-icon name="circle-info" :label="t('Info')" />
+    </craft-tab>
+    <div slot="panel">
+      <slot name="info" />
+    </div>
+
+    <craft-tab v-if="payload.activityTimelineUrl" slot="tab">
+      <craft-icon name="wave-pulse" :label="t('Activity')" />
+    </craft-tab>
+    <div v-if="payload.activityTimelineUrl" slot="panel">
+      <component
+        :is="pane ? 'craft-pane' : 'div'"
+        :appearance="pane ? 'plain' : undefined"
+      >
+        <div
+          v-if="pane"
+          slot="header"
+          class="px-2 py-1 border-b border-b-(--c-color-neutral-border-quiet)"
+        >
+          <h3 slot="title" class="text-xs/4">{{ t('Activity') }}</h3>
+        </div>
+        <ActivityTimeline
+          :active="activityTabOpen"
+          :url="payload.activityTimelineUrl"
+          :element-type="payload.elementType"
+          :element-id="payload.canonicalId"
+          :site-id="payload.siteId"
+          :page-url="payload.activityPageUrl"
+          :refresh-token="activityTimelineVersion"
+        />
+      </component>
+    </div>
+
+    <craft-tab slot="tab">
+      <craft-icon name="clock-rotate-left" :label="t('Revisions')" />
+    </craft-tab>
+    <div slot="panel">
+      <component
+        :is="pane ? 'craft-pane' : 'div'"
+        :appearance="pane ? 'plain' : undefined"
+      >
+        <div
+          v-if="pane"
+          slot="header"
+          class="px-2 py-1 border-b border-b-(--c-color-neutral-border-quiet)"
+        >
+          <h3 slot="title" class="text-xs/4">{{ t('Revisions') }}</h3>
+        </div>
+        <RevisionsList :items="payload.contextMenu?.items ?? []" />
+      </component>
+    </div>
+  </craft-tabs>
+</template>
+
+<style scoped>
+  craft-tabs::part(base) {
+    gap: var(--c-spacing-sm);
+  }
+
+  craft-tabs::part(strip) {
+    border: 0;
+  }
+
+  craft-tab {
+    display: grid;
+    width: var(--c-size-touch-target);
+    padding: 0;
+    place-items: center;
+    border: 1px solid transparent;
+    border-radius: var(--c-radius-md);
+    aspect-ratio: 1;
+    background-color: white;
+  }
+
+  craft-tab[selected='true'] {
+    border-color: var(--c-color-neutral-border-normal);
+    background-color: var(--c-color-neutral-fill-normal);
+    color: var(--c-color-neutral-on-normal);
+
+    &::after {
+      display: none;
+    }
+  }
+</style>
diff --git a/resources/js/modules/elements/components/ElementEditScreen.vue b/resources/js/modules/elements/components/ElementEditScreen.vue
index 2403c33cec5..a600e4750e2 100644
--- a/resources/js/modules/elements/components/ElementEditScreen.vue
+++ b/resources/js/modules/elements/components/ElementEditScreen.vue
@@ -16,8 +16,8 @@
   import FormRenderer from '@/modules/forms/FormRenderer.vue';
   import {useElementEditor} from '@/modules/elements/composables/useElementEditor';
   import {useElementActionMenu} from '@/modules/elements/composables/useElementActionMenu';
-  import RevisionsList from '@/modules/elements/components/RevisionsList.vue';
   import AutosaveMessage from '@/modules/elements/components/AutosaveMessage.vue';
+  import ElementDetailsTabs from '@/modules/elements/components/ElementDetailsTabs.vue';
   import type {FormValues} from '@/modules/forms/types';
 
   const props = defineProps<{
@@ -37,6 +37,7 @@
 
   const {
     activity,
+    activityTimelineVersion,
     autosave,
     discardDraft,
     errors,
@@ -99,7 +100,10 @@
   ]);
 
   const hasDetails = computed(
-    () => Boolean(sidebarPayload.value) || Boolean(payload.metadataHtml)
+    () =>
+      Boolean(sidebarPayload.value) ||
+      Boolean(payload.metadataHtml) ||
+      Boolean(payload.activityTimelineUrl)
   );
 
   // Mirrors the legacy wording: a changed draft names the draft, anything else
@@ -280,15 +284,13 @@
               v-if="hasDetails || $slots['details-header']"
               class="element-editor__details"
             >
-              <craft-tabs size="small" placement="inline-end" collapsible>
-                <craft-tab slot="tab">
-                  <craft-icon
-                    name="circle-info"
-                    :label="t('Info')"
-                  ></craft-icon>
-                </craft-tab>
-                <div slot="panel">
-                  <craft-pane appearance="plain">
+              <ElementDetailsTabs
+                :payload="payload"
+                :activity-timeline-version="activityTimelineVersion"
+                pane
+              >
+                <template #info>
+                  <craft-pane appearance="plain" padding="none">
                     <div
                       slot="header"
                       class="px-2 py-1 border-b border-b-(--c-color-neutral-border-quiet)"
@@ -319,48 +321,8 @@
                       </div>
                     </div>
                   </craft-pane>
-                </div>
-
-                <craft-tab slot="tab" id="tab-1">
-                  <craft-icon
-                    name="wave-pulse"
-                    :label="t('Activity')"
-                  ></craft-icon>
-                </craft-tab>
-                <div slot="panel">
-                  <craft-pane appearance="plain">
-                    <div
-                      slot="header"
-                      class="px-2 py-1 border-b border-b-(--c-color-neutral-border-quiet)"
-                    >
-                      <h3 slot="title" class="text-xs/4">
-                        {{ t('Activity') }}
-                      </h3>
-                    </div>
-                    @TODO
-                  </craft-pane>
-                </div>
-
-                <craft-tab slot="tab">
-                  <craft-icon
-                    name="clock-rotate-left"
-                    :label="t('Revisions')"
-                  ></craft-icon>
-                </craft-tab>
-                <div slot="panel">
-                  <craft-pane appearance="plain">
-                    <div
-                      slot="header"
-                      class="px-2 py-1 border-b border-b-(--c-color-neutral-border-quiet)"
-                    >
-                      <h3 slot="title" class="text-xs/4">
-                        {{ t('Revisions') }}
-                      </h3>
-                    </div>
-                    <RevisionsList :items="payload.contextMenu?.items ?? []" />
-                  </craft-pane>
-                </div>
-              </craft-tabs>
+                </template>
+              </ElementDetailsTabs>
             </div>
           </div>
         </form>
@@ -458,33 +420,4 @@
       align-items: start;
     }
   }
-
-  craft-tabs::part(base) {
-    gap: var(--c-spacing-sm);
-  }
-
-  craft-tabs::part(strip) {
-    border: 0;
-  }
-
-  craft-tab {
-    padding: 0;
-    width: var(--c-size-touch-target);
-    background-color: white;
-    aspect-ratio: 1;
-    display: grid;
-    place-items: center;
-    border-radius: var(--c-radius-md);
-    border: 1px solid transparent;
-  }
-
-  craft-tab[selected='true'] {
-    background-color: var(--c-color-neutral-fill-normal);
-    border-color: var(--c-color-neutral-border-normal);
-    color: var(--c-color-neutral-on-normal);
-
-    &:after {
-      display: none;
-    }
-  }
 </style>
diff --git a/resources/js/modules/elements/components/ElementEditor.vue b/resources/js/modules/elements/components/ElementEditor.vue
index eb6589a0cae..c402fe91401 100644
--- a/resources/js/modules/elements/components/ElementEditor.vue
+++ b/resources/js/modules/elements/components/ElementEditor.vue
@@ -16,6 +16,7 @@
   import {useElementEditor} from '@/modules/elements/composables/useElementEditor';
   import {useElementActionMenu} from '@/modules/elements/composables/useElementActionMenu';
   import type {FormValues} from '@/modules/forms/types';
+  import ElementDetailsTabs from '@/modules/elements/components/ElementDetailsTabs.vue';
 
   const props = defineProps<{
     /**
@@ -27,6 +28,7 @@
 
   const {
     activity,
+    activityTimelineVersion,
     autosave,
     discardDraft,
     errors,
@@ -262,29 +264,41 @@
   <slot :payload="payload" />
 
   <LayoutSlot
-    v-if="sidebarPayload || payload.metadataHtml || $slots['details-header']"
+    v-if="
+      sidebarPayload ||
+      payload.metadataHtml ||
+      payload.activityTimelineUrl ||
+      $slots['details-header']
+    "
     name="details"
   >
-    <!-- Anything the element type shows above its meta fields, e.g. an
-      asset's file preview. -->
-    <slot name="details-header" :payload="payload" />
+    <ElementDetailsTabs
+      :payload="payload"
+      :activity-timeline-version="activityTimelineVersion"
+    >
+      <template #info>
+        <!-- Anything the element type shows above its meta fields, e.g. an
+          asset's file preview. -->
+        <slot name="details-header" :payload="payload" />
 
-    <!--
-      The meta fields render as their own Form, bridged into the same Inertia
-      form as the field layout above, so they submit as ordinary inputs.
-    -->
-    <FormRenderer
-      v-if="sidebarPayload"
-      ref="sidebarRenderer"
-      :payload="sidebarPayload"
-      :errors="sidebarErrors"
-      :modified="autosave.modified.value"
-      @update:mutation="onSidebarMutation"
-    />
+        <!--
+          The meta fields render as their own Form, bridged into the same Inertia
+          form as the field layout above, so they submit as ordinary inputs.
+        -->
+        <FormRenderer
+          v-if="sidebarPayload"
+          ref="sidebarRenderer"
+          :payload="sidebarPayload"
+          :errors="sidebarErrors"
+          :modified="autosave.modified.value"
+          @update:mutation="onSidebarMutation"
+        />
 
-    <DynamicHtmlRenderer
-      v-if="payload.metadataHtml"
-      :html="payload.metadataHtml"
-    />
+        <DynamicHtmlRenderer
+          v-if="payload.metadataHtml"
+          :html="payload.metadataHtml"
+        />
+      </template>
+    </ElementDetailsTabs>
   </LayoutSlot>
 </template>
diff --git a/resources/js/modules/elements/composables/useElementAutosave.ts b/resources/js/modules/elements/composables/useElementAutosave.ts
index 8c730a9fd98..10c0bd4d240 100644
--- a/resources/js/modules/elements/composables/useElementAutosave.ts
+++ b/resources/js/modules/elements/composables/useElementAutosave.ts
@@ -198,7 +198,6 @@ export function useElementAutosave<T extends object>(
 
   // Re-armed per call, so a pending save always waits out the newest change.
   const delay = ref(delays.discrete);
-
   // `useDebounceFn` hands back no reference to the timer it arms, so there is
   // nothing to clear when a save is called off mid-debounce. The callback is
   // gated instead: `cancel()` disarms it and the timer fires into a no-op.
diff --git a/resources/js/modules/elements/composables/useElementEditor.test.ts b/resources/js/modules/elements/composables/useElementEditor.test.ts
index 47a35765319..3d4425d6aa1 100644
--- a/resources/js/modules/elements/composables/useElementEditor.test.ts
+++ b/resources/js/modules/elements/composables/useElementEditor.test.ts
@@ -47,21 +47,36 @@ function payload(
     canonicalId: 12,
     elementType: 'craft\\elements\\Entry',
     siteId: 1,
+    fieldLayoutId: undefined,
+    title: undefined,
+    docTitle: undefined,
+    crumbs: undefined,
+    readOnly: undefined,
     draftId: null,
     isProvisionalDraft: false,
     canAutosave: false,
     form: null,
     sidebarForm: null,
+    metadataHtml: undefined,
+    statusLabelHtml: undefined,
     saveUrl: '/actions/entries/save-entry',
     applyDraftUrl: '/actions/elements/apply-draft',
     autosaveUrl: '/actions/elements/save-draft',
     discardDraftUrl: '/actions/elements/delete-draft',
+    notice: undefined,
+    mergeNotice: undefined,
+    canDiscardDraft: undefined,
+    submitButtonLabel: undefined,
     activityUrl: null,
+    activityTimelineUrl: undefined,
+    activityPageUrl: undefined,
     updatedTimestamps: {element: 1, canonical: 1},
     formActions: [],
     headerActions: [],
     actionMenu: [],
     previewTargets: [],
+    elementDisplayName: undefined,
+    contextMenu: undefined,
     ...overrides,
   };
 }
diff --git a/resources/js/modules/elements/composables/useElementEditor.ts b/resources/js/modules/elements/composables/useElementEditor.ts
index 5272486b8d6..2261ea5ff8f 100644
--- a/resources/js/modules/elements/composables/useElementEditor.ts
+++ b/resources/js/modules/elements/composables/useElementEditor.ts
@@ -87,6 +87,8 @@ export interface ElementEditPayload {
   previewTargets: Array<{label: string; url: string}>;
   elementDisplayName: string;
   activityUrl: string | null;
+  activityTimelineUrl: string | null;
+  activityPageUrl: string | null;
   updatedTimestamps: {element: number | null; canonical: number | null};
   contextMenu: {
     label: string;
@@ -316,6 +318,7 @@ export function useElementEditor({saveData}: Options = {}) {
   // so the shared save pipeline (elevated sessions, error handling, the
   // processing flag) is reused rather than reimplemented per action.
   const pendingAction = ref<ElementFormAction | null>(null);
+  const activityTimelineVersion = ref(0);
 
   const {save} = useSettingsSave(
     form,
@@ -372,9 +375,13 @@ export function useElementEditor({saveData}: Options = {}) {
         // applying a provisional draft deletes the draft it would write them to.
         autosave.cancel();
 
-        // The save itself moved the element's `dateUpdated`; without this the
-        // next poll would report our own write as someone else's change.
-        activity.rebase(props.updatedTimestamps);
+        if (!slideout) {
+          // The save itself moved the element's `dateUpdated`; without this the
+          // next poll would report our own write as someone else's change.
+          activity.rebase(props.updatedTimestamps);
+        }
+
+        activityTimelineVersion.value++;
       },
     }
   );
@@ -520,6 +527,7 @@ export function useElementEditor({saveData}: Options = {}) {
 
   return {
     activity,
+    activityTimelineVersion,
     autosave,
     discardDraft,
     submitAction,
diff --git a/resources/js/modules/forms/MarkdownControl.vue b/resources/js/modules/forms/MarkdownControl.vue
index 726545a2c97..0c6d8f7d80a 100644
--- a/resources/js/modules/forms/MarkdownControl.vue
+++ b/resources/js/modules/forms/MarkdownControl.vue
@@ -26,14 +26,6 @@
   const emit = defineEmits<{
     (event: 'update:value', value: string, kind: 'typing'): void;
   }>();
-
-  function onInput(event: Event): void {
-    if (!(event.target instanceof HTMLTextAreaElement)) {
-      throw new TypeError('Expected a textarea event target.');
-    }
-
-    emit('update:value', event.target.value, 'typing');
-  }
 </script>
 
 <template>
@@ -51,7 +43,13 @@
     :required="editable && required"
     :aria-invalid="invalid ? 'true' : undefined"
     .value="value ?? ''"
-    @input="onInput"
+    @input="
+      emit(
+        'update:value',
+        ($event.target as HTMLTextAreaElement).value,
+        'typing'
+      )
+    "
   />
   <craft-text-expander
     v-if="editable && control.props.textExpanderTriggers"
diff --git a/resources/js/modules/settings/composables/useSettingsSave.ts b/resources/js/modules/settings/composables/useSettingsSave.ts
index a882583389c..86ad137fd3a 100644
--- a/resources/js/modules/settings/composables/useSettingsSave.ts
+++ b/resources/js/modules/settings/composables/useSettingsSave.ts
@@ -130,6 +130,7 @@ export function useSettingsSave<T extends object>(
         });
 
         form.processing = false;
+        options.onSuccess?.();
 
         // An opener that registered `onSaved` refreshes itself, and knows
         // better than we do what actually needs refreshing. Before the close:
diff --git a/resources/js/pages/content/Activity.vue b/resources/js/pages/content/Activity.vue
new file mode 100644
index 00000000000..c6c22bab440
--- /dev/null
+++ b/resources/js/pages/content/Activity.vue
@@ -0,0 +1,22 @@
+<script setup lang="ts">
+  import ActivityTimeline from '@/modules/activity/components/ActivityTimeline.vue';
+
+  defineProps<{
+    activityTimelineUrl: string;
+    elementType: string;
+    elementId: number;
+    siteId: number | null;
+  }>();
+</script>
+
+<template>
+  <craft-pane appearance="raised" padding="none">
+    <ActivityTimeline
+      active
+      :url="activityTimelineUrl"
+      :element-type="elementType"
+      :element-id="elementId"
+      :site-id="siteId"
+    />
+  </craft-pane>
+</template>
diff --git a/routes/actions.php b/routes/actions.php
index ef28b476f23..c7fdc5b3da8 100644
--- a/routes/actions.php
+++ b/routes/actions.php
@@ -32,6 +32,9 @@
 use CraftCms\Cms\Http\Controllers\Dashboard\Widgets\NewUsersController;
 use CraftCms\Cms\Http\Controllers\Dashboard\WidgetsController;
 use CraftCms\Cms\Http\Controllers\EditionController;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityCommentsController;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityMentionSuggestionsController;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityTimelineController;
 use CraftCms\Cms\Http\Controllers\Elements\CopyElementValuesController;
 use CraftCms\Cms\Http\Controllers\Elements\CreateElementController;
 use CraftCms\Cms\Http\Controllers\Elements\DeleteElementController;
@@ -242,6 +245,13 @@
         Route::post('elements/delete-draft', [ElementDraftsController::class, 'destroy']);
         Route::post('elements/revert', [ElementRevisionsController::class, 'revert']);
         Route::post('elements/validate', ValidateElementController::class);
+        Route::post('elements/activity', ActivityTimelineController::class);
+        Route::middleware('throttle:60,1')->group(function () {
+            Route::post('elements/activity/comments', [ActivityCommentsController::class, 'store']);
+            Route::patch('elements/activity/comments', [ActivityCommentsController::class, 'update']);
+            Route::delete('elements/activity/comments', [ActivityCommentsController::class, 'destroy']);
+        });
+        Route::get('elements/activity/mentions', ActivityMentionSuggestionsController::class)->middleware('throttle:120,1');
         Route::post('elements/recent-activity', ElementActivityController::class);
         Route::post('elements/update-field-layout', UpdateFieldLayoutController::class);
         Route::post('elements/duplicate', [DuplicateElementController::class, 'duplicate']);
diff --git a/routes/cp.php b/routes/cp.php
index d410e6593de..3e602d59cd0 100644
--- a/routes/cp.php
+++ b/routes/cp.php
@@ -16,6 +16,7 @@
 use CraftCms\Cms\Http\Controllers\ContentIndexController;
 use CraftCms\Cms\Http\Controllers\Dashboard\DashboardController;
 use CraftCms\Cms\Http\Controllers\Elements\EditElementController;
+use CraftCms\Cms\Http\Controllers\Elements\ElementActivityController;
 use CraftCms\Cms\Http\Controllers\Elements\ElementRedirectController;
 use CraftCms\Cms\Http\Controllers\Elements\ElementRevisionsController;
 use CraftCms\Cms\Http\Controllers\Elements\PreviewElementController;
@@ -188,6 +189,11 @@
         ...$idSlugParams,
         'page' => '[^\/]+',
     ]);
+    Route::get('entries/{section}/{id}{slug?}/activity', [ElementActivityController::class, 'index'])->where($idSlugParams);
+    Route::get('content/{page}/{section}/{id}{slug?}/activity', [ElementActivityController::class, 'index'])->where([
+        ...$idSlugParams,
+        'page' => '[^\/]+',
+    ]);
     Route::get('assets/edit/{id}{slug}', EditAssetController::class)->where($idSlugParams);
     Route::get('entries/{section}/{id}{slug?}', EditEntryController::class)->where($idSlugParams);
     Route::get('content/{page}/{section}/{id}{slug?}', EditEntryController::class)->where([
diff --git a/src/Activity/ActivityComments.php b/src/Activity/ActivityComments.php
index 89ec0bdfaf8..cb1ce2b6ef8 100644
--- a/src/Activity/ActivityComments.php
+++ b/src/Activity/ActivityComments.php
@@ -86,17 +86,19 @@ public function canMention(User $user, ElementInterface $subject): bool
             && Gate::forUser($user)->allows('view', $subject);
     }
 
-    public function render(ActivityEvent $version, User $viewer): HtmlString
-    {
+    /**
+     * @param  Collection<int|string, User>|null  $mentionedUsers
+     */
+    public function render(
+        ActivityEvent $version,
+        User $viewer,
+        ?Collection $mentionedUsers = null,
+    ): HtmlString {
         $mentions = $this->mentions($version);
-        $users = User::find()
-            ->id($mentions->keys()->all())
-            ->status(null)
-            ->collect()
-            ->keyBy('id');
+        $mentionedUsers ??= $this->mentionedUsers(collect([$version]));
         $html = $this->markdown->transform(
             $version->data['markdown'],
-            function (Document $document) use ($mentions, $users, $viewer): void {
+            function (Document $document) use ($mentions, $mentionedUsers, $viewer): void {
                 foreach ($this->mentionNodes($document) as $node) {
                     $reference = $node->getIdentifier();
                     $mention = ctype_digit($reference) ? $mentions->get((int) $reference) : null;
@@ -108,7 +110,7 @@ function (Document $document) use ($mentions, $users, $viewer): void {
                     }
 
                     $id = (int) $reference;
-                    $user = $users->get($id);
+                    $user = $mentionedUsers->get($id);
                     $canView = $user !== null && Gate::forUser($viewer)->allows('view', $user);
                     $username = $canView ? ($user->username ?? $mention['username']) : $mention['username'];
 
@@ -123,6 +125,31 @@ function (Document $document) use ($mentions, $users, $viewer): void {
         return new HtmlString($this->htmlSanitizers->sanitize($html));
     }
 
+    /**
+     * @param  Collection<array-key, ActivityEvent>  $versions
+     * @return Collection<int|string, User>
+     */
+    public function mentionedUsers(Collection $versions): Collection
+    {
+        $ids = $versions
+            ->filter(fn (ActivityEvent $version): bool => $version->eventType !== CommentDeleted::class
+                && is_a($version->eventType, CommentEvent::class, true))
+            ->flatMap(fn (ActivityEvent $version): Collection => $this->mentions($version)->keys())
+            ->unique()
+            ->values()
+            ->all();
+
+        if ($ids === []) {
+            return collect();
+        }
+
+        return User::find()
+            ->id($ids)
+            ->status(null)
+            ->collect()
+            ->keyBy('id');
+    }
+
     public function notificationText(ActivityEvent $version, User $viewer): string
     {
         $html = $this->render($version, $viewer)->toHtml();
diff --git a/src/Activity/ActivityTimelinePresenter.php b/src/Activity/ActivityTimelinePresenter.php
new file mode 100644
index 00000000000..c7b0abcc86c
--- /dev/null
+++ b/src/Activity/ActivityTimelinePresenter.php
@@ -0,0 +1,174 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Activity;
+
+use CraftCms\Cms\Activity\Data\ActivityActor;
+use CraftCms\Cms\Activity\EventTypes\CommentCreated;
+use CraftCms\Cms\Activity\EventTypes\CommentDeleted;
+use CraftCms\Cms\Activity\EventTypes\CommentEdited;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
+use CraftCms\Cms\Support\Facades\I18N;
+use CraftCms\Cms\Translation\Formatter;
+use CraftCms\Cms\Translation\Locale;
+use CraftCms\Cms\User\Elements\User;
+use Illuminate\Contracts\Support\Htmlable;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Facades\Gate;
+
+class ActivityTimelinePresenter
+{
+    public function __construct(
+        private readonly Activities $activities,
+        private readonly ActivityComments $comments,
+    ) {}
+
+    /**
+     * @template TKey of array-key
+     *
+     * @param  Collection<int, ActivityEvent>  $events
+     * @param  Collection<TKey, ActivityEvent>|null  $selectedVersions
+     * @return Collection<int, array<string, mixed>>
+     */
+    public function events(
+        Collection $events,
+        User $viewer,
+        ?Collection $selectedVersions = null,
+    ): Collection {
+        $selectedVersions ??= $this->latestVersions($events);
+        $versions = $events->mapWithKeys(fn (ActivityEvent $event): array => [
+            $event->id => $selectedVersions->get($event->id, $event),
+        ]);
+        $actors = $this->actors($versions);
+        $mentionedUsers = $this->comments->mentionedUsers($versions);
+        $formatter = I18N::getFormatter();
+
+        return $events->map(fn (ActivityEvent $root): array => $this->event(
+            $root,
+            $versions->get($root->id),
+            $viewer,
+            $actors,
+            $mentionedUsers,
+            $formatter,
+        ));
+    }
+
+    /**
+     * @param  Collection<int, ActivityEvent>  $events
+     * @return Collection<string, ActivityEvent>
+     */
+    private function latestVersions(Collection $events): Collection
+    {
+        $commentIds = $events
+            ->where('eventType', CommentCreated::class)
+            ->pluck('id');
+
+        if ($commentIds->isEmpty()) {
+            return collect();
+        }
+
+        return ActivityEvent::query()
+            ->whereIn('rootEventId', $commentIds)
+            ->newestFirst()
+            ->groupLimit(1, 'rootEventId')
+            ->get()
+            ->keyBy('rootEventId');
+    }
+
+    /**
+     * @param  Collection<array-key, ActivityEvent>  $events
+     * @return Collection<int|string, User>
+     */
+    private function actors(Collection $events): Collection
+    {
+        $ids = $events
+            ->flatMap(fn (ActivityEvent $event): array => [
+                $event->actorType === ActivityActor::TYPE_USER ? $event->actorId : null,
+                $event->snapshots['impersonator']['id'] ?? null,
+            ])
+            ->filter()
+            ->unique()
+            ->values()
+            ->all();
+
+        if ($ids === []) {
+            return collect();
+        }
+
+        return User::find()
+            ->id($ids)
+            ->status(null)
+            ->collect()
+            ->keyBy('id');
+    }
+
+    /**
+     * @param  Collection<int|string, User>  $actors
+     * @param  Collection<int|string, User>  $mentionedUsers
+     * @return array<string, mixed>
+     */
+    private function event(
+        ActivityEvent $root,
+        ActivityEvent $event,
+        User $viewer,
+        Collection $actors,
+        Collection $mentionedUsers,
+        Formatter $formatter,
+    ): array {
+        $actor = $event->actorType === ActivityActor::TYPE_USER && $event->actorId !== null
+            ? $actors->get($event->actorId)
+            : null;
+        $impersonatorSnapshot = $event->snapshots['impersonator'] ?? null;
+        $impersonator = $impersonatorSnapshot === null
+            ? null
+            : $actors->get($impersonatorSnapshot['id']);
+        $isComment = $root->eventType === CommentCreated::class;
+        $formatted = $this->activities->format($event);
+        $deleted = $isComment && $event->eventType === CommentDeleted::class;
+        $canEdit = $isComment && ! $deleted && $root->actorId === $viewer->id;
+        $occurredAt = $root->occurredAt->setTimezone($formatter->timeZone);
+
+        return [
+            'id' => $root->id,
+            'icon' => $this->activities->icon($event),
+            'occurredAt' => $root->occurredAt->toIso8601String(),
+            'formattedOccurredAt' => [
+                'date' => $occurredAt->toDateString(),
+                'dateLabel' => $formatter->asDate($occurredAt, Locale::LENGTH_MEDIUM),
+                'time' => $formatter->asTime($occurredAt, Locale::LENGTH_SHORT),
+                'full' => $formatter->asDateTime($occurredAt, Locale::LENGTH_LONG, true),
+            ],
+            'actor' => [
+                'label' => $event->snapshots['actor']['label'],
+                'url' => $actor && Gate::forUser($viewer)->allows('view', $actor) ? $actor->getCpEditUrl() : null,
+                'deleted' => $event->actorType === ActivityActor::TYPE_USER
+                    && $event->actorId !== null
+                    && $actor === null,
+            ],
+            'impersonator' => $impersonatorSnapshot === null ? null : [
+                'label' => $impersonatorSnapshot['label'],
+                'url' => $impersonator && Gate::forUser($viewer)->allows('view', $impersonator)
+                    ? $impersonator->getCpEditUrl()
+                    : null,
+                'deleted' => $impersonator === null,
+            ],
+            'source' => [
+                'label' => $event->snapshots['source']['label'],
+            ],
+            'description' => [
+                'text' => $formatted instanceof Htmlable ? null : $formatted,
+                'html' => $formatted instanceof Htmlable ? $formatted->toHtml() : null,
+            ],
+            'changes' => $event->changes,
+            'comment' => $isComment ? [
+                'html' => $deleted ? null : $this->comments->render($event, $viewer, $mentionedUsers)->toHtml(),
+                'markdown' => $canEdit ? $event->data['markdown'] : null,
+                'edited' => $event->eventType === CommentEdited::class,
+                'deleted' => $deleted,
+                'canEdit' => $canEdit,
+                'canDelete' => ! $deleted && ($root->actorId === $viewer->id || $viewer->admin),
+            ] : null,
+        ];
+    }
+}
diff --git a/src/Activity/DraftActivity.php b/src/Activity/DraftActivity.php
index a9c591dc2bd..a6e501f5217 100644
--- a/src/Activity/DraftActivity.php
+++ b/src/Activity/DraftActivity.php
@@ -130,13 +130,23 @@ public function subscribe(): array
     /**
      * @param  string[]  $dirtyAttributes
      * @param  string[]  $dirtyFields
+     * @param  array<string, mixed>|null  $moveOrigin
      */
     public function recordProvisionalApplied(
         Entry $entry,
         Entry $original,
         array $dirtyAttributes,
         array $dirtyFields,
+        ?array $moveOrigin,
     ): void {
+        if ($moveOrigin !== null) {
+            StructuralElementActivity::recordMoved(
+                $entry,
+                $moveOrigin,
+                StructuralElementActivity::position($moveOrigin['structure'], $entry),
+            );
+        }
+
         EntryActivity::recordUpdated($entry, $original, $dirtyAttributes, $dirtyFields);
     }
 }
diff --git a/src/Activity/ElementWriteActivity.php b/src/Activity/ElementWriteActivity.php
index af00a055ebd..2bcd431a63d 100644
--- a/src/Activity/ElementWriteActivity.php
+++ b/src/Activity/ElementWriteActivity.php
@@ -22,7 +22,7 @@
     /** @var WeakMap<ElementInterface, bool> */
     private WeakMap $writes;
 
-    /** @var WeakMap<ElementInterface, Entry> */
+    /** @var WeakMap<ElementInterface, array{entry: Entry, authorChanged: bool}> */
     private WeakMap $originalEntries;
 
     /** @var WeakMap<ElementInterface, Asset> */
@@ -59,7 +59,10 @@ public function handleElementSaving(ElementSaving $event): void
             $original = EntryActivity::original($element);
 
             if ($original !== null) {
-                $this->originalEntries[$element] = $original;
+                $this->originalEntries[$element] = [
+                    'entry' => $original,
+                    'authorChanged' => $element->getAuthorIds() !== $original->getAuthorIds(),
+                ];
             }
         }
 
@@ -99,9 +102,10 @@ public function handleElementSaved(ElementSaved $event): void
             } elseif ($originalEntry !== null) {
                 EntryActivity::recordUpdated(
                     $element,
-                    $originalEntry,
+                    $originalEntry['entry'],
                     $element->getDirtyAttributes(),
                     $element->getDirtyFields(),
+                    $originalEntry['authorChanged'],
                 );
             }
         }
diff --git a/src/Activity/EntryActivity.php b/src/Activity/EntryActivity.php
index e5219aa91e7..c317ce9a2ae 100644
--- a/src/Activity/EntryActivity.php
+++ b/src/Activity/EntryActivity.php
@@ -9,9 +9,12 @@
 use CraftCms\Cms\Activity\EventTypes\ElementCreated;
 use CraftCms\Cms\Activity\EventTypes\ElementStatusChanged;
 use CraftCms\Cms\Activity\EventTypes\ElementUpdated;
+use CraftCms\Cms\Element\Contracts\ElementInterface;
 use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Field\BaseRelationField;
 use CraftCms\Cms\Support\Facades\Activities;
 use CraftCms\Cms\Support\Facades\Sites;
+use CraftCms\Cms\User\Elements\User;
 use DateTimeInterface;
 
 use function CraftCms\Cms\t;
@@ -61,7 +64,12 @@ public static function recordUpdated(
         Entry $original,
         array $dirtyAttributes,
         array $dirtyFields,
+        bool $authorChanged = true,
     ): void {
+        if (! $authorChanged) {
+            $dirtyAttributes = array_values(array_diff($dirtyAttributes, ['authorIds']));
+        }
+
         [$changes, $contentChanged] = self::changes($entry, $original, $dirtyAttributes, $dirtyFields);
         $oldStatus = $original->getStatus();
         $newStatus = $entry->getStatus();
@@ -103,8 +111,9 @@ private static function changes(
                 continue;
             }
 
-            $old = self::attributeValue($original, $attribute);
-            $new = self::attributeValue($entry, $attribute);
+            [$old, $new] = $attribute === 'authorIds'
+                ? self::authorValues($entry, $original)
+                : [self::attributeValue($original, $attribute), self::attributeValue($entry, $attribute)];
             self::appendChange($changes, $contentChanged, t($label), $old, $new);
         }
 
@@ -113,8 +122,14 @@ private static function changes(
                 continue;
             }
 
-            $old = $field->serializeValue($original->getFieldValue($field->handle), $original);
-            $new = $field->serializeValue($entry->getFieldValue($field->handle), $entry);
+            if ($field instanceof BaseRelationField) {
+                $old = self::elementValues($original->getFieldValue($field->handle)->all());
+                $new = self::elementValues($entry->getFieldValue($field->handle)->all());
+            } else {
+                $old = $field->serializeValue($original->getFieldValue($field->handle), $original);
+                $new = $field->serializeValue($entry->getFieldValue($field->handle), $entry);
+            }
+
             self::appendChange(
                 $changes,
                 $contentChanged,
@@ -159,11 +174,40 @@ private static function attributeValue(Entry $entry, string $attribute): mixed
     {
         return match ($attribute) {
             'enabledForSite' => $entry->getEnabledForSite(),
-            'authorIds' => $entry->getAuthorIds(),
             default => $entry->{$attribute},
         };
     }
 
+    /** @return array{list<array<string, mixed>>, list<array<string, mixed>>} */
+    private static function authorValues(Entry $entry, Entry $original): array
+    {
+        $oldIds = $original->getAuthorIds();
+        $newIds = $entry->getAuthorIds();
+        $ids = array_values(array_unique([...$oldIds, ...$newIds]));
+        $authors = $ids === []
+            ? collect()
+            : User::find()->id($ids)->status(null)->collect()->keyBy('id');
+
+        return [
+            self::elementValues(collect($oldIds)->map($authors->get(...))->filter()->all()),
+            self::elementValues(collect($newIds)->map($authors->get(...))->filter()->all()),
+        ];
+    }
+
+    /**
+     * @param  list<ElementInterface>  $elements
+     * @return list<array<string, mixed>>
+     */
+    private static function elementValues(array $elements): array
+    {
+        return array_map(fn (ElementInterface $element): array => [
+            'elementType' => $element::class,
+            'id' => $element->id,
+            'label' => $element->getUiLabel(),
+            'siteId' => $element->siteId,
+        ], $elements);
+    }
+
     private static function normalizeSafeValue(mixed &$value): bool
     {
         if ($value instanceof BackedEnum) {
diff --git a/src/Activity/EventTypes/CommentCreated.php b/src/Activity/EventTypes/CommentCreated.php
index 1541f4c5129..804348e51cd 100644
--- a/src/Activity/EventTypes/CommentCreated.php
+++ b/src/Activity/EventTypes/CommentCreated.php
@@ -4,9 +4,4 @@
 
 namespace CraftCms\Cms\Activity\EventTypes;
 
-class CommentCreated extends CommentEvent
-{
-    protected const string LABEL = 'Commented';
-
-    protected const string ICON = 'comment';
-}
+class CommentCreated extends CommentEvent {}
diff --git a/src/Activity/EventTypes/CommentDeleted.php b/src/Activity/EventTypes/CommentDeleted.php
index 972bb9796b5..122266a2a87 100644
--- a/src/Activity/EventTypes/CommentDeleted.php
+++ b/src/Activity/EventTypes/CommentDeleted.php
@@ -4,9 +4,18 @@
 
 namespace CraftCms\Cms\Activity\EventTypes;
 
+use CraftCms\Cms\Activity\Models\ActivityEvent;
+
+use function CraftCms\Cms\t;
+
 class CommentDeleted extends CommentEvent
 {
     protected const string LABEL = 'Comment removed';
 
     protected const string ICON = 'comment-slash';
+
+    public static function format(ActivityEvent $event): string
+    {
+        return t('Removed a comment.');
+    }
 }
diff --git a/src/Activity/EventTypes/CommentEdited.php b/src/Activity/EventTypes/CommentEdited.php
index fda8a2382cb..3f53ae59884 100644
--- a/src/Activity/EventTypes/CommentEdited.php
+++ b/src/Activity/EventTypes/CommentEdited.php
@@ -4,9 +4,4 @@
 
 namespace CraftCms\Cms\Activity\EventTypes;
 
-class CommentEdited extends CommentEvent
-{
-    protected const string LABEL = 'Comment edited';
-
-    protected const string ICON = 'comment';
-}
+class CommentEdited extends CommentEvent {}
diff --git a/src/Activity/EventTypes/CommentEvent.php b/src/Activity/EventTypes/CommentEvent.php
index ebbb8ab8dfa..a5db11d6eb0 100644
--- a/src/Activity/EventTypes/CommentEvent.php
+++ b/src/Activity/EventTypes/CommentEvent.php
@@ -7,12 +7,19 @@
 use CraftCms\Cms\Activity\ActivityEventType;
 use CraftCms\Cms\Activity\Data\ActivityActor;
 use CraftCms\Cms\Activity\Data\ActivitySubject;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
 use CraftCms\Cms\Site\Data\Site;
 use CraftCms\Cms\User\Elements\User;
 
+use function CraftCms\Cms\t;
+
 abstract class CommentEvent extends ActivityEventType
 {
+    protected const string LABEL = 'Commented';
+
+    protected const string ICON = 'comment';
+
     /** @param list<array{id: int, username: string}> $mentions */
     public function __construct(
         ElementInterface|ActivitySubject $subject,
@@ -34,4 +41,9 @@ public function data(): array
             'mentions' => $this->mentions,
         ];
     }
+
+    public static function format(ActivityEvent $event): string
+    {
+        return t('Commented.');
+    }
 }
diff --git a/src/Activity/StructuralElementActivity.php b/src/Activity/StructuralElementActivity.php
index c766491c444..a52dda133a3 100644
--- a/src/Activity/StructuralElementActivity.php
+++ b/src/Activity/StructuralElementActivity.php
@@ -44,7 +44,7 @@ public static function recordDuplicated(ElementInterface $source, ElementInterfa
      */
     public static function recordMoved(ElementInterface $element, array $origin, array $destination): void
     {
-        if (! self::shouldRecordMovement($element) || $origin === $destination) {
+        if ($origin === $destination) {
             return;
         }
 
diff --git a/src/Element/Drafts.php b/src/Element/Drafts.php
index b07bab5b664..f73b879d5d5 100644
--- a/src/Element/Drafts.php
+++ b/src/Element/Drafts.php
@@ -6,6 +6,7 @@
 
 use CraftCms\Cms\Activity\DraftActivity;
 use CraftCms\Cms\Activity\EventTypes\DraftDiscarded as DraftDiscardedActivityEvent;
+use CraftCms\Cms\Activity\StructuralElementActivity;
 use CraftCms\Cms\Cms;
 use CraftCms\Cms\Database\Table;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
@@ -18,6 +19,7 @@
 use CraftCms\Cms\Element\Queries\Contracts\ElementQueryInterface;
 use CraftCms\Cms\Element\Validation\ElementRules;
 use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Field\BaseRelationField;
 use CraftCms\Cms\Support\Arr;
 use CraftCms\Cms\Support\Facades\Activities;
 use CraftCms\Cms\Support\Facades\Sites;
@@ -266,16 +268,42 @@ public function applyDraft(ElementInterface $draft, array $newAttributes = []):
                     $this->elements->mergeCanonicalChanges($draft);
                 }
 
-                $entryActivity = (
+                if (
                     $draft instanceof Entry &&
                     $draft->isProvisionalDraft &&
                     $draft->getPrimaryOwnerId() === null &&
                     $canonical instanceof Entry
-                ) ? [
-                    $canonical,
-                    $draft->getModifiedAttributes(),
-                    $draft->getModifiedFields(),
-                ] : null;
+                ) {
+                    $modifiedAttributes = $draft->getModifiedAttributes();
+                    $modifiedFields = $draft->getModifiedFields();
+                    if (in_array('authorIds', $modifiedAttributes, true)) {
+                        $canonical->getAuthorIds();
+                    }
+
+                    foreach ($canonical->getFieldLayout()?->getCustomFields() ?? [] as $field) {
+                        if ($field instanceof BaseRelationField && in_array($field->handle, $modifiedFields, true)) {
+                            $value = $canonical->getFieldValue($field->handle);
+
+                            if ($value instanceof ElementQueryInterface) {
+                                $canonical->setFieldValue($field->handle, $value->collect());
+                            }
+                        }
+                    }
+
+                    $moveOrigin = $canonical->structureId !== null && $canonical->getParentId() !== $draft->getParentId()
+                        ? StructuralElementActivity::position(
+                            Structures::getStructureById($canonical->structureId)->uid,
+                            $canonical,
+                        )
+                        : null;
+
+                    $entryActivity = [
+                        $canonical,
+                        $modifiedAttributes,
+                        $modifiedFields,
+                        $moveOrigin,
+                    ];
+                }
 
                 // "Duplicate" the draft with the canonical element’s ID and UID
                 $newCanonical = $this->elements->updateCanonicalElement($draft, array_merge($newAttributes, [
diff --git a/src/Http/Controllers/Elements/ActivityCommentsController.php b/src/Http/Controllers/Elements/ActivityCommentsController.php
new file mode 100644
index 00000000000..4c17c2ac33e
--- /dev/null
+++ b/src/Http/Controllers/Elements/ActivityCommentsController.php
@@ -0,0 +1,125 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Controllers\Elements;
+
+use CraftCms\Cms\Activity\Activities;
+use CraftCms\Cms\Activity\ActivityComments;
+use CraftCms\Cms\Activity\ActivityTimelinePresenter;
+use CraftCms\Cms\Activity\Data\ActivitySubject;
+use CraftCms\Cms\Activity\EventTypes\CommentCreated;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
+use CraftCms\Cms\Element\Contracts\ElementInterface;
+use CraftCms\Cms\Http\Requests\ActivityCommentRequest;
+use CraftCms\Cms\Site\Data\Site;
+use CraftCms\Cms\User\Elements\User;
+use Illuminate\Http\JsonResponse;
+
+use function CraftCms\Cms\currentUserElement;
+
+readonly class ActivityCommentsController
+{
+    public function __construct(
+        private Activities $activities,
+        private ActivityComments $comments,
+        private ActivityTimelinePresenter $presenter,
+    ) {}
+
+    public function store(ActivityCommentRequest $request): JsonResponse
+    {
+        $subject = $request->subject();
+        $element = $request->subjectElement();
+        $user = $this->currentUser();
+        $event = $this->comments->create(
+            $subject,
+            $user,
+            $this->site($element),
+            $request->string('markdown')->toString(),
+        );
+
+        return new JsonResponse([
+            'event' => $this->presenter->events(collect([$event]), $user)->first(),
+        ]);
+    }
+
+    public function update(ActivityCommentRequest $request): JsonResponse
+    {
+        $subject = $request->subject();
+        $element = $request->subjectElement();
+        $comment = $this->comment($subject, $element, $request->string('commentId')->toString());
+        $user = $this->currentUser();
+
+        abort_unless($comment->actorId === $user->id, 403, 'Only the comment author may edit it.');
+
+        $version = $this->comments->edit(
+            $comment,
+            $user,
+            $request->string('markdown')->toString(),
+            $subject,
+        );
+
+        return $this->versionResponse($comment, $version, $user);
+    }
+
+    public function destroy(ActivityCommentRequest $request): JsonResponse
+    {
+        $subject = $request->subject();
+        $element = $request->subjectElement();
+        $comment = $this->comment($subject, $element, $request->string('commentId')->toString());
+        $user = $this->currentUser();
+
+        abort_unless(
+            $comment->actorId === $user->id || $user->admin,
+            403,
+            'Only the comment author or an administrator may remove it.',
+        );
+
+        return $this->versionResponse(
+            $comment,
+            $this->comments->delete($comment, $user),
+            $user,
+        );
+    }
+
+    private function comment(
+        ElementInterface $subject,
+        ElementInterface $element,
+        string $commentId,
+    ): ActivityEvent {
+        return $this->activities->query()
+            ->subject(ActivitySubject::fromElement($subject))
+            ->where('siteId', $this->site($element)?->id)
+            ->where('eventType', CommentCreated::class)
+            ->whereNull('rootEventId')
+            ->findOrFail($commentId);
+    }
+
+    private function versionResponse(
+        ActivityEvent $comment,
+        ActivityEvent $version,
+        User $viewer,
+    ): JsonResponse {
+        return new JsonResponse([
+            'event' => $this->presenter->events(
+                collect([$comment]),
+                $viewer,
+                collect([$comment->id => $version]),
+            )->first(),
+        ]);
+    }
+
+    private function site(ElementInterface $element): ?Site
+    {
+        if ($element->siteId === null) {
+            return null;
+        }
+
+        return Site::get($element->siteId) ?? abort(400, 'The activity site could not be found.');
+    }
+
+    private function currentUser(): User
+    {
+        return currentUserElement() ?? abort(401);
+    }
+}
diff --git a/src/Http/Controllers/Elements/ActivityMentionSuggestionsController.php b/src/Http/Controllers/Elements/ActivityMentionSuggestionsController.php
new file mode 100644
index 00000000000..4fcc2e9075a
--- /dev/null
+++ b/src/Http/Controllers/Elements/ActivityMentionSuggestionsController.php
@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Controllers\Elements;
+
+use CraftCms\Cms\Activity\ActivityComments;
+use CraftCms\Cms\Element\Contracts\ElementInterface;
+use CraftCms\Cms\Http\Requests\ActivityMentionSuggestionsRequest;
+use CraftCms\Cms\User\Elements\User;
+use Illuminate\Database\Query\Builder;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Str;
+use LogicException;
+
+readonly class ActivityMentionSuggestionsController
+{
+    private const int MaxCandidates = 250;
+
+    public function __construct(private ActivityComments $comments) {}
+
+    public function __invoke(ActivityMentionSuggestionsRequest $request): JsonResponse
+    {
+        return new JsonResponse($this->suggestions($request, $request->subject())->all());
+    }
+
+    /** @return Collection<int, array{label: string, value: string, keywords: array{string}, data: array{hint: string}}> */
+    private function suggestions(
+        ActivityMentionSuggestionsRequest $request,
+        ElementInterface $subject,
+    ): Collection {
+        $search = Str::lower(Str::after($request->string('query')->toString(), '@'));
+        $limit = $request->integer('limit', 10);
+        $query = User::find()->status(User::STATUS_ACTIVE);
+
+        if ($search !== '') {
+            $query->where(fn (Builder $query) => $query
+                ->whereLike('users.fullName', "%$search%")
+                ->orWhereLike('users.username', "%$search%"));
+        }
+
+        return $query
+            ->orderBy('elements.id')
+            ->limit(self::MaxCandidates)
+            ->collect()
+            ->filter(fn (User $user): bool => $this->comments->canMention($user, $subject))
+            ->take($limit)
+            ->map(function (User $user): array {
+                $username = $user->username ?? throw new LogicException('Mentionable users require a username.');
+                $escapedUsername = Str::replace(['\\', '[', ']'], ['\\\\', '\\[', '\\]'], $username);
+
+                return [
+                    'label' => $user->name,
+                    'value' => sprintf('[@%s](craft-user:%d)', $escapedUsername, $user->id),
+                    'keywords' => [$username],
+                    'data' => ['hint' => "@$username"],
+                ];
+            })
+            ->values();
+    }
+}
diff --git a/src/Http/Controllers/Elements/ActivityTimelineController.php b/src/Http/Controllers/Elements/ActivityTimelineController.php
new file mode 100644
index 00000000000..e92ea16251b
--- /dev/null
+++ b/src/Http/Controllers/Elements/ActivityTimelineController.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Controllers\Elements;
+
+use CraftCms\Cms\Activity\Activities;
+use CraftCms\Cms\Activity\ActivityTimelinePresenter;
+use CraftCms\Cms\Activity\Data\ActivitySubject;
+use CraftCms\Cms\Http\Requests\ActivityTimelineRequest;
+use Illuminate\Http\JsonResponse;
+
+use function CraftCms\Cms\currentUserElement;
+
+readonly class ActivityTimelineController
+{
+    private const int EmbeddedLimit = 25;
+
+    public function __construct(
+        private Activities $activities,
+        private ActivityTimelinePresenter $presenter,
+    ) {}
+
+    public function __invoke(ActivityTimelineRequest $request): JsonResponse
+    {
+        $subject = $request->subject();
+        $element = $request->subjectElement();
+        $query = $this->activities->query()
+            ->subject(ActivitySubject::fromElement($subject))
+            ->whereNull('rootEventId');
+
+        if ($element->siteId !== null) {
+            $query->site($element->siteId);
+        }
+
+        if (! $request->boolean('all')) {
+            $query->limit(self::EmbeddedLimit);
+        }
+
+        return new JsonResponse([
+            'events' => $this->presenter->events(
+                $query->get()->reverse()->values(),
+                currentUserElement() ?? abort(401),
+            )->all(),
+        ]);
+    }
+}
diff --git a/src/Http/Controllers/Elements/ElementActivityController.php b/src/Http/Controllers/Elements/ElementActivityController.php
index fa754bfc285..d9b53eece77 100644
--- a/src/Http/Controllers/Elements/ElementActivityController.php
+++ b/src/Http/Controllers/Elements/ElementActivityController.php
@@ -7,12 +7,20 @@
 use CraftCms\Cms\Element\Data\ElementActivity as ElementActivityData;
 use CraftCms\Cms\Element\ElementActivity;
 use CraftCms\Cms\Element\Enums\ElementActivityType;
+use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Http\Controllers\Elements\Concerns\ElementCrumbs;
 use CraftCms\Cms\Http\Requests\ElementRequest;
+use CraftCms\Cms\Http\Responses\CpScreenResponse;
+use CraftCms\Cms\Support\Url;
 use Illuminate\Http\JsonResponse;
 use Symfony\Component\HttpFoundation\Response;
 
+use function CraftCms\Cms\t;
+
 readonly class ElementActivityController
 {
+    use ElementCrumbs;
+
     public function __construct(
         private ElementRequest $request,
         private ElementActivity $elementActivity,
@@ -45,4 +53,39 @@ public function __invoke(): Response
             'canonicalUpdatedTimestamp' => $element->getCanonical()->dateUpdated->getTimestamp(),
         ]);
     }
+
+    public function index(): CpScreenResponse|Response
+    {
+        $element = $this->request->element([
+            'id' => $this->request->route('id'),
+        ]);
+
+        if ($element instanceof Response) {
+            return $element;
+        }
+
+        if (! $element instanceof Entry) {
+            abort(400, 'No entry was identified by the request.');
+        }
+
+        $entry = $element->getCanonical(true);
+
+        return new CpScreenResponse()
+            ->title(t('Activity for “{title}”', [
+                'title' => $entry->getUiLabel(),
+            ]))
+            ->crumbs([
+                ...$this->crumbs($entry, current: false),
+                [
+                    'label' => t('Activity'),
+                    'current' => true,
+                ],
+            ])
+            ->inertiaPage('content/Activity', [
+                'activityTimelineUrl' => Url::actionUrl('elements/activity', ['all' => true]),
+                'elementType' => $entry::class,
+                'elementId' => $entry->id,
+                'siteId' => $entry->siteId,
+            ]);
+    }
 }
diff --git a/src/Http/Requests/ActivityCommentRequest.php b/src/Http/Requests/ActivityCommentRequest.php
new file mode 100644
index 00000000000..b83bae29495
--- /dev/null
+++ b/src/Http/Requests/ActivityCommentRequest.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Requests;
+
+class ActivityCommentRequest extends ActivityRequest
+{
+    public const int MaxLength = 10_000;
+
+    /** @return array<string, list<string>> */
+    public function rules(): array
+    {
+        $commentId = ['required', 'integer', 'min:1'];
+        $markdown = ['required', 'string', 'max:'.self::MaxLength];
+
+        return [
+            ...parent::rules(),
+            ...match ($this->method()) {
+                'POST' => ['markdown' => $markdown],
+                'PATCH' => ['commentId' => $commentId, 'markdown' => $markdown],
+                'DELETE' => ['commentId' => $commentId],
+                default => abort(405),
+            },
+        ];
+    }
+}
diff --git a/src/Http/Requests/ActivityMentionSuggestionsRequest.php b/src/Http/Requests/ActivityMentionSuggestionsRequest.php
new file mode 100644
index 00000000000..fb1c70085f6
--- /dev/null
+++ b/src/Http/Requests/ActivityMentionSuggestionsRequest.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Requests;
+
+class ActivityMentionSuggestionsRequest extends ActivityRequest
+{
+    /** @return array<string, list<string>> */
+    public function rules(): array
+    {
+        return [
+            ...parent::rules(),
+            'query' => ['nullable', 'string', 'max:100'],
+            'limit' => ['nullable', 'integer', 'min:1', 'max:20'],
+        ];
+    }
+}
diff --git a/src/Http/Requests/ActivityRequest.php b/src/Http/Requests/ActivityRequest.php
new file mode 100644
index 00000000000..26ffcff50eb
--- /dev/null
+++ b/src/Http/Requests/ActivityRequest.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Requests;
+
+use CraftCms\Cms\Element\Contracts\ElementInterface;
+use Illuminate\Support\Facades\Gate;
+
+abstract class ActivityRequest extends ElementRequest
+{
+    private ?ElementInterface $subject = null;
+
+    private ?ElementInterface $subjectElement = null;
+
+    public function authorize(): bool
+    {
+        return Gate::allows('view', $this->subject());
+    }
+
+    public function subject(): ElementInterface
+    {
+        return $this->subject ??= $this->subjectElement()->getCanonical(true);
+    }
+
+    public function subjectElement(): ElementInterface
+    {
+        if ($this->subjectElement !== null) {
+            return $this->subjectElement;
+        }
+
+        $element = $this->element();
+
+        abort_unless($element instanceof ElementInterface, 400, 'No element was identified by the request.');
+
+        return $this->subjectElement = $element;
+    }
+}
diff --git a/src/Http/Requests/ActivityTimelineRequest.php b/src/Http/Requests/ActivityTimelineRequest.php
new file mode 100644
index 00000000000..6af82487b2c
--- /dev/null
+++ b/src/Http/Requests/ActivityTimelineRequest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Http\Requests;
+
+class ActivityTimelineRequest extends ActivityRequest
+{
+    /** @return array<string, list<string>> */
+    public function rules(): array
+    {
+        return [
+            ...parent::rules(),
+            'all' => ['sometimes', 'boolean'],
+        ];
+    }
+}
diff --git a/src/Http/ViewModels/AssetEditViewModel.php b/src/Http/ViewModels/AssetEditViewModel.php
index 7c1bb42007e..027d4508a60 100644
--- a/src/Http/ViewModels/AssetEditViewModel.php
+++ b/src/Http/ViewModels/AssetEditViewModel.php
@@ -38,6 +38,14 @@ protected function elementSaveUrl(): string
         return Url::actionUrl('elements/save');
     }
 
+    #[Override]
+    public function activityTimelineUrl(): ?string
+    {
+        return $this->asset->id
+            ? Url::actionUrl('elements/activity')
+            : null;
+    }
+
     public function volumeId(): ?int
     {
         return $this->asset->getVolumeId();
diff --git a/src/Http/ViewModels/ElementEditViewModel.php b/src/Http/ViewModels/ElementEditViewModel.php
index 20bc039b3d3..4da1a2847d3 100644
--- a/src/Http/ViewModels/ElementEditViewModel.php
+++ b/src/Http/ViewModels/ElementEditViewModel.php
@@ -279,6 +279,18 @@ public function activityUrl(): ?string
             : null;
     }
 
+    /** Where this editor's activity timeline is loaded on demand. */
+    public function activityTimelineUrl(): ?string
+    {
+        return null;
+    }
+
+    /** Where the full activity page can be viewed. */
+    public function activityPageUrl(): ?string
+    {
+        return null;
+    }
+
     /**
      * The element's and its canonical's last-modified stamps at render time.
      * Activity polling compares these against the server's to notice that
diff --git a/src/Http/ViewModels/EntryEditViewModel.php b/src/Http/ViewModels/EntryEditViewModel.php
index e6197499b1c..4f11bf6e6da 100644
--- a/src/Http/ViewModels/EntryEditViewModel.php
+++ b/src/Http/ViewModels/EntryEditViewModel.php
@@ -7,6 +7,7 @@
 use CraftCms\Cms\Entry\Elements\Entry;
 use CraftCms\Cms\Http\Requests\ElementRequest;
 use CraftCms\Cms\Support\Url;
+use Illuminate\Support\Uri;
 use Override;
 
 /**
@@ -29,6 +30,28 @@ protected function elementSaveUrl(): string
         return Url::actionUrl('entries/save-entry');
     }
 
+    #[Override]
+    public function activityTimelineUrl(): ?string
+    {
+        return $this->entry->getCanonical(true)->id
+            ? Url::actionUrl('elements/activity')
+            : null;
+    }
+
+    #[Override]
+    public function activityPageUrl(): ?string
+    {
+        $canonical = $this->entry->getCanonical(true);
+
+        if (! $canonical->id || ! $canonical->sectionId) {
+            return null;
+        }
+
+        $url = Uri::of($canonical->getCpEditUrl());
+
+        return $url->withPath("{$url->path()}/activity")->value();
+    }
+
     public function sectionHandle(): ?string
     {
         return $this->entry->getSection()?->handle;
diff --git a/src/Support/Facades/Drafts.php b/src/Support/Facades/Drafts.php
index b239561f594..8db17ecd4c3 100644
--- a/src/Support/Facades/Drafts.php
+++ b/src/Support/Facades/Drafts.php
@@ -13,6 +13,7 @@
  * @method static string generateDraftName(int $canonicalId)
  * @method static bool saveElementAsDraft(\CraftCms\Cms\Element\Contracts\ElementInterface $element, int|null $creatorId = null, string|null $name = null, string|null $notes = null, bool $markAsSaved = true)
  * @method static \CraftCms\Cms\Element\Contracts\ElementInterface applyDraft(\CraftCms\Cms\Element\Contracts\ElementInterface $draft, array $newAttributes = [])
+ * @method static bool discardDraft(\CraftCms\Cms\Element\Contracts\ElementInterface $draft)
  * @method static void removeDraftData(\CraftCms\Cms\Element\Contracts\ElementInterface $draft)
  * @method static void purgeUnsavedDrafts()
  * @method static int insertDraftRow(string|null $name, string|null $notes = null, int|null $creatorId = null, int|null $canonicalId = null, bool $trackChanges = false, bool $provisional = false)
diff --git a/tests/Feature/Activity/EntryActivityTest.php b/tests/Feature/Activity/EntryActivityTest.php
index dc9d143476b..c2c28fe2ad3 100644
--- a/tests/Feature/Activity/EntryActivityTest.php
+++ b/tests/Feature/Activity/EntryActivityTest.php
@@ -22,7 +22,9 @@
 use CraftCms\Cms\Entry\Elements\Entry;
 use CraftCms\Cms\Entry\Models\Entry as EntryModel;
 use CraftCms\Cms\Entry\Models\EntryType;
+use CraftCms\Cms\Field\Entries as EntriesField;
 use CraftCms\Cms\Field\PlainText;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityTimelineController;
 use CraftCms\Cms\Http\Controllers\Elements\ElementDraftsController;
 use CraftCms\Cms\Http\Controllers\Entries\StoreEntryController;
 use CraftCms\Cms\Section\Models\Section;
@@ -30,6 +32,7 @@
 use CraftCms\Cms\Support\Facades\Elements;
 use CraftCms\Cms\Support\Facades\Sites;
 use CraftCms\Cms\User\Elements\User;
+use CraftCms\Cms\User\Models\User as UserModel;
 use Illuminate\Support\Facades\Date;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Event;
@@ -93,6 +96,56 @@
     ]);
 });
 
+it('shows author and relational changes in the activity timeline', function () {
+    $oldAuthor = User::findOne();
+    $author = UserModel::factory()->createElement(['fullName' => 'Ada Lovelace']);
+    $oldTarget = EntryModel::factory()->createElement(['title' => 'Old target']);
+    $newTarget = EntryModel::factory()->createElement(['title' => 'New target']);
+    $result = EntryModel::factory()
+        ->withField('relatedEntries', EntriesField::class, value: [$oldTarget->id])
+        ->createElementWithFields();
+    $entry = $result->element;
+    $field = $result->fields->get('relatedEntries');
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+
+    $entry->setAuthorIds([$author->id]);
+    $entry->setFieldValue($field->handle, [$newTarget->id]);
+
+    expect(Elements::saveElement($entry, updateSearchIndex: false))->toBeTrue();
+
+    $changes = collect(postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $entry->id,
+        'siteId' => $entry->siteId,
+    ])->assertOk()->json('events.0.changes'))
+        ->keyBy('label');
+
+    expect($changes['Authors']['old'])->toBe([[
+        'elementType' => User::class,
+        'id' => $oldAuthor->id,
+        'label' => $oldAuthor->getUiLabel(),
+        'siteId' => $oldAuthor->siteId,
+    ]])
+        ->and($changes['Authors']['new'])->toBe([[
+            'elementType' => User::class,
+            'id' => $author->id,
+            'label' => 'Ada Lovelace',
+            'siteId' => $author->siteId,
+        ]])
+        ->and($changes[$field->name]['old'])->toBe([[
+            'elementType' => Entry::class,
+            'id' => $oldTarget->id,
+            'label' => 'Old target',
+            'siteId' => $oldTarget->siteId,
+        ]])
+        ->and($changes[$field->name]['new'])->toBe([[
+            'elementType' => Entry::class,
+            'id' => $newTarget->id,
+            'label' => 'New target',
+            'siteId' => $newTarget->siteId,
+        ]]);
+});
+
 it('records a status change instead of a generic update', function () {
     $result = EntryModel::factory()
         ->withField('bodyField', PlainText::class, value: 'Old body')
@@ -220,6 +273,63 @@
         );
 });
 
+it('shows author and relational changes applied from provisional drafts', function () {
+    $firstTarget = EntryModel::factory()->createElement(['title' => 'First target']);
+    $secondTarget = EntryModel::factory()->createElement(['title' => 'Second target']);
+    $result = EntryModel::factory()
+        ->withField('relatedEntries', EntriesField::class)
+        ->createElementWithFields();
+    $entry = $result->element;
+    $field = $result->fields->get('relatedEntries');
+    $oldAuthor = User::findOne();
+    $entry->setAuthorIds([$oldAuthor->id]);
+    Elements::saveElement($entry, updateSearchIndex: false);
+    $newAuthor = UserModel::factory()->createElement(['fullName' => 'Ada Lovelace']);
+    $draft = app(Drafts::class)->createDraft($entry, User::findOne()->id, provisional: true);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+
+    $draft->setAuthorIds([$newAuthor->id]);
+    $draft->setFieldValue($field->handle, [$firstTarget->id, $secondTarget->id]);
+    expect(Elements::saveElement($draft, updateSearchIndex: false))->toBeTrue();
+
+    app(Drafts::class)->applyDraft($draft);
+
+    $changes = collect(postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $entry->id,
+        'siteId' => $entry->siteId,
+    ])->assertOk()->json('events.0.changes'))
+        ->keyBy('label');
+
+    expect($changes['Authors']['old'])->toBe([[
+        'elementType' => User::class,
+        'id' => $oldAuthor->id,
+        'label' => $oldAuthor->getUiLabel(),
+        'siteId' => $oldAuthor->siteId,
+    ]])
+        ->and($changes['Authors']['new'])->toBe([[
+            'elementType' => User::class,
+            'id' => $newAuthor->id,
+            'label' => 'Ada Lovelace',
+            'siteId' => $newAuthor->siteId,
+        ]])
+        ->and($changes[$field->name]['old'])->toBe([])
+        ->and($changes[$field->name]['new'])->toBe([
+            [
+                'elementType' => Entry::class,
+                'id' => $firstTarget->id,
+                'label' => 'First target',
+                'siteId' => $firstTarget->siteId,
+            ],
+            [
+                'elementType' => Entry::class,
+                'id' => $secondTarget->id,
+                'label' => 'Second target',
+                'siteId' => $secondTarget->siteId,
+            ],
+        ]);
+});
+
 it('records draft creation and its initial save', function () {
     $entry = EntryModel::factory()->createElement(['title' => 'Original title']);
     DB::table(Table::ACTIVITYEVENTS)->delete();
diff --git a/tests/Feature/Activity/StructuralElementActivityTest.php b/tests/Feature/Activity/StructuralElementActivityTest.php
index 0ea385f8d52..0a2510bb6a0 100644
--- a/tests/Feature/Activity/StructuralElementActivityTest.php
+++ b/tests/Feature/Activity/StructuralElementActivityTest.php
@@ -10,20 +10,28 @@
 use CraftCms\Cms\Activity\EventTypes\ElementMoved;
 use CraftCms\Cms\Database\Table;
 use CraftCms\Cms\Element\Actions\Duplicate;
+use CraftCms\Cms\Element\Drafts;
 use CraftCms\Cms\Element\Operations\ElementDeletions;
 use CraftCms\Cms\Element\Operations\ElementDuplicates;
 use CraftCms\Cms\Entry\Elements\Entry;
 use CraftCms\Cms\Entry\Models\Entry as EntryModel;
 use CraftCms\Cms\Entry\Models\EntryType;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityTimelineController;
+use CraftCms\Cms\Section\Enums\SectionType;
 use CraftCms\Cms\Section\Models\Section;
 use CraftCms\Cms\Site\Models\Site;
+use CraftCms\Cms\Structure\Enums\Mode;
+use CraftCms\Cms\Structure\Models\Structure;
 use CraftCms\Cms\Structure\Structures;
+use CraftCms\Cms\Support\Facades\Elements;
+use CraftCms\Cms\Support\Facades\Sections;
 use CraftCms\Cms\Support\Facades\Sites;
 use CraftCms\Cms\User\Elements\User;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Queue;
 
 use function Pest\Laravel\actingAs;
+use function Pest\Laravel\postJson;
 
 beforeEach(function () {
     actingAs(User::findOne());
@@ -137,6 +145,39 @@
     );
 });
 
+it('shows parent changes applied from provisional drafts in the activity timeline', function () {
+    $structure = Structure::factory()->create();
+    $entryType = EntryType::factory()->create();
+    $section = Section::factory()->withEntryTypes($entryType)->create([
+        'type' => SectionType::Structure,
+        'structureId' => $structure->id,
+    ]);
+    Sections::refreshSections();
+    $parent = EntryModel::factory()->forSection($section)->forEntryType($entryType)->createElement(['title' => 'Parent']);
+    $moved = EntryModel::factory()->forSection($section)->forEntryType($entryType)->createElement(['title' => 'Moved']);
+    app(Structures::class)->appendToRoot($structure->id, $parent, Mode::Insert);
+    app(Structures::class)->appendToRoot($structure->id, $moved, Mode::Insert);
+    $parent = structuredEntry($parent->id, $structure->id);
+    $moved = structuredEntry($moved->id, $structure->id);
+    $draft = app(Drafts::class)->createDraft($moved, User::findOne()->id, provisional: true);
+    $draft->setParentId($parent->id);
+    Elements::saveElement($draft, updateSearchIndex: false);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+
+    app(Drafts::class)->applyDraft($draft);
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $moved->id,
+        'siteId' => $moved->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonPath(
+            'events.0.description.text',
+            'Moved from the position after Parent at the top level to the first position in Parent.',
+        );
+});
+
 it('records both merge subjects without nested updates or deletion', function () {
     $merged = EntryModel::factory()->createElement(['title' => 'Merged entry']);
     $prevailing = EntryModel::factory()->createElement(['title' => 'Prevailing entry']);
diff --git a/tests/Feature/Http/Controllers/Assets/EditAssetControllerTest.php b/tests/Feature/Http/Controllers/Assets/EditAssetControllerTest.php
index 28d7bc03f82..7b4806d30b3 100644
--- a/tests/Feature/Http/Controllers/Assets/EditAssetControllerTest.php
+++ b/tests/Feature/Http/Controllers/Assets/EditAssetControllerTest.php
@@ -69,6 +69,8 @@
             ->where('folderId', $this->folder->id)
             ->where('title', 'Current Title')
             ->where('readOnly', false)
+            ->where('activityTimelineUrl', fn (?string $url) => is_string($url)
+                && str_contains($url, 'elements/activity'))
         );
 });
 
diff --git a/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php b/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php
new file mode 100644
index 00000000000..4075e00d7bd
--- /dev/null
+++ b/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php
@@ -0,0 +1,694 @@
+<?php
+
+declare(strict_types=1);
+
+use CraftCms\Cms\Activity\Activities;
+use CraftCms\Cms\Activity\ActivityEventType;
+use CraftCms\Cms\Activity\Data\ActivityActor;
+use CraftCms\Cms\Activity\Data\ActivityChange;
+use CraftCms\Cms\Activity\Data\ActivitySource;
+use CraftCms\Cms\Activity\EventTypes\ElementCreated;
+use CraftCms\Cms\Activity\EventTypes\ElementUpdated;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
+use CraftCms\Cms\Auth\Impersonation;
+use CraftCms\Cms\Database\Table;
+use CraftCms\Cms\Edition;
+use CraftCms\Cms\Element\Drafts;
+use CraftCms\Cms\Element\Revisions;
+use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Entry\Models\Entry as EntryModel;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityCommentsController;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityMentionSuggestionsController;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityTimelineController;
+use CraftCms\Cms\Http\Requests\ActivityCommentRequest;
+use CraftCms\Cms\Site\Models\Site;
+use CraftCms\Cms\Support\Facades\Elements;
+use CraftCms\Cms\Support\Facades\Sites;
+use CraftCms\Cms\Support\Facades\Users;
+use CraftCms\Cms\User\Elements\User;
+use CraftCms\Cms\User\Models\User as UserModel;
+use CraftCms\Cms\User\Notifications\ActivityMentionNotification;
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\Date;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Notification;
+use Illuminate\Support\HtmlString;
+use Illuminate\Testing\Fluent\AssertableJson;
+use Inertia\Testing\AssertableInertia;
+
+use function CraftCms\Cms\cp_url;
+use function Pest\Laravel\actingAs;
+use function Pest\Laravel\deleteJson;
+use function Pest\Laravel\get;
+use function Pest\Laravel\getJson;
+use function Pest\Laravel\patchJson;
+use function Pest\Laravel\postJson;
+
+beforeEach(function () {
+    actingAs(User::findOne());
+
+    $this->entry = EntryModel::factory()->createElement(['title' => 'Release notes']);
+    $this->createCommentUrl = action([ActivityCommentsController::class, 'store']);
+    $this->editCommentUrl = action([ActivityCommentsController::class, 'update']);
+    $this->deleteCommentUrl = action([ActivityCommentsController::class, 'destroy']);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+});
+
+it('renders the entry activity page', function () {
+    $url = cp_url(sprintf(
+        '%s/%d-%s/activity',
+        $this->entry->getSection()->getCpIndexUri(),
+        $this->entry->id,
+        $this->entry->slug,
+    ));
+
+    get($url)
+        ->assertOk()
+        ->assertInertia(fn (AssertableInertia $page) => $page
+            ->component('content/Activity')
+            ->where('title', 'Activity for “Release notes”')
+            ->where('elementType', Entry::class)
+            ->where('elementId', $this->entry->id)
+            ->where('siteId', $this->entry->siteId)
+            ->where('activityTimelineUrl', fn (string $url) => str_contains($url, 'elements/activity') && str_contains($url, 'all=1'))
+        );
+});
+
+it('requires authentication and the subject view permission', function () {
+    Auth::logout();
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])->assertUnauthorized();
+
+    actingAs(UserModel::factory()->createElement(['admin' => false]));
+
+    postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => 'Unauthorized comment',
+    ])->assertForbidden();
+});
+
+it('requires a comment ID for edit and delete requests', function () {
+    $data = [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ];
+
+    patchJson($this->editCommentUrl, [...$data, 'markdown' => 'Edited'])
+        ->assertUnprocessable();
+    deleteJson($this->deleteCommentUrl, $data)
+        ->assertUnprocessable();
+});
+
+it('returns the requested site timeline oldest first with safe formatted details', function () {
+    $activities = app(Activities::class);
+    $otherSite = Site::factory()->create();
+    Sites::refreshSites();
+    $actor = UserModel::factory()->createElement(['fullName' => 'Ada Lovelace']);
+
+    Date::setTestNow('2026-08-24 09:00:00');
+    $neutral = $activities->record(new ElementCreated(subject: $this->entry, actor: $actor));
+
+    Date::setTestNow('2026-08-25 10:30:00');
+    $updated = $activities->record(new ElementUpdated(
+        subject: $this->entry,
+        actor: $actor,
+        site: Sites::getSiteById($this->entry->siteId),
+        changes: [new ActivityChange('Title', 'Draft', 'Release notes')],
+    ));
+
+    $activities->record(new ElementUpdated(
+        subject: $this->entry,
+        site: Sites::getSiteById($otherSite->id),
+    ));
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJson(fn (AssertableJson $json) => $json
+            ->has('events', 2)
+            ->where('events.0.id', $neutral->id)
+            ->where('events.0.icon', 'plus')
+            ->where('events.0.actor.label', 'Ada Lovelace')
+            ->whereType('events.0.actor.url', 'string')
+            ->where('events.0.actor.deleted', false)
+            ->where('events.1.id', $updated->id)
+            ->where('events.1.changes.0.label', 'Title')
+            ->where('events.1.changes.0.old', 'Draft')
+            ->where('events.1.changes.0.new', 'Release notes')
+            ->etc());
+});
+
+it('returns impersonator details', function () {
+    $impersonator = UserModel::factory()->admin()->createElement(['fullName' => 'Grace Hopper']);
+    $actor = UserModel::factory()->createElement(['fullName' => 'Ada Lovelace']);
+    app(Impersonation::class)->setImpersonatorId($impersonator->id);
+    app(Activities::class)->record(new ElementUpdated(subject: $this->entry, actor: $actor));
+    app(Impersonation::class)->setImpersonatorId(null);
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonPath('events.0.impersonator.label', 'Grace Hopper')
+        ->assertJsonPath('events.0.impersonator.deleted', false)
+        ->assertJsonPath('events.0.actor.label', 'Ada Lovelace');
+});
+
+it('formats timeline dates in the viewer preferred timezone', function () {
+    $viewer = User::findOne();
+    Users::saveUserPreferences($viewer, ['timeZone' => 'Europe/Brussels']);
+    Date::setTestNow(new DateTimeImmutable('2026-08-25 22:30:00', new DateTimeZone('UTC')));
+    app(Activities::class)->record(new ElementUpdated(subject: $this->entry));
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonPath('events.0.formattedOccurredAt.date', '2026-08-26')
+        ->assertJsonPath('events.0.formattedOccurredAt.dateLabel', 'Aug 26, 2026')
+        ->assertJsonPath('events.0.formattedOccurredAt.time', '12:30 AM')
+        ->assertJsonPath('events.0.formattedOccurredAt.full', 'August 26, 2026 at 12:30:00 AM GMT+2');
+});
+
+it('limits embedded timelines and returns every event for the full timeline', function () {
+    Date::setTestNow('2026-08-25 10:30:00');
+    $events = collect(range(1, 26))
+        ->map(fn () => app(Activities::class)->record(new ElementUpdated(subject: $this->entry)));
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonCount(25, 'events')
+        ->assertJsonPath('events.0.id', $events[1]->id)
+        ->assertJsonPath('events.24.id', $events[25]->id);
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'all' => true,
+    ])
+        ->assertOk()
+        ->assertJsonCount(26, 'events')
+        ->assertJsonPath('events.0.id', $events[0]->id)
+        ->assertJsonPath('events.25.id', $events[25]->id);
+});
+
+it('keeps deleted actors identifiable and sanitizes plugin descriptions', function () {
+    $activities = app(Activities::class);
+    $actor = UserModel::factory()->createElement(['fullName' => 'Deleted editor']);
+
+    $event = $activities->record(new TimelineFormattedActivity(subject: $this->entry, actor: $actor));
+    DB::table(Table::ELEMENTS)->where('id', $actor->id)->delete();
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJson(fn (AssertableJson $json) => $json
+            ->where('events.0.id', $event->id)
+            ->where('events.0.icon', 'bolt')
+            ->where('events.0.actor.label', 'Deleted editor')
+            ->where('events.0.actor.url', null)
+            ->where('events.0.actor.deleted', true)
+            ->where('events.0.description.html', '<strong>Formatted safely</strong>')
+            ->where('events.0.description.text', null)
+            ->etc());
+});
+
+it('shows plugin actors without profile links and allows a default icon', function () {
+    $event = app(Activities::class)->record(new TimelineUniconedActivity(
+        subject: $this->entry,
+        actor: new ActivityActor('test.webhook', 'Webhook', auth()->id()),
+    ));
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJson(fn (AssertableJson $json) => $json
+            ->where('events.0.id', $event->id)
+            ->where('events.0.icon', null)
+            ->where('events.0.actor.label', 'Webhook')
+            ->where('events.0.actor.url', null)
+            ->where('events.0.actor.deleted', false)
+            ->etc());
+});
+
+it('shows canonical activity for drafts and revisions', function (string $derivative) {
+    $activities = app(Activities::class);
+    $event = $activities->record(new ElementCreated(subject: $this->entry));
+
+    $derivativeId = match ($derivative) {
+        'draftId' => app(Drafts::class)->createDraft($this->entry, auth()->id(), name: 'Working draft')->draftId,
+        'revisionId' => Elements::getElementById(
+            app(Revisions::class)->createRevision($this->entry, auth()->id(), 'Revision notes'),
+        )->revisionId,
+    };
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        $derivative => $derivativeId,
+    ])
+        ->assertOk()
+        ->assertJsonPath('events.0.id', $event->id);
+})->with([
+    'draft' => 'draftId',
+    'revision' => 'revisionId',
+]);
+
+it('lets a collaborator with view access post a safe Markdown comment without save access', function () {
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $collaborator = UserModel::factory()
+        ->withPermissions([
+            'accessCp',
+            "editSite:$site->uid",
+            "viewEntries:$section->uid",
+            "viewPeerEntries:$section->uid",
+        ])
+        ->createElement(['admin' => false, 'fullName' => 'Grace Hopper']);
+
+    actingAs($collaborator);
+
+    $response = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => '**Ship it.** <script>bad()</script>',
+    ])
+        ->assertOk()
+        ->assertJsonPath('event.description.text', 'Commented.')
+        ->assertJsonPath('event.actor.label', 'Grace Hopper')
+        ->assertJsonPath('event.comment.edited', false)
+        ->assertJsonPath('event.comment.deleted', false)
+        ->assertJsonPath('event.comment.canEdit', true)
+        ->assertJsonPath('event.comment.canDelete', true);
+
+    expect($response->json('event.comment.html'))->toContain('<strong>Ship it.</strong>')
+        ->not->toContain('<script>');
+
+    postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => " \n\t ",
+    ])->assertUnprocessable();
+
+    postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => str_repeat('x', ActivityCommentRequest::MaxLength + 1),
+    ])->assertUnprocessable();
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonCount(1, 'events')
+        ->assertJsonPath('events.0.comment.html', $response->json('event.comment.html'));
+});
+
+it('suggests active control panel users who can view the subject', function () {
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $permissions = [
+        'accessCp',
+        "editSite:$site->uid",
+        "viewEntries:$section->uid",
+        "viewPeerEntries:$section->uid",
+    ];
+    UserModel::factory()
+        ->count(50)
+        ->withPermissions(['accessCp'])
+        ->create(['fullName' => 'Grace Denied']);
+    $eligible = UserModel::factory()
+        ->withPermissions($permissions)
+        ->createElement(['fullName' => 'Grace Hopper', 'username' => 'grace']);
+    UserModel::factory()
+        ->withPermissions(['accessCp'])
+        ->createElement(['fullName' => 'Grace Denied', 'username' => 'grace-denied']);
+    UserModel::factory()
+        ->withPermissions($permissions)
+        ->createElement([
+            'active' => false,
+            'fullName' => 'Grace Inactive',
+            'username' => 'grace-inactive',
+        ]);
+
+    getJson(action(ActivityMentionSuggestionsController::class).'?'.http_build_query([
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'query' => '@grace',
+        'limit' => 10,
+    ]))
+        ->assertOk()
+        ->assertExactJson([[
+            'label' => 'Grace Hopper',
+            'value' => "[@grace](craft-user:$eligible->id)",
+            'keywords' => ['grace'],
+            'data' => ['hint' => '@grace'],
+        ]]);
+});
+
+it('renders eligible structured mentions as links and other mention syntax as text', function () {
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $mentioned = UserModel::factory()
+        ->withPermissions([
+            'accessCp',
+            "editSite:$site->uid",
+            "viewEntries:$section->uid",
+            "viewPeerEntries:$section->uid",
+        ])
+        ->createElement(['fullName' => 'Grace Hopper', 'username' => 'grace']);
+
+    $response = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => "Hello [@grace](craft-user:$mentioned->id) and @plain.",
+    ])->assertOk();
+
+    $document = new DOMDocument;
+    $document->loadHTML(
+        $response->json('event.comment.html'),
+        LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD,
+    );
+    $link = $document->getElementsByTagName('a')->item(0);
+
+    expect($link)->toBeInstanceOf(DOMElement::class)
+        ->and($link->textContent)->toBe('@grace')
+        ->and($document->textContent)->toBe('Hello @grace and @plain.');
+
+    $ineligible = UserModel::factory()
+        ->withPermissions(['accessCp'])
+        ->createElement(['username' => 'ineligible']);
+
+    $ineligibleHtml = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => "Hello [@ineligible](craft-user:$ineligible->id).",
+    ])->assertOk()->json('event.comment.html');
+
+    $plainHtml = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => 'Hello @grace.',
+    ])->assertOk()->json('event.comment.html');
+
+    $literalHtml = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => "Literal \\[@ineligible](craft-user:$ineligible->id) and `[@ineligible](craft-user:$ineligible->id)`.",
+    ])->assertOk()->json('event.comment.html');
+
+    expect(html_entity_decode(strip_tags($ineligibleHtml)))->toContain('@ineligible')
+        ->and($ineligibleHtml)->not->toContain('<a')
+        ->and(html_entity_decode(strip_tags($plainHtml)))->toContain('@grace')
+        ->and($plainHtml)->not->toContain('<a')
+        ->and(html_entity_decode(strip_tags($literalHtml)))->toContain('@ineligible')
+        ->and($literalHtml)->not->toContain('<a');
+});
+
+it('keeps mentions readable when users are renamed or deleted', function () {
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $author = User::findOne();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $viewPermissions = [
+        'accessCp',
+        "editSite:$site->uid",
+        "viewEntries:$section->uid",
+        "viewPeerEntries:$section->uid",
+    ];
+    $mentioned = UserModel::factory()
+        ->withPermissions($viewPermissions)
+        ->createElement(['username' => 'grace']);
+    $markdown = "Hello [@grace](craft-user:$mentioned->id).";
+
+    $commentId = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => $markdown,
+    ])->assertOk()->json('event.id');
+
+    DB::table(Table::USERS)->where('id', $mentioned->id)->update(['username' => 'grace-new']);
+
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $commentId,
+        'markdown' => $markdown,
+    ])->assertOk();
+
+    $viewer = UserModel::factory()
+        ->withPermissions($viewPermissions)
+        ->createElement(['username' => 'viewer']);
+    actingAs($viewer);
+
+    $hiddenLiveUserHtml = postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])->assertOk()->json('events.0.comment.html');
+
+    expect($hiddenLiveUserHtml)->toContain('grace-new')->not->toContain('<a');
+
+    DB::table(Table::ELEMENTS)->where('id', $mentioned->id)->delete();
+    actingAs($author);
+
+    $deletedUserHtml = postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])->assertOk()->json('events.0.comment.html');
+
+    expect($deletedUserHtml)->toContain('grace-new')->not->toContain('<a');
+});
+
+it('notifies mentioned users with the comment text', function () {
+    Notification::fake();
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $mentioned = UserModel::factory()
+        ->withPermissions([
+            'accessCp',
+            "editSite:$site->uid",
+            "viewEntries:$section->uid",
+            "viewPeerEntries:$section->uid",
+        ])
+        ->createElement(['username' => 'grace']);
+    postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => "Hello [@grace](craft-user:$mentioned->id).",
+    ])->assertOk();
+
+    $notifiable = UserModel::query()->findOrFail($mentioned->id);
+
+    Notification::assertSentTo(
+        $notifiable,
+        ActivityMentionNotification::class,
+        fn (ActivityMentionNotification $notification): bool => $notification->toDatabase($notifiable)['message']
+            === 'Hello @grace.',
+    );
+});
+
+it('notifies users newly mentioned in each comment edit', function () {
+    Notification::fake();
+    Edition::set(Edition::Pro);
+    Site::factory()->create();
+    Sites::refreshSites();
+    $section = $this->entry->getSection();
+    $site = Sites::getSiteById($this->entry->siteId);
+    $permissions = [
+        'accessCp',
+        "editSite:$site->uid",
+        "viewEntries:$section->uid",
+        "viewPeerEntries:$section->uid",
+    ];
+    $grace = UserModel::factory()->withPermissions($permissions)->createElement(['username' => 'grace']);
+    $ada = UserModel::factory()->withPermissions($permissions)->createElement(['username' => 'ada']);
+
+    $commentId = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => "Hello [@grace](craft-user:$grace->id).",
+    ])->assertOk()->json('event.id');
+
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $commentId,
+        'markdown' => "Hello [@ada](craft-user:$ada->id).",
+    ])->assertOk();
+
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $commentId,
+        'markdown' => "Hello [@grace](craft-user:$grace->id) and [@ada](craft-user:$ada->id).",
+    ])->assertOk();
+
+    Notification::assertSentTimes(ActivityMentionNotification::class, 3);
+    Notification::assertSentToTimes(
+        UserModel::query()->findOrFail($grace->id),
+        ActivityMentionNotification::class,
+        2,
+    );
+    Notification::assertSentTo(
+        UserModel::query()->findOrFail($ada->id),
+        ActivityMentionNotification::class,
+    );
+});
+
+it('edits and removes a comment in place on the timeline', function () {
+    $author = User::findOne();
+    Date::setTestNow('2026-08-25 10:00:00');
+
+    $created = postJson($this->createCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'markdown' => 'First version',
+    ])->assertOk()->json('event');
+
+    app(Activities::class)->record(new ElementUpdated(subject: $this->entry));
+
+    Date::setTestNow('2026-08-25 11:00:00');
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $created['id'],
+        'markdown' => 'Second version',
+    ])
+        ->assertOk()
+        ->assertJsonPath('event.id', $created['id'])
+        ->assertJsonPath('event.description.text', 'Commented.')
+        ->assertJsonPath('event.occurredAt', $created['occurredAt'])
+        ->assertJsonPath('event.comment.edited', true)
+        ->assertJsonPath('event.comment.deleted', false)
+        ->assertJsonPath('event.comment.markdown', 'Second version');
+
+    $otherAdmin = UserModel::factory()->createElement(['admin' => true]);
+    actingAs($otherAdmin);
+
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $created['id'],
+        'markdown' => 'Admin rewrite',
+    ])->assertForbidden();
+
+    deleteJson($this->deleteCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $created['id'],
+    ])
+        ->assertOk()
+        ->assertJsonPath('event.id', $created['id'])
+        ->assertJsonPath('event.icon', 'comment-slash')
+        ->assertJsonPath('event.actor.label', $otherAdmin->name)
+        ->assertJsonPath('event.description.text', 'Removed a comment.')
+        ->assertJsonPath('event.occurredAt', $created['occurredAt'])
+        ->assertJsonPath('event.comment.deleted', true)
+        ->assertJsonPath('event.comment.canEdit', false)
+        ->assertJsonPath('event.comment.canDelete', false);
+
+    actingAs($author);
+
+    patchJson($this->editCommentUrl, [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+        'commentId' => $created['id'],
+        'markdown' => 'Resurrected',
+    ])->assertUnprocessable();
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->entry->siteId,
+    ])
+        ->assertOk()
+        ->assertJsonCount(2, 'events')
+        ->assertJsonPath('events.0.id', $created['id'])
+        ->assertJsonPath('events.0.description.text', 'Removed a comment.')
+        ->assertJsonPath('events.0.comment.deleted', true);
+});
+
+class TimelineFormattedActivity extends ActivityEventType
+{
+    protected const string LABEL = 'Fallback label';
+
+    protected const string ICON = 'bolt';
+
+    public static function source(): ActivitySource
+    {
+        return new ActivitySource('test', 'Test Plugin', 'app');
+    }
+
+    public static function format(ActivityEvent $event): HtmlString
+    {
+        return new HtmlString('<strong>Formatted safely</strong><script>bad()</script>');
+    }
+}
+
+class TimelineUniconedActivity extends ActivityEventType
+{
+    protected const string LABEL = 'Received webhook';
+}
diff --git a/tests/Feature/Http/Controllers/Entries/EditEntryControllerTest.php b/tests/Feature/Http/Controllers/Entries/EditEntryControllerTest.php
index 63bcfa7e656..b0a068ef330 100644
--- a/tests/Feature/Http/Controllers/Entries/EditEntryControllerTest.php
+++ b/tests/Feature/Http/Controllers/Entries/EditEntryControllerTest.php
@@ -74,6 +74,10 @@
             ->where('sectionHandle', 'news')
             ->where('saveId', $this->entry->id)
             ->where('readOnly', false)
+            ->where('activityTimelineUrl', fn (?string $url) => is_string($url)
+                && str_contains($url, 'elements/activity'))
+            ->where('activityPageUrl', fn (?string $url) => is_string($url)
+                && str_ends_with((string) parse_url($url, PHP_URL_PATH), '/activity'))
         );
 });
 
@@ -206,6 +210,8 @@
         ->assertInertia(fn (AssertableInertia $page) => $page
             ->component('content/Edit')
             ->where('readOnly', true)
+            ->where('activityTimelineUrl', fn (?string $url) => is_string($url)
+                && str_contains($url, 'elements/activity'))
             ->where('canAutosave', false)
             ->where('notice', fn (?string $notice) => is_string($notice)
                 && str_contains($notice, 'viewing a revision'))
diff --git a/workbench/database/seeders/DatabaseSeeder.php b/workbench/database/seeders/DatabaseSeeder.php
index 76e40e17624..2b12ca3fc5d 100644
--- a/workbench/database/seeders/DatabaseSeeder.php
+++ b/workbench/database/seeders/DatabaseSeeder.php
@@ -4,15 +4,33 @@
 
 namespace Workbench\Database\Seeders;
 
+use CraftCms\Cms\Activity\ActivityComments;
+use CraftCms\Cms\Activity\Data\ActivityChange;
+use CraftCms\Cms\Activity\Data\ActivitySubject;
+use CraftCms\Cms\Activity\EventTypes\DraftApplied;
+use CraftCms\Cms\Activity\EventTypes\DraftCreated;
+use CraftCms\Cms\Activity\EventTypes\DraftDiscarded;
+use CraftCms\Cms\Activity\EventTypes\DraftSaved;
+use CraftCms\Cms\Activity\EventTypes\ElementCreated;
+use CraftCms\Cms\Activity\EventTypes\ElementRestored;
+use CraftCms\Cms\Activity\EventTypes\ElementStatusChanged;
+use CraftCms\Cms\Activity\EventTypes\ElementTrashed;
+use CraftCms\Cms\Activity\EventTypes\ElementUpdated;
+use CraftCms\Cms\Activity\EventTypes\RevisionRestored;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
 use CraftCms\Cms\Asset\Data\Volume;
+use CraftCms\Cms\Auth\Impersonation;
 use CraftCms\Cms\Cp\Data\NotificationButtonData;
 use CraftCms\Cms\Cp\Enums\ButtonVariant;
 use CraftCms\Cms\Cp\Notifications\CpNotification;
+use CraftCms\Cms\Database\Factories\UserFactory;
 use CraftCms\Cms\Database\LaravelMigrations;
 use CraftCms\Cms\Database\Migrations\Install;
 use CraftCms\Cms\Edition;
 use CraftCms\Cms\Entry\Data\EntryType;
 use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Field\Markdown;
+use CraftCms\Cms\FieldLayout\LayoutElements\CustomField;
 use CraftCms\Cms\FieldLayout\LayoutElements\Entries\EntryTitleField;
 use CraftCms\Cms\FieldLayout\Models\FieldLayout;
 use CraftCms\Cms\Filesystem\Filesystems\Local;
@@ -22,6 +40,7 @@
 use CraftCms\Cms\Section\Enums\SectionType;
 use CraftCms\Cms\Site\Data\Site;
 use CraftCms\Cms\Support\Env;
+use CraftCms\Cms\Support\Facades\Activities;
 use CraftCms\Cms\Support\Facades\Elements;
 use CraftCms\Cms\Support\Facades\EntryTypes;
 use CraftCms\Cms\Support\Facades\Fields;
@@ -39,6 +58,7 @@
 use Illuminate\Database\Seeder;
 use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\Context;
+use Illuminate\Support\Facades\Date;
 use RuntimeException;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Output\ConsoleOutput;
@@ -167,8 +187,28 @@ public function run(): void
 
         $this->components->info('Creating default entry types & sections...');
 
+        $markdownField = null;
+        $this->components->task('Creating Markdown field', function () use (&$markdownField): void {
+            $markdownField = Fields::createField([
+                'type' => Markdown::class,
+                'name' => 'Body',
+                'handle' => 'body',
+                'searchable' => true,
+                'settings' => [
+                    'initialRows' => 12,
+                    'showStats' => true,
+                ],
+            ]);
+
+            if (! Fields::saveField($markdownField)) {
+                throw new RuntimeException('Failed to create the Markdown field.');
+            }
+        });
+
+        Fields::refreshFields();
+
         $fieldLayout = null;
-        $this->components->task('Creating field layout', function () use (&$fieldLayout) {
+        $this->components->task('Creating field layout', function () use (&$fieldLayout, $markdownField) {
             $fieldLayout = FieldLayout::create([
                 'uid' => Str::uuid()->toString(),
                 'type' => Entry::class,
@@ -183,6 +223,11 @@ public function run(): void
                                     'type' => EntryTitleField::class,
                                     'required' => true,
                                 ],
+                                [
+                                    'uid' => Str::uuid()->toString(),
+                                    'type' => CustomField::class,
+                                    'fieldUid' => $markdownField->uid,
+                                ],
                             ],
                         ],
                     ],
@@ -205,10 +250,10 @@ public function run(): void
         $this->createSection($site, 'Pages', SectionType::Structure, '{parent.uri}/{slug}', [$pageType]);
         $this->createSection($site, 'Posts', SectionType::Channel, 'blog/{slug}', [$pageType]);
 
-        $this->createSampleEntries($site->id);
+        $this->createSampleEntries($site);
     }
 
-    private function createSampleEntries(int $siteId): void
+    private function createSampleEntries(Site $site): void
     {
         $this->components->info('Creating sample entries...');
 
@@ -216,7 +261,7 @@ private function createSampleEntries(int $siteId): void
         $posts = Sections::getSectionByHandle('posts');
         $pages = Sections::getSectionByHandle('pages');
 
-        $this->components->task('Post entries', function () use ($siteId, $pageType, $posts) {
+        $this->components->task('Post entries', function () use ($site, $pageType, $posts) {
             $titles = [
                 'Welcome to Craft 6',
                 'Porting the element index to Vue',
@@ -228,18 +273,38 @@ private function createSampleEntries(int $siteId): void
             ];
 
             foreach ($titles as $i => $title) {
-                $this->createEntry($siteId, $posts->id, $pageType->id, $title, now()->subDays($i));
+                $this->createEntry($site->id, $posts->id, $pageType->id, $title, now()->subDays($i));
             }
 
             // One pending and one disabled entry, for testing the status filter
-            $this->createEntry($siteId, $posts->id, $pageType->id, 'Scheduled for next week', now()->addWeek());
-            $this->createEntry($siteId, $posts->id, $pageType->id, 'Draft ideas (disabled)', now()->subMonth(), enabled: false);
+            $this->createEntry($site->id, $posts->id, $pageType->id, 'Scheduled for next week', now()->addWeek());
+            $this->createEntry($site->id, $posts->id, $pageType->id, 'Draft ideas (disabled)', now()->subMonth(), enabled: false);
         });
 
-        $this->components->task('Page entries', function () use ($siteId, $pageType, $pages) {
+        $this->components->task('Page entries', function () use ($site, $pageType, $pages) {
             foreach (['About', 'Contact', 'Pricing'] as $i => $title) {
-                $this->createEntry($siteId, $pages->id, $pageType->id, $title, now()->subDays($i + 1));
+                $this->createEntry($site->id, $pages->id, $pageType->id, $title, now()->subDays($i + 1));
             }
+
+            $activityEntry = $this->createEntry(
+                $site->id,
+                $pages->id,
+                $pageType->id,
+                'Activity timeline',
+                now()->subDays(4),
+                body: <<<'MARKDOWN'
+## Activity timeline playground
+
+This entry contains representative seeded activity for Craft’s core event types.
+
+- Field and status changes
+- Draft and revision activity
+- New, edited, and removed comments
+- An accidental deletion and recovery
+MARKDOWN,
+            );
+
+            $this->seedActivity($activityEntry, $site);
         });
     }
 
@@ -250,7 +315,8 @@ private function createEntry(
         string $title,
         \DateTimeInterface $postDate,
         bool $enabled = true,
-    ): void {
+        ?string $body = null,
+    ): Entry {
         $entry = new Entry;
         $entry->siteId = $siteId;
         $entry->sectionId = $sectionId;
@@ -259,10 +325,136 @@ private function createEntry(
         $entry->slug = Str::slug($title);
         $entry->postDate = $postDate;
         $entry->enabled = $enabled;
+        $entry->setFieldValue('body', $body ?? "This is seeded Markdown content for **{$title}**.");
+
+        if (! Elements::saveElement($entry)) {
+            throw new RuntimeException("Failed to create the {$title} entry.");
+        }
+
+        return $entry;
+    }
+
+    private function seedActivity(Entry $entry, Site $site): void
+    {
+        $user = User::query()->firstOrFail();
+        $editor = UserFactory::new()->createElement([
+            'fullName' => 'Ada Lovelace',
+            'username' => 'ada',
+            'email' => 'ada@example.com',
+        ]);
+        $userElement = $user->asElement();
+        $comments = app(ActivityComments::class);
+        $impersonation = app(Impersonation::class);
+        $bodyField = $entry->getFieldLayout()?->getFieldByHandle('body')
+            ?? throw new RuntimeException('Failed to find the Body field.');
+        $subject = ActivitySubject::fromElement($entry);
+        ActivityEvent::query()->subject($subject)->delete();
+        $startedAt = now()->subDays(7);
+        $events = [
+            [0, new ElementCreated(
+                subject: new ActivitySubject(
+                    type: $subject->type,
+                    id: $subject->id,
+                    label: 'Activity log',
+                ),
+                actor: $user,
+                site: $site,
+            )],
+            [2, new ElementUpdated(
+                subject: $entry,
+                actor: $user,
+                site: $site,
+                changes: [
+                    new ActivityChange('Title', 'Activity log', 'Activity timeline'),
+                    new ActivityChange($bodyField->name, null, 'Added an overview of the activity timeline.'),
+                ],
+            )],
+            [4, new ElementStatusChanged(
+                subject: $entry,
+                site: $site,
+                oldStatus: 'disabled',
+                newStatus: 'live',
+            )],
+            [24, new DraftCreated(subject: $entry, actor: $user, site: $site)],
+            [25, new DraftSaved(
+                subject: $entry,
+                actor: $user,
+                site: $site,
+                changes: [new ActivityChange(
+                    $bodyField->name,
+                    'Added an overview of the activity timeline.',
+                    'Added draft and revision examples.',
+                )],
+            )],
+            [31, new DraftApplied(subject: $entry, actor: $user, site: $site)],
+            [72, new ElementUpdated(
+                subject: $entry,
+                actor: $user,
+                site: $site,
+                changes: [
+                    new ActivityChange('Title', 'Activity timeline', 'Activity timeline overview'),
+                    new ActivityChange('Slug', 'activity-timeline', 'activity-timeline-overview'),
+                    new ActivityChange(
+                        'Post Date',
+                        $startedAt->copy()->addDays(3)->toDateString(),
+                        $startedAt->copy()->addDays(4)->toDateString(),
+                    ),
+                    new ActivityChange(
+                        $bodyField->name,
+                        'Added draft and revision examples.',
+                        'Added comment and recovery examples.',
+                    ),
+                ],
+            )],
+            [96, new RevisionRestored(subject: $entry, site: $site, revisionNum: 2)],
+            [120, new DraftCreated(subject: $entry, actor: $user, site: $site)],
+            [121, new DraftSaved(
+                subject: $entry,
+                actor: $user,
+                site: $site,
+                changes: [new ActivityChange($bodyField->name, 'Draft and revision examples', 'Alternative introduction')],
+            )],
+            [123, new DraftDiscarded(subject: $entry, actor: $user, site: $site)],
+            [144, new ElementTrashed(subject: $entry, actor: $user, site: $site)],
+            [145, new ElementRestored(subject: $entry, actor: $user, site: $site)],
+        ];
+
+        try {
+            foreach ($events as [$hours, $event]) {
+                Date::setTestNow($startedAt->copy()->addHours($hours));
+                Activities::record($event);
+            }
 
-        Elements::saveElement($entry);
+            Date::setTestNow($startedAt->copy()->addHours(12));
+            $comments->create($entry, $userElement, $site, 'Could we include examples of draft and revision activity?');
+
+            Date::setTestNow($startedAt->copy()->addHours(54));
+            $editedComment = $comments->create($entry, $userElement, $site, 'Could we make the change summary easier to scan?');
+
+            Date::setTestNow($startedAt->copy()->addHours(55));
+            $comments->edit($editedComment, $userElement, 'Could we keep short change summaries expanded?', $entry);
+
+            Date::setTestNow($startedAt->copy()->addHours(132));
+            $removedComment = $comments->create($entry, $userElement, $site, 'This note is no longer relevant.');
+
+            Date::setTestNow($startedAt->copy()->addHours(133));
+            $comments->delete($removedComment, $userElement);
+
+            Date::setTestNow($startedAt->copy()->addHours(146));
+            $impersonation->setImpersonatorId($user->id);
+            Activities::record(new ElementUpdated(
+                subject: $entry,
+                actor: $editor,
+                site: $site,
+                changes: [new ActivityChange('Title', 'Activity timeline overview', 'Activity timeline')],
+            ));
+        } finally {
+            $impersonation->setImpersonatorId(null);
+            Date::setTestNow();
+        }
     }
 
+    /** @param list<EntryType> $entryTypes */
     public function createSection(Site $site, string $title, SectionType $sectionType = SectionType::Channel, ?string $uriFormat = null, array $entryTypes = []): ?Section
     {
         $section = null;

From 39461ba9da981e63efe320e737a64519f4cf9177 Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Fri, 4 Sep 2026 14:38:51 +0200
Subject: [PATCH 2/5] Fix activity UI CI failures

---
 .github/workflows/js-ci.yml                              | 7 ++++++-
 .github/workflows/storybook.yml                          | 9 ++++++++-
 .../Element/Queries/Concerns/QueriesEagerlyTest.php      | 7 ++++++-
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/js-ci.yml b/.github/workflows/js-ci.yml
index 9052d97a857..075f1f43c93 100644
--- a/.github/workflows/js-ci.yml
+++ b/.github/workflows/js-ci.yml
@@ -45,7 +45,7 @@ jobs:
         # `testbench typescript:transform` and `testbench wayfinder:generate`
         # derive their output from controllers, DTOs, and routes in src/.
         run: |
-          echo "value=js-ci-v3-${{ runner.os }}-${{ hashFiles('package-lock.json', 'composer.lock', 'package.json', 'packages/*/package.json', 'packages/craftcms-ui/src/**', 'packages/craftcms-ui/tsconfig*.json', 'packages/craftcms-ui/vite.config.*', 'packages/craftcms-ui/tsdown.config.*', 'packages/craftcms-garnish/src/**', 'packages/craftcms-garnish/tsconfig*.json', 'packages/craftcms-garnish/vite.config.*', 'routes/**/*.php', 'src/**/*.php', 'workbench/**/*.php') }}" >> "$GITHUB_OUTPUT"
+          echo "value=js-ci-v4-${{ runner.os }}-${{ hashFiles('package-lock.json', 'composer.lock', 'package.json', 'packages/*/package.json', 'packages/craftcms-ui/src/**', 'packages/craftcms-ui/tsconfig*.json', 'packages/craftcms-ui/vite.config.*', 'packages/craftcms-ui/tsdown.config.*', 'packages/craftcms-garnish/src/**', 'packages/craftcms-garnish/tsconfig*.json', 'packages/craftcms-garnish/vite.config.*', 'routes/**/*.php', 'src/**/*.php', 'workbench/**/*.php') }}" >> "$GITHUB_OUTPUT"
 
       - name: Restore install + build + generated cache
         id: cache
@@ -57,6 +57,7 @@ jobs:
             packages/craftcms-ui/dist
             packages/craftcms-garnish/dist
             vendor
+            cms-assets/resources/icons
             resources/js/actions
             resources/js/routes
             resources/js/wayfinder
@@ -74,6 +75,10 @@ jobs:
             env:
               CRAFT_FONTAWESOME_TOKEN: ${{ secrets.CRAFT_FONTAWESOME_TOKEN }}
 
+      - name: Copy icons
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: composer copy-icons
+
       # Build the garnish package so its `dist/*.d.ts` exist — `vue-tsc` resolves
       # `@craftcms/garnish` from `dist` (its `types`), and dist is gitignored.
       # Without this the typecheck job fails to resolve the module.
diff --git a/.github/workflows/storybook.yml b/.github/workflows/storybook.yml
index 32ffe1397c2..83322c45cbe 100644
--- a/.github/workflows/storybook.yml
+++ b/.github/workflows/storybook.yml
@@ -59,7 +59,7 @@ jobs:
         # Keep this in sync with .github/workflows/js-ci.yml so the built assets
         # and generated files are shared between the two workflows.
         run: |
-          echo "value=js-ci-v3-${{ runner.os }}-${{ hashFiles('package-lock.json', 'composer.lock', 'package.json', 'packages/*/package.json', 'packages/craftcms-ui/src/**', 'packages/craftcms-ui/tsconfig*.json', 'packages/craftcms-ui/vite.config.*', 'packages/craftcms-ui/tsdown.config.*', 'packages/craftcms-garnish/src/**', 'packages/craftcms-garnish/tsconfig*.json', 'packages/craftcms-garnish/vite.config.*', 'routes/**/*.php', 'src/**/*.php', 'workbench/**/*.php') }}" >> "$GITHUB_OUTPUT"
+          echo "value=js-ci-v4-${{ runner.os }}-${{ hashFiles('package-lock.json', 'composer.lock', 'package.json', 'packages/*/package.json', 'packages/craftcms-ui/src/**', 'packages/craftcms-ui/tsconfig*.json', 'packages/craftcms-ui/vite.config.*', 'packages/craftcms-ui/tsdown.config.*', 'packages/craftcms-garnish/src/**', 'packages/craftcms-garnish/tsconfig*.json', 'packages/craftcms-garnish/vite.config.*', 'routes/**/*.php', 'src/**/*.php', 'workbench/**/*.php') }}" >> "$GITHUB_OUTPUT"
 
       - name: Restore install + build + generated cache
         id: cache
@@ -71,6 +71,7 @@ jobs:
             packages/craftcms-ui/dist
             packages/craftcms-garnish/dist
             vendor
+            cms-assets/resources/icons
             resources/js/actions
             resources/js/routes
             resources/js/wayfinder
@@ -88,6 +89,10 @@ jobs:
             env:
               CRAFT_FONTAWESOME_TOKEN: ${{ secrets.CRAFT_FONTAWESOME_TOKEN }}
 
+      - name: Copy icons
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: composer copy-icons
+
       # Build the garnish package so its `dist/*.d.ts` exist — `vue-tsc` resolves
       # `@craftcms/garnish` from `dist` (its `types`), and dist is gitignored.
       - name: Build @craftcms/garnish
@@ -141,6 +146,7 @@ jobs:
             packages/craftcms-ui/dist
             packages/craftcms-garnish/dist
             vendor
+            cms-assets/resources/icons
             resources/js/actions
             resources/js/routes
             resources/js/wayfinder
@@ -184,6 +190,7 @@ jobs:
             packages/craftcms-ui/dist
             packages/craftcms-garnish/dist
             vendor
+            cms-assets/resources/icons
             resources/js/actions
             resources/js/routes
             resources/js/wayfinder
diff --git a/tests/Feature/Element/Queries/Concerns/QueriesEagerlyTest.php b/tests/Feature/Element/Queries/Concerns/QueriesEagerlyTest.php
index e0164f81791..a4a26d7eddc 100644
--- a/tests/Feature/Element/Queries/Concerns/QueriesEagerlyTest.php
+++ b/tests/Feature/Element/Queries/Concerns/QueriesEagerlyTest.php
@@ -14,6 +14,7 @@
 use CraftCms\Cms\Section\Models\Section;
 use CraftCms\Cms\Support\Facades\ElementCaches;
 use CraftCms\Cms\Support\Facades\Elements;
+use CraftCms\Cms\Support\Facades\Sections;
 use CraftCms\Cms\User\Elements\User;
 use Illuminate\Support\Facades\DB;
 
@@ -32,6 +33,7 @@
     $section = Section::factory()->create([
         'handle' => 'blog',
     ]);
+    Sections::refreshSections();
 
     $entryType = EntryType::factory()->create([
         'fieldLayoutId' => $fieldLayout->id,
@@ -47,7 +49,10 @@
             'fieldLayoutId' => $fieldLayout->id,
         ]);
 
-        $relatedEntry = EntryModel::factory()->create();
+        $relatedEntry = EntryModel::factory()
+            ->forSection($section)
+            ->forEntryType($entryType)
+            ->create();
 
         $entryElement = entryQuery()->id($model->id)->firstOrFail();
         $entryElement->title = 'Test entry '.$model->id;

From 914f54b2f8399254de04ab070d6cad6fcacc089c Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Fri, 4 Sep 2026 14:46:04 +0200
Subject: [PATCH 3/5] Make activity response assertions portable

---
 tests/Feature/Activity/EntryActivityTest.php | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tests/Feature/Activity/EntryActivityTest.php b/tests/Feature/Activity/EntryActivityTest.php
index c2c28fe2ad3..8040ab455e5 100644
--- a/tests/Feature/Activity/EntryActivityTest.php
+++ b/tests/Feature/Activity/EntryActivityTest.php
@@ -120,25 +120,25 @@
     ])->assertOk()->json('events.0.changes'))
         ->keyBy('label');
 
-    expect($changes['Authors']['old'])->toBe([[
+    expect($changes['Authors']['old'])->toEqual([[
         'elementType' => User::class,
         'id' => $oldAuthor->id,
         'label' => $oldAuthor->getUiLabel(),
         'siteId' => $oldAuthor->siteId,
     ]])
-        ->and($changes['Authors']['new'])->toBe([[
+        ->and($changes['Authors']['new'])->toEqual([[
             'elementType' => User::class,
             'id' => $author->id,
             'label' => 'Ada Lovelace',
             'siteId' => $author->siteId,
         ]])
-        ->and($changes[$field->name]['old'])->toBe([[
+        ->and($changes[$field->name]['old'])->toEqual([[
             'elementType' => Entry::class,
             'id' => $oldTarget->id,
             'label' => 'Old target',
             'siteId' => $oldTarget->siteId,
         ]])
-        ->and($changes[$field->name]['new'])->toBe([[
+        ->and($changes[$field->name]['new'])->toEqual([[
             'elementType' => Entry::class,
             'id' => $newTarget->id,
             'label' => 'New target',
@@ -301,20 +301,20 @@
     ])->assertOk()->json('events.0.changes'))
         ->keyBy('label');
 
-    expect($changes['Authors']['old'])->toBe([[
+    expect($changes['Authors']['old'])->toEqual([[
         'elementType' => User::class,
         'id' => $oldAuthor->id,
         'label' => $oldAuthor->getUiLabel(),
         'siteId' => $oldAuthor->siteId,
     ]])
-        ->and($changes['Authors']['new'])->toBe([[
+        ->and($changes['Authors']['new'])->toEqual([[
             'elementType' => User::class,
             'id' => $newAuthor->id,
             'label' => 'Ada Lovelace',
             'siteId' => $newAuthor->siteId,
         ]])
         ->and($changes[$field->name]['old'])->toBe([])
-        ->and($changes[$field->name]['new'])->toBe([
+        ->and($changes[$field->name]['new'])->toEqual([
             [
                 'elementType' => Entry::class,
                 'id' => $firstTarget->id,

From ac383cba6570790c48e90772dee368ff156d4b87 Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Sat, 5 Sep 2026 08:50:54 +0200
Subject: [PATCH 4/5] Apply activity UI review pass

---
 .../activity/components/ActivityTimeline.vue  | 21 ++++--
 .../components/ActivityTimelineChanges.vue    | 15 +++--
 .../components/ActivityTimelineComment.vue    | 14 ++--
 .../composables/useActivityTimeline.ts        | 67 +++++++++----------
 4 files changed, 61 insertions(+), 56 deletions(-)

diff --git a/resources/js/modules/activity/components/ActivityTimeline.vue b/resources/js/modules/activity/components/ActivityTimeline.vue
index c486f9f3669..7ad1a2b7704 100644
--- a/resources/js/modules/activity/components/ActivityTimeline.vue
+++ b/resources/js/modules/activity/components/ActivityTimeline.vue
@@ -12,8 +12,15 @@
 
   const props = defineProps<ActivityTimelineProps>();
   const timeline = ref<HTMLElement | null>(null);
-  const {addOrUpdateEvent, dayGroups, events, load, scrollToEnd, status} =
-    useActivityTimeline(props, timeline);
+  const {
+    addOrUpdateEvent,
+    dayGroups,
+    events,
+    hasLoaded,
+    load,
+    scrollToEnd,
+    status,
+  } = useActivityTimeline(props, timeline);
 
   async function commentCreated(event: ActivityEvent): Promise<void> {
     addOrUpdateEvent(event);
@@ -25,7 +32,7 @@
   <div class="activity-timeline">
     <div ref="timeline" class="activity-timeline__scroll" scroll-region>
       <div
-        v-if="status === 'loading'"
+        v-if="!hasLoaded && status === 'loading'"
         class="activity-timeline__status"
         role="status"
       >
@@ -34,7 +41,7 @@
       </div>
 
       <div
-        v-else-if="status === 'error'"
+        v-else-if="!hasLoaded && status === 'error'"
         class="activity-timeline__status"
         role="alert"
       >
@@ -51,13 +58,13 @@
       </div>
 
       <p
-        v-else-if="status === 'loaded' && events.length === 0"
+        v-else-if="hasLoaded && events.length === 0"
         class="activity-timeline__status"
       >
         {{ t('No activity has been recorded yet.') }}
       </p>
 
-      <div v-else-if="status === 'loaded'" class="activity-timeline__rail">
+      <div v-else-if="hasLoaded" class="activity-timeline__rail">
         <div v-if="pageUrl" class="activity-timeline__full-link">
           <CpLink :href="pageUrl">
             {{ t('View all activity') }}
@@ -86,7 +93,7 @@
     </div>
 
     <div
-      v-if="status === 'loaded'"
+      v-if="hasLoaded"
       class="activity-timeline__composer"
       data-activity-comment-composer
     >
diff --git a/resources/js/modules/activity/components/ActivityTimelineChanges.vue b/resources/js/modules/activity/components/ActivityTimelineChanges.vue
index 045780cf7cb..da1ef720c6e 100644
--- a/resources/js/modules/activity/components/ActivityTimelineChanges.vue
+++ b/resources/js/modules/activity/components/ActivityTimelineChanges.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
   import {t} from '@craftcms/ui';
+  import '@craftcms/ui/components/disclosure/disclosure';
   import {computed, shallowRef} from 'vue';
   import Modal from '@/common/components/Modal.vue';
   import ActivityTimelineChangeList from './ActivityTimelineChangeList.vue';
@@ -22,13 +23,17 @@
 
 <template>
   <craft-card class="activity-timeline__changes">
-    <details v-if="showInline" open>
-      <summary>{{ changeCountLabel(changes.length) }}</summary>
+    <craft-disclosure
+      v-if="showInline"
+      :label="changeCountLabel(changes.length)"
+      opened
+    >
       <ActivityTimelineChangeList
+        slot="content"
         class="activity-timeline__change-list"
         :changes="changes"
       />
-    </details>
+    </craft-disclosure>
 
     <div v-else class="activity-timeline__changes-summary">
       <span>{{ changeCountLabel(changes.length) }}</span>
@@ -66,10 +71,6 @@
     margin-block-start: var(--c-spacing-sm);
   }
 
-  .activity-timeline__changes details > summary {
-    cursor: pointer;
-  }
-
   .activity-timeline__change-list {
     margin-block-start: var(--c-spacing-sm);
   }
diff --git a/resources/js/modules/activity/components/ActivityTimelineComment.vue b/resources/js/modules/activity/components/ActivityTimelineComment.vue
index 8b837f594a1..aaff50c73e4 100644
--- a/resources/js/modules/activity/components/ActivityTimelineComment.vue
+++ b/resources/js/modules/activity/components/ActivityTimelineComment.vue
@@ -204,23 +204,23 @@
               : t('Couldn’t update comment.')
           }}
         </p>
-        <button
+        <craft-button
           v-if="!creating"
           type="button"
-          class="btn small"
+          size="small"
           @click="cancelEditing"
         >
           {{ t('Cancel') }}
-        </button>
-        <button
+        </craft-button>
+        <craft-button
           type="button"
-          class="btn submit"
-          :class="{small: !creating}"
+          variant="primary"
+          :size="creating ? 'medium' : 'small'"
           :disabled="draft.trim() === '' || mutating"
           @click="saveComment"
         >
           {{ creating ? t('Comment') : t('Save') }}
-        </button>
+        </craft-button>
       </div>
     </div>
   </div>
diff --git a/resources/js/modules/activity/composables/useActivityTimeline.ts b/resources/js/modules/activity/composables/useActivityTimeline.ts
index 4bde8b8a003..a084cce9ea3 100644
--- a/resources/js/modules/activity/composables/useActivityTimeline.ts
+++ b/resources/js/modules/activity/composables/useActivityTimeline.ts
@@ -1,5 +1,6 @@
 import {actionClient} from '@craftcms/ui';
-import {computed, nextTick, ref, watch, type Ref} from 'vue';
+import {computed, nextTick, onScopeDispose, watch, type Ref} from 'vue';
+import {useFetch} from '@/common/composables/useFetch';
 
 export interface ActivityTarget {
   label: string;
@@ -58,54 +59,49 @@ export function useActivityTimeline(
   props: ActivityTimelineProps,
   timeline: Ref<HTMLElement | null>
 ) {
-  const events = ref<ActivityEvent[]>([]);
-  const status = ref<'idle' | 'loading' | 'loaded' | 'error'>('idle');
+  const {
+    data,
+    state: status,
+    execute,
+    abort,
+  } = useFetch<ActivityTimelineResponse>(
+    computed(() => props.url),
+    {
+      method: 'post',
+      axiosInstance: actionClient,
+      immediate: false,
+      refetch: false,
+      onSuccess: () => void scrollToEnd(),
+    }
+  );
+  const events = computed(() => data.value?.events ?? []);
+  const hasLoaded = computed(() => data.value !== null);
 
-  function requestData() {
-    return {
-      elementType: props.elementType,
-      elementId: props.elementId,
-      siteId: props.siteId,
-    };
-  }
+  onScopeDispose(abort);
 
   async function load(): Promise<void> {
     if (props.elementId === null) {
       return;
     }
 
-    const refreshing = status.value === 'loaded';
-
-    if (!refreshing) {
-      status.value = 'loading';
-    }
-
-    try {
-      const {data} = await actionClient.post<ActivityTimelineResponse>(
-        props.url,
-        requestData()
-      );
-
-      events.value = data.events;
-      status.value = 'loaded';
-      await scrollToEnd();
-    } catch {
-      if (!refreshing) {
-        status.value = 'error';
-      }
-    }
+    await execute({
+      elementType: props.elementType,
+      elementId: props.elementId,
+      siteId: props.siteId,
+    });
   }
 
   function addOrUpdateEvent(event: ActivityEvent): void {
     const index = events.value.findIndex(({id}) => id === event.id);
+    const updatedEvents = [...events.value];
 
     if (index === -1) {
-      events.value.push(event);
-
-      return;
+      updatedEvents.push(event);
+    } else {
+      updatedEvents[index] = event;
     }
 
-    events.value[index] = event;
+    data.value = {events: updatedEvents};
   }
 
   async function scrollToEnd(): Promise<void> {
@@ -129,7 +125,7 @@ export function useActivityTimeline(
   watch(
     () => props.refreshToken,
     () => {
-      if (status.value === 'loaded') {
+      if (hasLoaded.value) {
         void load();
       }
     }
@@ -156,6 +152,7 @@ export function useActivityTimeline(
     addOrUpdateEvent,
     dayGroups,
     events,
+    hasLoaded,
     load,
     scrollToEnd,
     status,

From 38f55d036f1cb5908d8a2e51aa8ca780c9ad298c Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Sat, 5 Sep 2026 14:58:14 +0200
Subject: [PATCH 5/5] Fix activity recording and editor regressions

---
 .../ActivityTimelineComment.test.ts           | 101 ++++++++++++++
 .../components/ActivityTimelineComment.vue    |   8 +-
 src/Activity/ActivityComments.php             |  20 ++-
 src/Activity/AssetActivity.php                |   5 +-
 src/Activity/DraftActivity.php                |  75 ++++++++---
 src/Activity/ElementActivity.php              |   5 +-
 src/Activity/ElementWriteActivity.php         |  10 +-
 src/Activity/EntryActivity.php                |  22 ++-
 src/Activity/StructuralElementActivity.php    |  34 ++---
 src/Element/Drafts.php                        | 114 ++++++----------
 src/Element/Events/ElementPersisted.php       |  16 +++
 src/Element/Operations/ElementWrites.php      |  14 +-
 src/Structure/Structures.php                  |  21 ++-
 .../Feature/Activity/ActivityCommentsTest.php |  85 +++++++++++-
 .../Activity/ActivityTransactionsTest.php     | 126 ++++++++++++++++++
 tests/Feature/Activity/EntryActivityTest.php  |  55 ++++++++
 .../StructuralElementActivityTest.php         |  22 ++-
 .../ActivityTimelineControllerTest.php        |  10 +-
 18 files changed, 570 insertions(+), 173 deletions(-)
 create mode 100644 resources/js/modules/activity/components/ActivityTimelineComment.test.ts
 create mode 100644 src/Element/Events/ElementPersisted.php
 create mode 100644 tests/Feature/Activity/ActivityTransactionsTest.php

diff --git a/resources/js/modules/activity/components/ActivityTimelineComment.test.ts b/resources/js/modules/activity/components/ActivityTimelineComment.test.ts
new file mode 100644
index 00000000000..421d88f34a8
--- /dev/null
+++ b/resources/js/modules/activity/components/ActivityTimelineComment.test.ts
@@ -0,0 +1,101 @@
+import {actionClient, type CraftTextExpander} from '@craftcms/ui';
+import {createApp, h, nextTick} from 'vue';
+import {afterEach, expect, it, vi} from 'vite-plus/test';
+import ActivityTimelineComment from './ActivityTimelineComment.vue';
+
+vi.mock('../../markdown-field/markdown-field', () => {
+  customElements.define(
+    'craft-markdown-field',
+    class extends HTMLElement {
+      connectedCallback() {
+        const textarea = document.createElement('textarea');
+        textarea.id = this.id;
+        this.id += '-editor';
+        this.append(textarea);
+      }
+    }
+  );
+
+  return {};
+});
+
+const container = document.createElement('div');
+let app: ReturnType<typeof createApp>;
+
+afterEach(() => {
+  app.unmount();
+  container.remove();
+  vi.restoreAllMocks();
+});
+
+it('inserts mentions into the active composer without changing another comment', async () => {
+  vi.spyOn(HTMLElement.prototype, 'offsetWidth', 'get').mockReturnValue(1);
+  vi.spyOn(actionClient, 'get').mockResolvedValue({
+    data: [{label: 'Ada Lovelace', value: '[@ada](craft-user:42)'}],
+  });
+
+  document.body.append(container);
+  app = createApp({
+    render: () =>
+      [1, 2].map((elementId) =>
+        h(ActivityTimelineComment, {
+          elementType: 'CraftCms\\Cms\\Entry\\Elements\\Entry',
+          elementId,
+          siteId: 1,
+        })
+      ),
+  });
+  app.mount(container);
+  await nextTick();
+
+  const editors = [...container.querySelectorAll('textarea')];
+  expect(editors).toHaveLength(2);
+  expect(new Set(editors.map((editor) => editor.id)).size).toBe(2);
+
+  for (const composer of container.querySelectorAll(
+    '[data-activity-comment-draft]'
+  )) {
+    const editor = composer.querySelector('textarea')!;
+    const label = composer.querySelector('label')!;
+    const expander = composer.querySelector<CraftTextExpander>(
+      'craft-text-expander'
+    )!;
+    await expander.updateComplete;
+
+    expect(label.control).toBe(editor);
+    expect(editor.getAttribute('aria-controls')).toBe(
+      expander.querySelector('[role="listbox"]')!.id
+    );
+  }
+
+  const [firstEditor, secondEditor] = editors as [
+    HTMLTextAreaElement,
+    HTMLTextAreaElement,
+  ];
+  firstEditor.value = 'Another comment';
+  firstEditor.dispatchEvent(new InputEvent('input', {bubbles: true}));
+  secondEditor.focus();
+  secondEditor.value = 'Hello @ad';
+  secondEditor.setSelectionRange(9, 9);
+  secondEditor.dispatchEvent(new InputEvent('input', {bubbles: true}));
+
+  const secondComposer = secondEditor.closest('[data-activity-comment-draft]')!;
+  await vi.waitFor(() => {
+    expect(
+      secondComposer.querySelector('[role="option"]')?.textContent
+    ).toContain('Ada Lovelace');
+    expect(
+      secondComposer
+        .querySelector('[role="option"]')
+        ?.getAttribute('aria-selected')
+    ).toBe('true');
+  });
+
+  secondEditor.dispatchEvent(
+    new KeyboardEvent('keydown', {key: 'Enter', bubbles: true})
+  );
+  await nextTick();
+
+  expect(secondEditor.value).toBe('Hello [@ada](craft-user:42)');
+  expect(firstEditor.value).toBe('Another comment');
+});
diff --git a/resources/js/modules/activity/components/ActivityTimelineComment.vue b/resources/js/modules/activity/components/ActivityTimelineComment.vue
index aaff50c73e4..78a7e601817 100644
--- a/resources/js/modules/activity/components/ActivityTimelineComment.vue
+++ b/resources/js/modules/activity/components/ActivityTimelineComment.vue
@@ -1,6 +1,6 @@
 <script setup lang="ts">
   import {actionClient, t} from '@craftcms/ui';
-  import {computed, shallowRef} from 'vue';
+  import {computed, shallowRef, useId} from 'vue';
   import {
     destroy,
     store,
@@ -51,11 +51,7 @@
         ]
       : []),
   ]);
-  const editorId = computed(() =>
-    creating.value
-      ? 'activity-comment-draft'
-      : `activity-comment-${props.event!.id}`
-  );
+  const editorId = `activity-comment-${useId()}`;
   const toolbarButtons = [
     'bold',
     'italic',
diff --git a/src/Activity/ActivityComments.php b/src/Activity/ActivityComments.php
index cb1ce2b6ef8..11492ec504e 100644
--- a/src/Activity/ActivityComments.php
+++ b/src/Activity/ActivityComments.php
@@ -15,7 +15,6 @@
 use CraftCms\Cms\Site\Data\Site;
 use CraftCms\Cms\Support\HtmlSanitizer\HtmlSanitizerManager;
 use CraftCms\Cms\User\Elements\User;
-use CraftCms\Cms\User\Models\User as UserModel;
 use CraftCms\Cms\User\Notifications\ActivityMentionNotification;
 use Illuminate\Support\Collection;
 use Illuminate\Support\Facades\DB;
@@ -28,6 +27,7 @@
 use League\CommonMark\Node\Block\Document;
 use League\CommonMark\Node\Inline\Text;
 use League\CommonMark\Node\NodeIterator;
+use Throwable;
 use UnexpectedValueException;
 
 use function CraftCms\Cms\t;
@@ -219,10 +219,20 @@ private function mutate(
     /** @param list<array{id: int, username: string}> $mentions */
     private function scheduleMentionNotifications(ActivityEvent $version, array $mentions): void
     {
-        Notification::send(
-            UserModel::query()->findMany(array_column($mentions, 'id')),
-            new ActivityMentionNotification($version),
-        );
+        if ($mentions === []) {
+            return;
+        }
+
+        DB::afterCommit(function () use ($version, $mentions): void {
+            try {
+                Notification::send(
+                    User::find()->id(array_column($mentions, 'id'))->status(null)->collect(),
+                    new ActivityMentionNotification($version),
+                );
+            } catch (Throwable $exception) {
+                report($exception);
+            }
+        });
     }
 
     /** @return list<array{id: int, username: string}> */
diff --git a/src/Activity/AssetActivity.php b/src/Activity/AssetActivity.php
index 371fbb415b8..dca7801b125 100644
--- a/src/Activity/AssetActivity.php
+++ b/src/Activity/AssetActivity.php
@@ -14,10 +14,9 @@
 /** @internal */
 class AssetActivity
 {
-    public static function shouldRecord(Asset $asset, bool $recordActivity): bool
+    public static function shouldRecord(Asset $asset): bool
     {
-        return $recordActivity &&
-            ! $asset->propagating &&
+        return ! $asset->propagating &&
             $asset->tempFilePath !== null &&
             $asset->ruleset->getScenario() === AssetRules::SCENARIO_REPLACE;
     }
diff --git a/src/Activity/DraftActivity.php b/src/Activity/DraftActivity.php
index a6e501f5217..4ea2eb77e07 100644
--- a/src/Activity/DraftActivity.php
+++ b/src/Activity/DraftActivity.php
@@ -4,6 +4,7 @@
 
 namespace CraftCms\Cms\Activity;
 
+use Closure;
 use CraftCms\Cms\Activity\EventTypes\DraftApplied as DraftAppliedActivityEvent;
 use CraftCms\Cms\Activity\EventTypes\DraftCreated as DraftCreatedActivityEvent;
 use CraftCms\Cms\Activity\EventTypes\DraftSaved;
@@ -11,11 +12,14 @@
 use CraftCms\Cms\Element\Contracts\ElementInterface;
 use CraftCms\Cms\Element\Events\DraftApplied;
 use CraftCms\Cms\Element\Events\DraftCreated;
-use CraftCms\Cms\Element\Events\ElementSaved;
+use CraftCms\Cms\Element\Events\ElementPersisted;
 use CraftCms\Cms\Element\Events\ElementSaving;
+use CraftCms\Cms\Element\Queries\Contracts\ElementQueryInterface;
 use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Field\BaseRelationField;
 use CraftCms\Cms\Site\Sites;
 use CraftCms\Cms\Support\Facades\Activities;
+use CraftCms\Cms\Support\Facades\Structures;
 use Illuminate\Container\Attributes\Singleton;
 use Illuminate\Support\Facades\DB;
 use LogicException;
@@ -70,7 +74,7 @@ public function handleElementSaving(ElementSaving $event): void
         ];
     }
 
-    public function handleElementSaved(ElementSaved $event): void
+    public function handleElementPersisted(ElementPersisted $event): void
     {
         $write = $this->writes[$event->element] ?? null;
         unset($this->writes[$event->element]);
@@ -121,32 +125,59 @@ public function subscribe(): array
     {
         return [
             ElementSaving::class => 'handleElementSaving',
-            ElementSaved::class => 'handleElementSaved',
+            ElementPersisted::class => 'handleElementPersisted',
             DraftCreated::class => 'handleDraftCreated',
             DraftApplied::class => 'handleDraftApplied',
         ];
     }
 
-    /**
-     * @param  string[]  $dirtyAttributes
-     * @param  string[]  $dirtyFields
-     * @param  array<string, mixed>|null  $moveOrigin
-     */
-    public function recordProvisionalApplied(
-        Entry $entry,
-        Entry $original,
-        array $dirtyAttributes,
-        array $dirtyFields,
-        ?array $moveOrigin,
-    ): void {
-        if ($moveOrigin !== null) {
-            StructuralElementActivity::recordMoved(
-                $entry,
-                $moveOrigin,
-                StructuralElementActivity::position($moveOrigin['structure'], $entry),
-            );
+    /** @return Closure(Entry): void|null */
+    public function captureProvisionalApply(ElementInterface $canonical, ElementInterface $draft): ?Closure
+    {
+        if (
+            ! $draft instanceof Entry ||
+            ! $draft->isProvisionalDraft ||
+            $draft->getPrimaryOwnerId() !== null ||
+            ! $canonical instanceof Entry
+        ) {
+            return null;
+        }
+
+        $original = clone $canonical;
+        $dirtyAttributes = $draft->getModifiedAttributes();
+        $dirtyFields = $draft->getModifiedFields();
+
+        if (in_array('authorIds', $dirtyAttributes, true)) {
+            $original->getAuthorIds();
+        }
+
+        foreach ($original->getFieldLayout()?->getCustomFields() ?? [] as $field) {
+            if ($field instanceof BaseRelationField && in_array($field->handle, $dirtyFields, true)) {
+                $value = $original->getFieldValue($field->handle);
+
+                if ($value instanceof ElementQueryInterface) {
+                    $original->setFieldValue($field->handle, (clone $value)->status(null)->collect());
+                }
+            }
         }
 
-        EntryActivity::recordUpdated($entry, $original, $dirtyAttributes, $dirtyFields);
+        $moveOrigin = $original->structureId !== null && $original->getParentId() !== $draft->getParentId()
+            ? StructuralElementActivity::position(
+                Structures::getStructureById($original->structureId)->uid,
+                $original,
+            )
+            : null;
+
+        return function (Entry $entry) use ($original, $dirtyAttributes, $dirtyFields, $moveOrigin): void {
+            if ($moveOrigin !== null) {
+                StructuralElementActivity::recordMoved(
+                    $entry,
+                    $moveOrigin,
+                    StructuralElementActivity::position($moveOrigin['structure'], $entry),
+                );
+            }
+
+            EntryActivity::recordUpdated($entry, $original, $dirtyAttributes, $dirtyFields);
+        };
     }
 }
diff --git a/src/Activity/ElementActivity.php b/src/Activity/ElementActivity.php
index 7f6a751160c..7330d4377ce 100644
--- a/src/Activity/ElementActivity.php
+++ b/src/Activity/ElementActivity.php
@@ -19,10 +19,9 @@ public static function shouldRecord(ElementInterface $element): bool
             (! $element instanceof NestedElementInterface || $element->getPrimaryOwnerId() === null);
     }
 
-    public static function shouldRecordWrite(ElementInterface $element, bool $recordActivity = true): bool
+    public static function shouldRecordWrite(ElementInterface $element): bool
     {
-        return $recordActivity &&
-            self::shouldRecord($element) &&
+        return self::shouldRecord($element) &&
             ! $element->propagating &&
             ! $element->resaving &&
             ! $element->mergingCanonicalChanges;
diff --git a/src/Activity/ElementWriteActivity.php b/src/Activity/ElementWriteActivity.php
index 2bcd431a63d..a273ae36e68 100644
--- a/src/Activity/ElementWriteActivity.php
+++ b/src/Activity/ElementWriteActivity.php
@@ -7,7 +7,7 @@
 use CraftCms\Cms\Activity\EventTypes\ElementSiteAdded;
 use CraftCms\Cms\Asset\Elements\Asset;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
-use CraftCms\Cms\Element\Events\ElementSaved;
+use CraftCms\Cms\Element\Events\ElementPersisted;
 use CraftCms\Cms\Element\Events\ElementSaving;
 use CraftCms\Cms\Entry\Elements\Entry;
 use CraftCms\Cms\Site\Sites;
@@ -45,8 +45,8 @@ public function handleElementSaving(ElementSaving $event): void
             return;
         }
 
-        $recordEntry = $element instanceof Entry && EntryActivity::shouldRecord($element, true);
-        $recordAsset = $element instanceof Asset && AssetActivity::shouldRecord($element, true);
+        $recordEntry = $element instanceof Entry && ElementActivity::shouldRecordWrite($element);
+        $recordAsset = $element instanceof Asset && AssetActivity::shouldRecord($element);
         $recordElement = ElementActivity::shouldRecordWrite($element);
 
         if (! $recordEntry && ! $recordAsset && ! $recordElement) {
@@ -71,7 +71,7 @@ public function handleElementSaving(ElementSaving $event): void
         }
     }
 
-    public function handleElementSaved(ElementSaved $event): void
+    public function handleElementPersisted(ElementPersisted $event): void
     {
         $element = $event->element;
 
@@ -141,7 +141,7 @@ public function subscribe(): array
     {
         return [
             ElementSaving::class => 'handleElementSaving',
-            ElementSaved::class => 'handleElementSaved',
+            ElementPersisted::class => 'handleElementPersisted',
         ];
     }
 }
diff --git a/src/Activity/EntryActivity.php b/src/Activity/EntryActivity.php
index c317ce9a2ae..32b84b24736 100644
--- a/src/Activity/EntryActivity.php
+++ b/src/Activity/EntryActivity.php
@@ -10,6 +10,8 @@
 use CraftCms\Cms\Activity\EventTypes\ElementStatusChanged;
 use CraftCms\Cms\Activity\EventTypes\ElementUpdated;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
+use CraftCms\Cms\Element\ElementCollection;
+use CraftCms\Cms\Element\Queries\Contracts\ElementQueryInterface;
 use CraftCms\Cms\Entry\Elements\Entry;
 use CraftCms\Cms\Field\BaseRelationField;
 use CraftCms\Cms\Support\Facades\Activities;
@@ -33,11 +35,6 @@ class EntryActivity
         'authorIds' => 'Authors',
     ];
 
-    public static function shouldRecord(Entry $entry, bool $recordActivity): bool
-    {
-        return ElementActivity::shouldRecordWrite($entry, $recordActivity);
-    }
-
     public static function original(Entry $entry): ?Entry
     {
         return Entry::find()
@@ -123,8 +120,8 @@ private static function changes(
             }
 
             if ($field instanceof BaseRelationField) {
-                $old = self::elementValues($original->getFieldValue($field->handle)->all());
-                $new = self::elementValues($entry->getFieldValue($field->handle)->all());
+                $old = self::relationValues($original->getFieldValue($field->handle));
+                $new = self::relationValues($entry->getFieldValue($field->handle));
             } else {
                 $old = $field->serializeValue($original->getFieldValue($field->handle), $original);
                 $new = $field->serializeValue($entry->getFieldValue($field->handle), $entry);
@@ -194,6 +191,17 @@ private static function authorValues(Entry $entry, Entry $original): array
         ];
     }
 
+    /**
+     * @param  ElementQueryInterface|ElementCollection<int, ElementInterface>  $value
+     * @return list<array<string, mixed>>
+     */
+    private static function relationValues(ElementQueryInterface|ElementCollection $value): array
+    {
+        return self::elementValues($value instanceof ElementQueryInterface
+            ? (clone $value)->status(null)->all()
+            : $value->all());
+    }
+
     /**
      * @param  list<ElementInterface>  $elements
      * @return list<array<string, mixed>>
diff --git a/src/Activity/StructuralElementActivity.php b/src/Activity/StructuralElementActivity.php
index a52dda133a3..043ef5b05d8 100644
--- a/src/Activity/StructuralElementActivity.php
+++ b/src/Activity/StructuralElementActivity.php
@@ -15,19 +15,9 @@
 /** @internal */
 class StructuralElementActivity
 {
-    public static function shouldRecord(ElementInterface $element): bool
-    {
-        return ElementActivity::shouldRecord($element);
-    }
-
-    public static function shouldRecordMovement(ElementInterface $element): bool
-    {
-        return ElementActivity::shouldRecordWrite($element);
-    }
-
     public static function recordDuplicated(ElementInterface $source, ElementInterface $duplicate): void
     {
-        if (! self::shouldRecord($duplicate)) {
+        if (! ElementActivity::shouldRecord($duplicate)) {
             return;
         }
 
@@ -76,26 +66,20 @@ public static function position(string $structureUid, ElementInterface $element)
     {
         return [
             'structure' => $structureUid,
-            'parent' => self::nullableReference($element->getParent()),
-            'previousSibling' => self::nullableReference($element->getPrevSibling()),
+            'parent' => self::reference($element->getParent()),
+            'previousSibling' => self::reference($element->getPrevSibling()),
         ];
     }
 
-    /** @return array{type: string, id: string, label: string} */
-    private static function reference(ElementInterface $element): array
-    {
-        return self::subjectReference(ActivitySubject::fromElement($element));
-    }
-
     /** @return array{type: string, id: string, label: string}|null */
-    private static function nullableReference(?ElementInterface $element): ?array
+    private static function reference(?ElementInterface $element): ?array
     {
-        return $element ? self::reference($element) : null;
-    }
+        if ($element === null) {
+            return null;
+        }
+
+        $subject = ActivitySubject::fromElement($element);
 
-    /** @return array{type: string, id: string, label: string} */
-    private static function subjectReference(ActivitySubject $subject): array
-    {
         return [
             'type' => $subject->type,
             'id' => $subject->id,
diff --git a/src/Element/Drafts.php b/src/Element/Drafts.php
index f73b879d5d5..bb5d0275995 100644
--- a/src/Element/Drafts.php
+++ b/src/Element/Drafts.php
@@ -6,7 +6,6 @@
 
 use CraftCms\Cms\Activity\DraftActivity;
 use CraftCms\Cms\Activity\EventTypes\DraftDiscarded as DraftDiscardedActivityEvent;
-use CraftCms\Cms\Activity\StructuralElementActivity;
 use CraftCms\Cms\Cms;
 use CraftCms\Cms\Database\Table;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
@@ -18,8 +17,6 @@
 use CraftCms\Cms\Element\Exceptions\InvalidElementException;
 use CraftCms\Cms\Element\Queries\Contracts\ElementQueryInterface;
 use CraftCms\Cms\Element\Validation\ElementRules;
-use CraftCms\Cms\Entry\Elements\Entry;
-use CraftCms\Cms\Field\BaseRelationField;
 use CraftCms\Cms\Support\Arr;
 use CraftCms\Cms\Support\Facades\Activities;
 use CraftCms\Cms\Support\Facades\Sites;
@@ -152,21 +149,21 @@ public function createDraft(
                     }),
             );
 
+            event(new DraftCreated(
+                canonical: $canonical,
+                creatorId: $creatorId,
+                provisional: $provisional,
+                draftName: $name,
+                draftNotes: $notes,
+                draft: $draft,
+            ));
+
             DB::commit();
         } catch (Throwable $e) {
             DB::rollBack();
             throw $e;
         }
 
-        event(new DraftCreated(
-            canonical: $canonical,
-            creatorId: $creatorId,
-            provisional: $provisional,
-            draftName: $name,
-            draftNotes: $notes,
-            draft: $draft,
-        ));
-
         return $draft;
     }
 
@@ -201,17 +198,31 @@ public function saveElementAsDraft(ElementInterface $element, ?int $creatorId =
     {
         $name ??= t('First draft');
 
-        // Create the draft row
-        $draftId = $this->insertDraftRow($name, $notes, $creatorId);
+        DB::beginTransaction();
+
+        try {
+            $draftId = $this->insertDraftRow($name, $notes, $creatorId);
+
+            $element->draftId = $draftId;
+            $element->draftCreatorId = $creatorId;
+            $element->draftName = $name;
+            $element->draftNotes = $notes;
+            $element->markDraftAsSaved = $markAsSaved;
+
+            if (! $this->elements->saveElement($element)) {
+                DB::rollBack();
+
+                return false;
+            }
+
+            DB::commit();
+        } catch (Throwable $exception) {
+            DB::rollBack();
 
-        $element->draftId = $draftId;
-        $element->draftCreatorId = $creatorId;
-        $element->draftName = $name;
-        $element->draftNotes = $notes;
-        $element->markDraftAsSaved = $markAsSaved;
+            throw $exception;
+        }
 
-        // Try to save and return the result
-        return $this->elements->saveElement($element);
+        return true;
     }
 
     /**
@@ -260,7 +271,7 @@ public function applyDraft(ElementInterface $draft, array $newAttributes = []):
 
         DB::beginTransaction();
         try {
-            $entryActivity = null;
+            $recordActivity = null;
 
             if ($canonical !== $draft) {
                 // Merge in any attribute & field values that were updated in the canonical element, but not the draft
@@ -268,42 +279,7 @@ public function applyDraft(ElementInterface $draft, array $newAttributes = []):
                     $this->elements->mergeCanonicalChanges($draft);
                 }
 
-                if (
-                    $draft instanceof Entry &&
-                    $draft->isProvisionalDraft &&
-                    $draft->getPrimaryOwnerId() === null &&
-                    $canonical instanceof Entry
-                ) {
-                    $modifiedAttributes = $draft->getModifiedAttributes();
-                    $modifiedFields = $draft->getModifiedFields();
-                    if (in_array('authorIds', $modifiedAttributes, true)) {
-                        $canonical->getAuthorIds();
-                    }
-
-                    foreach ($canonical->getFieldLayout()?->getCustomFields() ?? [] as $field) {
-                        if ($field instanceof BaseRelationField && in_array($field->handle, $modifiedFields, true)) {
-                            $value = $canonical->getFieldValue($field->handle);
-
-                            if ($value instanceof ElementQueryInterface) {
-                                $canonical->setFieldValue($field->handle, $value->collect());
-                            }
-                        }
-                    }
-
-                    $moveOrigin = $canonical->structureId !== null && $canonical->getParentId() !== $draft->getParentId()
-                        ? StructuralElementActivity::position(
-                            Structures::getStructureById($canonical->structureId)->uid,
-                            $canonical,
-                        )
-                        : null;
-
-                    $entryActivity = [
-                        $canonical,
-                        $modifiedAttributes,
-                        $modifiedFields,
-                        $moveOrigin,
-                    ];
-                }
+                $recordActivity = $this->activity->captureProvisionalApply($canonical, $draft);
 
                 // "Duplicate" the draft with the canonical element’s ID and UID
                 $newCanonical = $this->elements->updateCanonicalElement($draft, array_merge($newAttributes, [
@@ -324,9 +300,16 @@ public function applyDraft(ElementInterface $draft, array $newAttributes = []):
                 $newCanonical = $draft;
             }
 
-            if ($entryActivity !== null && $newCanonical instanceof Entry) {
-                $this->activity->recordProvisionalApplied($newCanonical, ...$entryActivity);
-            }
+            $recordActivity?->__invoke($newCanonical);
+
+            event(new DraftApplied(
+                canonical: $newCanonical,
+                creatorId: $draft->draftCreatorId,
+                provisional: $draft->isProvisionalDraft,
+                draftName: $draft->draftName,
+                draftNotes: $draft->draftNotes,
+                draft: $draft,
+            ));
 
             DB::commit();
         } catch (Throwable $e) {
@@ -340,15 +323,6 @@ public function applyDraft(ElementInterface $draft, array $newAttributes = []):
             throw $e;
         }
 
-        event(new DraftApplied(
-            canonical: $newCanonical,
-            creatorId: $draft->draftCreatorId,
-            provisional: $draft->isProvisionalDraft,
-            draftName: $draft->draftName,
-            draftNotes: $draft->draftNotes,
-            draft: $draft,
-        ));
-
         // if we were on another site when the applyDraft was triggered,
         // ensure we return the canonical element for the site we were on
         if ($newCanonical->siteId !== $originalDraft->siteId) {
diff --git a/src/Element/Events/ElementPersisted.php b/src/Element/Events/ElementPersisted.php
new file mode 100644
index 00000000000..276d36697e1
--- /dev/null
+++ b/src/Element/Events/ElementPersisted.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CraftCms\Cms\Element\Events;
+
+use CraftCms\Cms\Element\Contracts\ElementInterface;
+
+/** Dispatched after the element is persisted, before its database transaction commits. */
+class ElementPersisted
+{
+    public function __construct(
+        public ElementInterface $element,
+        public bool $isNew = false,
+    ) {}
+}
diff --git a/src/Element/Operations/ElementWrites.php b/src/Element/Operations/ElementWrites.php
index a39f90f1c47..d52796b23d9 100644
--- a/src/Element/Operations/ElementWrites.php
+++ b/src/Element/Operations/ElementWrites.php
@@ -11,6 +11,7 @@
 use CraftCms\Cms\Element\ElementHelper;
 use CraftCms\Cms\Element\Elements;
 use CraftCms\Cms\Element\Events\ElementLifecyclePropagated;
+use CraftCms\Cms\Element\Events\ElementPersisted;
 use CraftCms\Cms\Element\Events\ElementPropagated;
 use CraftCms\Cms\Element\Events\ElementPropagating;
 use CraftCms\Cms\Element\Events\ElementResaved;
@@ -48,7 +49,6 @@
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Event;
 use Illuminate\Support\Facades\Log;
-use InvalidArgumentException;
 use Throwable;
 
 use function CraftCms\Cms\currentUser;
@@ -563,7 +563,11 @@ protected function saveInternal(
                                     siteSettingsRecord: $siteElementRecord,
                                     inheritedUpdateSearchIndex: $resolvedUpdateSearchIndex,
                                 )) {
-                                    throw new InvalidArgumentException;
+                                    DB::rollBack();
+                                    $this->resetElement($element, $originalFirstSave, $originalIsNewForSite, $originalPropagateAll);
+                                    $element->dateUpdated = $originalDateUpdated;
+
+                                    return false;
                                 }
 
                                 $siteElements[$siteId] = $siteElement;
@@ -625,6 +629,8 @@ protected function saveInternal(
                         BulkOps::trackElement($element);
                     }
 
+                    event(new ElementPersisted($element, $isNewElement));
+
                     DB::commit();
                 } catch (Throwable $throwable) {
                     DB::rollBack();
@@ -632,10 +638,6 @@ protected function saveInternal(
                     $this->resetElement($element, $originalFirstSave, $originalIsNewForSite, $originalPropagateAll);
                     $element->dateUpdated = $originalDateUpdated;
 
-                    if ($throwable instanceof InvalidArgumentException) {
-                        return false;
-                    }
-
                     throw $throwable;
                 } finally {
                     $element->newSiteIds = $newSiteIds;
diff --git a/src/Structure/Structures.php b/src/Structure/Structures.php
index f0a823ce7e7..40a1c11fefc 100644
--- a/src/Structure/Structures.php
+++ b/src/Structure/Structures.php
@@ -4,6 +4,7 @@
 
 namespace CraftCms\Cms\Structure;
 
+use CraftCms\Cms\Activity\ElementActivity;
 use CraftCms\Cms\Activity\StructuralElementActivity;
 use CraftCms\Cms\Database\Table;
 use CraftCms\Cms\Element\Contracts\ElementInterface;
@@ -419,16 +420,10 @@ private function doIt(
             $mode = Mode::Insert;
         }
 
-        $recordMove = $mode === Mode::Update && StructuralElementActivity::shouldRecordMovement($element);
+        $recordMove = $mode === Mode::Update && ElementActivity::shouldRecordWrite($element);
         $structureUid = null;
         $origin = null;
 
-        if ($recordMove) {
-            $structureUid = $this->getStructureById($structureId)->uid
-                ?? throw new Exception("Structure $structureId does not have a UID.");
-            $origin = StructuralElementActivity::position($structureUid, $element);
-        }
-
         /** @var Mode::Insert|Mode::Update $mode */
         [$beforeEvent, $afterEvent] = match ($mode) {
             Mode::Insert => [StructureElementInserted::class, ElementInserted::class],
@@ -466,6 +461,18 @@ private function doIt(
 
         DB::beginTransaction();
         try {
+            if ($recordMove) {
+                $structureUid = $this->getStructureById($structureId)->uid
+                    ?? throw new Exception("Structure $structureId does not have a UID.");
+                $originalElement = $element::find()
+                    ->id($element->id)
+                    ->siteId($element->siteId)
+                    ->structureId($structureId)
+                    ->status(null)
+                    ->one() ?? throw new Exception('Unable to capture the original element position.');
+                $origin = StructuralElementActivity::position($structureUid, $originalElement);
+            }
+
             if (! $structureElementModel->$method($targetElementModel)) {
                 DB::rollBack();
                 $this->releaseLock($structureId, $ownsLock);
diff --git a/tests/Feature/Activity/ActivityCommentsTest.php b/tests/Feature/Activity/ActivityCommentsTest.php
index 5229fd47e33..007f39e74e4 100644
--- a/tests/Feature/Activity/ActivityCommentsTest.php
+++ b/tests/Feature/Activity/ActivityCommentsTest.php
@@ -6,20 +6,28 @@
 use CraftCms\Cms\Activity\EventTypes\CommentCreated;
 use CraftCms\Cms\Activity\EventTypes\CommentDeleted;
 use CraftCms\Cms\Activity\EventTypes\CommentEdited;
+use CraftCms\Cms\Activity\Models\ActivityEvent;
 use CraftCms\Cms\Cp\Notifications\CpNotification;
+use CraftCms\Cms\Cp\Notifications\NotificationCenter;
 use CraftCms\Cms\Database\Table;
 use CraftCms\Cms\Edition;
 use CraftCms\Cms\Entry\Models\Entry;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityCommentsController;
 use CraftCms\Cms\Site\Models\Site;
 use CraftCms\Cms\Support\Facades\Sites;
 use CraftCms\Cms\Support\Facades\UserPermissions;
 use CraftCms\Cms\User\Elements\User;
 use CraftCms\Cms\User\Models\User as UserModel;
 use CraftCms\Cms\User\Notifications\ActivityMentionNotification;
+use CraftCms\Cms\User\Notifications\SendQueuedUserNotifications;
+use Illuminate\Notifications\ChannelManager;
 use Illuminate\Notifications\Channels\DatabaseChannel;
 use Illuminate\Notifications\Channels\MailChannel;
+use Illuminate\Support\Facades\Auth;
 use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Exceptions;
 use Illuminate\Support\Facades\Notification;
+use Illuminate\Support\Facades\Queue;
 use Illuminate\Validation\ValidationException;
 
 beforeEach(function () {
@@ -175,6 +183,79 @@
     $this->comments->edit($comment, $this->author, $editedMarkdown, $this->entry);
 
     Notification::assertSentTimes(ActivityMentionNotification::class, 2);
-    Notification::assertSentTo(UserModel::query()->findOrFail($this->mentioned->id), ActivityMentionNotification::class);
-    Notification::assertSentTo(UserModel::query()->findOrFail($added->id), ActivityMentionNotification::class);
+    Notification::assertSentTo($this->mentioned, ActivityMentionNotification::class);
+    Notification::assertSentTo($added, ActivityMentionNotification::class);
 });
+
+it('delivers queued mention notifications through the configured auth model', function () {
+    config()->set('auth.providers.users.model', ActivityCommentNotificationUser::class);
+    Auth::forgetGuards();
+    Notification::swap(new ChannelManager(app()));
+    Queue::fake();
+
+    $this->comments->create(
+        $this->entry,
+        $this->author,
+        $this->site,
+        "Hello [@grace](craft-user:{$this->mentioned->id}).",
+    );
+
+    $job = Queue::pushed(
+        SendQueuedUserNotifications::class,
+        fn (SendQueuedUserNotifications $job): bool => $job->channels === [DatabaseChannel::class],
+    )->sole();
+    unserialize(serialize($job))->handle(app(ChannelManager::class));
+
+    $recipient = ActivityCommentNotificationUser::query()->findOrFail($this->mentioned->id);
+    $this->actingAs($recipient);
+
+    expect($recipient->notifications()->sole()->data['message'])->toBe('Hello @grace.')
+        ->and(app(NotificationCenter::class)->get())->toHaveCount(1);
+});
+
+it('returns accepted comments when notification dispatch fails after commit', function (bool $editing) {
+    $comment = $editing
+        ? $this->comments->create($this->entry, $this->author, $this->site, 'First version')
+        : null;
+    $baselineDepth = DB::transactionLevel();
+    $dispatchDepth = null;
+    $failure = new RuntimeException('Notification queue unavailable.');
+    Exceptions::fake();
+    Notification::swap(new ChannelManager(app()));
+    config()->set('queue.default', 'sync');
+    Queue::before(function () use (&$dispatchDepth, $failure): void {
+        $dispatchDepth = DB::transactionLevel();
+
+        throw $failure;
+    });
+
+    $markdown = "Accepted comment [@grace](craft-user:{$this->mentioned->id}).";
+    $data = [
+        'elementType' => $this->entry::class,
+        'elementId' => $this->entry->id,
+        'siteId' => $this->site->id,
+        'markdown' => $markdown,
+    ];
+    $response = $editing
+        ? $this->patchJson(action([ActivityCommentsController::class, 'update']), [
+            ...$data,
+            'commentId' => $comment->id,
+        ])
+        : $this->postJson(action([ActivityCommentsController::class, 'store']), $data);
+
+    $response->assertSuccessful()->assertJsonPath('event.comment.markdown', $markdown);
+    $event = ActivityEvent::query()->eventTypes($editing ? CommentEdited::class : CommentCreated::class)->sole();
+
+    expect($event->data['markdown'])->toBe($markdown)
+        ->and($dispatchDepth)->toBe($baselineDepth);
+    Exceptions::assertReported(fn (RuntimeException $exception): bool => $exception === $failure);
+})->with([
+    'creating' => false,
+    'editing' => true,
+]);
+
+class ActivityCommentNotificationUser extends UserModel
+{
+    #[Override]
+    protected $table = Table::USERS;
+}
diff --git a/tests/Feature/Activity/ActivityTransactionsTest.php b/tests/Feature/Activity/ActivityTransactionsTest.php
new file mode 100644
index 00000000000..eedee97d670
--- /dev/null
+++ b/tests/Feature/Activity/ActivityTransactionsTest.php
@@ -0,0 +1,126 @@
+<?php
+
+declare(strict_types=1);
+
+use CraftCms\Cms\Activity\Models\ActivityEvent;
+use CraftCms\Cms\Database\Table;
+use CraftCms\Cms\Element\Drafts;
+use CraftCms\Cms\Entry\Elements\Entry;
+use CraftCms\Cms\Entry\Models\Entry as EntryModel;
+use CraftCms\Cms\Http\Controllers\Elements\ActivityTimelineController;
+use CraftCms\Cms\Http\Controllers\Elements\SaveElementController;
+use CraftCms\Cms\Support\Facades\Elements;
+use CraftCms\Cms\User\Elements\User;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Exceptions;
+
+beforeEach(function () {
+    $this->actingAs(User::findOne());
+});
+
+it('preserves content after a failed save and shows a successful retry once in the timeline', function () {
+    $entry = EntryModel::factory()->createElement(['title' => 'Original title']);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+    Exceptions::fake();
+    $recordingFails = true;
+    ActivityEvent::creating(function (): void {
+        throw new RuntimeException('Activity insert failed.');
+    });
+    $data = [
+        'elementType' => Entry::class,
+        'elementId' => $entry->id,
+        'siteId' => $entry->siteId,
+        'title' => 'Changed title',
+    ];
+
+    $this->postJson(action([SaveElementController::class, 'store']), $data)->assertServerError();
+
+    expect(Entry::find()->id($entry->id)->status(null)->one()->title)->toBe('Original title');
+    $this->postJson(action(ActivityTimelineController::class), $data)
+        ->assertOk()->assertJsonCount(0, 'events');
+
+    $recordingFails = false;
+    $this->postJson(action([SaveElementController::class, 'store']), $data)->assertSuccessful();
+
+    expect(Entry::find()->id($entry->id)->status(null)->one()->title)->toBe('Changed title');
+    $this->postJson(action(ActivityTimelineController::class), $data)
+        ->assertOk()->assertJsonCount(1, 'events')
+        ->assertJsonPath('events.0.changes.0.old', 'Original title')
+        ->assertJsonPath('events.0.changes.0.new', 'Changed title');
+});
+
+it('rolls back entry and draft edits when activity recording fails', function (bool $draft, string $exceptionType) {
+    $entry = EntryModel::factory()->createElement(['title' => 'Original title']);
+
+    if ($draft) {
+        $entry = app(Drafts::class)->createDraft($entry, User::findOne()->id);
+    }
+
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+    ActivityEvent::creating(fn () => throw new $exceptionType('Activity insert failed.'));
+    $entry->title = 'Changed title';
+
+    expect(fn () => Elements::saveElement($entry, updateSearchIndex: false))
+        ->toThrow($exceptionType, 'Activity insert failed.');
+
+    $saved = Entry::find()->id($entry->id)->drafts(null)->status(null)->one();
+
+    expect($saved->title)->toBe('Original title')
+        ->and(ActivityEvent::query()->count())->toBe(0);
+})->with(['canonical entry' => false, 'named draft' => true])
+    ->with([RuntimeException::class, InvalidArgumentException::class]);
+
+it('rolls back draft creation when activity recording fails', function () {
+    $entry = EntryModel::factory()->createElement();
+    $elementCount = DB::table(Table::ELEMENTS)->count();
+    ActivityEvent::creating(fn () => throw new RuntimeException('Activity insert failed.'));
+
+    expect(fn () => app(Drafts::class)->createDraft($entry, User::findOne()->id))
+        ->toThrow(RuntimeException::class, 'Activity insert failed.');
+
+    expect(DB::table(Table::DRAFTS)->count())->toBe(0)
+        ->and(DB::table(Table::ELEMENTS)->count())->toBe($elementCount)
+        ->and(ActivityEvent::query()->count())->toBe(0);
+});
+
+it('rolls back draft application when activity recording fails', function () {
+    $entry = EntryModel::factory()->createElement(['title' => 'Original title']);
+    $draft = app(Drafts::class)->createDraft($entry, User::findOne()->id);
+    $draft->title = 'Changed title';
+    Elements::saveElement($draft, updateSearchIndex: false);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+    ActivityEvent::creating(fn () => throw new RuntimeException('Activity insert failed.'));
+
+    expect(fn () => app(Drafts::class)->applyDraft($draft))
+        ->toThrow(RuntimeException::class, 'Activity insert failed.');
+
+    expect(Entry::find()->id($entry->id)->status(null)->one()->title)->toBe('Original title')
+        ->and(DB::table(Table::DRAFTS)->where('id', $draft->draftId)->exists())->toBeTrue()
+        ->and(Entry::find()->id($draft->id)->drafts()->status(null)->one()->title)->toBe('Changed title')
+        ->and(ActivityEvent::query()->count())->toBe(0);
+});
+
+it('rolls back unpublished draft creation when activity recording fails', function () {
+    $entry = EntryModel::factory()->createElement();
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+    ActivityEvent::creating(fn () => throw new RuntimeException('Activity insert failed.'));
+
+    expect(fn () => app(Drafts::class)->saveElementAsDraft($entry, User::findOne()->id))
+        ->toThrow(RuntimeException::class, 'Activity insert failed.');
+
+    expect(DB::table(Table::DRAFTS)->count())->toBe(0)
+        ->and(Entry::find()->id($entry->id)->status(null)->one()->getIsDraft())->toBeFalse()
+        ->and(ActivityEvent::query()->count())->toBe(0);
+});
+
+it('returns validation failures without leaving an unpublished draft row', function () {
+    $entry = EntryModel::factory()->createElement();
+    $entry->title = str_repeat('x', 256);
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+
+    expect(app(Drafts::class)->saveElementAsDraft($entry, User::findOne()->id))->toBeFalse()
+        ->and($entry->errors()->has('title'))->toBeTrue()
+        ->and(DB::table(Table::DRAFTS)->count())->toBe(0)
+        ->and(Entry::find()->id($entry->id)->status(null)->one()->getIsDraft())->toBeFalse()
+        ->and(ActivityEvent::query()->count())->toBe(0);
+});
diff --git a/tests/Feature/Activity/EntryActivityTest.php b/tests/Feature/Activity/EntryActivityTest.php
index 8040ab455e5..82568f83b0b 100644
--- a/tests/Feature/Activity/EntryActivityTest.php
+++ b/tests/Feature/Activity/EntryActivityTest.php
@@ -146,6 +146,61 @@
         ]]);
 });
 
+it('shows changes between disabled relation targets in the activity timeline', function (bool $provisional) {
+    $oldTarget = EntryModel::factory()->createElement(['title' => 'Old disabled']);
+    $newTarget = EntryModel::factory()->createElement(['title' => 'New disabled']);
+
+    foreach ([$oldTarget, $newTarget] as $target) {
+        $target->enabled = false;
+        expect(Elements::saveElement($target, updateSearchIndex: false))->toBeTrue();
+    }
+
+    $result = EntryModel::factory()
+        ->withField('relatedEntries', EntriesField::class, value: [$oldTarget->id])
+        ->createElementWithFields();
+    $entry = $result->element;
+    $field = $result->fields->get('relatedEntries');
+    $edited = $provisional
+        ? app(Drafts::class)->createDraft($entry, User::findOne()->id, provisional: true)
+        : $entry;
+    DB::table(Table::ACTIVITYEVENTS)->delete();
+
+    $edited->setFieldValue($field->handle, [$newTarget->id]);
+
+    expect(Elements::saveElement($edited, updateSearchIndex: false))->toBeTrue();
+
+    if ($provisional) {
+        app(Drafts::class)->applyDraft($edited);
+    }
+
+    $stored = Entry::find()->id($entry->id)->siteId($entry->siteId)->status(null)->one();
+
+    expect($stored->getFieldValue($field->handle)->status(null)->ids())->toBe([$newTarget->id]);
+
+    postJson(action(ActivityTimelineController::class), [
+        'elementType' => Entry::class,
+        'elementId' => $entry->id,
+        'siteId' => $entry->siteId,
+    ])->assertOk()->assertJsonCount(1, 'events')->assertJsonPath('events.0.changes', [[
+        'label' => $field->name,
+        'old' => [[
+            'elementType' => Entry::class,
+            'id' => $oldTarget->id,
+            'label' => 'Old disabled',
+            'siteId' => $oldTarget->siteId,
+        ]],
+        'new' => [[
+            'elementType' => Entry::class,
+            'id' => $newTarget->id,
+            'label' => 'New disabled',
+            'siteId' => $newTarget->siteId,
+        ]],
+    ]]);
+})->with([
+    'direct save' => false,
+    'provisional draft' => true,
+]);
+
 it('records a status change instead of a generic update', function () {
     $result = EntryModel::factory()
         ->withField('bodyField', PlainText::class, value: 'Old body')
diff --git a/tests/Feature/Activity/StructuralElementActivityTest.php b/tests/Feature/Activity/StructuralElementActivityTest.php
index 0a2510bb6a0..23867b7aeb9 100644
--- a/tests/Feature/Activity/StructuralElementActivityTest.php
+++ b/tests/Feature/Activity/StructuralElementActivityTest.php
@@ -145,7 +145,7 @@
     );
 });
 
-it('shows parent changes applied from provisional drafts in the activity timeline', function () {
+it('shows parent changes in the activity timeline', function (bool $provisional) {
     $structure = Structure::factory()->create();
     $entryType = EntryType::factory()->create();
     $section = Section::factory()->withEntryTypes($entryType)->create([
@@ -159,12 +159,19 @@
     app(Structures::class)->appendToRoot($structure->id, $moved, Mode::Insert);
     $parent = structuredEntry($parent->id, $structure->id);
     $moved = structuredEntry($moved->id, $structure->id);
-    $draft = app(Drafts::class)->createDraft($moved, User::findOne()->id, provisional: true);
-    $draft->setParentId($parent->id);
-    Elements::saveElement($draft, updateSearchIndex: false);
+    $edited = $provisional
+        ? app(Drafts::class)->createDraft($moved, User::findOne()->id, provisional: true)
+        : $moved;
     DB::table(Table::ACTIVITYEVENTS)->delete();
 
-    app(Drafts::class)->applyDraft($draft);
+    $edited->setParentId($parent->id);
+    expect(Elements::saveElement($edited, updateSearchIndex: false))->toBeTrue();
+
+    if ($provisional) {
+        app(Drafts::class)->applyDraft($edited);
+    }
+
+    expect(structuredEntry($moved->id, $structure->id)->getParentId())->toBe($parent->id);
 
     postJson(action(ActivityTimelineController::class), [
         'elementType' => Entry::class,
@@ -176,7 +183,10 @@
             'events.0.description.text',
             'Moved from the position after Parent at the top level to the first position in Parent.',
         );
-});
+})->with([
+    'canonical entry save' => false,
+    'provisional draft application' => true,
+]);
 
 it('records both merge subjects without nested updates or deletion', function () {
     $merged = EntryModel::factory()->createElement(['title' => 'Merged entry']);
diff --git a/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php b/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php
index 4075e00d7bd..6ee79698d81 100644
--- a/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php
+++ b/tests/Feature/Http/Controllers/Elements/ActivityTimelineControllerTest.php
@@ -532,12 +532,10 @@
         'markdown' => "Hello [@grace](craft-user:$mentioned->id).",
     ])->assertOk();
 
-    $notifiable = UserModel::query()->findOrFail($mentioned->id);
-
     Notification::assertSentTo(
-        $notifiable,
+        $mentioned,
         ActivityMentionNotification::class,
-        fn (ActivityMentionNotification $notification): bool => $notification->toDatabase($notifiable)['message']
+        fn (ActivityMentionNotification $notification): bool => $notification->toDatabase($mentioned)['message']
             === 'Hello @grace.',
     );
 });
@@ -583,12 +581,12 @@
 
     Notification::assertSentTimes(ActivityMentionNotification::class, 3);
     Notification::assertSentToTimes(
-        UserModel::query()->findOrFail($grace->id),
+        $grace,
         ActivityMentionNotification::class,
         2,
     );
     Notification::assertSentTo(
-        UserModel::query()->findOrFail($ada->id),
+        $ada,
         ActivityMentionNotification::class,
     );
 });