diff --git a/frontend/src/lib/features/collections/CollectionBacklog.svelte b/frontend/src/lib/features/collections/CollectionBacklog.svelte
index 8481fd428..fe5e18ba2 100644
--- a/frontend/src/lib/features/collections/CollectionBacklog.svelte
+++ b/frontend/src/lib/features/collections/CollectionBacklog.svelte
@@ -1,6 +1,5 @@
 <script>
   import { onMount } from 'svelte';
-  import { useEventListener } from 'runed';
   import { items } from '../../api/items.js';
   import { iterations } from '../../api/milestones.js';
   import { t } from '../../stores/i18n.svelte.js';
@@ -24,6 +23,7 @@
   import { sortBacklogIterations } from './backlogIterationOrder.js';
   import ItemPicker from '../../pickers/ItemPicker.svelte';
   import { backlogStore } from '../../stores/backlogStore.svelte.js';
+  import { onWorkItemRefresh } from '../../stores/workItemRefresh.js';
   import { workspaceDataStore } from '../../stores/workspaceDataStore.svelte.js';
   import { collectionPreferences } from '../../stores/collectionPreferences.svelte.js';
   import { itemModalStore } from '../../stores/itemModalStore.svelte.js';
@@ -228,10 +228,10 @@
   const styles = useGradientStyles();
 
   // Listen for newly created items
-  async function handleRefreshWorkItems(event) {
-    if (!event.detail?.itemId) return;
+  async function handleRefreshWorkItems(detail) {
+    if (!detail?.itemId) return;
     try {
-      const newItem = event.detail.item ?? await items.get(event.detail.itemId);
+      const newItem = detail.item ?? await items.get(detail.itemId);
       // Collection QL and sub-filters depend on server state, so verify rather
       // than assume membership. Unknown never permits an insert; it reconciles.
       const membership = await resolveCreatedItemMembership(newItem, {
@@ -251,7 +251,7 @@
     }
   }
 
-  useEventListener(() => window, 'refresh-work-items', handleRefreshWorkItems);
+  $effect(() => onWorkItemRefresh(handleRefreshWorkItems));
 
   onMount(async () => {
     if (workspaceId) {
diff --git a/frontend/src/lib/features/collections/CollectionBoard.svelte b/frontend/src/lib/features/collections/CollectionBoard.svelte
index 50cc4d3dd..7f0ceb076 100644
--- a/frontend/src/lib/features/collections/CollectionBoard.svelte
+++ b/frontend/src/lib/features/collections/CollectionBoard.svelte
@@ -2,6 +2,7 @@
   import { onMount, untrack } from 'svelte';
   import { useEventListener } from 'runed';
   import { t } from '../../stores/i18n.svelte.js';
+  import { onWorkItemRefresh } from '../../stores/workItemRefresh.js';
   import { items as itemsApi } from '../../api/items.js';
   import { getAssignableUsers } from '../../api/users.js';
   import { labels as labelsApi } from '../../api/misc.js';
@@ -263,10 +264,10 @@
   }
 
   // Listen for newly created items
-  async function handleRefreshWorkItems(event) {
-    if (!event.detail?.itemId) return;
+  async function handleRefreshWorkItems(detail) {
+    if (!detail?.itemId) return;
     try {
-      const newItem = event.detail.item ?? (await itemsApi.get(event.detail.itemId));
+      const newItem = detail.item ?? (await itemsApi.get(detail.itemId));
       const membership = await resolveCreatedItemMembership(newItem, createdItemScope());
       if (membership === 'member') {
         // A create event can arrive more than once (modal event plus a delta or
@@ -281,7 +282,7 @@
     }
   }
 
-  useEventListener(() => window, 'refresh-work-items', handleRefreshWorkItems);
+  $effect(() => onWorkItemRefresh(handleRefreshWorkItems));
 
   // Quick-add functions
 
diff --git a/frontend/src/lib/features/collections/CollectionList.svelte b/frontend/src/lib/features/collections/CollectionList.svelte
index ac3453645..5a97ec028 100644
--- a/frontend/src/lib/features/collections/CollectionList.svelte
+++ b/frontend/src/lib/features/collections/CollectionList.svelte
@@ -1,7 +1,7 @@
 <script>
-  import { useEventListener } from 'runed';
   import { t } from '../../stores/i18n.svelte.js';
   import { errorToast } from '../../stores/toasts.svelte.js';
+  import { onWorkItemRefresh } from '../../stores/workItemRefresh.js';
   import {
     applyCollectionItem,
     collectionStore,
@@ -98,16 +98,18 @@
 
   let gridMinWidth = $derived(listGridMinWidth(listColumns));
 
-  useEventListener(() => window, 'refresh-work-items', (/** @type {CustomEvent} */ event) => {
-    const item = event.detail?.item;
-    // Workspace-scoped views can apply the item immediately as a display
-    // optimization. Collection membership is verified by the store's
-    // coalesced reconciliation instead of one query per event.
-    if (item && !collectionId && Number(item.workspace_id) === Number(workspaceId)) {
-      applyCollectionItem(item);
-    }
-    scheduleCollectionReconciliation();
-  });
+  $effect(() =>
+    onWorkItemRefresh((detail) => {
+      const item = detail?.item;
+      // Workspace-scoped views can apply the item immediately as a display
+      // optimization. Collection membership is verified by the store's
+      // coalesced reconciliation instead of one query per event.
+      if (item && !collectionId && Number(item.workspace_id) === Number(workspaceId)) {
+        applyCollectionItem(item);
+      }
+      scheduleCollectionReconciliation();
+    })
+  );
 
   // Scoped SSE invalidations (WI-1624): any frame runs the existing delta fetch,
   // and a reconnect reconciles. Without this the list kept showing items that
diff --git a/frontend/src/lib/features/items/ItemDetail.svelte b/frontend/src/lib/features/items/ItemDetail.svelte
index c1ba301a2..f1b8fa5e8 100644
--- a/frontend/src/lib/features/items/ItemDetail.svelte
+++ b/frontend/src/lib/features/items/ItemDetail.svelte
@@ -36,6 +36,7 @@
   import { useItemEventStream } from '../../composables/useItemEventStream.svelte.js';
   import { notificationActions } from '../../stores/notifications.js';
   import { agentRuns } from '../../stores/agentRuns.svelte.js';
+  import { onWorkItemRefresh } from '../../stores/workItemRefresh.js';
   import {
     registerContextCommands,
     unregisterContextCommands,
@@ -300,17 +301,23 @@ import NativeSelect from '../../components/NativeSelect.svelte';
 
   useEventListener(() => document, 'keydown', handleItemDetailShortcuts);
 
-  // Reload child items when a new child is created against the item currently open.
-  useEventListener(() => window, 'refresh-work-items', (/** @type {CustomEvent<{parentId?: number}>} */ event) => {
-    const parentId = event?.detail?.parentId;
-    if (parentId == null) return;
-    const currentId = itemDetailStore.item?.id;
-    if (currentId == null) return;
-    if (Number(parentId) !== Number(currentId)) return;
-    itemDetailStore.loadChildItems().catch((err) => {
-      console.error('Failed to reload child items after child creation:', err);
-    });
-  });
+  // Reload child items when a new child is created against the item currently
+  // open. The coordinator batches a burst; check every parent it named.
+  $effect(() =>
+    onWorkItemRefresh((detail) => {
+      const currentId = itemDetailStore.item?.id;
+      if (currentId == null) return;
+      const parents = detail?.parentIds?.length
+        ? detail.parentIds
+        : detail?.parentId != null
+          ? [detail.parentId]
+          : [];
+      if (!parents.some((parentId) => Number(parentId) === Number(currentId))) return;
+      itemDetailStore.loadChildItems().catch((err) => {
+        console.error('Failed to reload child items after child creation:', err);
+      });
+    })
+  );
 
   function handleFocusStatus() {
     // Focus the status field by starting edit mode
diff --git a/frontend/src/lib/features/items/ItemDetailSidebar.svelte b/frontend/src/lib/features/items/ItemDetailSidebar.svelte
index 83953e6ab..f37b77a64 100644
--- a/frontend/src/lib/features/items/ItemDetailSidebar.svelte
+++ b/frontend/src/lib/features/items/ItemDetailSidebar.svelte
@@ -659,7 +659,7 @@
       />
     {/snippet}
     {#if item?.id}
-      <ItemSLAPanel itemId={item.id} />
+      <ItemSLAPanel itemId={item.id} workspaceId={item.workspace_id} />
     {/if}
     <!-- DETAILS Section Header -->
     <div class="flex items-center justify-between mb-2">
diff --git a/frontend/src/lib/features/items/ItemSLAPanel.svelte b/frontend/src/lib/features/items/ItemSLAPanel.svelte
index a4cbdaf21..fb8a8c849 100644
--- a/frontend/src/lib/features/items/ItemSLAPanel.svelte
+++ b/frontend/src/lib/features/items/ItemSLAPanel.svelte
@@ -1,14 +1,14 @@
 <script>
-  import { useEventListener } from 'runed';
-  import { sla } from '../../api/sla.js';
   import Lozenge from '../../components/Lozenge.svelte';
   import Tooltip from '../../components/Tooltip.svelte';
   import Gauge from '@lucide/svelte/icons/gauge';
   import Clock from '@lucide/svelte/icons/clock';
   import { t } from '../../stores/i18n.svelte.js';
   import { formatInstant } from '../../utils/dateFormatter.js';
+  import { onWorkItemRefresh, workItemRefreshTouchesWorkspace } from '../../stores/workItemRefresh.js';
+  import { getItemSLA } from '../sla/slaState.js';
 
-  let { itemId = null } = $props();
+  let { itemId = null, workspaceId = null } = $props();
 
   // Server-computed remaining/breach state has to be re-read while a timer is
   // visible; elapsed time and business-hours transitions never reach the client
@@ -25,7 +25,7 @@
     const requestedItemId = itemId;
     loading = true;
     try {
-      const result = (await sla.getItemSLA(requestedItemId)) ?? [];
+      const result = (await getItemSLA(requestedItemId, workspaceId)) ?? [];
       // A newer request or an item switch supersedes this response.
       if (token !== requestToken) return;
       states = result;
@@ -51,8 +51,15 @@
   });
 
   // Item mutations (status, assignee, comments, etc.) are broadcast globally;
-  // refresh the derived SLA state when they happen.
-  useEventListener(() => window, 'refresh-work-items', () => void load());
+  // refresh the derived SLA state when they happen. Reading through slaState
+  // means the panel and any SLA badges in the same workspace share one batch,
+  // and a burst in another workspace is skipped entirely.
+  $effect(() =>
+    onWorkItemRefresh((detail) => {
+      if (!workItemRefreshTouchesWorkspace(detail, workspaceId)) return;
+      void load();
+    })
+  );
 
   function formatDuration(ms) {
     if (ms == null) return '';
diff --git a/frontend/src/lib/features/sla/SLABadge.svelte b/frontend/src/lib/features/sla/SLABadge.svelte
index 7c41f93e7..3a0cfdd14 100644
--- a/frontend/src/lib/features/sla/SLABadge.svelte
+++ b/frontend/src/lib/features/sla/SLABadge.svelte
@@ -1,9 +1,9 @@
 <script>
-  import { useEventListener } from 'runed';
   import Lozenge from '../../components/Lozenge.svelte';
   import Tooltip from '../../components/Tooltip.svelte';
   import { t } from '../../stores/i18n.svelte.js';
   import { formatInstant } from '../../utils/dateFormatter.js';
+  import { onWorkItemRefresh, workItemRefreshTouchesWorkspace } from '../../stores/workItemRefresh.js';
   import { getItemSLA, getSLAThresholds, onSLAThresholdsInvalidated } from './slaState.js';
 
   let { itemId = null, workspaceId = null, refreshToken = 0 } = $props();
@@ -37,7 +37,12 @@
     };
   });
 
-  useEventListener(() => window, 'refresh-work-items', () => void load(itemId, workspaceId, refreshToken));
+  $effect(() =>
+    onWorkItemRefresh((detail) => {
+      if (!workItemRefreshTouchesWorkspace(detail, workspaceId)) return;
+      void load(itemId, workspaceId, refreshToken);
+    })
+  );
 
   // A threshold mutation in this tab must refresh mounted badges immediately;
   // failed mutations never emit, and other tabs pick the change up once the
diff --git a/frontend/src/lib/pages/Homepage.svelte b/frontend/src/lib/pages/Homepage.svelte
index 15b837bf7..6a96ee89b 100644
--- a/frontend/src/lib/pages/Homepage.svelte
+++ b/frontend/src/lib/pages/Homepage.svelte
@@ -18,6 +18,7 @@
   import Trash2 from '@lucide/svelte/icons/trash-2';
   import X from '@lucide/svelte/icons/x';
   import { useEventListener } from 'runed';
+  import { onWorkItemRefresh } from '../stores/workItemRefresh.js';
   import { createDashboardWidgetDrag } from '../composables/dashboardWidgetDrag.js';
   import { useDashboardCustomization } from '../composables/useDashboardCustomization.svelte.js';
   import { confirm } from '../composables/useConfirm.js';
@@ -112,7 +113,7 @@
   }
 
   useEventListener(() => window, 'refresh-workspaces', handleRefresh);
-  useEventListener(() => window, 'refresh-work-items', handleRefresh);
+  $effect(() => onWorkItemRefresh(handleRefresh));
 
   // --- Layout / mode handlers ---
 
diff --git a/frontend/src/lib/pages/useMainAppLifecycle.js b/frontend/src/lib/pages/useMainAppLifecycle.js
index 32397deea..5e0a3b8ba 100644
--- a/frontend/src/lib/pages/useMainAppLifecycle.js
+++ b/frontend/src/lib/pages/useMainAppLifecycle.js
@@ -12,6 +12,7 @@ import { authStore } from '../stores/auth.svelte.js';
 import { capabilitiesStore } from '../stores/capabilities.svelte.js';
 import { homepageStore } from '../stores/homepageStore.svelte.js';
 import { startNotificationPoller, stopNotificationPoller } from '../stores/notifications.js';
+import { onWorkItemRefresh } from '../stores/workItemRefresh.js';
 import { workspaceDataStore } from '../stores/workspaceDataStore.svelte.js';
 import { workspacesStore } from '../stores/workspaces.svelte.js';
 import { initDesktopFocusRefresh } from '../utils/desktopFocusRefresh.svelte.js';
@@ -124,20 +125,22 @@ export function useMainAppLifecycle({
       void workspacesStore.reload();
     };
     const handleRefreshWorkspaceData = () => void workspaceDataStore.refresh();
-    const handleRefreshWorkItems = () => homepageStore.invalidateSnapshot();
+    // The homepage only marks its snapshot stale here; the mounted Homepage
+    // component refreshes it. One coordinator owns the event so this is not a
+    // second independent listener.
+    const unsubscribeRefreshWorkItems = onWorkItemRefresh(() => homepageStore.invalidateSnapshot());
 
     window.addEventListener('show-create-modal', handleShowCreateModal);
     window.addEventListener(ADMIN_UI_MUTATION_EVENT, scheduleAdminUIRefresh);
     window.addEventListener('refresh-workspaces', handleRefreshWorkspaces);
     window.addEventListener('refresh-workspace-data', handleRefreshWorkspaceData);
-    window.addEventListener('refresh-work-items', handleRefreshWorkItems);
 
     return () => {
       window.removeEventListener('show-create-modal', handleShowCreateModal);
       window.removeEventListener(ADMIN_UI_MUTATION_EVENT, scheduleAdminUIRefresh);
       window.removeEventListener('refresh-workspaces', handleRefreshWorkspaces);
       window.removeEventListener('refresh-workspace-data', handleRefreshWorkspaceData);
-      window.removeEventListener('refresh-work-items', handleRefreshWorkItems);
+      unsubscribeRefreshWorkItems();
       if (adminUIRefreshTimer) clearTimeout(adminUIRefreshTimer);
     };
   });
diff --git a/frontend/src/lib/stores/workItemRefresh.js b/frontend/src/lib/stores/workItemRefresh.js
new file mode 100644
index 000000000..259563866
--- /dev/null
+++ b/frontend/src/lib/stores/workItemRefresh.js
@@ -0,0 +1,121 @@
+// One debounced reconciliation for the global `refresh-work-items` broadcast.
+//
+// The event is a "work items changed" signal. Surfaces used to add their own
+// window listener, so one mutation started several independent reads (homepage
+// snapshot, item SLA, child items, collection delta). This module owns the
+// single surface listener, merges a burst into one notification, and each
+// subscriber reconciles its own surface at most once.
+
+// Synchronous bursts (modal event plus an SSE frame plus a cross-tab frame)
+// coalesce into one flush. Zero delay keeps the reconciliation on the next
+// task without adding perceptible latency to a single mutation.
+const RECONCILE_DELAY_MS = 0;
+
+/**
+ * @typedef {Object} WorkItemRefresh
+ * @property {any} [item] Latest item in the burst.
+ * @property {number} [itemId] Latest item id in the burst.
+ * @property {number} [workspaceId] Latest workspace id in the burst.
+ * @property {number|null} [parentId] Latest parent id in the burst.
+ * @property {number[]} itemIds Every item id seen in the burst.
+ * @property {number[]} parentIds Every parent id seen in the burst.
+ */
+
+/** @type {Set<(detail: WorkItemRefresh) => void>} */
+const subscribers = new Set();
+/** @type {ReturnType<typeof setTimeout>|null} */
+let timer = null;
+/** @type {WorkItemRefresh|null} */
+let pending = null;
+
+function emptyDetail() {
+  return { itemIds: [], parentIds: [] };
+}
+
+function mergeDetail(current, event) {
+  const detail = current ?? emptyDetail();
+  const next = event?.detail ?? {};
+  if (next.item) detail.item = next.item;
+  if (next.itemId != null) detail.itemId = next.itemId;
+  if (next.workspaceId != null) detail.workspaceId = next.workspaceId;
+  if (next.parentId != null) detail.parentId = next.parentId;
+
+  const itemId = next.itemId ?? next.item?.id;
+  if (itemId != null && !detail.itemIds.includes(itemId)) detail.itemIds.push(itemId);
+  if (next.parentId != null && !detail.parentIds.includes(next.parentId)) {
+    detail.parentIds.push(next.parentId);
+  }
+  return detail;
+}
+
+function flush() {
+  timer = null;
+  const detail = pending ?? emptyDetail();
+  pending = null;
+  for (const subscriber of subscribers) {
+    try {
+      subscriber(detail);
+    } catch (error) {
+      console.error('refresh-work-items subscriber failed:', error);
+    }
+  }
+}
+
+function handleWindowEvent(event) {
+  pending = mergeDetail(pending, event);
+  if (timer != null) return;
+  timer = setTimeout(flush, RECONCILE_DELAY_MS);
+}
+
+/**
+ * Subscribe to one debounced reconciliation per `refresh-work-items` burst.
+ *
+ * @param {(detail: WorkItemRefresh) => void} subscriber
+ * @returns {() => void} unsubscribe
+ */
+export function onWorkItemRefresh(subscriber) {
+  if (typeof window === 'undefined') return () => {};
+  subscribers.add(subscriber);
+  if (subscribers.size === 1) {
+    window.addEventListener('refresh-work-items', handleWindowEvent);
+  }
+  return () => {
+    subscribers.delete(subscriber);
+    if (subscribers.size === 0) {
+      window.removeEventListener('refresh-work-items', handleWindowEvent);
+      if (timer != null) {
+        clearTimeout(timer);
+        timer = null;
+      }
+      pending = null;
+    }
+  };
+}
+
+/**
+ * Whether a burst names the given workspace, or carries no workspace to
+ * filter on. Lets a workspace-scoped surface skip a reconciliation that
+ * cannot affect it.
+ *
+ * @param {WorkItemRefresh} detail
+ * @param {number|null|undefined} workspaceId
+ * @returns {boolean}
+ */
+export function workItemRefreshTouchesWorkspace(detail, workspaceId) {
+  const eventWorkspace = detail?.item?.workspace_id ?? detail?.workspaceId ?? null;
+  if (eventWorkspace == null || workspaceId == null) return true;
+  return Number(eventWorkspace) === Number(workspaceId);
+}
+
+/** Test-only: drop subscribers and any pending reconciliation. */
+export function resetWorkItemRefresh() {
+  subscribers.clear();
+  if (typeof window !== 'undefined') {
+    window.removeEventListener('refresh-work-items', handleWindowEvent);
+  }
+  if (timer != null) {
+    clearTimeout(timer);
+    timer = null;
+  }
+  pending = null;
+}