diff --git a/frontend/src/components/ToolCallCard.vue b/frontend/src/components/ToolCallCard.vue
index f1723c8..54c0fdb 100644
--- a/frontend/src/components/ToolCallCard.vue
+++ b/frontend/src/components/ToolCallCard.vue
@@ -270,8 +270,11 @@ async function openEventSlideOver(id: number | undefined) {
   }
 }
 
-function closeEventSlideOver() {
+function closeEventSlideOver(changed = false) {
   eventSlideOverOpen.value = false;
+  if (changed) {
+    document.dispatchEvent(new Event("fable:calendar-changed"));
+  }
 }
 </script>
 
@@ -522,9 +525,9 @@ function closeEventSlideOver() {
     :event="eventSlideOverEntry"
     initial-date=""
     @close="closeEventSlideOver"
-    @created="closeEventSlideOver"
-    @updated="closeEventSlideOver"
-    @deleted="closeEventSlideOver"
+    @created="() => closeEventSlideOver(true)"
+    @updated="() => closeEventSlideOver(true)"
+    @deleted="() => closeEventSlideOver(true)"
   />
 </template>
 
diff --git a/frontend/src/views/HomeView.vue b/frontend/src/views/HomeView.vue
index 789fb08..c940f8e 100644
--- a/frontend/src/views/HomeView.vue
+++ b/frontend/src/views/HomeView.vue
@@ -77,9 +77,11 @@ function _dateRange() {
   const today = new Date()
   const nextWeek = new Date(today)
   nextWeek.setDate(today.getDate() + 7)
+  // Use full ISO strings so the server sees the correct UTC equivalent of
+  // local midnight / end-of-day rather than a naive UTC-midnight guess.
   return {
-    todayStr: today.toISOString().slice(0, 10) + 'T00:00:00',
-    nextWeekStr: nextWeek.toISOString().slice(0, 10) + 'T23:59:59',
+    todayStr: today.toISOString(),
+    nextWeekStr: nextWeek.toISOString(),
   }
 }
 
@@ -108,11 +110,7 @@ function _backgroundRefresh() {
 
 onMounted(async () => {
   // Phase 1: projects list + cross-project recent items + orphaned items + events — all parallel
-  const today = new Date();
-  const todayStr = today.toISOString().slice(0, 10) + "T00:00:00";
-  const nextWeek = new Date(today);
-  nextWeek.setDate(today.getDate() + 7);
-  const nextWeekStr = nextWeek.toISOString().slice(0, 10) + "T23:59:59";
+  const { todayStr, nextWeekStr } = _dateRange();
 
   const [projectsRes, recentRes, orphanTasksRes, orphanNotesRes, eventsRes] =
     await Promise.allSettled([
diff --git a/frontend/src/views/KnowledgeView.vue b/frontend/src/views/KnowledgeView.vue
index bb3a2cf..ad87da6 100644
--- a/frontend/src/views/KnowledgeView.vue
+++ b/frontend/src/views/KnowledgeView.vue
@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { ref, computed, watch, onMounted, onUnmounted, nextTick } from "vue";
 import { useRouter } from "vue-router";
-import { apiGet, apiPatch } from "@/api/client";
+import { apiGet, apiPatch, listEvents } from "@/api/client";
 import { fmtCompact } from "@/utils/dateFormat";
 import { useChatStore } from "@/stores/chat";
 import GraphView from "@/views/GraphView.vue";
@@ -167,15 +167,13 @@ async function fetchTodayBar() {
   try {
     const now = new Date();
     const end = new Date(now.getTime() + 7 * 86_400_000);
-    const [evData, taskData] = await Promise.all([
-      apiGet<{ events: UpcomingEvent[] }>(
-        `/api/events?from=${now.toISOString().slice(0, 10)}&to=${end.toISOString().slice(0, 10)}`
-      ).catch(() => ({ events: [] as UpcomingEvent[] })),
+    const [events, taskData] = await Promise.all([
+      listEvents(now.toISOString(), end.toISOString()).catch(() => [] as UpcomingEvent[]),
       apiGet<{ total: number }>(
         `/api/tasks?status=todo&status=in_progress&overdue=true&limit=1`
       ).catch(() => ({ total: 0 })),
     ]);
-    upcomingEvents.value = (evData.events ?? []).slice(0, 3);
+    upcomingEvents.value = events.slice(0, 3);
     overdueCount.value = taskData.total ?? 0;
   } catch { /* silent */ }
 }
diff --git a/src/fabledassistant/routes/events.py b/src/fabledassistant/routes/events.py
index 4108f3e..ac557df 100644
--- a/src/fabledassistant/routes/events.py
+++ b/src/fabledassistant/routes/events.py
@@ -96,11 +96,15 @@ async def update_event(event_id: int):
         if int_field in data:
             fields[int_field] = data[int_field]
     for dt_field in ("start_dt", "end_dt"):
-        if dt_field in data and data[dt_field]:
-            try:
-                fields[dt_field] = _parse_dt(data[dt_field])
-            except ValueError:
-                return jsonify({"error": f"Invalid datetime for {dt_field}"}), 400
+        if dt_field in data:
+            if data[dt_field] is None:
+                # Explicit null clears the field (e.g. removing end_dt)
+                fields[dt_field] = None
+            elif data[dt_field]:
+                try:
+                    fields[dt_field] = _parse_dt(data[dt_field])
+                except ValueError:
+                    return jsonify({"error": f"Invalid datetime for {dt_field}"}), 400
     event = await events_svc.update_event(
         user_id=_get_current_user_id(),
         event_id=event_id,
diff --git a/src/fabledassistant/services/events.py b/src/fabledassistant/services/events.py
index e399e75..cfc2f28 100644
--- a/src/fabledassistant/services/events.py
+++ b/src/fabledassistant/services/events.py
@@ -75,16 +75,24 @@ async def list_events(
     date_from: datetime,
     date_to: datetime,
 ) -> list[Event]:
-    """List events for user_id within [date_from, date_to]."""
+    """List events for user_id that overlap [date_from, date_to].
+
+    An event overlaps the range if it starts before date_to AND either
+    has no end_dt (point event) or its end_dt is after date_from.
+    This ensures multi-day events that span the query boundary are included.
+    """
     async with async_session() as session:
         result = await session.execute(
             select(Event).where(
                 Event.user_id == user_id,
-                Event.start_dt >= date_from,
                 Event.start_dt <= date_to,
+                or_(
+                    Event.end_dt.is_(None),
+                    Event.end_dt >= date_from,
+                ),
             ).order_by(Event.start_dt)
         )
-        return result.scalars().all()
+        return list(result.scalars().all())
 
 
 async def search_events(
@@ -124,8 +132,10 @@ async def update_event(user_id: int, event_id: int, **fields) -> Event | None:
         old_title = event.title  # capture before mutation for CalDAV lookup
         allowed = {"title", "start_dt", "end_dt", "all_day", "description",
                    "location", "color", "recurrence", "project_id"}
+        # Nullable fields that callers can explicitly set to None to clear
+        nullable = {"end_dt", "recurrence", "project_id"}
         for key, value in fields.items():
-            if key in allowed and value is not None:
+            if key in allowed and (value is not None or key in nullable):
                 setattr(event, key, value)
         await session.commit()
         await session.refresh(event)
@@ -153,16 +163,32 @@ async def delete_event(user_id: int, event_id: int) -> None:
 
 
 async def find_events_by_query(user_id: int, query: str) -> list[Event]:
-    """ILIKE search on title — used by AI update/delete tools."""
+    """ILIKE search on title — used by AI update/delete tools.
+
+    Returns upcoming events first (start_dt >= now), falling back to
+    past events so the AI operates on the most relevant match.
+    """
     q = f"%{query}%"
+    now = datetime.now(timezone.utc)
     async with async_session() as session:
-        result = await session.execute(
+        # Prefer events at or after now; fall back to past events
+        upcoming = (await session.execute(
             select(Event).where(
                 Event.user_id == user_id,
                 Event.title.ilike(q),
+                Event.start_dt >= now,
             ).order_by(Event.start_dt)
-        )
-        return result.scalars().all()
+        )).scalars().all()
+        if upcoming:
+            return list(upcoming)
+        past = (await session.execute(
+            select(Event).where(
+                Event.user_id == user_id,
+                Event.title.ilike(q),
+                Event.start_dt < now,
+            ).order_by(Event.start_dt.desc())
+        )).scalars().all()
+        return list(past)
 
 
 # ---------------------------------------------------------------------------
diff --git a/src/fabledassistant/services/tools.py b/src/fabledassistant/services/tools.py
index a351676..b40990f 100644
--- a/src/fabledassistant/services/tools.py
+++ b/src/fabledassistant/services/tools.py
@@ -1506,7 +1506,10 @@ async def execute_tool(
                 val = arguments.get(key)
                 if val:
                     try:
-                        fields[dt_field] = datetime.fromisoformat(val)
+                        dt = datetime.fromisoformat(val.replace("Z", "+00:00"))
+                        if dt.tzinfo is None:
+                            dt = dt.replace(tzinfo=timezone.utc)
+                        fields[dt_field] = dt
                     except (ValueError, TypeError):
                         return {"success": False, "error": f"Invalid datetime for {key}: {val!r}"}
             updated = await events_update_event(