diff --git a/apps/app/src/components/ai.tsx b/apps/app/src/components/ai.tsx
index 8f0bd1e4..a072e85f 100644
--- a/apps/app/src/components/ai.tsx
+++ b/apps/app/src/components/ai.tsx
@@ -43,8 +43,6 @@ const renderToolPart = (
   part: ChatMessagePart,
   index: number,
 ): React.ReactNode => {
-  if (!part.type?.startsWith("tool-")) return null;
-
   return <Tool key={`${part.type}-${index}`} toolPart={part as ToolPart} />;
 };
 
@@ -52,7 +50,7 @@ export function MessageComponent({
   message,
   isLastMessage,
 }: MessageComponentProps) {
-  const isAssistant = message?.role === "assistant";
+  const isAssistant = message.role === "assistant";
 
   return (
     <Message
@@ -64,17 +62,17 @@ export function MessageComponent({
       {isAssistant ? (
         <div className="group flex w-full flex-col gap-0 space-y-2">
           <div className="w-full">
-            {message?.parts
-              .filter((part) => part.type?.startsWith("tool-"))
+            {message.parts
+              .filter((part) => part.type.startsWith("tool-"))
               .map((part, index) => renderToolPart(part, index))}
           </div>
           <MessageContent
             className="prose w-full min-w-0 flex-1 rounded-lg bg-transparent p-0 text-foreground"
             markdown
           >
-            {message?.parts
+            {message.parts
               .filter((part) => part.type === "text")
-              .map((part) => (part.type === "text" ? part.text : ""))
+              .map((part) => part.text)
               .join("")}
           </MessageContent>
 
@@ -104,7 +102,7 @@ export function MessageComponent({
       ) : (
         <div className="group flex w-full flex-col items-end gap-1">
           <MessageContent className="max-w-[85%] rounded-3xl bg-muted px-5 py-2.5 whitespace-pre-wrap text-primary sm:max-w-[75%]">
-            {message?.parts
+            {message.parts
               .map((part) => (part.type === "text" ? part.text : ""))
               .join("")}
           </MessageContent>
@@ -193,7 +191,7 @@ function ThreadChatbot() {
             </div>
           )}
 
-          {messages?.map((message, index) => {
+          {messages.map((message, index) => {
             const isLastMessage = index === messages.length - 1;
 
             return (
diff --git a/apps/app/src/components/prompt-kit/response-stream.tsx b/apps/app/src/components/prompt-kit/response-stream.tsx
index 8aa4daec..dae0dffd 100644
--- a/apps/app/src/components/prompt-kit/response-stream.tsx
+++ b/apps/app/src/components/prompt-kit/response-stream.tsx
@@ -76,8 +76,6 @@ function useTextStream({
     if (modeRef.current === "typewriter") {
       if (normalizedSpeed < 25) return 1;
       return Math.max(1, Math.round((normalizedSpeed - 25) / 10));
-    } else if (modeRef.current === "fade") {
-      return 1;
     }
 
     return 1;
@@ -234,7 +232,7 @@ function useTextStream({
 
     if (typeof textStream === "string") {
       processStringTypewriter(textStream);
-    } else if (textStream) {
+    } else {
       processAsyncIterable(textStream);
     }
   }, [textStream, reset, processStringTypewriter, processAsyncIterable]);
@@ -388,7 +386,7 @@ function ResponseStream({
     }
   };
 
-  const Container = as as keyof React.JSX.IntrinsicElements;
+  const Container = as;
 
   return <Container className={className}>{renderContent()}</Container>;
 }
diff --git a/apps/app/src/components/sign-in-with-google-button.tsx b/apps/app/src/components/sign-in-with-google-button.tsx
index 0be73121..45c68d83 100644
--- a/apps/app/src/components/sign-in-with-google-button.tsx
+++ b/apps/app/src/components/sign-in-with-google-button.tsx
@@ -22,7 +22,7 @@ export function SignInWithGoogleButton() {
       return data;
     },
     onError: (error) => {
-      toast.error(error.message ?? "An unknown error occurred");
+      toast.error(error.message);
     },
   });
 
diff --git a/apps/app/src/components/ui/field.tsx b/apps/app/src/components/ui/field.tsx
index 2d4e7f88..64516e36 100644
--- a/apps/app/src/components/ui/field.tsx
+++ b/apps/app/src/components/ui/field.tsx
@@ -194,7 +194,7 @@ function FieldError({
       ...new Map(errors.map((error) => [error?.message, error])).values(),
     ];
 
-    if (uniqueErrors?.length == 1) {
+    if (uniqueErrors.length === 1) {
       return uniqueErrors[0]?.message;
     }
 
diff --git a/apps/app/src/lib/trpc/query-client.ts b/apps/app/src/lib/trpc/query-client.ts
index 30592e68..db3033e8 100644
--- a/apps/app/src/lib/trpc/query-client.ts
+++ b/apps/app/src/lib/trpc/query-client.ts
@@ -29,7 +29,7 @@ export function makeQueryClient() {
     },
     queryCache: new QueryCache({
       onError: (error) => {
-        console.error(error.message ?? "Something went wrong");
+        console.error(error.message);
       },
     }),
   });
diff --git a/apps/app/src/routes/login.tsx b/apps/app/src/routes/login.tsx
index 489f8eda..d51ee7bc 100644
--- a/apps/app/src/routes/login.tsx
+++ b/apps/app/src/routes/login.tsx
@@ -61,7 +61,7 @@ function Login() {
       toast.success("Magic link printed to the server logs");
     },
     onError: (error) => {
-      toast.error(error.message ?? "An unknown error occurred");
+      toast.error(error.message);
     },
   });
 
diff --git a/apps/web/next-env.d.ts b/apps/web/next-env.d.ts
index ce4e94a6..a419cbe4 100644
--- a/apps/web/next-env.d.ts
+++ b/apps/web/next-env.d.ts
@@ -1,7 +1,7 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
-import "./.next/types/root-params.d.ts";
+import "./.next/dev/types/routes.d.ts";
+import "./.next/dev/types/root-params.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.
diff --git a/apps/web/src/app/api/[...trpc]/route.ts b/apps/web/src/app/api/[...trpc]/route.ts
index 6ba37876..e71d9fba 100644
--- a/apps/web/src/app/api/[...trpc]/route.ts
+++ b/apps/web/src/app/api/[...trpc]/route.ts
@@ -2,14 +2,13 @@ import { createOpenApiFetchHandler } from "trpc-to-openapi";
 
 import { appRouter, createContext } from "@repo/api";
 
-const handler = (req: Request) => {
-  return createOpenApiFetchHandler({
+const handler = (req: Request) =>
+  createOpenApiFetchHandler({
     endpoint: "/api/v1",
     req,
     router: appRouter,
     createContext: () => createContext({ headers: req.headers }),
   });
-};
 
 export {
   handler as GET,
diff --git a/apps/web/src/components/calendar/flows/create-event/create-queue-provider.tsx b/apps/web/src/components/calendar/flows/create-event/create-queue-provider.tsx
index a1a5b731..1bd50874 100644
--- a/apps/web/src/components/calendar/flows/create-event/create-queue-provider.tsx
+++ b/apps/web/src/components/calendar/flows/create-event/create-queue-provider.tsx
@@ -38,12 +38,14 @@ export function CreateQueueProvider({ children }: CreateQueueProviderProps) {
     [createMutation, removeOptimisticAction],
   );
 
-  const logic = React.useMemo(() => {
-    return createCreateQueueMachine({
-      createEvent,
-      removeOptimisticAction,
-    });
-  }, [createEvent, removeOptimisticAction]);
+  const logic = React.useMemo(
+    () =>
+      createCreateQueueMachine({
+        createEvent,
+        removeOptimisticAction,
+      }),
+    [createEvent, removeOptimisticAction],
+  );
 
   return (
     <CreateQueueContext.Provider logic={logic}>
diff --git a/apps/web/src/components/calendar/flows/create-event/create-queue.ts b/apps/web/src/components/calendar/flows/create-event/create-queue.ts
index 59a31f2b..d09a4d90 100644
--- a/apps/web/src/components/calendar/flows/create-event/create-queue.ts
+++ b/apps/web/src/components/calendar/flows/create-event/create-queue.ts
@@ -20,7 +20,7 @@ export interface CreateQueueItem {
 }
 
 export function hasAttendees(event: CalendarEvent) {
-  return !!event.attendees && event.attendees.length > 0;
+  return (event.attendees?.length ?? 0) > 0;
 }
 
 export type CreateEvent = (item: CreateQueueItem) => Promise<unknown>;
diff --git a/apps/web/src/components/calendar/flows/delete-event/delete-queue-provider.tsx b/apps/web/src/components/calendar/flows/delete-event/delete-queue-provider.tsx
index 0a7ce159..2c658729 100644
--- a/apps/web/src/components/calendar/flows/delete-event/delete-queue-provider.tsx
+++ b/apps/web/src/components/calendar/flows/delete-event/delete-queue-provider.tsx
@@ -55,12 +55,14 @@ export function DeleteQueueProvider({ children }: DeleteQueueProviderProps) {
     [deleteMutation, removeOptimisticAction],
   );
 
-  const logic = React.useMemo(() => {
-    return createDeleteQueueMachine({
-      deleteEvent,
-      removeOptimisticAction,
-    });
-  }, [deleteEvent, removeOptimisticAction]);
+  const logic = React.useMemo(
+    () =>
+      createDeleteQueueMachine({
+        deleteEvent,
+        removeOptimisticAction,
+      }),
+    [deleteEvent, removeOptimisticAction],
+  );
 
   return (
     <DeleteQueueContext.Provider logic={logic}>
diff --git a/apps/web/src/components/calendar/flows/delete-event/delete-queue.ts b/apps/web/src/components/calendar/flows/delete-event/delete-queue.ts
index 540e57b2..2c4fd146 100644
--- a/apps/web/src/components/calendar/flows/delete-event/delete-queue.ts
+++ b/apps/web/src/components/calendar/flows/delete-event/delete-queue.ts
@@ -20,11 +20,11 @@ export interface DeleteQueueItem {
 }
 
 export function isRecurring(event: CalendarEvent) {
-  return !!event.recurringEventId;
+  return Boolean(event.recurringEventId);
 }
 
 export function hasAttendees(event: CalendarEvent) {
-  return !!event.attendees && event.attendees.length > 0;
+  return (event.attendees?.length ?? 0) > 0;
 }
 
 export type DeleteEvent = (item: DeleteQueueItem) => Promise<unknown>;
diff --git a/apps/web/src/components/calendar/flows/event-form/event-form-state-provider.tsx b/apps/web/src/components/calendar/flows/event-form/event-form-state-provider.tsx
index c0f773c6..bd8fb343 100644
--- a/apps/web/src/components/calendar/flows/event-form/event-form-state-provider.tsx
+++ b/apps/web/src/components/calendar/flows/event-form/event-form-state-provider.tsx
@@ -26,11 +26,13 @@ export function EventFormStateProvider({
     return item;
   }, []);
 
-  const logic = React.useMemo(() => {
-    return createEventFormMachine({
-      updateEvent,
-    });
-  }, [updateEvent]);
+  const logic = React.useMemo(
+    () =>
+      createEventFormMachine({
+        updateEvent,
+      }),
+    [updateEvent],
+  );
 
   return (
     <EventFormStateContext.Provider logic={logic}>
diff --git a/apps/web/src/components/calendar/flows/update-event/update-queue-provider.tsx b/apps/web/src/components/calendar/flows/update-event/update-queue-provider.tsx
index 2dfb2584..0c4f52b9 100644
--- a/apps/web/src/components/calendar/flows/update-event/update-queue-provider.tsx
+++ b/apps/web/src/components/calendar/flows/update-event/update-queue-provider.tsx
@@ -101,12 +101,14 @@ export function UpdateQueueProvider({ children }: UpdateQueueProviderProps) {
     [updateMutation, removeOptimisticAction],
   );
 
-  const logic = React.useMemo(() => {
-    return createUpdateQueueMachine({
-      updateEvent,
-      removeOptimisticAction,
-    });
-  }, [updateEvent, removeOptimisticAction]);
+  const logic = React.useMemo(
+    () =>
+      createUpdateQueueMachine({
+        updateEvent,
+        removeOptimisticAction,
+      }),
+    [updateEvent, removeOptimisticAction],
+  );
 
   return (
     <UpdateQueueContext.Provider logic={logic}>
diff --git a/apps/web/src/components/calendar/flows/update-event/update-queue.ts b/apps/web/src/components/calendar/flows/update-event/update-queue.ts
index 7ea58e6b..c3debdde 100644
--- a/apps/web/src/components/calendar/flows/update-event/update-queue.ts
+++ b/apps/web/src/components/calendar/flows/update-event/update-queue.ts
@@ -40,11 +40,11 @@ export interface UpdateQueueItem {
 }
 
 export function isRecurring(event: CalendarEvent) {
-  return !!event.recurringEventId;
+  return Boolean(event.recurringEventId);
 }
 
 export function hasAttendees(event: CalendarEvent) {
-  return !!event.attendees && event.attendees.length > 0;
+  return (event.attendees?.length ?? 0) > 0;
 }
 
 export type UpdateEvent = (item: UpdateQueueItem) => Promise<unknown>;
diff --git a/apps/web/src/components/calendar/header/calendar-picker/calendar-picker.tsx b/apps/web/src/components/calendar/header/calendar-picker/calendar-picker.tsx
index 880e1806..be8f3318 100644
--- a/apps/web/src/components/calendar/header/calendar-picker/calendar-picker.tsx
+++ b/apps/web/src/components/calendar/header/calendar-picker/calendar-picker.tsx
@@ -87,18 +87,20 @@ function CalendarPickerContent() {
   const calendarPreferences = useCalendarStore((s) => s.calendarPreferences);
   const { isActionMenuOpen } = useCalendarPickerContext();
 
-  const visibleCalendars = React.useMemo(() => {
-    return data?.accounts
-      .flatMap((account) => account.calendars)
-      .filter((calendar) => {
-        const preference = getCalendarPreference(
-          calendarPreferences,
-          calendar.provider.accountId,
-          calendar.id,
-        );
-        return !preference?.hidden;
-      });
-  }, [data, calendarPreferences]);
+  const visibleCalendars = React.useMemo(
+    () =>
+      data?.accounts
+        .flatMap((account) => account.calendars)
+        .filter((calendar) => {
+          const preference = getCalendarPreference(
+            calendarPreferences,
+            calendar.provider.accountId,
+            calendar.id,
+          );
+          return !preference?.hidden;
+        }),
+    [data, calendarPreferences],
+  );
 
   if (!data) {
     return null;
diff --git a/apps/web/src/components/calendar/timeline/header/solar-terminator-map/solar-terminator-map.tsx b/apps/web/src/components/calendar/timeline/header/solar-terminator-map/solar-terminator-map.tsx
index 0445ced8..5355f5dd 100644
--- a/apps/web/src/components/calendar/timeline/header/solar-terminator-map/solar-terminator-map.tsx
+++ b/apps/web/src/components/calendar/timeline/header/solar-terminator-map/solar-terminator-map.tsx
@@ -127,7 +127,7 @@ export function SolarTerminatorMap({
     if (terminator.length > 0) {
       // Go to right edge at same latitude
       dayCoords.push([180, terminator[terminator.length - 1]?.[1] || 0]);
-      if ((sunDeclination ?? 0) >= 0) {
+      if (sunDeclination >= 0) {
         // Close across the northern boundary when the sun is over the northern hemisphere
         dayCoords.push([180, 90]);
         dayCoords.push([-180, 90]);
@@ -156,7 +156,7 @@ export function SolarTerminatorMap({
         );
       });
 
-    return lineGenerator(dayCoords) + "Z" || "";
+    return lineGenerator(dayCoords) + "Z";
   }, [terminator, projection, sunDeclination]);
 
   return (
diff --git a/apps/web/src/components/calendar/timeline/header/timezone.tsx b/apps/web/src/components/calendar/timeline/header/timezone.tsx
index bc3c2e10..29aef70b 100644
--- a/apps/web/src/components/calendar/timeline/header/timezone.tsx
+++ b/apps/web/src/components/calendar/timeline/header/timezone.tsx
@@ -64,9 +64,10 @@ function TimeDisplay({ className, timeZoneId }: TimeDisplayProps) {
   const use12Hour = useCalendarStore((s) => s.calendarSettings.use12Hour);
   const locale = useCalendarStore((s) => s.calendarSettings.locale);
 
-  const time = React.useMemo(() => {
-    return currentTime.withTimeZone(timeZoneId);
-  }, [currentTime, timeZoneId]);
+  const time = React.useMemo(
+    () => currentTime.withTimeZone(timeZoneId),
+    [currentTime, timeZoneId],
+  );
 
   return (
     <div className={cn("flex flex-col items-end gap-0.5", className)}>
diff --git a/apps/web/src/components/calendar/timeline/timeline.tsx b/apps/web/src/components/calendar/timeline/timeline.tsx
index c986408e..3e56f349 100644
--- a/apps/web/src/components/calendar/timeline/timeline.tsx
+++ b/apps/web/src/components/calendar/timeline/timeline.tsx
@@ -41,9 +41,9 @@ function useHours(timeZone: string) {
 
     const start = startOfDay(date, { timeZone: defaultTimeZone });
 
-    const hours = HOURS.map((time) => {
-      return start.add({ hours: time.hour }).withTimeZone(timeZone);
-    });
+    const hours = HOURS.map((time) =>
+      start.add({ hours: time.hour }).withTimeZone(timeZone),
+    );
 
     return hours.map((hour) => ({
       label: formatTime({
diff --git a/apps/web/src/components/command-bar/window-stack-provider.tsx b/apps/web/src/components/command-bar/window-stack-provider.tsx
index 4196c804..80455072 100644
--- a/apps/web/src/components/command-bar/window-stack-provider.tsx
+++ b/apps/web/src/components/command-bar/window-stack-provider.tsx
@@ -49,9 +49,10 @@ export function WindowStackProvider({ children }: WindowStackProviderProps) {
     ];
   }, [selectedEvents]);
 
-  const windows = React.useMemo<StackWindowEntry[]>(() => {
-    return [...eventWindows, ...stack];
-  }, [eventWindows, stack]);
+  const windows = React.useMemo<StackWindowEntry[]>(
+    () => [...eventWindows, ...stack],
+    [eventWindows, stack],
+  );
 
   const [activeWindowId, setActiveWindowId] = React.useState<string | null>(
     () => windows[0]?.id ?? null,
diff --git a/apps/web/src/components/date-picker.tsx b/apps/web/src/components/date-picker.tsx
index 9a1a529b..11eb179b 100644
--- a/apps/web/src/components/date-picker.tsx
+++ b/apps/web/src/components/date-picker.tsx
@@ -14,12 +14,14 @@ export function DatePicker() {
 
   const displayedDays = useDisplayedDays();
 
-  const displayedMonth = React.useMemo(() => {
-    return Temporal.PlainYearMonth.from({
-      year: currentDate.year,
-      month: currentDate.month,
-    });
-  }, [currentDate.year, currentDate.month]);
+  const displayedMonth = React.useMemo(
+    () =>
+      Temporal.PlainYearMonth.from({
+        year: currentDate.year,
+        month: currentDate.month,
+      }),
+    [currentDate.year, currentDate.month],
+  );
 
   const calendarRef = React.useRef<HTMLDivElement>(null);
 
diff --git a/apps/web/src/components/event-form/ai-input/hooks/use-expanding-input.ts b/apps/web/src/components/event-form/ai-input/hooks/use-expanding-input.ts
index 475b3a25..71e6f945 100644
--- a/apps/web/src/components/event-form/ai-input/hooks/use-expanding-input.ts
+++ b/apps/web/src/components/event-form/ai-input/hooks/use-expanding-input.ts
@@ -11,8 +11,8 @@ export const useExpandingInput = (value: string) => {
   const placeCursorAtEnd = useCallback(() => {
     if (!textareaRef.current) return;
     textareaRef.current.focus();
-    textareaRef.current.selectionStart = textareaRef.current.value.length ?? 0;
-    textareaRef.current.selectionEnd = textareaRef.current.value.length ?? 0;
+    textareaRef.current.selectionStart = textareaRef.current.value.length;
+    textareaRef.current.selectionEnd = textareaRef.current.value.length;
   }, []);
 
   useUpdateEffect(() => {
diff --git a/apps/web/src/components/event-form/fields/attendees/attendee-list.tsx b/apps/web/src/components/event-form/fields/attendees/attendee-list.tsx
index 8fe570a1..c40b84f5 100644
--- a/apps/web/src/components/event-form/fields/attendees/attendee-list.tsx
+++ b/apps/web/src/components/event-form/fields/attendees/attendee-list.tsx
@@ -37,10 +37,7 @@ interface AttendeeAvatarProps {
 
 function AttendeeAvatar({ name, email, className }: AttendeeAvatarProps) {
   const initials = React.useMemo(() => {
-    const initials =
-      name?.trim().length && name?.trim().length > 0
-        ? name?.charAt(0)
-        : email.charAt(0);
+    const initials = name?.trim() ? name.charAt(0) : email.charAt(0);
 
     return initials.toUpperCase();
   }, [name, email]);
@@ -70,7 +67,7 @@ function AttendeeInfo({
   organizer,
   className,
 }: AttendeeInfoProps) {
-  const showName = name?.trim()?.length && name?.trim().length > 0;
+  const showName = name?.trim().length && name.trim().length > 0;
 
   return (
     <div className={cn("flex min-w-0 grow flex-col select-none", className)}>
@@ -125,10 +122,6 @@ function AttendeeStatusIcon({ status, className }: AttendeeStatusProps) {
     }
   };
 
-  if (!Icon) {
-    return null;
-  }
-
   return (
     <div
       className={cn(
diff --git a/apps/web/src/components/event-form/fields/calendar-field.tsx b/apps/web/src/components/event-form/fields/calendar-field.tsx
index 43958af9..e174125b 100644
--- a/apps/web/src/components/event-form/fields/calendar-field.tsx
+++ b/apps/web/src/components/event-form/fields/calendar-field.tsx
@@ -53,9 +53,7 @@ export function CalendarField({
   const trpc = useTRPC();
   const { data } = useQuery(trpc.calendars.list.queryOptions());
 
-  const items = React.useMemo(() => {
-    return data?.accounts ?? [];
-  }, [data]);
+  const items = React.useMemo(() => data?.accounts ?? [], [data]);
 
   const onSelect = React.useCallback(
     (calendar: Calendar) => {
@@ -65,11 +63,13 @@ export function CalendarField({
     [onChange, onBlur],
   );
 
-  const selected = React.useMemo(() => {
-    return data?.accounts
-      .flatMap((item) => item.calendars)
-      .find((item) => item.id === value.id);
-  }, [data, value]);
+  const selected = React.useMemo(
+    () =>
+      data?.accounts
+        .flatMap((item) => item.calendars)
+        .find((item) => item.id === value.id),
+    [data, value],
+  );
 
   return (
     <CalendarListPicker items={items} onSelect={onSelect} value={selected}>
diff --git a/apps/web/src/components/event-form/fields/date/date-input.tsx b/apps/web/src/components/event-form/fields/date/date-input.tsx
index 3974ff52..486a2084 100644
--- a/apps/web/src/components/event-form/fields/date/date-input.tsx
+++ b/apps/web/src/components/event-form/fields/date/date-input.tsx
@@ -89,9 +89,10 @@ export function DateInput({
     return value.toPlainDate();
   }, [value, allDay, start]);
 
-  const defaultMonth = React.useMemo(() => {
-    return value.toPlainDate().toPlainYearMonth();
-  }, [value]);
+  const defaultMonth = React.useMemo(
+    () => value.toPlainDate().toPlainYearMonth(),
+    [value],
+  );
 
   const [displayedMonth, setDisplayedMonth] =
     React.useState<Temporal.PlainYearMonth>(date.toPlainYearMonth());
@@ -296,9 +297,10 @@ function TemporalCalendar({
   onMonthChange,
   min,
 }: TemporalCalendarProps) {
-  const legacySelected = React.useMemo(() => {
-    return toDate(selected, { timeZone });
-  }, [selected, timeZone]);
+  const legacySelected = React.useMemo(
+    () => toDate(selected, { timeZone }),
+    [selected, timeZone],
+  );
 
   const legacyOnSelect = React.useCallback(
     (date: Date) => {
diff --git a/apps/web/src/components/event-form/fields/date/use-time-suggestions.ts b/apps/web/src/components/event-form/fields/date/use-time-suggestions.ts
index 53f35f74..4585fa19 100644
--- a/apps/web/src/components/event-form/fields/date/use-time-suggestions.ts
+++ b/apps/web/src/components/event-form/fields/date/use-time-suggestions.ts
@@ -75,13 +75,15 @@ export function useTimeSuggestionsList() {
   const settings = useCalendarSettings();
   const defaultTimeZone = useDefaultTimeZone();
 
-  return React.useMemo(() => {
-    return generateList({
-      locale: settings.locale,
-      timeZone: defaultTimeZone,
-      use12Hour: settings.use12Hour,
-    });
-  }, [settings.locale, defaultTimeZone, settings.use12Hour]);
+  return React.useMemo(
+    () =>
+      generateList({
+        locale: settings.locale,
+        timeZone: defaultTimeZone,
+        use12Hour: settings.use12Hour,
+      }),
+    [settings.locale, defaultTimeZone, settings.use12Hour],
+  );
 }
 
 export function useTimeSuggestions(searchValue: string) {
diff --git a/apps/web/src/components/event-form/fields/description-field.tsx b/apps/web/src/components/event-form/fields/description-field.tsx
index 88852c51..4cce0150 100644
--- a/apps/web/src/components/event-form/fields/description-field.tsx
+++ b/apps/web/src/components/event-form/fields/description-field.tsx
@@ -22,7 +22,7 @@ export function DescriptionField({
 
   const onTextareaChange = React.useCallback(
     (e: React.ChangeEvent<HTMLTextAreaElement>) => {
-      onChange?.(e.target.value);
+      onChange(e.target.value);
     },
     [onChange],
   );
diff --git a/apps/web/src/components/event-form/recurrences/fields/day-of-week-field.tsx b/apps/web/src/components/event-form/recurrences/fields/day-of-week-field.tsx
index 35834786..beb781f8 100644
--- a/apps/web/src/components/event-form/recurrences/fields/day-of-week-field.tsx
+++ b/apps/web/src/components/event-form/recurrences/fields/day-of-week-field.tsx
@@ -32,7 +32,7 @@ export function DayOfWeekField({ value, onValueChange }: DayOfWeekFieldProps) {
     <ToggleGroup
       variant="outline"
       multiple
-      value={value ?? []}
+      value={value}
       onValueChange={(v) => onValueChange(v as Weekday[])}
       className="w-full"
     >
diff --git a/apps/web/src/components/event-form/recurrences/recurrence-dialog.tsx b/apps/web/src/components/event-form/recurrences/recurrence-dialog.tsx
index e97fe9d3..64d4dcb6 100644
--- a/apps/web/src/components/event-form/recurrences/recurrence-dialog.tsx
+++ b/apps/web/src/components/event-form/recurrences/recurrence-dialog.tsx
@@ -110,9 +110,7 @@ export function RecurrenceDialog({
     },
   });
 
-  const min = React.useMemo(() => {
-    return toDate(start);
-  }, [start]);
+  const min = React.useMemo(() => toDate(start), [start]);
 
   return (
     <Dialog open={open} onOpenChange={setOpen}>
diff --git a/apps/web/src/components/event-form/recurrences/recurrence-field.tsx b/apps/web/src/components/event-form/recurrences/recurrence-field.tsx
index c88e4440..60ef6d72 100644
--- a/apps/web/src/components/event-form/recurrences/recurrence-field.tsx
+++ b/apps/web/src/components/event-form/recurrences/recurrence-field.tsx
@@ -54,9 +54,7 @@ export function RecurrenceField({
     return baseEvent?.recurrence;
   }, [value, baseEvent?.recurrence]);
 
-  const timeZone = React.useMemo(() => {
-    return date.timeZoneId;
-  }, [date]);
+  const timeZone = React.useMemo(() => date.timeZoneId, [date]);
 
   const recurrence = useRecurrence({
     recurrence: displayRecurrence ?? undefined,
@@ -75,7 +73,7 @@ export function RecurrenceField({
           <Button
             id={id}
             variant="ghost"
-            disabled={disabled || !!recurringEventId}
+            disabled={disabled || Boolean(recurringEventId)}
             className={cn(
               "flex h-8 w-full justify-start focus:bg-accent-light focus-visible:bg-accent-light data-[state=open]:bg-accent-light data-[state=open]:dark:bg-accent-light",
               className,
diff --git a/apps/web/src/components/event-form/utils/transform/input.ts b/apps/web/src/components/event-form/utils/transform/input.ts
index a27b2892..fb8de4eb 100644
--- a/apps/web/src/components/event-form/utils/transform/input.ts
+++ b/apps/web/src/components/event-form/utils/transform/input.ts
@@ -5,7 +5,7 @@ import type {
   FormValues,
 } from "@/components/event-form/utils/schema";
 import type { Calendar, CalendarEvent, DraftEvent } from "@/lib/interfaces";
-import { createEventId, isDraftEvent } from "@/lib/utils/calendar";
+import { isDraftEvent } from "@/lib/utils/calendar";
 
 interface ParseDateTimeOptions {
   defaultTimeZone: string;
@@ -32,7 +32,7 @@ export function parseAttendees(
   return (
     event.attendees?.map((attendee) => ({
       id: attendee.id,
-      email: attendee.email ?? "",
+      email: attendee.email,
       status: attendee.status,
       type: attendee.type,
       name: attendee.name ?? "",
@@ -60,7 +60,7 @@ export function parseDraftEvent({
   const end = parseDateTime(event.end, { defaultTimeZone: timeZone });
 
   return {
-    id: event?.id ?? createEventId(),
+    id: event.id,
     type: "draft",
     title: event.title ?? "",
     start,
@@ -73,7 +73,7 @@ export function parseDraftEvent({
     recurringEventId: event.recurringEventId,
     attendees: parseAttendees(event),
     response: event.response,
-    calendar: event?.calendar ?? {
+    calendar: event.calendar ?? {
       id: defaultCalendar.id,
       provider: defaultCalendar.provider,
     },
@@ -103,7 +103,7 @@ export function parseCalendarEvent({
     end,
     location: event.location ?? "",
     description: event.description ?? "",
-    allDay: event.allDay ?? false,
+    allDay: event.allDay,
     availability: event.availability ?? "busy",
     recurrence: event.recurrence,
     recurringEventId: event.recurringEventId,
diff --git a/apps/web/src/components/settings-dialog/tabs/accounts/connected-accounts-list.tsx b/apps/web/src/components/settings-dialog/tabs/accounts/connected-accounts-list.tsx
index 52b0f6a2..d030307d 100644
--- a/apps/web/src/components/settings-dialog/tabs/accounts/connected-accounts-list.tsx
+++ b/apps/web/src/components/settings-dialog/tabs/accounts/connected-accounts-list.tsx
@@ -32,7 +32,7 @@ export function ConnectedAccountsList() {
     );
   }
 
-  if (data?.accounts.length === 0) {
+  if (data.accounts.length === 0) {
     return (
       <div className="py-8 text-center text-muted-foreground">
         <p>No accounts connected yet.</p>
@@ -43,7 +43,7 @@ export function ConnectedAccountsList() {
 
   return (
     <ul className="flex flex-col gap-y-2">
-      {data?.accounts.map((account) => (
+      {data.accounts.map((account) => (
         <React.Fragment key={account.id}>
           <AccountListItem account={account} />
           <Separator className="last:hidden" />
diff --git a/apps/web/src/components/settings-dialog/tabs/accounts/default-calendar-picker.tsx b/apps/web/src/components/settings-dialog/tabs/accounts/default-calendar-picker.tsx
index 0f1e533c..fedd8c38 100644
--- a/apps/web/src/components/settings-dialog/tabs/accounts/default-calendar-picker.tsx
+++ b/apps/web/src/components/settings-dialog/tabs/accounts/default-calendar-picker.tsx
@@ -72,7 +72,7 @@ export function DefaultCalendarPicker() {
       <Label htmlFor="default-calendar" className="sr-only">
         Default Calendar
       </Label>
-      <Select value={data?.defaultCalendar.id} onValueChange={onValueChange}>
+      <Select value={data.defaultCalendar.id} onValueChange={onValueChange}>
         <SelectTrigger
           id="default-calendar"
           className="w-fit max-w-full min-w-48"
@@ -80,7 +80,7 @@ export function DefaultCalendarPicker() {
           <SelectValue placeholder="Select default calendar" />
         </SelectTrigger>
         <SelectContent>
-          {data?.accounts.map((account) => (
+          {data.accounts.map((account) => (
             <SelectGroup key={account.id}>
               <SelectLabel className="py-1.5 text-xs">
                 {account.name}
diff --git a/apps/web/src/hooks/calendar/use-event-collection.ts b/apps/web/src/hooks/calendar/use-event-collection.ts
index 5927bc65..de2e6b2c 100644
--- a/apps/web/src/hooks/calendar/use-event-collection.ts
+++ b/apps/web/src/hooks/calendar/use-event-collection.ts
@@ -225,9 +225,11 @@ export function useWeekRowItems(
     );
   }, [collection.itemsByDay, showWeekends, range.start, range.end]);
 
-  return useMemo(() => {
-    return placeIntoLanes(items, defaultTimeZone).map((lane) =>
-      lane.map((p) => p.item),
-    );
-  }, [items, defaultTimeZone]);
+  return useMemo(
+    () =>
+      placeIntoLanes(items, defaultTimeZone).map((lane) =>
+        lane.map((p) => p.item),
+      ),
+    [items, defaultTimeZone],
+  );
 }
diff --git a/apps/web/src/hooks/calendar/use-events.ts b/apps/web/src/hooks/calendar/use-events.ts
index de2cd910..4b149917 100644
--- a/apps/web/src/hooks/calendar/use-events.ts
+++ b/apps/web/src/hooks/calendar/use-events.ts
@@ -34,15 +34,10 @@ export function useSelectDisplayItems() {
   const defaultTimeZone = useDefaultTimeZone();
 
   return React.useCallback(
-    (data: RouterOutputs["events"]["list"]) => {
-      if (!data.events) {
-        return [];
-      }
-
-      return data.events.map((event) =>
+    (data: RouterOutputs["events"]["list"]) =>
+      data.events.map((event) =>
         createEventDisplayItem(event, defaultTimeZone),
-      );
-    },
+      ),
     [defaultTimeZone],
   );
 }
diff --git a/apps/web/src/hooks/calendar/use-grid-layout.ts b/apps/web/src/hooks/calendar/use-grid-layout.ts
index 21dcae29..18140a5e 100644
--- a/apps/web/src/hooks/calendar/use-grid-layout.ts
+++ b/apps/web/src/hooks/calendar/use-grid-layout.ts
@@ -11,11 +11,13 @@ export function useMonthViewGridLayout() {
   const showWeekends = useCalendarStore((s) => s.viewPreferences.showWeekends);
   const days = useWeekDays();
 
-  return React.useMemo(() => {
-    const columnSizes = days.map((day) => {
-      return showWeekends || !isWeekend(day) ? "minmax(0,1fr)" : "0fr";
-    });
-
-    return columnSizes.join(" ");
-  }, [days, showWeekends]);
+  return React.useMemo(
+    () =>
+      days
+        .map((day) =>
+          showWeekends || !isWeekend(day) ? "minmax(0,1fr)" : "0fr",
+        )
+        .join(" "),
+    [days, showWeekends],
+  );
 }
diff --git a/apps/web/src/hooks/use-sidebar-resize.ts b/apps/web/src/hooks/use-sidebar-resize.ts
index e73e6015..52238977 100644
--- a/apps/web/src/hooks/use-sidebar-resize.ts
+++ b/apps/web/src/hooks/use-sidebar-resize.ts
@@ -99,11 +99,8 @@ export function useSidebarResize({
   );
 
   const isIncreasingWidth = React.useCallback(
-    (currentX: number, referenceX: number): boolean => {
-      return direction === "left"
-        ? currentX < referenceX
-        : currentX > referenceX;
-    },
+    (currentX: number, referenceX: number): boolean =>
+      direction === "left" ? currentX < referenceX : currentX > referenceX,
     [direction],
   );
 
diff --git a/apps/web/src/lib/db.ts b/apps/web/src/lib/db.ts
index fafd15bb..49795ba4 100644
--- a/apps/web/src/lib/db.ts
+++ b/apps/web/src/lib/db.ts
@@ -207,17 +207,19 @@ export function useLiveEventById(id: string) {
     [id],
   );
 
-  return React.useMemo(() => {
-    return result ? mapEventQuery(result) : undefined;
-  }, [result]);
+  return React.useMemo(
+    () => (result ? mapEventQuery(result) : undefined),
+    [result],
+  );
 }
 
 export function useOngoingEvent(): CalendarEvent[] {
   const now = useZonedDateTime();
 
-  const nowEpoch = React.useMemo(() => {
-    return now.toInstant().epochMilliseconds;
-  }, [now]);
+  const nowEpoch = React.useMemo(
+    () => now.toInstant().epochMilliseconds,
+    [now],
+  );
 
   const result = useLiveQuery(async () => {
     const rows = await db.events
@@ -235,9 +237,10 @@ export function useOngoingEvent(): CalendarEvent[] {
 export function useUpcomingEvent(): CalendarEvent[] {
   const now = useZonedDateTime();
 
-  const nowEpoch = React.useMemo(() => {
-    return now.toInstant().epochMilliseconds;
-  }, [now]);
+  const nowEpoch = React.useMemo(
+    () => now.toInstant().epochMilliseconds,
+    [now],
+  );
 
   const result = useLiveQuery(async () => {
     const candidates = await db.events
diff --git a/apps/web/src/lib/utils/events.ts b/apps/web/src/lib/utils/events.ts
index 2c17a7d1..9900a5a0 100644
--- a/apps/web/src/lib/utils/events.ts
+++ b/apps/web/src/lib/utils/events.ts
@@ -3,7 +3,7 @@ import { Conference } from "@repo/providers/interfaces";
 import type { Attendee, CalendarEvent } from "@/lib/interfaces";
 
 export function isUserOnlyAttendee(attendees: Attendee[]): boolean {
-  if (!attendees || attendees.length === 0) {
+  if (attendees.length === 0) {
     return true;
   }
 
@@ -27,11 +27,11 @@ export function requiresAttendeeConfirmation(
 export function requiresRecurrenceConfirmation(
   recurringEventId: string | undefined,
 ): boolean {
-  return !!recurringEventId;
+  return Boolean(recurringEventId);
 }
 
 export function isMeeting(event: CalendarEvent): boolean {
-  return !!event.attendees && event.attendees.length > 1;
+  return (event.attendees?.length ?? 0) > 1;
 }
 
 type OnlineMeetingEvent = CalendarEvent & {
@@ -51,5 +51,5 @@ export function isOnlineMeeting(
     return false;
   }
 
-  return !!event.conference.video?.joinUrl;
+  return Boolean(event.conference.video?.joinUrl);
 }
diff --git a/apps/web/src/store/calendar-store.ts b/apps/web/src/store/calendar-store.ts
index 88c3762a..5dc4aa20 100644
--- a/apps/web/src/store/calendar-store.ts
+++ b/apps/web/src/store/calendar-store.ts
@@ -135,8 +135,8 @@ export type PersistedState = Pick<
 
 export const createCalendarStore = (
   initState: Omit<CalendarStore, keyof CalendarActions> = defaultInitState,
-) => {
-  return createStore<CalendarStore>()(
+) =>
+  createStore<CalendarStore>()(
     devtools(
       persist(
         (...a) => ({
@@ -167,4 +167,3 @@ export const createCalendarStore = (
     ),
     shallow,
   );
-};
diff --git a/packages/api/src/routers/calendars.ts b/packages/api/src/routers/calendars.ts
index c6a357a6..a9973c75 100644
--- a/packages/api/src/routers/calendars.ts
+++ b/packages/api/src/routers/calendars.ts
@@ -19,7 +19,7 @@ export const calendarsRouter = createTRPCRouter({
         ({ account }) => account.accountId === input.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.provider.accountId}`,
@@ -129,7 +129,7 @@ export const calendarsRouter = createTRPCRouter({
         ({ account }) => account.accountId === input.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.provider.accountId}`,
@@ -159,7 +159,7 @@ export const calendarsRouter = createTRPCRouter({
         ({ account }) => account.accountId === input.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.provider.accountId}`,
@@ -208,7 +208,7 @@ export const calendarsRouter = createTRPCRouter({
         ({ account }) => account.accountId === input.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.provider.accountId}`,
diff --git a/packages/api/src/routers/events.ts b/packages/api/src/routers/events.ts
index 01b5d7dd..7817b7c8 100644
--- a/packages/api/src/routers/events.ts
+++ b/packages/api/src/routers/events.ts
@@ -96,7 +96,7 @@ export const eventsRouter = createTRPCRouter({
           account.accountId === input.calendar.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.calendar.provider.accountId}`,
@@ -148,7 +148,7 @@ export const eventsRouter = createTRPCRouter({
           account.accountId === input.calendar.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.calendar.provider.accountId}`,
@@ -177,7 +177,7 @@ export const eventsRouter = createTRPCRouter({
   create: calendarProcedure
     .input(
       createEventInputSchema.extend({
-        sendUpdate: z.boolean().optional().default(true),
+        sendUpdate: z.boolean().default(true),
       }),
     )
     .mutation(async ({ ctx, input }) => {
@@ -186,7 +186,7 @@ export const eventsRouter = createTRPCRouter({
           account.accountId === input.calendar.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.calendar.provider.accountId}`,
@@ -216,7 +216,7 @@ export const eventsRouter = createTRPCRouter({
     .input(
       z.object({
         data: patchEventInputSchema,
-        sendUpdate: z.boolean().optional().default(true),
+        sendUpdate: z.boolean().default(true),
         move: z
           .object({
             source: z.object({
@@ -247,7 +247,7 @@ export const eventsRouter = createTRPCRouter({
             account.accountId === data.calendar.provider.accountId,
         );
 
-        if (!provider?.client) {
+        if (!provider) {
           throw new TRPCError({
             code: "NOT_FOUND",
             message: `Calendar client not found for providerAccountId: ${data.calendar.provider.accountId}`,
@@ -416,7 +416,7 @@ export const eventsRouter = createTRPCRouter({
           }),
         }),
         eventId: z.string(),
-        sendUpdate: z.boolean().optional().default(true),
+        sendUpdate: z.boolean().default(true),
       }),
     )
     .mutation(async ({ ctx, input }) => {
@@ -425,7 +425,7 @@ export const eventsRouter = createTRPCRouter({
           account.accountId === input.calendar.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.calendar.provider.accountId}`,
@@ -458,7 +458,7 @@ export const eventsRouter = createTRPCRouter({
           }),
         }),
         eventId: z.string(),
-        sendUpdate: z.boolean().optional().default(true),
+        sendUpdate: z.boolean().default(true),
       }),
     )
     .mutation(async ({ ctx, input }) => {
@@ -549,7 +549,7 @@ export const eventsRouter = createTRPCRouter({
           account.accountId === input.calendar.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Calendar client not found for providerAccountId: ${input.calendar.provider.accountId}`,
diff --git a/packages/api/src/routers/tasks.ts b/packages/api/src/routers/tasks.ts
index 9b03181d..5fff559f 100644
--- a/packages/api/src/routers/tasks.ts
+++ b/packages/api/src/routers/tasks.ts
@@ -12,7 +12,7 @@ export const tasksRouter = createTRPCRouter({
         ({ account }) => account.accountId === input.provider.accountId,
       );
 
-      if (!provider?.client) {
+      if (!provider) {
         throw new TRPCError({
           code: "NOT_FOUND",
           message: `Task client not found for providerAccountId: ${input.provider.accountId}`,
diff --git a/packages/api/src/trpc.ts b/packages/api/src/trpc.ts
index f5fb0be4..9b445c81 100644
--- a/packages/api/src/trpc.ts
+++ b/packages/api/src/trpc.ts
@@ -42,10 +42,10 @@ export const createTRPCContext = async (opts: {
       ...opts,
       db,
       redis,
-      session: opts.session?.session,
-      user: opts.session?.user,
+      session: opts.session.session,
+      user: opts.session.user,
       rateLimit: {
-        id: opts.session?.user?.id ?? getIp(opts.headers),
+        id: opts.session.user.id,
       },
     };
   }
@@ -61,7 +61,7 @@ export const createTRPCContext = async (opts: {
     session: session?.session,
     user: session?.user,
     rateLimit: {
-      id: session?.user?.id ?? getIp(opts.headers),
+      id: session?.user.id ?? getIp(opts.headers),
     },
   };
 };
@@ -128,7 +128,7 @@ export const protectedProcedure = t.procedure
       ctx: {
         ...ctx,
         session: ctx.session!,
-        user: ctx.user!,
+        user: ctx.user,
       },
     });
   });
diff --git a/packages/api/src/utils/index.ts b/packages/api/src/utils/index.ts
index 5dc1b635..6da282a2 100644
--- a/packages/api/src/utils/index.ts
+++ b/packages/api/src/utils/index.ts
@@ -16,7 +16,7 @@ export function findProviderOrThrow(
     ({ account }) => account.accountId === providerAccountId,
   );
 
-  if (!provider?.client) {
+  if (!provider) {
     throw new TRPCError({
       code: "NOT_FOUND",
       message: `Could not find provider for providerAccountId: ${providerAccountId}`,
diff --git a/packages/api/src/utils/maps/routes/directions.ts b/packages/api/src/utils/maps/routes/directions.ts
index 758463a7..16c2bfb5 100644
--- a/packages/api/src/utils/maps/routes/directions.ts
+++ b/packages/api/src/utils/maps/routes/directions.ts
@@ -290,9 +290,7 @@ export async function directions(input: DirectionsInput) {
         ...(leg.duration
           ? {
               duration: {
-                trafficAware: leg.duration
-                  ? parseDuration(leg.duration)
-                  : undefined,
+                trafficAware: parseDuration(leg.duration),
                 static: leg.staticDuration
                   ? parseDuration(leg.staticDuration)
                   : undefined,
diff --git a/packages/auth/src/utils/account-linking.ts b/packages/auth/src/utils/account-linking.ts
index e015c5bf..cc938538 100644
--- a/packages/auth/src/utils/account-linking.ts
+++ b/packages/auth/src/utils/account-linking.ts
@@ -68,7 +68,7 @@ export const handleUnlinkAccount = createAuthMiddleware(async (ctx) => {
     }
 
     const defaultAccount = await db.query.account.findFirst({
-      where: (table, { eq }) => eq(table.id, user!.defaultAccountId),
+      where: (table, { eq }) => eq(table.id, user.defaultAccountId),
     });
 
     if (defaultAccount?.accountId !== ctx.body?.accountId) {
@@ -76,7 +76,7 @@ export const handleUnlinkAccount = createAuthMiddleware(async (ctx) => {
     }
 
     const newDefaultAccount = await db.query.account.findFirst({
-      where: (table, { eq }) => eq(table.userId, user!.id),
+      where: (table, { eq }) => eq(table.userId, user.id),
     });
 
     if (!newDefaultAccount) {
diff --git a/packages/google-calendar/src/colors/interfaces.ts b/packages/google-calendar/src/colors/interfaces.ts
index 36f7e9eb..01960e8d 100644
--- a/packages/google-calendar/src/colors/interfaces.ts
+++ b/packages/google-calendar/src/colors/interfaces.ts
@@ -12,6 +12,6 @@ export interface Colors {
   updated?: string;
 }
 
-export interface GetColorsInput extends GoogleCalendarRequestOptions {}
+export type GetColorsInput = GoogleCalendarRequestOptions;
 
 export type GetColorsResponse = Colors;
diff --git a/packages/microsoft-calendar/src/groups/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/groups/calendar-view/interfaces.ts
index 143a6030..e3b9cf6b 100644
--- a/packages/microsoft-calendar/src/groups/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -35,4 +36,6 @@ export interface GroupCalendarViewDeltaInput extends MicrosoftCalendarRequestOpt
   expand?: string[];
 }
 
-export type GroupCalendarViewDeltaResponse = DeltaCollectionResponse<Event>;
+export type GroupCalendarViewDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/groups/calendar/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/groups/calendar/calendar-view/interfaces.ts
index 62ae2330..6305a84a 100644
--- a/packages/microsoft-calendar/src/groups/calendar/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/calendar/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -35,5 +36,6 @@ export interface GroupCalendarCalendarViewDeltaInput extends MicrosoftCalendarRe
   expand?: string[];
 }
 
-export type GroupCalendarCalendarViewDeltaResponse =
-  DeltaCollectionResponse<Event>;
+export type GroupCalendarCalendarViewDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/groups/calendar/events/instances/interfaces.ts b/packages/microsoft-calendar/src/groups/calendar/events/instances/interfaces.ts
index 1dd463df..2a913bf9 100644
--- a/packages/microsoft-calendar/src/groups/calendar/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/calendar/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -37,5 +38,6 @@ export interface GroupCalendarEventInstanceDeltaInput extends MicrosoftCalendarR
   expand?: string[];
 }
 
-export type GroupCalendarEventInstanceDeltaResponse =
-  DeltaCollectionResponse<Event>;
+export type GroupCalendarEventInstanceDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/groups/calendar/events/interfaces.ts b/packages/microsoft-calendar/src/groups/calendar/events/interfaces.ts
index 8e10d624..4e20f0a4 100644
--- a/packages/microsoft-calendar/src/groups/calendar/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/calendar/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -52,7 +53,9 @@ export interface GroupCalendarEventDeltaInput extends MicrosoftCalendarRequestOp
   expand?: string[];
 }
 
-export type GroupCalendarEventDeltaResponse = DeltaCollectionResponse<Event>;
+export type GroupCalendarEventDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
 
 export interface GroupCalendarDeleteEventInput extends MicrosoftCalendarRequestOptions {
   groupId: string;
@@ -72,7 +75,7 @@ export type GroupCalendarGetEventResponse = Event;
 export interface GroupCalendarUpdateEventInput extends MicrosoftCalendarRequestOptions {
   groupId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type GroupCalendarUpdateEventResponse = Event;
diff --git a/packages/microsoft-calendar/src/groups/events/instances/interfaces.ts b/packages/microsoft-calendar/src/groups/events/instances/interfaces.ts
index c640a086..5fe941ca 100644
--- a/packages/microsoft-calendar/src/groups/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -37,4 +38,6 @@ export interface GroupEventInstanceDeltaInput extends MicrosoftCalendarRequestOp
   expand?: string[];
 }
 
-export type GroupEventInstanceDeltaResponse = DeltaCollectionResponse<Event>;
+export type GroupEventInstanceDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/groups/events/interfaces.ts b/packages/microsoft-calendar/src/groups/events/interfaces.ts
index c85ae9fa..4f57c05a 100644
--- a/packages/microsoft-calendar/src/groups/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/groups/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -52,7 +53,9 @@ export interface GroupEventDeltaInput extends MicrosoftCalendarRequestOptions {
   expand?: string[];
 }
 
-export type GroupEventDeltaResponse = DeltaCollectionResponse<Event>;
+export type GroupEventDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
 
 export interface GroupDeleteEventInput extends MicrosoftCalendarRequestOptions {
   groupId: string;
@@ -72,7 +75,7 @@ export type GroupGetEventResponse = Event;
 export interface GroupUpdateEventInput extends MicrosoftCalendarRequestOptions {
   groupId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type GroupUpdateEventResponse = Event;
diff --git a/packages/microsoft-calendar/src/interfaces.ts b/packages/microsoft-calendar/src/interfaces.ts
index cfe76744..29ea72ff 100644
--- a/packages/microsoft-calendar/src/interfaces.ts
+++ b/packages/microsoft-calendar/src/interfaces.ts
@@ -27,6 +27,13 @@ export interface DeltaCollectionResponse<T> extends CollectionResponse<T> {
   "@odata.deltaLink"?: string | null;
 }
 
+export interface DeltaRemovedEvent {
+  id: string;
+  "@removed": {
+    reason: "deleted";
+  };
+}
+
 export type ODataCountResponse = number;
 
 export interface Attachment extends Entity {
@@ -52,7 +59,7 @@ export interface Attachment extends Entity {
   [key: string]: unknown;
 }
 
-export interface AttachmentCollectionResponse extends CollectionResponse<Attachment> {}
+export type AttachmentCollectionResponse = CollectionResponse<Attachment>;
 
 export interface AttachmentItem {
   attachmentType: AttachmentType;
@@ -103,7 +110,7 @@ export interface Calendar extends Entity {
   [key: string]: unknown;
 }
 
-export interface CalendarCollectionResponse extends CollectionResponse<Calendar> {}
+export type CalendarCollectionResponse = CollectionResponse<Calendar>;
 
 export type CalendarColor =
   | "auto"
@@ -126,7 +133,7 @@ export interface CalendarGroup extends Entity {
   [key: string]: unknown;
 }
 
-export interface CalendarGroupCollectionResponse extends CollectionResponse<CalendarGroup> {}
+export type CalendarGroupCollectionResponse = CollectionResponse<CalendarGroup>;
 
 export interface CalendarPermission extends Entity {
   allowedRoles?: CalendarRoleType[];
@@ -137,7 +144,8 @@ export interface CalendarPermission extends Entity {
   [key: string]: unknown;
 }
 
-export interface CalendarPermissionCollectionResponse extends CollectionResponse<CalendarPermission> {}
+export type CalendarPermissionCollectionResponse =
+  CollectionResponse<CalendarPermission>;
 
 export type CalendarRoleType =
   | "none"
@@ -149,9 +157,12 @@ export type CalendarRoleType =
   | "delegateWithPrivateEventAccess"
   | "custom";
 
+// Graph's OpenAPI marks every field optional. The docs only define dateTime and
+// timeZone; both are expected when the type is present.
+// https://learn.microsoft.com/en-us/graph/api/resources/datetimetimezone
 export interface DateTimeTimeZone {
-  dateTime?: string;
-  timeZone?: string | null;
+  dateTime: string;
+  timeZone: string;
   [key: string]: unknown;
 }
 
@@ -175,13 +186,19 @@ export interface Entity {
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. Calendar event docs always
+// expect start and end on GET/create; PATCH sends Partial<Event> with only
+// changed fields. Caveat: a $select that leaves out start or end returns
+// objects this type overpromises on — select both, or treat the response as
+// partial.
+// https://learn.microsoft.com/en-us/graph/api/resources/event
 export interface Event extends OutlookItem {
   allowNewTimeProposals?: boolean | null;
   attendees?: Attendee[];
   body?: ItemBody;
   bodyPreview?: string | null;
   cancelledOccurrences?: string[];
-  end?: DateTimeTimeZone;
+  end: DateTimeTimeZone;
   hasAttachments?: boolean | null;
   hideAttendees?: boolean | null;
   iCalUId?: string | null;
@@ -210,7 +227,7 @@ export interface Event extends OutlookItem {
   sensitivity?: Sensitivity;
   seriesMasterId?: string | null;
   showAs?: FreeBusyStatus;
-  start?: DateTimeTimeZone;
+  start: DateTimeTimeZone;
   subject?: string | null;
   transactionId?: string | null;
   type?: EventType;
@@ -225,7 +242,7 @@ export interface Event extends OutlookItem {
   [key: string]: unknown;
 }
 
-export interface EventCollectionResponse extends CollectionResponse<Event> {}
+export type EventCollectionResponse = CollectionResponse<Event>;
 
 export type EventType =
   | "singleInstance"
@@ -237,7 +254,7 @@ export interface Extension extends Entity {
   [key: string]: unknown;
 }
 
-export interface ExtensionCollectionResponse extends CollectionResponse<Extension> {}
+export type ExtensionCollectionResponse = CollectionResponse<Extension>;
 
 export interface FreeBusyError {
   message?: string | null;
@@ -292,8 +309,12 @@ export type LocationUniqueIdType =
   | "private"
   | "bing";
 
+// Graph's OpenAPI marks every field optional. Create docs require id and
+// value for each property in multiValueExtendedProperties.
+// https://learn.microsoft.com/en-us/graph/api/multivaluelegacyextendedproperty-post-multivalueextendedproperties?view=graph-rest-1.0
 export interface MultiValueLegacyExtendedProperty extends Entity {
-  value?: (string | null)[];
+  id: string;
+  value: (string | null)[];
   [key: string]: unknown;
 }
 
@@ -330,17 +351,24 @@ export interface OutlookItem extends Entity {
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks both as optional (the type is shared with access
+// reviews, which omit pattern for one-time reviews). For calendar events,
+// both are required when recurrence is set.
+// https://learn.microsoft.com/en-us/graph/outlook-schedule-recurring-events
 export interface PatternedRecurrence {
-  pattern?: RecurrencePattern;
-  range?: RecurrenceRange;
+  pattern: RecurrencePattern;
+  range: RecurrenceRange;
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. The docs only define number and
+// type; both are expected on a phone entry.
+// https://learn.microsoft.com/en-us/graph/api/resources/phone?view=graph-rest-1.0
 export interface Phone {
   language?: string | null;
-  number?: string | null;
+  number: string;
   region?: string | null;
-  type?: PhoneType;
+  type: PhoneType;
   [key: string]: unknown;
 }
 
@@ -365,19 +393,25 @@ export interface PhysicalAddress {
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks emailAddress optional. The docs only define
+// emailAddress; it is expected on a recipient.
+// https://learn.microsoft.com/en-us/graph/api/resources/recipient
 export interface Recipient {
-  emailAddress?: EmailAddress;
+  emailAddress: EmailAddress;
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. Docs require type and interval
+// for every pattern; other fields are required only for specific types.
+// https://learn.microsoft.com/en-us/graph/api/resources/recurrencepattern
 export interface RecurrencePattern {
   dayOfMonth?: number;
   daysOfWeek?: DayOfWeek[];
   firstDayOfWeek?: DayOfWeek;
   index?: WeekIndex;
-  interval?: number;
+  interval: number;
   month?: number;
-  type?: RecurrencePatternType;
+  type: RecurrencePatternType;
   [key: string]: unknown;
 }
 
@@ -389,12 +423,15 @@ export type RecurrencePatternType =
   | "absoluteYearly"
   | "relativeYearly";
 
+// Graph's OpenAPI marks every field optional. Docs require type and startDate
+// for every range; endDate / numberOfOccurrences depend on type.
+// https://learn.microsoft.com/en-us/graph/api/resources/recurrencerange
 export interface RecurrenceRange {
   endDate?: string | null;
   numberOfOccurrences?: number;
   recurrenceTimeZone?: string | null;
-  startDate?: string | null;
-  type?: RecurrenceRangeType;
+  startDate: string;
+  type: RecurrenceRangeType;
   [key: string]: unknown;
 }
 
@@ -424,38 +461,54 @@ export interface ScheduleInformation {
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. Docs mark only isPrivate,
+// location, and subject as optional; start, end, and status are expected.
+// https://learn.microsoft.com/en-us/graph/api/resources/scheduleitem
 export interface ScheduleItem {
-  end?: DateTimeTimeZone;
+  end: DateTimeTimeZone;
   isPrivate?: boolean | null;
   location?: string | null;
-  start?: DateTimeTimeZone;
-  status?: FreeBusyStatus;
+  start: DateTimeTimeZone;
+  status: FreeBusyStatus;
   subject?: string | null;
   [key: string]: unknown;
 }
 
 export type Sensitivity = "normal" | "personal" | "private" | "confidential";
 
+// Graph's OpenAPI marks id/value optional (id via Entity). Create docs require
+// both id and value for each property in the collection.
+// https://learn.microsoft.com/en-us/graph/api/singlevaluelegacyextendedproperty-post-singlevalueextendedproperties?view=graph-rest-1.0
 export interface SingleValueLegacyExtendedProperty extends Entity {
-  value?: string | null;
+  id: string;
+  value: string;
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. The docs only define start and
+// end; both are expected on a time slot.
+// https://learn.microsoft.com/en-us/graph/api/resources/timeslot
 export interface TimeSlot {
-  end?: DateTimeTimeZone;
-  start?: DateTimeTimeZone;
+  end: DateTimeTimeZone;
+  start: DateTimeTimeZone;
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks name optional. Docs only define name; it is expected
+// when the type is present.
+// https://learn.microsoft.com/en-us/graph/api/resources/timezonebase
 export interface TimeZoneBase {
-  name?: string | null;
+  name: string;
   [key: string]: unknown;
 }
 
+// Graph's OpenAPI marks every field optional. createUploadSession always
+// returns uploadUrl, expirationDateTime, and nextExpectedRanges.
+// https://learn.microsoft.com/en-us/graph/api/attachment-createuploadsession?view=graph-rest-1.0
 export interface UploadSession {
-  expirationDateTime?: string | null;
-  nextExpectedRanges?: (string | null)[];
-  uploadUrl?: string | null;
+  expirationDateTime: string;
+  nextExpectedRanges: string[];
+  uploadUrl: string;
   [key: string]: unknown;
 }
 
diff --git a/packages/microsoft-calendar/src/users/calendar-groups/calendars/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/users/calendar-groups/calendars/calendar-view/interfaces.ts
index c810265b..830b72bc 100644
--- a/packages/microsoft-calendar/src/users/calendar-groups/calendars/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar-groups/calendars/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -41,4 +42,4 @@ export interface CalendarGroupCalendarCalendarViewDeltaInput extends MicrosoftCa
 }
 
 export type CalendarGroupCalendarCalendarViewDeltaResponse =
-  DeltaCollectionResponse<Event>;
+  DeltaCollectionResponse<Event | DeltaRemovedEvent>;
diff --git a/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/instances/interfaces.ts b/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/instances/interfaces.ts
index fc79e90b..72d7dc8e 100644
--- a/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -43,4 +44,4 @@ export interface CalendarGroupCalendarEventInstanceDeltaInput extends MicrosoftC
 }
 
 export type CalendarGroupCalendarEventInstanceDeltaResponse =
-  DeltaCollectionResponse<Event>;
+  DeltaCollectionResponse<Event | DeltaRemovedEvent>;
diff --git a/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/interfaces.ts b/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/interfaces.ts
index 6ba5d1c9..2c82323c 100644
--- a/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar-groups/calendars/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -60,8 +61,9 @@ export interface CalendarGroupCalendarEventDeltaInput extends MicrosoftCalendarR
   expand?: string[];
 }
 
-export type CalendarGroupCalendarEventDeltaResponse =
-  DeltaCollectionResponse<Event>;
+export type CalendarGroupCalendarEventDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
 
 export interface CalendarGroupCalendarDeleteEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
@@ -87,7 +89,7 @@ export interface CalendarGroupCalendarUpdateEventInput extends MicrosoftCalendar
   calendarGroupId: string;
   calendarId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type CalendarGroupCalendarUpdateEventResponse = Event;
diff --git a/packages/microsoft-calendar/src/users/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/users/calendar-view/interfaces.ts
index 741330e4..a3864e08 100644
--- a/packages/microsoft-calendar/src/users/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -35,4 +36,6 @@ export interface CalendarViewDeltaInput extends MicrosoftCalendarRequestOptions
   expand?: string[];
 }
 
-export type CalendarViewDeltaResponse = DeltaCollectionResponse<Event>;
+export type CalendarViewDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/calendar/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/users/calendar/calendar-view/interfaces.ts
index 6f3db933..88f4f2a1 100644
--- a/packages/microsoft-calendar/src/users/calendar/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -35,5 +36,6 @@ export interface DefaultCalendarCalendarViewDeltaInput extends MicrosoftCalendar
   expand?: string[];
 }
 
-export type DefaultCalendarCalendarViewDeltaResponse =
-  DeltaCollectionResponse<Event>;
+export type DefaultCalendarCalendarViewDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/calendar/events/instances/interfaces.ts b/packages/microsoft-calendar/src/users/calendar/events/instances/interfaces.ts
index c17aecca..00caab6e 100644
--- a/packages/microsoft-calendar/src/users/calendar/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -37,5 +38,6 @@ export interface DefaultCalendarEventInstanceDeltaInput extends MicrosoftCalenda
   expand?: string[];
 }
 
-export type DefaultCalendarEventInstanceDeltaResponse =
-  DeltaCollectionResponse<Event>;
+export type DefaultCalendarEventInstanceDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/calendar/events/interfaces.ts b/packages/microsoft-calendar/src/users/calendar/events/interfaces.ts
index e55dea2c..1343f996 100644
--- a/packages/microsoft-calendar/src/users/calendar/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendar/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -52,7 +53,9 @@ export interface DefaultCalendarEventDeltaInput extends MicrosoftCalendarRequest
   expand?: string[];
 }
 
-export type DefaultCalendarEventDeltaResponse = DeltaCollectionResponse<Event>;
+export type DefaultCalendarEventDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
 
 export interface DefaultCalendarDeleteEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
@@ -72,7 +75,7 @@ export type DefaultCalendarGetEventResponse = Event;
 export interface DefaultCalendarUpdateEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type DefaultCalendarUpdateEventResponse = Event;
diff --git a/packages/microsoft-calendar/src/users/calendars/calendar-view/interfaces.ts b/packages/microsoft-calendar/src/users/calendars/calendar-view/interfaces.ts
index 26ab4b13..1e8c4505 100644
--- a/packages/microsoft-calendar/src/users/calendars/calendar-view/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendars/calendar-view/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -37,4 +38,6 @@ export interface CalendarCalendarViewDeltaInput extends MicrosoftCalendarRequest
   expand?: string[];
 }
 
-export type CalendarCalendarViewDeltaResponse = DeltaCollectionResponse<Event>;
+export type CalendarCalendarViewDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/calendars/events/instances/interfaces.ts b/packages/microsoft-calendar/src/users/calendars/events/instances/interfaces.ts
index a6a66732..3732c6da 100644
--- a/packages/microsoft-calendar/src/users/calendars/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendars/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -39,4 +40,6 @@ export interface CalendarEventInstanceDeltaInput extends MicrosoftCalendarReques
   expand?: string[];
 }
 
-export type CalendarEventInstanceDeltaResponse = DeltaCollectionResponse<Event>;
+export type CalendarEventInstanceDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/calendars/events/interfaces.ts b/packages/microsoft-calendar/src/users/calendars/events/interfaces.ts
index b1420f14..8d22d1b8 100644
--- a/packages/microsoft-calendar/src/users/calendars/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/calendars/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -56,7 +57,9 @@ export interface CalendarEventDeltaInput extends MicrosoftCalendarRequestOptions
   expand?: string[];
 }
 
-export type CalendarEventDeltaResponse = DeltaCollectionResponse<Event>;
+export type CalendarEventDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
 
 export interface CalendarDeleteEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
@@ -79,7 +82,7 @@ export interface CalendarUpdateEventInput extends MicrosoftCalendarRequestOption
   userId: string;
   calendarId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type CalendarUpdateEventResponse = Event;
diff --git a/packages/microsoft-calendar/src/users/events/instances/interfaces.ts b/packages/microsoft-calendar/src/users/events/instances/interfaces.ts
index 25b24d3e..e7355219 100644
--- a/packages/microsoft-calendar/src/users/events/instances/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/events/instances/interfaces.ts
@@ -1,5 +1,6 @@
 import type {
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -37,4 +38,6 @@ export interface InstanceDeltaInput extends MicrosoftCalendarRequestOptions {
   expand?: string[];
 }
 
-export type InstanceDeltaResponse = DeltaCollectionResponse<Event>;
+export type InstanceDeltaResponse = DeltaCollectionResponse<
+  Event | DeltaRemovedEvent
+>;
diff --git a/packages/microsoft-calendar/src/users/events/interfaces.ts b/packages/microsoft-calendar/src/users/events/interfaces.ts
index 17ee56ce..0292c39d 100644
--- a/packages/microsoft-calendar/src/users/events/interfaces.ts
+++ b/packages/microsoft-calendar/src/users/events/interfaces.ts
@@ -2,6 +2,7 @@ import type {
   Calendar,
   DateTimeTimeZone,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event,
   EventCollectionResponse,
   MicrosoftCalendarRequestOptions,
@@ -52,7 +53,7 @@ export interface DeltaInput extends MicrosoftCalendarRequestOptions {
   expand?: string[];
 }
 
-export type DeltaResponse = DeltaCollectionResponse<Event>;
+export type DeltaResponse = DeltaCollectionResponse<Event | DeltaRemovedEvent>;
 
 export interface DeleteEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
@@ -72,7 +73,7 @@ export type GetEventResponse = Event;
 export interface UpdateEventInput extends MicrosoftCalendarRequestOptions {
   userId: string;
   eventId: string;
-  event: Event;
+  event: Partial<Event>;
 }
 
 export type UpdateEventResponse = Event;
diff --git a/packages/providers/src/calendars/google-calendar/calendars/index.ts b/packages/providers/src/calendars/google-calendar/calendars/index.ts
index 7deb2672..0f44f6c5 100644
--- a/packages/providers/src/calendars/google-calendar/calendars/index.ts
+++ b/packages/providers/src/calendars/google-calendar/calendars/index.ts
@@ -8,7 +8,7 @@ import type {
   CalendarProviderCalendarsUpdateOptions,
 } from "../../../interfaces/providers";
 import { ProviderError } from "../../../lib/provider-error";
-import { parseGoogleCalendarCalendarListEntry } from "./utils";
+import { parseCalendar } from "./parse";
 
 export class GoogleCalendarCalendars {
   constructor(
@@ -21,7 +21,7 @@ export class GoogleCalendarCalendars {
       const { items } = await this.client.calendarList.list({});
 
       return items.map((calendar) =>
-        parseGoogleCalendarCalendarListEntry({
+        parseCalendar({
           providerAccountId: this.providerAccountId,
           entry: calendar,
         }),
@@ -35,7 +35,7 @@ export class GoogleCalendarCalendars {
     return this.withErrorHandler("calendars.get", async () => {
       const calendar = await this.client.calendarList.get({ calendarId });
 
-      return parseGoogleCalendarCalendarListEntry({
+      return parseCalendar({
         providerAccountId: this.providerAccountId,
         entry: calendar,
       });
@@ -52,7 +52,7 @@ export class GoogleCalendarCalendars {
         timeZone: calendar.timeZone,
       });
 
-      return parseGoogleCalendarCalendarListEntry({
+      return parseCalendar({
         providerAccountId: this.providerAccountId,
         entry: createdCalendar,
       });
@@ -69,7 +69,7 @@ export class GoogleCalendarCalendars {
         summary: calendar.name,
       });
 
-      return parseGoogleCalendarCalendarListEntry({
+      return parseCalendar({
         providerAccountId: this.providerAccountId,
         entry: updatedCalendar,
       });
diff --git a/packages/providers/src/calendars/google-calendar/calendars/utils.ts b/packages/providers/src/calendars/google-calendar/calendars/parse.ts
similarity index 80%
rename from packages/providers/src/calendars/google-calendar/calendars/utils.ts
rename to packages/providers/src/calendars/google-calendar/calendars/parse.ts
index bc4b76b2..0fe51e5b 100644
--- a/packages/providers/src/calendars/google-calendar/calendars/utils.ts
+++ b/packages/providers/src/calendars/google-calendar/calendars/parse.ts
@@ -1,15 +1,15 @@
 import type { Calendar } from "../../../interfaces";
 import type { GoogleCalendarCalendarListEntry } from "../interfaces";
 
-interface ParsedGoogleCalendarCalendarListEntryOptions {
+interface ParseCalendarOptions {
   providerAccountId: string;
   entry: GoogleCalendarCalendarListEntry;
 }
 
-export function parseGoogleCalendarCalendarListEntry({
+export function parseCalendar({
   providerAccountId,
   entry,
-}: ParsedGoogleCalendarCalendarListEntryOptions): Calendar {
+}: ParseCalendarOptions): Calendar {
   return {
     id: entry.id!,
     name: entry.summaryOverride ?? entry.summary!,
diff --git a/packages/providers/src/calendars/google-calendar/events/conferences/utils.ts b/packages/providers/src/calendars/google-calendar/conferences.ts
similarity index 70%
rename from packages/providers/src/calendars/google-calendar/events/conferences/utils.ts
rename to packages/providers/src/calendars/google-calendar/conferences.ts
index 81a56319..e33fb8ab 100644
--- a/packages/providers/src/calendars/google-calendar/events/conferences/utils.ts
+++ b/packages/providers/src/calendars/google-calendar/conferences.ts
@@ -1,11 +1,13 @@
 import type {
   ConferenceDataInput,
   CreateConferenceRequest,
+  EntryPoint,
+  EntryPointInput,
 } from "@analog/google-calendar";
 import { detectMeetingLink } from "@analog/meeting-links";
 
-import type { Conference } from "../../../../interfaces";
-import type { GoogleCalendarEvent } from "../../interfaces";
+import type { Conference } from "../../interfaces";
+import type { GoogleCalendarEvent } from "./interfaces";
 
 function parseConferenceRequestStatus(status?: string) {
   if (status === "pending" || status === "success" || status === "failure") {
@@ -123,7 +125,7 @@ function isCreatingConferenceRequest(
   return createRequest.status?.statusCode !== "success";
 }
 
-export function parseConferenceData(
+export function parseConference(
   event: GoogleCalendarEvent,
 ): Conference | undefined {
   if (isCreatingConferenceRequest(event.conferenceData?.createRequest)) {
@@ -212,7 +214,7 @@ export function parseConferenceData(
   };
 }
 
-export function toConferenceData(
+export function formatConference(
   conference: Conference,
 ): ConferenceDataInput | undefined {
   if (conference.type === "conference") {
@@ -228,3 +230,70 @@ export function toConferenceData(
     },
   };
 }
+
+function formatEntryPointInput(entryPoint: EntryPoint): EntryPointInput {
+  return {
+    accessCode: entryPoint.accessCode,
+    entryPointFeatures: entryPoint.entryPointFeatures,
+    entryPointType: entryPoint.entryPointType!,
+    label: entryPoint.label,
+    meetingCode: entryPoint.meetingCode,
+    passcode: entryPoint.passcode,
+    password: entryPoint.password,
+    pin: entryPoint.pin,
+    regionCode: entryPoint.regionCode,
+    uri: entryPoint.uri!,
+  };
+}
+
+export function formatConferenceInput(
+  conferenceData: GoogleCalendarEvent["conferenceData"],
+): ConferenceDataInput | undefined {
+  if (!conferenceData) {
+    return undefined;
+  }
+
+  // A createRequest with status "success" is a completed conference (see
+  // isCreatingConferenceRequest above), so copy it instead of re-echoing the
+  // request.
+  if (
+    (!conferenceData.createRequest ||
+      conferenceData.createRequest.status?.statusCode === "success") &&
+    conferenceData.entryPoints?.length
+  ) {
+    const [entryPoint, ...entryPoints] = conferenceData.entryPoints;
+
+    return {
+      ...conferenceData,
+      conferenceSolution: {
+        iconUri: conferenceData.conferenceSolution?.iconUri,
+        key: {
+          type: conferenceData.conferenceSolution!.key!.type!,
+        },
+        name: conferenceData.conferenceSolution?.name,
+      },
+      entryPoints: [
+        formatEntryPointInput(entryPoint!),
+        ...entryPoints.map(formatEntryPointInput),
+      ],
+    };
+  }
+
+  if (!conferenceData.createRequest) {
+    return undefined;
+  }
+
+  // Re-sending the same requestId is an idempotent no-op that keeps a
+  // conferenceData body present; omitting it would clear the conference
+  // because updates always send conferenceDataVersion=1.
+  return {
+    createRequest: {
+      requestId: conferenceData.createRequest.requestId!,
+      ...(conferenceData.createRequest.conferenceSolutionKey?.type && {
+        conferenceSolutionKey: {
+          type: conferenceData.createRequest.conferenceSolutionKey.type,
+        },
+      }),
+    },
+  };
+}
diff --git a/packages/providers/src/calendars/google-calendar/events/format.ts b/packages/providers/src/calendars/google-calendar/events/format.ts
new file mode 100644
index 00000000..78e3ea9d
--- /dev/null
+++ b/packages/providers/src/calendars/google-calendar/events/format.ts
@@ -0,0 +1,297 @@
+import type {
+  ConferenceDataInput,
+  EventAttendee,
+  EventAttendeeInput,
+  EventDateTime,
+  EventInput,
+} from "@analog/google-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type { CreateEventInput, UpdateEventPatch } from "@repo/schemas";
+
+import type { Attendee, AttendeeStatus } from "../../../interfaces";
+import { toRecurrenceProperties } from "../../../lib/recurrences/export";
+import { formatConference, formatConferenceInput } from "../conferences";
+import type {
+  GoogleCalendarDate,
+  GoogleCalendarDateTime,
+  GoogleCalendarEvent,
+  GoogleCalendarEventAttendeeResponseStatus,
+} from "../interfaces";
+
+function formatAttendeeInput(attendee: EventAttendee): EventAttendeeInput {
+  return {
+    additionalGuests: attendee.additionalGuests,
+    comment: attendee.comment,
+    displayName: attendee.displayName,
+    email: attendee.email!,
+    optional: attendee.optional,
+    resource: attendee.resource,
+    responseStatus: attendee.responseStatus,
+  };
+}
+
+function formatReminders(
+  reminders: GoogleCalendarEvent["reminders"],
+): EventInput["reminders"] {
+  if (!reminders) {
+    return undefined;
+  }
+
+  return {
+    overrides: reminders.overrides?.map((reminder) => ({
+      ...reminder,
+      method: reminder.method!,
+      minutes: reminder.minutes!,
+    })),
+    useDefault: reminders.useDefault,
+  };
+}
+
+export function formatEventInput(event: GoogleCalendarEvent) {
+  if (event.eventType && event.eventType !== "default") {
+    throw new Error(
+      `Google Calendar ${event.eventType} events cannot be updated`,
+    );
+  }
+
+  return {
+    anyoneCanAddSelf: event.anyoneCanAddSelf,
+    attachments: event.attachments?.map((attachment) => ({
+      fileUrl: attachment.fileUrl!,
+      iconLink: attachment.iconLink,
+      mimeType: attachment.mimeType,
+      title: attachment.title,
+    })),
+    attendees: event.attendees?.map(formatAttendeeInput),
+    attendeesOmitted: event.attendeesOmitted,
+    conferenceData: formatConferenceInput(event.conferenceData),
+    description: event.description,
+    end: event.end!,
+    eventType: "default" as const,
+    extendedProperties: event.extendedProperties,
+    guestsCanInviteOthers: event.guestsCanInviteOthers,
+    guestsCanModify: event.guestsCanModify,
+    guestsCanSeeOtherGuests: event.guestsCanSeeOtherGuests,
+    location: event.location,
+    originalStartTime: event.originalStartTime,
+    recurrence: event.recurrence,
+    reminders: formatReminders(event.reminders),
+    sequence: event.sequence,
+    source: event.source,
+    start: event.start!,
+    status: event.status,
+    summary: event.summary,
+    transparency: event.transparency,
+    visibility: event.visibility,
+    ...(event.eventLabelId
+      ? { eventLabelId: event.eventLabelId, eventLabelVersion: 1 as const }
+      : { colorId: event.colorId }),
+  };
+}
+
+export function formatDate(
+  value: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime,
+): GoogleCalendarDate | GoogleCalendarDateTime {
+  if (value instanceof Temporal.PlainDate) {
+    return {
+      date: value.toString(),
+    };
+  }
+
+  if (value instanceof Temporal.Instant) {
+    return {
+      dateTime: value.toString(),
+    };
+  }
+
+  return {
+    dateTime: value.toString({ timeZoneName: "never", offset: "auto" }),
+    timeZone: value.timeZoneId,
+  };
+}
+
+export function formatAttendee(attendee: Attendee): EventAttendeeInput {
+  return {
+    email: attendee.email,
+    displayName: attendee.name,
+    ...(attendee.type === "optional" ? { optional: true } : {}),
+    ...(attendee.type === "resource" ? { resource: true } : {}),
+    responseStatus: formatAttendeeStatus(attendee.status),
+    comment: attendee.comment,
+    additionalGuests: attendee.additionalGuests,
+  };
+}
+
+function formatRecurrence(event: CreateEventInput | UpdateEventPatch) {
+  // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
+  if (event.recurrence === null) {
+    return [];
+  }
+
+  if (!event.recurrence) {
+    return undefined;
+  }
+
+  return toRecurrenceProperties(event.recurrence);
+}
+
+function formatAttendees(event: CreateEventInput | UpdateEventPatch) {
+  if (!event.attendees) {
+    return undefined;
+  }
+
+  return event.attendees.map(formatAttendee);
+}
+
+function formatEventConference(event: CreateEventInput | UpdateEventPatch) {
+  if (event.conference === null) {
+    return null;
+  }
+
+  if (!event.conference) {
+    return undefined;
+  }
+
+  return formatConference(event.conference);
+}
+
+function formatTransparency(
+  event: CreateEventInput | UpdateEventPatch,
+): "opaque" | "transparent" | undefined {
+  if (!event.availability) {
+    return undefined;
+  }
+
+  if (event.availability === "free") {
+    return "transparent";
+  }
+
+  return "opaque";
+}
+
+export function formatEvent(event: CreateEventInput) {
+  if (event.color) {
+    throw new Error("Google Calendar event colors are not supported");
+  }
+
+  return {
+    id: event.id,
+    summary: event.title,
+    description: event.description,
+    location: event.location,
+    visibility: event.visibility,
+    start: formatDate(event.start),
+    end: formatDate(event.end),
+    transparency: formatTransparency(event),
+    attendees: formatAttendees(event),
+    conferenceData: event.conference
+      ? formatConference(event.conference)
+      : undefined,
+    // Should always be 1 to ensure conference data is retained for all event modification requests.
+    conferenceDataVersion: 1 as const,
+    // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
+    recurrence: formatRecurrence(event),
+  };
+}
+
+interface EventUpdateOverrides {
+  attendees?: EventAttendeeInput[];
+  calendarId: string;
+  conferenceData?: ConferenceDataInput | null;
+  conferenceDataVersion: 1;
+  description?: string | null;
+  end: EventDateTime;
+  location?: string | null;
+  recurrence?: string[];
+  start: EventDateTime;
+  summary?: string;
+  transparency?: "opaque" | "transparent";
+  visibility?: "confidential" | "default" | "private" | "public";
+}
+
+export function formatEventPatch(
+  event: UpdateEventPatch,
+  existingEvent: GoogleCalendarEvent,
+): EventUpdateOverrides {
+  if (event.color) {
+    throw new Error("Google Calendar event colors are not supported");
+  }
+
+  return {
+    calendarId: event.calendar.id,
+    // Should always be 1 to ensure conference data is retained for all event modification requests.
+    conferenceDataVersion: 1,
+    start: event.start ? formatDate(event.start) : existingEvent.start!,
+    end: event.end ? formatDate(event.end) : existingEvent.end!,
+    // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
+    recurrence:
+      event.recurrence !== undefined
+        ? formatRecurrence(event)
+        : existingEvent.recurrence,
+    ...(event.title !== undefined ? { summary: event.title } : {}),
+    // A null patch value is sent as an explicit null in the PUT body to clear
+    // the field (recurrence clears as [] instead — the insert type has no null).
+    ...(event.description !== undefined
+      ? { description: event.description }
+      : {}),
+    ...(event.location !== undefined ? { location: event.location } : {}),
+    ...(event.visibility !== undefined ? { visibility: event.visibility } : {}),
+    ...(event.availability !== undefined
+      ? { transparency: formatTransparency(event) }
+      : {}),
+    ...(event.attendees !== undefined
+      ? { attendees: formatAttendees(event) }
+      : {}),
+    // A "conference"-shaped patch is display-only and maps to no input: skip
+    // the key so the echoed conferenceData survives the full-replace PUT.
+    ...(event.conference === null || event.conference?.type === "create"
+      ? { conferenceData: formatEventConference(event) }
+      : {}),
+  };
+}
+
+export function formatAttendeeStatus(
+  status: AttendeeStatus,
+): GoogleCalendarEventAttendeeResponseStatus {
+  if (status === "unknown") {
+    return "needsAction";
+  }
+
+  return status;
+}
+
+export function attendeesWithSelfResponse(
+  attendees: EventAttendee[] | undefined,
+  status: AttendeeStatus,
+  comment?: string | null,
+) {
+  if (!attendees) {
+    throw new Error("Event has no attendees");
+  }
+
+  const attendee = attendees.find((attendee) => attendee.self);
+
+  if (!attendee) {
+    throw new Error("User is not an attendee");
+  }
+
+  const input = formatAttendeeInput(attendee);
+
+  if (comment === undefined) {
+    return [
+      {
+        ...input,
+        responseStatus: formatAttendeeStatus(status),
+      },
+    ];
+  }
+
+  return [
+    {
+      ...input,
+      comment,
+      responseStatus: formatAttendeeStatus(status),
+    },
+  ];
+}
diff --git a/packages/providers/src/calendars/google-calendar/events/index.ts b/packages/providers/src/calendars/google-calendar/events/index.ts
index 6fb0cfea..c079415e 100644
--- a/packages/providers/src/calendars/google-calendar/events/index.ts
+++ b/packages/providers/src/calendars/google-calendar/events/index.ts
@@ -24,14 +24,13 @@ import type {
 import { ProviderError } from "../../../lib/provider-error";
 import {
   attendeesWithSelfResponse,
-  createEventParams,
-  parseGoogleCalendarEventDate,
-  parseGoogleCalendarEvent,
-  toGoogleCalendarAttendee,
-  toGoogleCalendarAttendeeResponseStatus,
-  toGoogleCalendarEventInput,
-  updateEventParams,
-} from "./utils";
+  formatAttendee,
+  formatAttendeeStatus,
+  formatEvent,
+  formatEventInput,
+  formatEventPatch,
+} from "./format";
+import { parseEvent, parseEventDate } from "./parse";
 
 const MAX_EVENTS_PER_CALENDAR = 250;
 
@@ -57,10 +56,10 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
         });
 
         const events = (items ?? []).map((event) =>
-          parseGoogleCalendarEvent({
+          parseEvent({
             calendar,
             event,
-            defaultTimeZone: timeZone ?? "UTC",
+            defaultTimeZone: timeZone,
           }),
         );
 
@@ -136,9 +135,7 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
                 event: {
                   id: event.id!,
                   recurringEventId: event.recurringEventId,
-                  originalStartTime: parseGoogleCalendarEventDate(
-                    event.originalStartTime!,
-                  ),
+                  originalStartTime: parseEventDate(event.originalStartTime!),
                   calendar: {
                     id: calendar.id,
                     provider: calendar.provider,
@@ -163,7 +160,7 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
 
           changes.push({
             status: "updated",
-            event: parseGoogleCalendarEvent({
+            event: parseEvent({
               calendar,
               event,
               defaultTimeZone: timeZone,
@@ -239,7 +236,7 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
         eventId,
       });
 
-      return parseGoogleCalendarEvent({
+      return parseEvent({
         calendar,
         event,
         defaultTimeZone: timeZone ?? "UTC",
@@ -256,11 +253,11 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
       try {
         const createdEvent = await this.client.events.insert({
           calendarId: calendar.id,
-          ...createEventParams(event),
+          ...formatEvent(event),
           sendUpdates: sendUpdate ? "all" : "none",
         });
 
-        return parseGoogleCalendarEvent({
+        return parseEvent({
           calendar,
           event: createdEvent,
         });
@@ -302,8 +299,8 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
 
       const updatedEvent = await this.client.events.update({
         eventId,
-        ...toGoogleCalendarEventInput(existingEvent),
-        ...updateEventParams(event, existingEvent),
+        ...formatEventInput(existingEvent),
+        ...formatEventPatch(event, existingEvent),
         ...(response
           ? event.attendees === undefined
             ? {
@@ -320,15 +317,13 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
                 attendees: event.attendees.map((attendee) =>
                   attendee.email === selfEmail
                     ? {
-                        ...toGoogleCalendarAttendee(attendee),
+                        ...formatAttendee(attendee),
                         ...(response.comment !== undefined
                           ? { comment: response.comment }
                           : {}),
-                        responseStatus: toGoogleCalendarAttendeeResponseStatus(
-                          response.status,
-                        ),
+                        responseStatus: formatAttendeeStatus(response.status),
                       }
-                    : toGoogleCalendarAttendee(attendee),
+                    : formatAttendee(attendee),
                 ),
               }
           : {}),
@@ -339,7 +334,7 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
         headers: { "If-Match": event.etag ?? existingEvent.etag },
       });
 
-      return parseGoogleCalendarEvent({
+      return parseEvent({
         calendar,
         event: updatedEvent,
       });
@@ -378,7 +373,7 @@ export class GoogleCalendarEvents implements CalendarProviderEvents {
         sendUpdates: sendUpdate ? "all" : "none",
       });
 
-      return parseGoogleCalendarEvent({
+      return parseEvent({
         calendar: destinationCalendar,
         event,
       });
diff --git a/packages/providers/src/calendars/google-calendar/events/parse.ts b/packages/providers/src/calendars/google-calendar/events/parse.ts
new file mode 100644
index 00000000..4b952188
--- /dev/null
+++ b/packages/providers/src/calendars/google-calendar/events/parse.ts
@@ -0,0 +1,261 @@
+import type { EventDateTime } from "@analog/google-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type {
+  Attendee,
+  AttendeeStatus,
+  Calendar,
+  CalendarEvent,
+} from "../../../interfaces";
+import { parseTextRecurrence } from "../../../lib/recurrences/parse";
+import { parseConference } from "../conferences";
+import type {
+  GoogleCalendarDate,
+  GoogleCalendarDateTime,
+  GoogleCalendarEvent,
+  GoogleCalendarEventAttendee,
+  GoogleCalendarEventAttendeeResponseStatus,
+} from "../interfaces";
+
+const GMT_OFFSET =
+  /^GMT(?<sign>[+-])(?<hours>\d{1,2})(?::?(?<minutes>[0-5]\d))?$/;
+
+function parseTimeZone(timeZone: string) {
+  // Normalize Google-style GMT offsets to IANA or UTC-compatible time zones
+  if (!timeZone) {
+    return timeZone;
+  }
+
+  if (timeZone === "GMT") {
+    return "UTC";
+  }
+
+  const match = GMT_OFFSET.exec(timeZone);
+
+  if (!match?.groups) {
+    return timeZone;
+  }
+
+  const { sign, hours, minutes } = match.groups;
+
+  if (!sign || !hours) {
+    return timeZone;
+  }
+
+  // If minutes are provided and not 00, fall back to a UTC offset which Temporal supports.
+  const hh = hours.padStart(2, "0");
+  const mm = minutes && minutes !== "00" ? minutes : "00";
+
+  return `${sign}${hh}:${mm}`;
+}
+
+function parseDate({ date }: GoogleCalendarDate) {
+  return Temporal.PlainDate.from(date);
+}
+
+function parseDateTime({ dateTime, timeZone }: GoogleCalendarDateTime) {
+  const instant = Temporal.Instant.from(dateTime);
+
+  if (!timeZone) {
+    return instant;
+  }
+
+  return instant.toZonedDateTimeISO(parseTimeZone(timeZone));
+}
+
+export function parseEventDate(value: EventDateTime) {
+  if (value.date) {
+    return parseDate({ date: value.date });
+  }
+
+  return parseDateTime({
+    dateTime: value.dateTime!,
+    timeZone: value.timeZone,
+  });
+}
+
+interface ParseEventOptions {
+  calendar: Calendar;
+  event: GoogleCalendarEvent;
+  defaultTimeZone?: string;
+}
+
+function parseStart(event: GoogleCalendarEvent) {
+  if (!event.start?.dateTime) {
+    return parseDate(event.start as GoogleCalendarDate);
+  }
+
+  return parseDateTime(event.start as GoogleCalendarDateTime);
+}
+
+function parseEnd(event: GoogleCalendarEvent) {
+  if (!event.start?.dateTime) {
+    return parseDate(event.end as GoogleCalendarDate);
+  }
+
+  return parseDateTime(event.end as GoogleCalendarDateTime);
+}
+
+function parseAttendees(event: GoogleCalendarEvent) {
+  if (!event.attendees) {
+    return [];
+  }
+
+  const attendees = event.attendees.map(parseAttendee);
+  const organizer = attendees.find((attendee) => attendee.organizer);
+
+  if (!organizer) {
+    return attendees;
+  }
+
+  if (attendees[0] === organizer) {
+    return attendees;
+  }
+
+  return [organizer, ...attendees.filter((attendee) => attendee !== organizer)];
+}
+
+function parseResponse(event: GoogleCalendarEvent) {
+  const selfAttendee = event.attendees?.find((a) => a.self);
+
+  if (!selfAttendee) {
+    return {};
+  }
+
+  return {
+    response: {
+      status: parseAttendeeStatus(selfAttendee.responseStatus ?? "needsAction"),
+      comment: selfAttendee.comment,
+    },
+  };
+}
+
+function parseEventRecurrence(
+  event: GoogleCalendarEvent,
+  defaultTimeZone: string,
+) {
+  const recurrence = event.recurrence
+    ? parseTextRecurrence({
+        lines: event.recurrence,
+        defaultTimeZone: parseTimeZone(
+          event.start?.timeZone ?? defaultTimeZone,
+        ),
+      })
+    : undefined;
+
+  if (!recurrence) {
+    return {};
+  }
+
+  return { recurrence };
+}
+
+function parseCreatedAt(event: GoogleCalendarEvent) {
+  if (!event.created) {
+    return {};
+  }
+
+  return { createdAt: Temporal.Instant.from(event.created) };
+}
+
+function parseUpdatedAt(event: GoogleCalendarEvent) {
+  if (!event.updated) {
+    return {};
+  }
+
+  return { updatedAt: Temporal.Instant.from(event.updated) };
+}
+
+function parseMetadata(event: GoogleCalendarEvent) {
+  return {
+    ...(event.recurrence ? { originalRecurrence: event.recurrence } : {}),
+    ...(event.recurringEventId
+      ? { recurringEventId: event.recurringEventId }
+      : {}),
+  };
+}
+
+export function parseEvent({
+  calendar,
+  event,
+  defaultTimeZone = "UTC",
+}: ParseEventOptions): CalendarEvent {
+  return {
+    // ID should always be present if not defined Google Calendar will generate one
+    id: event.id!,
+    title: event.summary!,
+    description: event.description,
+    start: parseStart(event),
+    end: parseEnd(event),
+    allDay: !event.start?.dateTime,
+    location: event.location,
+    status: event.status,
+    availability: event.transparency === "transparent" ? "free" : "busy",
+    attendees: parseAttendees(event),
+    url: event.htmlLink,
+    etag: event.etag,
+    visibility: event.visibility as
+      | "default"
+      | "public"
+      | "private"
+      | "confidential"
+      | undefined,
+    calendar: {
+      id: calendar.id,
+      provider: calendar.provider,
+    },
+    readOnly:
+      calendar.readOnly ||
+      [
+        "birthday",
+        "focusTime",
+        "fromGmail",
+        "outOfOffice",
+        "workingLocation",
+      ].includes(event.eventType ?? ""),
+    conference: parseConference(event),
+    ...parseResponse(event),
+    ...parseEventRecurrence(event, defaultTimeZone),
+    ...parseCreatedAt(event),
+    ...parseUpdatedAt(event),
+    recurringEventId: event.recurringEventId,
+    metadata: parseMetadata(event),
+  } as CalendarEvent;
+}
+
+function parseAttendeeStatus(
+  status: GoogleCalendarEventAttendeeResponseStatus,
+): AttendeeStatus {
+  if (status === "needsAction") {
+    return "unknown";
+  }
+
+  return status;
+}
+
+function parseAttendeeType(
+  attendee: GoogleCalendarEventAttendee,
+): "required" | "optional" | "resource" {
+  if (attendee.resource) {
+    return "resource";
+  }
+
+  if (attendee.optional) {
+    return "optional";
+  }
+
+  return "required";
+}
+
+export function parseAttendee(attendee: GoogleCalendarEventAttendee): Attendee {
+  return {
+    id: attendee.id,
+    email: attendee.email!,
+    name: attendee.displayName,
+    status: parseAttendeeStatus(attendee.responseStatus ?? "needsAction"),
+    type: parseAttendeeType(attendee),
+    comment: attendee.comment,
+    organizer: attendee.organizer,
+    additionalGuests: attendee.additionalGuests,
+  };
+}
diff --git a/packages/providers/src/calendars/google-calendar/events/utils.ts b/packages/providers/src/calendars/google-calendar/events/utils.ts
deleted file mode 100644
index aea22e44..00000000
--- a/packages/providers/src/calendars/google-calendar/events/utils.ts
+++ /dev/null
@@ -1,607 +0,0 @@
-import { Temporal } from "temporal-polyfill";
-
-import type {
-  ConferenceDataInput,
-  EntryPoint,
-  EntryPointInput,
-  EventAttendee,
-  EventAttendeeInput,
-  EventDateTime,
-  EventInput,
-} from "@analog/google-calendar";
-import type { CreateEventInput, UpdateEventPatch } from "@repo/schemas";
-
-import type {
-  Attendee,
-  AttendeeStatus,
-  Calendar,
-  CalendarEvent,
-  Recurrence,
-} from "../../../interfaces";
-import { toRecurrenceProperties } from "../../../lib/recurrences/export";
-import { parseTextRecurrence } from "../../../lib/recurrences/parse";
-import type {
-  GoogleCalendarDate,
-  GoogleCalendarDateTime,
-  GoogleCalendarEvent,
-  GoogleCalendarEventAttendee,
-  GoogleCalendarEventAttendeeResponseStatus,
-} from "../interfaces";
-import { parseConferenceData, toConferenceData } from "./conferences/utils";
-
-function toGoogleCalendarEntryPointInput(
-  entryPoint: EntryPoint,
-): EntryPointInput {
-  return {
-    accessCode: entryPoint.accessCode,
-    entryPointFeatures: entryPoint.entryPointFeatures,
-    entryPointType: entryPoint.entryPointType!,
-    label: entryPoint.label,
-    meetingCode: entryPoint.meetingCode,
-    passcode: entryPoint.passcode,
-    password: entryPoint.password,
-    pin: entryPoint.pin,
-    regionCode: entryPoint.regionCode,
-    uri: entryPoint.uri!,
-  };
-}
-
-function toGoogleCalendarConferenceDataInput(
-  conferenceData: GoogleCalendarEvent["conferenceData"],
-): ConferenceDataInput | undefined {
-  if (!conferenceData) {
-    return undefined;
-  }
-
-  // A createRequest with status "success" is a completed conference (see
-  // isCreatingConferenceRequest in ./conferences/utils.ts), so copy it instead
-  // of re-echoing the request.
-  if (
-    (!conferenceData.createRequest ||
-      conferenceData.createRequest.status?.statusCode === "success") &&
-    conferenceData.entryPoints?.length
-  ) {
-    const [entryPoint, ...entryPoints] = conferenceData.entryPoints;
-
-    return {
-      ...conferenceData,
-      conferenceSolution: {
-        iconUri: conferenceData.conferenceSolution?.iconUri,
-        key: {
-          type: conferenceData.conferenceSolution!.key!.type!,
-        },
-        name: conferenceData.conferenceSolution?.name,
-      },
-      entryPoints: [
-        toGoogleCalendarEntryPointInput(entryPoint!),
-        ...entryPoints.map(toGoogleCalendarEntryPointInput),
-      ],
-    };
-  }
-
-  if (!conferenceData.createRequest) {
-    return undefined;
-  }
-
-  // Re-sending the same requestId is an idempotent no-op that keeps a
-  // conferenceData body present; omitting it would clear the conference
-  // because updates always send conferenceDataVersion=1.
-  return {
-    createRequest: {
-      requestId: conferenceData.createRequest.requestId!,
-      ...(conferenceData.createRequest.conferenceSolutionKey?.type && {
-        conferenceSolutionKey: {
-          type: conferenceData.createRequest.conferenceSolutionKey.type,
-        },
-      }),
-    },
-  };
-}
-
-function toGoogleCalendarAttendeeInput(
-  attendee: EventAttendee,
-): EventAttendeeInput {
-  return {
-    additionalGuests: attendee.additionalGuests,
-    comment: attendee.comment,
-    displayName: attendee.displayName,
-    email: attendee.email!,
-    optional: attendee.optional,
-    resource: attendee.resource,
-    responseStatus: attendee.responseStatus,
-  };
-}
-
-function toGoogleCalendarRemindersInput(
-  reminders: GoogleCalendarEvent["reminders"],
-): EventInput["reminders"] {
-  if (!reminders) {
-    return undefined;
-  }
-
-  return {
-    overrides: reminders.overrides?.map((reminder) => ({
-      ...reminder,
-      method: reminder.method!,
-      minutes: reminder.minutes!,
-    })),
-    useDefault: reminders.useDefault,
-  };
-}
-
-export function toGoogleCalendarEventInput(event: GoogleCalendarEvent) {
-  if (event.eventType && event.eventType !== "default") {
-    throw new Error(
-      `Google Calendar ${event.eventType} events cannot be updated`,
-    );
-  }
-
-  return {
-    anyoneCanAddSelf: event.anyoneCanAddSelf,
-    attachments: event.attachments?.map((attachment) => ({
-      fileUrl: attachment.fileUrl!,
-      iconLink: attachment.iconLink,
-      mimeType: attachment.mimeType,
-      title: attachment.title,
-    })),
-    attendees: event.attendees?.map(toGoogleCalendarAttendeeInput),
-    attendeesOmitted: event.attendeesOmitted,
-    conferenceData: toGoogleCalendarConferenceDataInput(event.conferenceData),
-    description: event.description,
-    end: event.end!,
-    eventType: "default" as const,
-    extendedProperties: event.extendedProperties,
-    guestsCanInviteOthers: event.guestsCanInviteOthers,
-    guestsCanModify: event.guestsCanModify,
-    guestsCanSeeOtherGuests: event.guestsCanSeeOtherGuests,
-    location: event.location,
-    originalStartTime: event.originalStartTime,
-    recurrence: event.recurrence,
-    reminders: toGoogleCalendarRemindersInput(event.reminders),
-    sequence: event.sequence,
-    source: event.source,
-    start: event.start!,
-    status: event.status,
-    summary: event.summary,
-    transparency: event.transparency,
-    visibility: event.visibility,
-    ...(event.eventLabelId
-      ? { eventLabelId: event.eventLabelId, eventLabelVersion: 1 as const }
-      : { colorId: event.colorId }),
-  };
-}
-
-export function toGoogleCalendarDate(
-  value: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime,
-): GoogleCalendarDate | GoogleCalendarDateTime {
-  if (value instanceof Temporal.PlainDate) {
-    return {
-      date: value.toString(),
-    };
-  }
-
-  if (value instanceof Temporal.Instant) {
-    return {
-      dateTime: value.toString(),
-    };
-  }
-
-  return {
-    dateTime: value.toString({ timeZoneName: "never", offset: "auto" }),
-    timeZone: value.timeZoneId,
-  };
-}
-
-function parseDate({ date }: GoogleCalendarDate) {
-  return Temporal.PlainDate.from(date);
-}
-
-function normalizeGoogleTimeZone(timeZone: string) {
-  // Normalize Google-style GMT offsets to IANA or UTC-compatible time zones
-  if (!timeZone) {
-    return timeZone;
-  }
-
-  if (timeZone === "GMT") {
-    return "UTC";
-  }
-
-  const match = /^GMT([+-])(\d{1,2})(?::?([0-5]\d))?$/.exec(timeZone);
-
-  if (!match) {
-    return timeZone;
-  }
-
-  const [, sign, hoursStr, minutesStr] = match;
-
-  if (!sign || !hoursStr) {
-    return timeZone;
-  }
-
-  // If minutes are provided and not 00, fall back to a UTC offset which Temporal supports.
-  const hh = hoursStr.padStart(2, "0");
-  const mm = minutesStr && minutesStr !== "00" ? minutesStr : "00";
-
-  return `${sign}${hh}:${mm}`;
-}
-
-function parseDateTime({ dateTime, timeZone }: GoogleCalendarDateTime) {
-  const instant = Temporal.Instant.from(dateTime);
-
-  if (!timeZone) {
-    return instant;
-  }
-
-  const normalized = normalizeGoogleTimeZone(timeZone);
-  return instant.toZonedDateTimeISO(normalized);
-}
-
-export function parseGoogleCalendarEventDate(value: EventDateTime) {
-  if (value.date) {
-    return parseDate({ date: value.date });
-  }
-
-  return parseDateTime({
-    dateTime: value.dateTime!,
-    timeZone: value.timeZone,
-  });
-}
-
-function parseResponseStatus(event: GoogleCalendarEvent) {
-  const selfAttendee = event.attendees?.find((a) => a.self);
-
-  if (!selfAttendee) {
-    return undefined;
-  }
-
-  return {
-    status: parseGoogleCalendarAttendeeStatus(
-      selfAttendee.responseStatus ?? "needsAction",
-    ),
-    comment: selfAttendee.comment,
-  };
-}
-
-function parseRecurrence(
-  event: GoogleCalendarEvent,
-  timeZone: string,
-): Recurrence | undefined {
-  if (!event.recurrence) {
-    return undefined;
-  }
-
-  return parseTextRecurrence({
-    lines: event.recurrence,
-    defaultTimeZone: normalizeGoogleTimeZone(timeZone),
-  });
-}
-
-interface ParsedGoogleCalendarEventOptions {
-  calendar: Calendar;
-  event: GoogleCalendarEvent;
-  defaultTimeZone?: string;
-}
-
-export function parseGoogleCalendarEvent({
-  calendar,
-  event,
-  defaultTimeZone = "UTC",
-}: ParsedGoogleCalendarEventOptions): CalendarEvent {
-  const isAllDay = !event.start?.dateTime;
-  const response = parseResponseStatus(event);
-  const recurrence = parseRecurrence(
-    event,
-    event.start?.timeZone ?? defaultTimeZone,
-  );
-
-  return {
-    // ID should always be present if not defined Google Calendar will generate one
-    id: event.id!,
-    title: event.summary!,
-    description: event.description,
-    start: isAllDay
-      ? parseDate(event.start as GoogleCalendarDate)
-      : parseDateTime(event.start as GoogleCalendarDateTime),
-    end: isAllDay
-      ? parseDate(event.end as GoogleCalendarDate)
-      : parseDateTime(event.end as GoogleCalendarDateTime),
-    allDay: isAllDay,
-    location: event.location,
-    status: event.status,
-    availability: event.transparency === "transparent" ? "free" : "busy",
-    attendees: event.attendees
-      ? parseGoogleCalendarAttendeeList(event.attendees)
-      : [],
-    url: event.htmlLink,
-    etag: event.etag,
-    visibility: event.visibility as
-      | "default"
-      | "public"
-      | "private"
-      | "confidential"
-      | undefined,
-    calendar: {
-      id: calendar.id,
-      provider: calendar.provider,
-    },
-    readOnly:
-      calendar.readOnly ||
-      [
-        "birthday",
-        "focusTime",
-        "fromGmail",
-        "outOfOffice",
-        "workingLocation",
-      ].includes(event.eventType ?? ""),
-    conference: parseConferenceData(event),
-    ...(response ? { response } : {}),
-    ...(recurrence ? { recurrence } : {}),
-    ...(event.created
-      ? { createdAt: Temporal.Instant.from(event.created) }
-      : {}),
-    ...(event.updated
-      ? { updatedAt: Temporal.Instant.from(event.updated) }
-      : {}),
-    recurringEventId: event.recurringEventId,
-    metadata: {
-      ...(event.recurrence ? { originalRecurrence: event.recurrence } : {}),
-      ...(event.recurringEventId
-        ? { recurringEventId: event.recurringEventId }
-        : {}),
-    },
-  } as CalendarEvent;
-}
-
-export function toGoogleCalendarAttendee(
-  attendee: Attendee,
-): EventAttendeeInput {
-  return {
-    email: attendee.email,
-    displayName: attendee.name,
-    ...(attendee.type === "optional" ? { optional: true } : {}),
-    ...(attendee.type === "resource" ? { resource: true } : {}),
-    responseStatus: toGoogleCalendarAttendeeResponseStatus(attendee.status),
-    comment: attendee.comment,
-    additionalGuests: attendee.additionalGuests,
-  };
-}
-
-function toGoogleCalendarAttendees(
-  attendees: Attendee[],
-): EventAttendeeInput[] {
-  return attendees.map(toGoogleCalendarAttendee);
-}
-
-function recurrences(event: CreateEventInput | UpdateEventPatch) {
-  // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
-  if (event.recurrence === null) {
-    return [];
-  }
-
-  if (!event.recurrence) {
-    return undefined;
-  }
-
-  return toRecurrenceProperties(event.recurrence);
-}
-
-function attendees(event: CreateEventInput | UpdateEventPatch) {
-  if (!event.attendees) {
-    return undefined;
-  }
-
-  return toGoogleCalendarAttendees(event.attendees);
-}
-
-function conference(event: CreateEventInput | UpdateEventPatch) {
-  if (event.conference === null) {
-    return null;
-  }
-
-  if (!event.conference) {
-    return undefined;
-  }
-
-  return toConferenceData(event.conference);
-}
-
-function availability(
-  event: CreateEventInput | UpdateEventPatch,
-): "opaque" | "transparent" | undefined {
-  if (!event.availability) {
-    return undefined;
-  }
-
-  if (event.availability === "free") {
-    return "transparent";
-  }
-
-  return "opaque";
-}
-
-export function createEventParams(event: CreateEventInput) {
-  if (event.color) {
-    throw new Error("Google Calendar event colors are not supported");
-  }
-
-  return {
-    id: event.id,
-    summary: event.title,
-    description: event.description,
-    location: event.location,
-    visibility: event.visibility,
-    start: toGoogleCalendarDate(event.start),
-    end: toGoogleCalendarDate(event.end),
-    transparency: availability(event),
-    attendees: attendees(event),
-    conferenceData: event.conference
-      ? toConferenceData(event.conference)
-      : undefined,
-    // Should always be 1 to ensure conference data is retained for all event modification requests.
-    conferenceDataVersion: 1 as const,
-    // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
-    recurrence: recurrences(event),
-  };
-}
-
-interface GoogleCalendarEventUpdateOverrides {
-  attendees?: EventAttendeeInput[];
-  calendarId: string;
-  conferenceData?: ConferenceDataInput | null;
-  conferenceDataVersion: 1;
-  description?: string | null;
-  end: EventDateTime;
-  location?: string | null;
-  recurrence?: string[];
-  start: EventDateTime;
-  summary?: string;
-  transparency?: "opaque" | "transparent";
-  visibility?: "confidential" | "default" | "private" | "public";
-}
-
-export function updateEventParams(
-  event: UpdateEventPatch,
-  existingEvent: GoogleCalendarEvent,
-): GoogleCalendarEventUpdateOverrides {
-  if (event.color) {
-    throw new Error("Google Calendar event colors are not supported");
-  }
-
-  return {
-    calendarId: event.calendar.id,
-    // Should always be 1 to ensure conference data is retained for all event modification requests.
-    conferenceDataVersion: 1,
-    start: event.start
-      ? toGoogleCalendarDate(event.start)
-      : existingEvent.start!,
-    end: event.end ? toGoogleCalendarDate(event.end) : existingEvent.end!,
-    // TODO: how to handle recurrence when the time zone is changed (i.e. until, rDate, exDate).
-    recurrence:
-      event.recurrence !== undefined
-        ? recurrences(event)
-        : existingEvent.recurrence,
-    ...(event.title !== undefined ? { summary: event.title } : {}),
-    // A null patch value is sent as an explicit null in the PUT body to clear
-    // the field (recurrence clears as [] instead — the insert type has no null).
-    ...(event.description !== undefined
-      ? { description: event.description }
-      : {}),
-    ...(event.location !== undefined ? { location: event.location } : {}),
-    ...(event.visibility !== undefined ? { visibility: event.visibility } : {}),
-    ...(event.availability !== undefined
-      ? { transparency: availability(event) }
-      : {}),
-    ...(event.attendees !== undefined ? { attendees: attendees(event) } : {}),
-    // A "conference"-shaped patch is display-only and maps to no input: skip
-    // the key so the echoed conferenceData survives the full-replace PUT.
-    ...(event.conference === null || event.conference?.type === "create"
-      ? { conferenceData: conference(event) }
-      : {}),
-  };
-}
-
-export function toGoogleCalendarAttendeeResponseStatus(
-  status: AttendeeStatus,
-): GoogleCalendarEventAttendeeResponseStatus {
-  if (status === "unknown") {
-    return "needsAction";
-  }
-
-  return status;
-}
-
-export function attendeesWithSelfResponse(
-  attendees: EventAttendee[] | undefined,
-  status: AttendeeStatus,
-  comment?: string | null,
-) {
-  if (!attendees) {
-    throw new Error("Event has no attendees");
-  }
-
-  const attendee = attendees.find((attendee) => attendee.self);
-
-  if (!attendee) {
-    throw new Error("User is not an attendee");
-  }
-
-  const input = toGoogleCalendarAttendeeInput(attendee);
-
-  if (comment === undefined) {
-    return [
-      {
-        ...input,
-        responseStatus: toGoogleCalendarAttendeeResponseStatus(status),
-      },
-    ];
-  }
-
-  return [
-    {
-      ...input,
-      comment,
-      responseStatus: toGoogleCalendarAttendeeResponseStatus(status),
-    },
-  ];
-}
-
-function parseGoogleCalendarAttendeeStatus(
-  status: GoogleCalendarEventAttendeeResponseStatus,
-): AttendeeStatus {
-  if (status === "needsAction") {
-    return "unknown";
-  }
-
-  return status;
-}
-
-function parseGoogleCalendarAttendeeType(
-  attendee: GoogleCalendarEventAttendee,
-): "required" | "optional" | "resource" {
-  if (attendee.resource) {
-    return "resource";
-  }
-
-  if (attendee.optional) {
-    return "optional";
-  }
-
-  return "required";
-}
-
-export function parseGoogleCalendarAttendee(
-  attendee: GoogleCalendarEventAttendee,
-): Attendee {
-  return {
-    id: attendee.id,
-    email: attendee.email!,
-    name: attendee.displayName,
-    status: parseGoogleCalendarAttendeeStatus(
-      attendee.responseStatus ?? "needsAction",
-    ),
-    type: parseGoogleCalendarAttendeeType(attendee),
-    comment: attendee.comment,
-    organizer: attendee.organizer,
-    additionalGuests: attendee.additionalGuests,
-  };
-}
-
-export function parseGoogleCalendarAttendeeList(
-  attendees: GoogleCalendarEventAttendee[],
-): Attendee[] {
-  const mappedAttendees = attendees.map(parseGoogleCalendarAttendee);
-
-  // Find the organizer and move to index 0 if it exists
-  const organizerIndex = mappedAttendees.findIndex(
-    (attendee) => attendee.organizer,
-  );
-
-  if (organizerIndex > 0) {
-    const organizer = mappedAttendees[organizerIndex]!;
-
-    mappedAttendees.splice(organizerIndex, 1);
-    mappedAttendees.unshift(organizer);
-  }
-
-  return mappedAttendees;
-}
diff --git a/packages/providers/src/calendars/google-calendar/freebusy/index.ts b/packages/providers/src/calendars/google-calendar/freebusy/index.ts
index 1f4d36d3..f74ae2c2 100644
--- a/packages/providers/src/calendars/google-calendar/freebusy/index.ts
+++ b/packages/providers/src/calendars/google-calendar/freebusy/index.ts
@@ -5,7 +5,7 @@ import type {
   CalendarProviderFreeBusyQueryOptions,
 } from "../../../interfaces/providers";
 import { ProviderError } from "../../../lib/provider-error";
-import { parseGoogleCalendarFreeBusy } from "./utils";
+import { parseFreeBusy } from "./parse";
 
 export class GoogleCalendarFreeBusy implements CalendarProviderFreeBusy {
   constructor(private readonly client: GoogleCalendar) {}
@@ -23,7 +23,7 @@ export class GoogleCalendarFreeBusy implements CalendarProviderFreeBusy {
         items: schedules.map((id) => ({ id })),
       });
 
-      return parseGoogleCalendarFreeBusy(response);
+      return parseFreeBusy(response);
     });
   }
 
diff --git a/packages/providers/src/calendars/google-calendar/freebusy/utils.ts b/packages/providers/src/calendars/google-calendar/freebusy/parse.ts
similarity index 95%
rename from packages/providers/src/calendars/google-calendar/freebusy/utils.ts
rename to packages/providers/src/calendars/google-calendar/freebusy/parse.ts
index c4204e76..1132add5 100644
--- a/packages/providers/src/calendars/google-calendar/freebusy/utils.ts
+++ b/packages/providers/src/calendars/google-calendar/freebusy/parse.ts
@@ -3,7 +3,7 @@ import { Temporal } from "temporal-polyfill";
 import type { CalendarFreeBusy } from "../../../interfaces";
 import type { GoogleCalendarFreeBusyResponse } from "../interfaces";
 
-export function parseGoogleCalendarFreeBusy(
+export function parseFreeBusy(
   response: GoogleCalendarFreeBusyResponse,
 ): CalendarFreeBusy[] {
   return Object.entries(response.calendars).map<CalendarFreeBusy>(
diff --git a/packages/providers/src/calendars/microsoft-calendar/calendars/index.ts b/packages/providers/src/calendars/microsoft-calendar/calendars/index.ts
index 72810268..d328fb05 100644
--- a/packages/providers/src/calendars/microsoft-calendar/calendars/index.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/calendars/index.ts
@@ -13,7 +13,7 @@ import type {
   CalendarProviderCalendarsUpdateOptions,
 } from "../../../interfaces/providers";
 import { ProviderError } from "../../../lib/provider-error";
-import { parseMicrosoftCalendar } from "./utils";
+import { parseCalendar } from "./parse";
 
 export class MicrosoftCalendarCalendars {
   constructor(
@@ -44,7 +44,7 @@ export class MicrosoftCalendarCalendars {
         response: CalendarCollectionResponse,
       ): Promise<Calendar[]> => {
         const calendars = (response.value ?? []).map((calendar) =>
-          parseMicrosoftCalendar({
+          parseCalendar({
             calendar,
             providerAccountId: this.providerAccountId,
           }),
@@ -98,7 +98,7 @@ export class MicrosoftCalendarCalendars {
         select,
       });
 
-      return parseMicrosoftCalendar({
+      return parseCalendar({
         calendar,
         providerAccountId: this.providerAccountId,
       });
@@ -116,7 +116,7 @@ export class MicrosoftCalendarCalendars {
         },
       });
 
-      return parseMicrosoftCalendar({
+      return parseCalendar({
         calendar: createdCalendar,
         providerAccountId: this.providerAccountId,
       });
@@ -133,7 +133,7 @@ export class MicrosoftCalendarCalendars {
         calendar: { name: calendar.name },
       });
 
-      return parseMicrosoftCalendar({
+      return parseCalendar({
         calendar: updatedCalendar,
         providerAccountId: this.providerAccountId,
       });
diff --git a/packages/providers/src/calendars/microsoft-calendar/calendars/utils.ts b/packages/providers/src/calendars/microsoft-calendar/calendars/parse.ts
similarity index 79%
rename from packages/providers/src/calendars/microsoft-calendar/calendars/utils.ts
rename to packages/providers/src/calendars/microsoft-calendar/calendars/parse.ts
index f74745a0..22512e23 100644
--- a/packages/providers/src/calendars/microsoft-calendar/calendars/utils.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/calendars/parse.ts
@@ -2,15 +2,15 @@ import type { Calendar as MicrosoftCalendar } from "@analog/microsoft-calendar";
 
 import type { Calendar } from "../../../interfaces";
 
-interface ParseMicrosoftCalendarOptions {
+interface ParseCalendarOptions {
   providerAccountId: string;
   calendar: MicrosoftCalendar;
 }
 
-export function parseMicrosoftCalendar({
+export function parseCalendar({
   providerAccountId,
   calendar,
-}: ParseMicrosoftCalendarOptions): Calendar {
+}: ParseCalendarOptions): Calendar {
   return {
     id: calendar.id!,
     name: calendar.name!,
diff --git a/packages/providers/src/calendars/microsoft-calendar/events/conferences/utils.ts b/packages/providers/src/calendars/microsoft-calendar/conferences.ts
similarity index 89%
rename from packages/providers/src/calendars/microsoft-calendar/events/conferences/utils.ts
rename to packages/providers/src/calendars/microsoft-calendar/conferences.ts
index 3c6f211c..8b83cd71 100644
--- a/packages/providers/src/calendars/microsoft-calendar/events/conferences/utils.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/conferences.ts
@@ -1,9 +1,9 @@
 import { detectMeetingLink } from "@analog/meeting-links";
 import type { Event as MicrosoftEvent } from "@analog/microsoft-calendar";
 
-import type { Conference } from "../../../../interfaces";
+import type { Conference } from "../../interfaces";
 
-export function toMicrosoftConferenceData(conference: Conference) {
+export function formatConference(conference: Conference) {
   if (conference.type !== "create") {
     return undefined;
   }
@@ -62,9 +62,7 @@ function parseConferenceFallback(
   };
 }
 
-export function parseMicrosoftConference(
-  event: MicrosoftEvent,
-): Conference | undefined {
+export function parseConference(event: MicrosoftEvent): Conference | undefined {
   const joinUrl = event.onlineMeeting?.joinUrl ?? event.onlineMeetingUrl;
 
   if (!joinUrl) {
@@ -93,7 +91,7 @@ export function parseMicrosoftConference(
       },
       meetingCode: event.onlineMeeting?.conferenceId ?? undefined,
     },
-    ...(phoneNumbers && phoneNumbers.length > 0
+    ...(phoneNumbers.length > 0
       ? {
           phone: phoneNumbers.map((number) => ({
             joinUrl: {
diff --git a/packages/providers/src/calendars/microsoft-calendar/events/format.ts b/packages/providers/src/calendars/microsoft-calendar/events/format.ts
new file mode 100644
index 00000000..2fc52530
--- /dev/null
+++ b/packages/providers/src/calendars/microsoft-calendar/events/format.ts
@@ -0,0 +1,220 @@
+import type {
+  Attendee as MicrosoftEventAttendee,
+  Event as MicrosoftEvent,
+} from "@analog/microsoft-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type {
+  CreateEventInput,
+  MicrosoftEventMetadata,
+  UpdateEventPatch,
+} from "@repo/schemas";
+
+import type { Attendee } from "../../../interfaces";
+import { formatConference } from "../conferences";
+import { formatRecurrence, formatRecurrencePatch } from "../recurrence/format";
+
+interface FormatDateOptions {
+  value: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime;
+  originalTimeZone?: {
+    raw: string;
+    parsed?: string;
+  };
+}
+
+export function formatDate({ value, originalTimeZone }: FormatDateOptions) {
+  if (value instanceof Temporal.PlainDate) {
+    return {
+      dateTime: value.toPlainDateTime().toString(),
+      timeZone: originalTimeZone?.raw ?? "UTC",
+    };
+  }
+
+  // These events were created using another provider.
+  if (value instanceof Temporal.Instant) {
+    const dateTime = value
+      .toZonedDateTimeISO("UTC")
+      .toPlainDateTime()
+      .toString();
+
+    return {
+      dateTime,
+      timeZone: "UTC",
+    };
+  }
+
+  return {
+    dateTime: value.toPlainDateTime().toString(),
+    timeZone:
+      originalTimeZone?.parsed === value.timeZoneId
+        ? originalTimeZone.raw
+        : value.timeZoneId,
+  };
+}
+
+function formatMetadata(
+  metadata: CreateEventInput["metadata"],
+): MicrosoftEventMetadata {
+  if (!metadata) return {};
+  if ("originalStartTimeZone" in metadata) return metadata;
+  if ("originalEndTimeZone" in metadata) return metadata;
+  if ("onlineMeeting" in metadata) return metadata;
+  if ("recurrenceTimeZone" in metadata) return metadata;
+  return {};
+}
+
+function formatBody(event: CreateEventInput) {
+  if (!event.description) {
+    return {};
+  }
+
+  return { body: { contentType: "text" as const, content: event.description } };
+}
+
+function formatStart(event: CreateEventInput) {
+  const metadata = formatMetadata(event.metadata);
+
+  return formatDate({
+    value: event.start,
+    originalTimeZone: metadata.originalStartTimeZone,
+  });
+}
+
+function formatEnd(event: CreateEventInput) {
+  const metadata = formatMetadata(event.metadata);
+
+  return formatDate({
+    value: event.end,
+    originalTimeZone: metadata.originalEndTimeZone,
+  });
+}
+
+function formatLocation(event: CreateEventInput) {
+  if (!event.location) {
+    return {};
+  }
+
+  return { location: { displayName: event.location } };
+}
+
+function formatSensitivity(
+  visibility: CreateEventInput["visibility"],
+): MicrosoftEvent["sensitivity"] {
+  if (visibility === "default") return "normal";
+  if (visibility === "public") return "normal";
+  return visibility;
+}
+
+function formatAttendee(attendee: Attendee): MicrosoftEventAttendee {
+  return {
+    emailAddress: {
+      address: attendee.email,
+      name: attendee.name,
+    },
+    type: attendee.type,
+  };
+}
+
+function formatAttendees(event: CreateEventInput) {
+  return event.attendees?.map(formatAttendee);
+}
+
+function formatEventRecurrence(event: CreateEventInput) {
+  if (!event.recurrence) {
+    return {};
+  }
+
+  const metadata = formatMetadata(event.metadata);
+
+  return {
+    recurrence: formatRecurrence({
+      recurrence: event.recurrence,
+      start: event.start,
+      recurrenceTimeZone: metadata.recurrenceTimeZone,
+    }),
+  };
+}
+
+export function formatEvent(event: CreateEventInput): MicrosoftEvent {
+  return {
+    subject: event.title,
+    ...formatBody(event),
+    start: formatStart(event),
+    end: formatEnd(event),
+    isAllDay: event.allDay ?? false,
+    ...formatLocation(event),
+    ...(event.conference ? formatConference(event.conference) : {}),
+    showAs: event.availability,
+    sensitivity: formatSensitivity(event.visibility),
+    attendees: formatAttendees(event),
+    ...formatEventRecurrence(event),
+  };
+}
+
+interface FormatEventPatchOptions {
+  // Resolved master start for recurrence serialization; Graph requires
+  // range.startDate to match the master event's start date, which a sparse
+  // patch does not necessarily carry.
+  startForRecurrence?:
+    | Temporal.PlainDate
+    | Temporal.Instant
+    | Temporal.ZonedDateTime;
+}
+
+export function formatEventPatch(
+  event: UpdateEventPatch,
+  options: FormatEventPatchOptions = {},
+): Partial<MicrosoftEvent> {
+  const metadata = formatMetadata(event.metadata);
+
+  return {
+    ...(event.title !== undefined ? { subject: event.title } : {}),
+    ...(event.description !== undefined
+      ? {
+          body: {
+            contentType: "text" as const,
+            content: event.description ?? "",
+          },
+        }
+      : {}),
+    ...(event.start !== undefined
+      ? {
+          start: formatDate({
+            value: event.start,
+            originalTimeZone: metadata.originalStartTimeZone,
+          }),
+        }
+      : {}),
+    ...(event.end !== undefined
+      ? {
+          end: formatDate({
+            value: event.end,
+            originalTimeZone: metadata.originalEndTimeZone,
+          }),
+        }
+      : {}),
+    ...(event.allDay !== undefined ? { isAllDay: event.allDay } : {}),
+    ...(event.location !== undefined
+      ? { location: { displayName: event.location } }
+      : {}),
+    ...(event.availability !== undefined ? { showAs: event.availability } : {}),
+    ...(event.visibility !== undefined
+      ? { sensitivity: formatSensitivity(event.visibility) }
+      : {}),
+    ...(event.attendees !== undefined
+      ? { attendees: event.attendees.map(formatAttendee) }
+      : {}),
+    // Graph has no conference field to null out: clearing demotes the online
+    // meeting via isOnlineMeeting=false with the provider reset to "unknown".
+    ...(event.conference === null
+      ? { isOnlineMeeting: false, onlineMeetingProvider: "unknown" as const }
+      : event.conference
+        ? formatConference(event.conference)
+        : {}),
+    ...formatRecurrencePatch(
+      event.recurrence,
+      options.startForRecurrence ?? event.start,
+      metadata.recurrenceTimeZone,
+    ),
+  };
+}
diff --git a/packages/providers/src/calendars/microsoft-calendar/events/index.ts b/packages/providers/src/calendars/microsoft-calendar/events/index.ts
index e9076357..aa528b88 100644
--- a/packages/providers/src/calendars/microsoft-calendar/events/index.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/events/index.ts
@@ -1,3 +1,4 @@
+import { APIError } from "@analog/microsoft-calendar";
 import type {
   DefaultCalendarCalendarViewDeltaInput,
   DefaultCalendarCreateEventInput,
@@ -7,6 +8,7 @@ import type {
   DefaultCalendarListEventInput,
   DefaultCalendarUpdateEventInput,
   DeltaCollectionResponse,
+  DeltaRemovedEvent,
   Event as MicrosoftEvent,
   ListMoreInput,
   MicrosoftCalendar,
@@ -19,21 +21,48 @@ import type {
   CalendarProviderEventsDeleteOptions,
   CalendarProviderEventsGetOptions,
   CalendarProviderEventsListOptions,
+  CalendarProviderEventsMoveOptions,
   CalendarProviderEventsRespondOptions,
   CalendarProviderEventsUpdateOptions,
   CalendarProviderSyncOptions,
   CalendarProviderSyncResult,
 } from "../../../interfaces/providers";
 import { ProviderError } from "../../../lib/provider-error";
-import {
-  parseMicrosoftEvent,
-  toMicrosoftEvent,
-  toMicrosoftEventPatch,
-} from "./utils";
+import { formatEvent, formatEventPatch } from "./format";
+import { parseEvent } from "./parse";
 
 const MAX_EVENTS_PER_CALENDAR = 250;
 const TEXT_BODY_PREFERENCE = 'outlook.body-content-type="text"';
 
+// Graph owns these properties; they are rejected or silently ignored when they
+// are posted back, so a copied event must not carry them over. transactionId
+// identifies the original create, so carrying it over would make Graph dedupe
+// the copy into the source event instead of creating one.
+const SERVER_OWNED_EVENT_FIELDS = new Set([
+  "id",
+  "changeKey",
+  "iCalUId",
+  "webLink",
+  "createdDateTime",
+  "lastModifiedDateTime",
+  "seriesMasterId",
+  "onlineMeeting",
+  "onlineMeetingUrl",
+  "transactionId",
+]);
+
+function stripServerOwnedFields(event: MicrosoftEvent): MicrosoftEvent {
+  const copy = { ...event };
+
+  for (const key of Object.keys(copy)) {
+    if (key.startsWith("@odata") || SERVER_OWNED_EVENT_FIELDS.has(key)) {
+      delete copy[key];
+    }
+  }
+
+  return copy;
+}
+
 export class MicrosoftCalendarEvents implements CalendarProviderEvents {
   constructor(private readonly client: MicrosoftCalendar) {}
 
@@ -88,7 +117,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
       const endTime = timeMax.withTimeZone("UTC").toInstant().toString();
 
       const headers = {
-        Prefer: `outlook.timezone="${timeZone ?? "UTC"}", ${TEXT_BODY_PREFERENCE}`,
+        Prefer: `outlook.timezone="${timeZone}", ${TEXT_BODY_PREFERENCE}`,
       };
 
       const listPages = async (nextLink?: string): Promise<CalendarEvent[]> => {
@@ -103,7 +132,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
           });
 
           const events = (response.value ?? []).map((event) =>
-            parseMicrosoftEvent({ event, calendar }),
+            parseEvent({ event, calendar }),
           );
 
           if (!response["@odata.nextLink"]) {
@@ -119,7 +148,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
         });
 
         const events = (page.value ?? []).map((event) =>
-          parseMicrosoftEvent({ event, calendar }),
+          parseEvent({ event, calendar }),
         );
 
         if (!page["@odata.nextLink"]) {
@@ -156,12 +185,12 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
     timeMax,
     timeZone,
   }: CalendarProviderSyncOptions): Promise<CalendarProviderSyncResult> {
-    return this.withErrorHandler("events.sync", async () => {
+    const runSync = async (token: string | undefined) => {
       const startTime = timeMin?.withTimeZone("UTC").toInstant().toString();
       const endTime = timeMax?.withTimeZone("UTC").toInstant().toString();
 
       const headers = {
-        Prefer: `outlook.timezone="${timeZone ?? "UTC"}", ${TEXT_BODY_PREFERENCE}`,
+        Prefer: `outlook.timezone="${timeZone}", ${TEXT_BODY_PREFERENCE}`,
       };
 
       let syncToken: string | undefined;
@@ -170,9 +199,11 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
       const changes: CalendarEventSyncItem[] = [];
 
       do {
-        const link = pageToken ?? initialSyncToken;
+        const link = pageToken ?? token;
 
-        let response: DeltaCollectionResponse<MicrosoftEvent>;
+        let response: DeltaCollectionResponse<
+          MicrosoftEvent | DeltaRemovedEvent
+        >;
 
         if (link) {
           response = await this.calendarViewFor(calendar.id).deltaMore({
@@ -197,11 +228,11 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
         }
 
         for (const item of response.value ?? []) {
-          if (!item?.id) {
+          if (!item.id) {
             continue;
           }
 
-          if (item["@removed"]) {
+          if ("@removed" in item) {
             changes.push({
               status: "deleted",
               event: {
@@ -218,7 +249,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
 
           changes.push({
             status: "updated",
-            event: parseMicrosoftEvent({
+            event: parseEvent({
               event: item,
               calendar,
             }),
@@ -229,14 +260,95 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
         syncToken = response["@odata.deltaLink"] ?? undefined;
       } while (pageToken);
 
+      // The delta feed only carries the changed instances, so pull in the series
+      // masters they reference unless the feed already returned them.
+      const changedEventIds = new Set<string>();
+      const recurringEventIds = new Set<string>();
+
+      for (const change of changes) {
+        if (change.status === "deleted") {
+          continue;
+        }
+
+        changedEventIds.add(change.event.id);
+
+        if (change.event.recurringEventId) {
+          recurringEventIds.add(change.event.recurringEventId);
+        }
+      }
+
+      const recurringMasterEvents = await Promise.all(
+        Array.from(recurringEventIds)
+          .filter((eventId) => !changedEventIds.has(eventId))
+          .map((eventId) => this.get({ calendar, eventId, timeZone })),
+      );
+
+      const recurringChanges: CalendarEventSyncItem[] =
+        recurringMasterEvents.map((event) => ({
+          status: "updated",
+          event,
+        }));
+
+      changes.push(...recurringChanges);
+
       return {
         changes,
         syncToken,
-        status: "incremental",
       };
+    };
+
+    return this.withErrorHandler("events.sync", async () => {
+      try {
+        const result = await runSync(initialSyncToken);
+
+        return { ...result, status: "incremental" };
+      } catch (error) {
+        if (!this.isFullSyncRequiredError(error)) {
+          throw error;
+        }
+
+        // A full sync needs an explicit window; without one the retry can only
+        // fail with the generic guard below, which would hide the resync
+        // signal the caller has to act on.
+        if (!timeMin || !timeMax) {
+          throw error;
+        }
+
+        const result = await runSync(undefined);
+
+        // Assume if the new sync token is equal to the initial sync token,
+        // content hasn't changed
+        if (initialSyncToken === result.syncToken) {
+          return {
+            changes: [],
+            syncToken: initialSyncToken,
+            status: "incremental",
+          };
+        }
+
+        return { ...result, status: "full" };
+      }
     });
   }
 
+  // Graph expires and invalidates delta tokens; the 410 status and the sync
+  // state error codes both mean the delta link is unusable and the calendar has
+  // to be synced from scratch.
+  private isFullSyncRequiredError(error: unknown): boolean {
+    if (!(error instanceof APIError)) {
+      return false;
+    }
+
+    if (error.status === 410) {
+      return true;
+    }
+
+    return (
+      error.error?.error.code === "syncStateNotFound" ||
+      error.error?.error.code === "resyncRequired"
+    );
+  }
+
   async get({ calendar, eventId, timeZone }: CalendarProviderEventsGetOptions) {
     return this.withErrorHandler("events.get", async () => {
       const headers = {
@@ -249,7 +361,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
         headers,
       });
 
-      return parseMicrosoftEvent({
+      return parseEvent({
         event,
         calendar,
       });
@@ -268,11 +380,11 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
 
       const createdEvent = await this.eventsFor(calendar.id).create({
         userId: "me",
-        event: toMicrosoftEvent(event),
+        event: formatEvent(event),
         headers: { Prefer: TEXT_BODY_PREFERENCE },
       });
 
-      return parseMicrosoftEvent({
+      return parseEvent({
         event: createdEvent,
         calendar,
       });
@@ -309,7 +421,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
     const updatedEvent = await this.eventsFor(calendar.id).update({
       userId: "me",
       eventId,
-      event: toMicrosoftEventPatch(event, { startForRecurrence }),
+      event: formatEventPatch(event, { startForRecurrence }),
       ...(event.etag ? { ifMatch: event.etag } : {}),
       headers: { Prefer: TEXT_BODY_PREFERENCE },
     });
@@ -326,7 +438,7 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
       return this.get({ calendar, eventId });
     }
 
-    return parseMicrosoftEvent({
+    return parseEvent({
       event: updatedEvent,
       calendar,
     });
@@ -339,10 +451,38 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
     sendUpdate,
   }: CalendarProviderEventsDeleteOptions) {
     await this.withErrorHandler("events.delete", async () => {
+      // Deleting an organized meeting makes Graph email the attendees a
+      // cancellation, and no request shape suppresses that.
       if (!sendUpdate) {
         throw new Error("Microsoft Calendar does not support sendUpdate=false");
       }
 
+      // Cancelling is what notifies the attendees, but Graph only allows it on
+      // meetings the user organizes; event ids are calendar-independent, so the
+      // action is addressed through /me/events like the respond actions.
+      try {
+        await this.client.users.events.cancel({ userId: "me", eventId });
+
+        return;
+      } catch (error) {
+        // Graph rejects the action with a client error when the event is not
+        // an organized meeting: fall back to deleting the event. Auth,
+        // throttling, server and network failures are transient and must
+        // surface instead of silently deleting without notifying anyone.
+        const status = error instanceof APIError ? error.status : undefined;
+
+        if (
+          status === undefined ||
+          status < 400 ||
+          status >= 500 ||
+          status === 401 ||
+          status === 408 ||
+          status === 429
+        ) {
+          throw error;
+        }
+      }
+
       await this.eventsFor(calendarId).delete({
         userId: "me",
         eventId,
@@ -351,9 +491,38 @@ export class MicrosoftCalendarEvents implements CalendarProviderEvents {
     });
   }
 
-  async move() {
-    return this.withErrorHandler("events.move", () => {
-      throw new Error("Moving Microsoft Calendar events is not supported");
+  async move({
+    sourceCalendar,
+    destinationCalendar,
+    eventId,
+    etag,
+  }: CalendarProviderEventsMoveOptions) {
+    return this.withErrorHandler("events.move", async () => {
+      // Graph cannot move an event between calendars, so copy it into the
+      // destination calendar and delete the original. The source is read in UTC
+      // so the copy keeps the absolute times of the original.
+      const sourceEvent = await this.eventsFor(sourceCalendar.id).get({
+        userId: "me",
+        eventId,
+        headers: { Prefer: 'outlook.timezone="UTC"' },
+      });
+
+      const createdEvent = await this.eventsFor(destinationCalendar.id).create({
+        userId: "me",
+        event: stripServerOwnedFields(sourceEvent),
+        headers: { Prefer: TEXT_BODY_PREFERENCE },
+      });
+
+      await this.eventsFor(sourceCalendar.id).delete({
+        userId: "me",
+        eventId,
+        ...(etag ? { ifMatch: etag } : {}),
+      });
+
+      return parseEvent({
+        event: createdEvent,
+        calendar: destinationCalendar,
+      });
     });
   }
 
diff --git a/packages/providers/src/calendars/microsoft-calendar/events/parse.ts b/packages/providers/src/calendars/microsoft-calendar/events/parse.ts
new file mode 100644
index 00000000..1bf5dac2
--- /dev/null
+++ b/packages/providers/src/calendars/microsoft-calendar/events/parse.ts
@@ -0,0 +1,205 @@
+import type {
+  Attendee as MicrosoftEventAttendee,
+  Event as MicrosoftEvent,
+  ResponseStatus as MicrosoftEventAttendeeResponseStatus,
+} from "@analog/microsoft-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type {
+  Attendee,
+  AttendeeStatus,
+  Calendar,
+  CalendarEvent,
+} from "../../../interfaces";
+import { parseConference } from "../conferences";
+import { parseRecurrence } from "../recurrence/parse";
+import { parseDateTime, parseTimeZone } from "../utils";
+
+function parseDate(date: string) {
+  return Temporal.PlainDate.from(date);
+}
+
+interface ParseEventOptions {
+  calendar: Calendar;
+  event: MicrosoftEvent;
+}
+
+function parseStart(event: MicrosoftEvent) {
+  if (event.isAllDay) {
+    return parseDate(event.start.dateTime);
+  }
+
+  return parseDateTime(event.start.dateTime, event.start.timeZone);
+}
+
+function parseEnd(event: MicrosoftEvent) {
+  if (event.isAllDay) {
+    return parseDate(event.end.dateTime);
+  }
+
+  return parseDateTime(event.end.dateTime, event.end.timeZone);
+}
+
+function parseVisibility(
+  sensitivity: MicrosoftEvent["sensitivity"],
+): CalendarEvent["visibility"] {
+  if (sensitivity === "normal") return "default";
+  if (sensitivity === "personal") return "private";
+  return sensitivity;
+}
+
+function parseAttendees(event: MicrosoftEvent) {
+  return event.attendees?.map(parseAttendee) ?? [];
+}
+
+function parseResponseStatus(
+  event: MicrosoftEvent,
+): AttendeeStatus | undefined {
+  return event.responseStatus?.response
+    ? parseAttendeeStatus(event.responseStatus.response)
+    : undefined;
+}
+
+function parseResponse(event: MicrosoftEvent) {
+  const status = parseResponseStatus(event);
+
+  if (!status) {
+    return {};
+  }
+
+  return { response: { status } };
+}
+
+function parseCreatedAt(event: MicrosoftEvent) {
+  if (!event.createdDateTime) {
+    return {};
+  }
+
+  return { createdAt: Temporal.Instant.from(event.createdDateTime) };
+}
+
+function parseUpdatedAt(event: MicrosoftEvent) {
+  if (!event.lastModifiedDateTime) {
+    return {};
+  }
+
+  return { updatedAt: Temporal.Instant.from(event.lastModifiedDateTime) };
+}
+
+function parseOriginalStartTimeZone(event: MicrosoftEvent) {
+  if (!event.originalStartTimeZone) {
+    return {};
+  }
+
+  return {
+    originalStartTimeZone: {
+      raw: event.originalStartTimeZone,
+      parsed: parseTimeZone(event.originalStartTimeZone),
+    },
+  };
+}
+
+function parseOriginalEndTimeZone(event: MicrosoftEvent) {
+  if (!event.originalEndTimeZone) {
+    return {};
+  }
+
+  return {
+    originalEndTimeZone: {
+      raw: event.originalEndTimeZone,
+      parsed: parseTimeZone(event.originalEndTimeZone),
+    },
+  };
+}
+
+function parseRecurrenceTimeZone(event: MicrosoftEvent) {
+  if (!event.recurrence?.range.recurrenceTimeZone) {
+    return {};
+  }
+
+  return { recurrenceTimeZone: event.recurrence.range.recurrenceTimeZone };
+}
+
+function parseEventRecurrence(event: MicrosoftEvent) {
+  const recurrence = event.recurrence
+    ? parseRecurrence(event.recurrence)
+    : undefined;
+
+  if (!recurrence) {
+    return {};
+  }
+
+  return { recurrence };
+}
+
+function parseMetadata(event: MicrosoftEvent) {
+  return {
+    ...parseOriginalStartTimeZone(event),
+    ...parseOriginalEndTimeZone(event),
+    onlineMeeting: event.onlineMeeting,
+    ...parseRecurrenceTimeZone(event),
+  };
+}
+
+export function parseEvent({
+  calendar,
+  event,
+}: ParseEventOptions): CalendarEvent {
+  return {
+    id: event.id!,
+    title: event.subject!,
+    description: event.body?.content ?? undefined,
+    start: parseStart(event),
+    end: parseEnd(event),
+    allDay: event.isAllDay ?? false,
+    location: event.location?.displayName ?? undefined,
+    availability: event.showAs === "free" ? "free" : "busy",
+    visibility: parseVisibility(event.sensitivity),
+    attendees: parseAttendees(event),
+    url: event.webLink ?? undefined,
+    etag: event["@odata.etag"],
+    calendar: {
+      id: calendar.id,
+      provider: calendar.provider,
+    },
+    readOnly: calendar.readOnly,
+    conference: parseConference(event),
+    recurringEventId: event.seriesMasterId ?? undefined,
+    ...parseEventRecurrence(event),
+    ...parseResponse(event),
+    ...parseCreatedAt(event),
+    ...parseUpdatedAt(event),
+    metadata: parseMetadata(event),
+  } as CalendarEvent;
+}
+
+function parseAttendeeStatus(
+  status: MicrosoftEventAttendeeResponseStatus["response"],
+): AttendeeStatus {
+  if (status === "notResponded" || status === "none") {
+    return "unknown";
+  }
+
+  if (status === "accepted" || status === "organizer") {
+    return "accepted";
+  }
+
+  if (status === "tentativelyAccepted") {
+    return "tentative";
+  }
+
+  if (status === "declined") {
+    return "declined";
+  }
+
+  return "unknown";
+}
+
+export function parseAttendee(attendee: MicrosoftEventAttendee): Attendee {
+  return {
+    email: attendee.emailAddress.address!,
+    name: attendee.emailAddress.name ?? undefined,
+    status: parseAttendeeStatus(attendee.status?.response),
+    type: attendee.type!,
+  };
+}
diff --git a/packages/providers/src/calendars/microsoft-calendar/events/utils.ts b/packages/providers/src/calendars/microsoft-calendar/events/utils.ts
deleted file mode 100644
index 8a7f0341..00000000
--- a/packages/providers/src/calendars/microsoft-calendar/events/utils.ts
+++ /dev/null
@@ -1,698 +0,0 @@
-import type {
-  Attendee as MicrosoftEventAttendee,
-  DayOfWeek as MicrosoftDayOfWeek,
-  Event as MicrosoftEvent,
-  ResponseStatus as MicrosoftEventAttendeeResponseStatus,
-  PatternedRecurrence,
-  RecurrencePattern,
-  RecurrenceRange,
-  WeekIndex,
-} from "@analog/microsoft-calendar";
-import { Temporal } from "temporal-polyfill";
-
-import type {
-  CreateEventInput,
-  MicrosoftEventMetadata,
-  UpdateEventPatch,
-} from "@repo/schemas";
-import { toPlainDate, toZonedDateTime } from "@repo/temporal";
-
-import type {
-  Attendee,
-  AttendeeStatus,
-  Calendar,
-  CalendarEvent,
-  Recurrence,
-  Weekday,
-} from "../../../interfaces";
-import { parseDateTime, parseTimeZone, toMicrosoftDate } from "../utils";
-import {
-  parseMicrosoftConference,
-  toMicrosoftConferenceData,
-} from "./conferences/utils";
-
-function parseDate(date: string) {
-  return Temporal.PlainDate.from(date);
-}
-
-const WEEKDAY_TO_MICROSOFT_DAY: Record<Weekday, MicrosoftDayOfWeek> = {
-  MO: "monday",
-  TU: "tuesday",
-  WE: "wednesday",
-  TH: "thursday",
-  FR: "friday",
-  SA: "saturday",
-  SU: "sunday",
-};
-
-const MICROSOFT_DAY_TO_WEEKDAY: Record<MicrosoftDayOfWeek, Weekday> = {
-  monday: "MO",
-  tuesday: "TU",
-  wednesday: "WE",
-  thursday: "TH",
-  friday: "FR",
-  saturday: "SA",
-  sunday: "SU",
-};
-
-const WEEK_INDEX_TO_SET_POS: Record<WeekIndex, number> = {
-  first: 1,
-  second: 2,
-  third: 3,
-  fourth: 4,
-  last: -1,
-};
-
-// ISO dayOfWeek is 1 (Monday) through 7 (Sunday).
-const ISO_DAY_TO_MICROSOFT_DAY: MicrosoftDayOfWeek[] = [
-  "monday",
-  "tuesday",
-  "wednesday",
-  "thursday",
-  "friday",
-  "saturday",
-  "sunday",
-];
-
-export class RecurrenceConversionError extends Error {
-  constructor(message: string) {
-    super(`Cannot convert recurrence for Microsoft Calendar: ${message}`);
-    this.name = "RecurrenceConversionError";
-  }
-}
-
-function toSetPosWeekIndex(recurrence: Recurrence): WeekIndex {
-  const bySetPos = recurrence.bySetPos;
-
-  if (!bySetPos || bySetPos.length !== 1) {
-    throw new RecurrenceConversionError(
-      "bySetPos must contain exactly one of 1, 2, 3, 4, or -1",
-    );
-  }
-
-  switch (bySetPos[0]) {
-    case 1:
-      return "first";
-    case 2:
-      return "second";
-    case 3:
-      return "third";
-    case 4:
-      return "fourth";
-    case -1:
-      return "last";
-    default:
-      throw new RecurrenceConversionError(
-        `bySetPos value ${bySetPos[0]} has no Microsoft equivalent (supported: 1, 2, 3, 4, -1)`,
-      );
-  }
-}
-
-function toMicrosoftDaysOfWeek(byDay: Weekday[]): MicrosoftDayOfWeek[] {
-  return byDay.map((day) => WEEKDAY_TO_MICROSOFT_DAY[day]);
-}
-
-function toMicrosoftDayOfWeek(dayOfWeek: number): MicrosoftDayOfWeek {
-  const day = ISO_DAY_TO_MICROSOFT_DAY[dayOfWeek - 1];
-
-  if (!day) {
-    throw new RecurrenceConversionError(`invalid ISO weekday ${dayOfWeek}`);
-  }
-
-  return day;
-}
-
-function assertConvertibleRecurrence(recurrence: Recurrence) {
-  const unsupported: string[] = [];
-
-  if (recurrence.byYearDay?.length) unsupported.push("byYearDay");
-  if (recurrence.byWeekNo?.length) unsupported.push("byWeekNo");
-  if (recurrence.byHour?.length) unsupported.push("byHour");
-  if (recurrence.byMinute?.length) unsupported.push("byMinute");
-  if (recurrence.bySecond?.length) unsupported.push("bySecond");
-  if (recurrence.rDate?.length) unsupported.push("rDate");
-  if (recurrence.exDate?.length) unsupported.push("exDate");
-
-  if (recurrence.rscale && recurrence.rscale !== "GREGORIAN") {
-    unsupported.push(`rscale=${recurrence.rscale}`);
-  }
-
-  if (recurrence.skip && recurrence.skip !== "OMIT") {
-    unsupported.push(`skip=${recurrence.skip}`);
-  }
-
-  if (unsupported.length > 0) {
-    throw new RecurrenceConversionError(
-      `unsupported rule parts: ${unsupported.join(", ")}`,
-    );
-  }
-
-  if (recurrence.count !== undefined && recurrence.until !== undefined) {
-    throw new RecurrenceConversionError(
-      "count and until are mutually exclusive",
-    );
-  }
-
-  if (recurrence.freq === "WEEKLY" && recurrence.bySetPos?.length) {
-    throw new RecurrenceConversionError("bySetPos is not supported for WEEKLY");
-  }
-
-  if (
-    recurrence.until !== undefined &&
-    !(recurrence.until instanceof Temporal.PlainDate)
-  ) {
-    throw new RecurrenceConversionError(
-      "Microsoft recurrence only supports date-valued until",
-    );
-  }
-}
-
-function toMicrosoftRecurrencePattern(
-  recurrence: Recurrence,
-  start: Temporal.ZonedDateTime,
-): RecurrencePattern {
-  const interval = recurrence.interval ?? 1;
-
-  if (recurrence.byMonth && recurrence.freq !== "YEARLY") {
-    throw new RecurrenceConversionError(
-      `byMonth is only supported for YEARLY, got ${recurrence.freq}`,
-    );
-  }
-
-  if (
-    recurrence.byMonthDay &&
-    recurrence.freq !== "MONTHLY" &&
-    recurrence.freq !== "YEARLY"
-  ) {
-    throw new RecurrenceConversionError(
-      `byMonthDay is only supported for MONTHLY and YEARLY, got ${recurrence.freq}`,
-    );
-  }
-
-  switch (recurrence.freq) {
-    case "DAILY": {
-      if (recurrence.byDay?.length) {
-        throw new RecurrenceConversionError("byDay is not supported for DAILY");
-      }
-
-      return { type: "daily", interval };
-    }
-    case "WEEKLY": {
-      return {
-        type: "weekly",
-        interval,
-        daysOfWeek: recurrence.byDay?.length
-          ? toMicrosoftDaysOfWeek(recurrence.byDay)
-          : [toMicrosoftDayOfWeek(start.dayOfWeek)],
-        firstDayOfWeek: WEEKDAY_TO_MICROSOFT_DAY[recurrence.wkst ?? "MO"],
-      };
-    }
-    case "MONTHLY": {
-      if (recurrence.byDay?.length) {
-        return {
-          type: "relativeMonthly",
-          interval,
-          daysOfWeek: toMicrosoftDaysOfWeek(recurrence.byDay),
-          index: toSetPosWeekIndex(recurrence),
-        };
-      }
-
-      if (recurrence.byMonthDay && recurrence.byMonthDay.length !== 1) {
-        throw new RecurrenceConversionError(
-          "byMonthDay must contain exactly one day for MONTHLY",
-        );
-      }
-
-      const dayOfMonth = recurrence.byMonthDay?.[0] ?? start.day;
-
-      // RFC 5545 skips months without this day, but Outlook substitutes the
-      // month's last day, silently changing the rule's meaning.
-      if (dayOfMonth > 28) {
-        throw new RecurrenceConversionError(
-          `MONTHLY on day ${dayOfMonth} means "last day" in short months on Outlook, unlike the RFC rule`,
-        );
-      }
-
-      return { type: "absoluteMonthly", interval, dayOfMonth };
-    }
-    case "YEARLY": {
-      if (recurrence.byMonth && recurrence.byMonth.length !== 1) {
-        throw new RecurrenceConversionError(
-          "byMonth must contain exactly one month for YEARLY",
-        );
-      }
-
-      const month = recurrence.byMonth?.[0] ?? start.month;
-
-      if (recurrence.byDay?.length) {
-        return {
-          type: "relativeYearly",
-          interval,
-          month,
-          daysOfWeek: toMicrosoftDaysOfWeek(recurrence.byDay),
-          index: toSetPosWeekIndex(recurrence),
-        };
-      }
-
-      if (recurrence.byMonthDay && recurrence.byMonthDay.length !== 1) {
-        throw new RecurrenceConversionError(
-          "byMonthDay must contain exactly one day for YEARLY",
-        );
-      }
-
-      const dayOfMonth = recurrence.byMonthDay?.[0] ?? start.day;
-
-      // Same Outlook substitution as MONTHLY: Feb 29 and days beyond a fixed
-      // month's length roll to the month's last day instead of skipping.
-      const stableDays =
-        month === 2 ? 28 : [4, 6, 9, 11].includes(month) ? 30 : 31;
-
-      if (dayOfMonth > stableDays) {
-        throw new RecurrenceConversionError(
-          `YEARLY on month ${month}, day ${dayOfMonth} does not occur every year and rolls to the month's last day on Outlook`,
-        );
-      }
-
-      return { type: "absoluteYearly", interval, month, dayOfMonth };
-    }
-    default: {
-      throw new RecurrenceConversionError(
-        `frequency ${recurrence.freq ?? "(none)"} is not supported`,
-      );
-    }
-  }
-}
-
-interface ToMicrosoftRecurrenceOptions {
-  recurrence: Recurrence;
-  // The series master's start, never a selected occurrence's: Graph requires
-  // range.startDate to match the master event's start date.
-  start: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime;
-  recurrenceTimeZone?: string;
-}
-
-export function toMicrosoftRecurrence({
-  recurrence,
-  start,
-  recurrenceTimeZone,
-}: ToMicrosoftRecurrenceOptions): PatternedRecurrence {
-  assertConvertibleRecurrence(recurrence);
-
-  // Graph gets the zone verbatim (it may be a Windows name); Temporal
-  // conversions need the IANA equivalent.
-  const timeZone =
-    recurrenceTimeZone ??
-    (start instanceof Temporal.ZonedDateTime ? start.timeZoneId : "UTC");
-  const conversionTimeZone = parseTimeZone(timeZone) ?? "UTC";
-
-  // Graph expects range dates and pattern defaults (weekday, day of month)
-  // in recurrenceTimeZone, not the zone the event happened to be parsed in
-  // (events.get parses in the requested Prefer time zone, typically UTC).
-  const startDate = toPlainDate(start, { timeZone: conversionTimeZone });
-
-  const range: RecurrenceRange = {
-    startDate: startDate.toString(),
-    recurrenceTimeZone: timeZone,
-    ...(recurrence.count !== undefined
-      ? { type: "numbered", numberOfOccurrences: recurrence.count }
-      : recurrence.until !== undefined
-        ? {
-            type: "endDate",
-            endDate: toPlainDate(recurrence.until, {
-              timeZone: conversionTimeZone,
-            }).toString(),
-          }
-        : { type: "noEnd" }),
-  };
-
-  return {
-    pattern: toMicrosoftRecurrencePattern(
-      recurrence,
-      toZonedDateTime(start, { timeZone: conversionTimeZone }),
-    ),
-    range,
-  };
-}
-
-export function parseMicrosoftRecurrence(
-  recurrence: PatternedRecurrence,
-): Recurrence | undefined {
-  const { pattern, range } = recurrence;
-
-  if (!pattern?.type) {
-    return undefined;
-  }
-
-  const shared: Recurrence = {
-    ...(pattern.interval !== undefined ? { interval: pattern.interval } : {}),
-    ...(range?.type === "numbered" && range.numberOfOccurrences !== undefined
-      ? { count: range.numberOfOccurrences }
-      : {}),
-    // Graph's endDate is inclusive, matching RFC 5545 UNTIL for date values.
-    ...(range?.type === "endDate" && range.endDate
-      ? { until: Temporal.PlainDate.from(range.endDate) }
-      : {}),
-  };
-
-  const byDay = pattern.daysOfWeek?.map((day) => MICROSOFT_DAY_TO_WEEKDAY[day]);
-  const wkst = pattern.firstDayOfWeek
-    ? MICROSOFT_DAY_TO_WEEKDAY[pattern.firstDayOfWeek]
-    : undefined;
-
-  switch (pattern.type) {
-    case "daily":
-      return { ...shared, freq: "DAILY" };
-    case "weekly":
-      return {
-        ...shared,
-        freq: "WEEKLY",
-        ...(byDay?.length ? { byDay } : {}),
-        // Graph defaults firstDayOfWeek to sunday, unlike RFC 5545's implicit
-        // WKST=MO, so a missing field must parse as an explicit SU.
-        wkst: wkst ?? "SU",
-      };
-    case "absoluteMonthly":
-      return {
-        ...shared,
-        freq: "MONTHLY",
-        ...(pattern.dayOfMonth !== undefined
-          ? { byMonthDay: [pattern.dayOfMonth] }
-          : {}),
-      };
-    case "relativeMonthly":
-      return {
-        ...shared,
-        freq: "MONTHLY",
-        ...(byDay?.length ? { byDay } : {}),
-        bySetPos: [WEEK_INDEX_TO_SET_POS[pattern.index ?? "first"]],
-      };
-    case "absoluteYearly":
-      return {
-        ...shared,
-        freq: "YEARLY",
-        ...(pattern.month !== undefined ? { byMonth: [pattern.month] } : {}),
-        ...(pattern.dayOfMonth !== undefined
-          ? { byMonthDay: [pattern.dayOfMonth] }
-          : {}),
-      };
-    case "relativeYearly":
-      return {
-        ...shared,
-        freq: "YEARLY",
-        ...(pattern.month !== undefined ? { byMonth: [pattern.month] } : {}),
-        ...(byDay?.length ? { byDay } : {}),
-        bySetPos: [WEEK_INDEX_TO_SET_POS[pattern.index ?? "first"]],
-      };
-    default:
-      return undefined;
-  }
-}
-
-interface ParseMicrosoftEventOptions {
-  calendar: Calendar;
-  event: MicrosoftEvent;
-}
-
-function parseResponseStatus(
-  event: MicrosoftEvent,
-): AttendeeStatus | undefined {
-  return event.responseStatus?.response
-    ? parseMicrosoftAttendeeStatus(event.responseStatus.response)
-    : undefined;
-}
-
-function parseMicrosoftVisibility(
-  sensitivity: MicrosoftEvent["sensitivity"],
-): CalendarEvent["visibility"] {
-  if (sensitivity === "normal") return "default";
-  if (sensitivity === "personal") return "private";
-  return sensitivity;
-}
-
-function toMicrosoftSensitivity(
-  visibility: CreateEventInput["visibility"],
-): MicrosoftEvent["sensitivity"] {
-  if (visibility === "default") return "normal";
-  if (visibility === "public") return "normal";
-  return visibility;
-}
-
-function toMicrosoftAttendee(attendee: Attendee): MicrosoftEventAttendee {
-  return {
-    emailAddress: {
-      address: attendee.email,
-      name: attendee.name,
-    },
-    type: attendee.type,
-  };
-}
-
-export function parseMicrosoftEvent({
-  calendar,
-  event,
-}: ParseMicrosoftEventOptions): CalendarEvent {
-  const { start, end, isAllDay } = event;
-
-  if (!start || !end) {
-    throw new Error("Event start or end is missing");
-  }
-
-  const responseStatus = parseResponseStatus(event);
-  const recurrence = event.recurrence
-    ? parseMicrosoftRecurrence(event.recurrence)
-    : undefined;
-
-  return {
-    id: event.id!,
-    title: event.subject!,
-    description: event.body?.content ?? undefined,
-    start: isAllDay
-      ? parseDate(start.dateTime!)
-      : parseDateTime(start.dateTime!, start.timeZone!),
-    end: isAllDay
-      ? parseDate(end.dateTime!)
-      : parseDateTime(end.dateTime!, end.timeZone!),
-    allDay: isAllDay ?? false,
-    location: event.location?.displayName ?? undefined,
-    availability: event.showAs === "free" ? "free" : "busy",
-    visibility: parseMicrosoftVisibility(event.sensitivity),
-    attendees: event.attendees?.map(parseMicrosoftAttendee) ?? [],
-    url: event.webLink ?? undefined,
-    etag: event["@odata.etag"],
-    calendar: {
-      id: calendar.id,
-      provider: calendar.provider,
-    },
-    readOnly: calendar.readOnly,
-    conference: parseMicrosoftConference(event),
-    recurringEventId: event.seriesMasterId ?? undefined,
-    ...(recurrence ? { recurrence } : {}),
-    ...(responseStatus ? { response: { status: responseStatus } } : {}),
-    ...(event.createdDateTime
-      ? { createdAt: Temporal.Instant.from(event.createdDateTime) }
-      : {}),
-    ...(event.lastModifiedDateTime
-      ? { updatedAt: Temporal.Instant.from(event.lastModifiedDateTime) }
-      : {}),
-    metadata: {
-      ...(event.originalStartTimeZone
-        ? {
-            originalStartTimeZone: {
-              raw: event.originalStartTimeZone,
-              parsed: event.originalStartTimeZone
-                ? parseTimeZone(event.originalStartTimeZone)
-                : undefined,
-            },
-          }
-        : {}),
-      ...(event.originalEndTimeZone
-        ? {
-            originalEndTimeZone: {
-              raw: event.originalEndTimeZone,
-              parsed: event.originalEndTimeZone
-                ? parseTimeZone(event.originalEndTimeZone)
-                : undefined,
-            },
-          }
-        : {}),
-      onlineMeeting: event.onlineMeeting,
-      ...(event.recurrence?.range?.recurrenceTimeZone
-        ? { recurrenceTimeZone: event.recurrence.range.recurrenceTimeZone }
-        : {}),
-    },
-  } as CalendarEvent;
-}
-
-export function toMicrosoftEvent(event: CreateEventInput): MicrosoftEvent {
-  const metadata = toMicrosoftMetadata(event.metadata);
-
-  return {
-    subject: event.title,
-    ...(event.description
-      ? {
-          body: { contentType: "text", content: event.description },
-        }
-      : {}),
-    start: toMicrosoftDate({
-      value: event.start,
-      originalTimeZone: metadata?.originalStartTimeZone,
-    }),
-    end: toMicrosoftDate({
-      value: event.end,
-      originalTimeZone: metadata?.originalEndTimeZone,
-    }),
-    isAllDay: event.allDay ?? false,
-    ...(event.location ? { location: { displayName: event.location } } : {}),
-    ...(event.conference ? toMicrosoftConferenceData(event.conference) : {}),
-    showAs: event.availability,
-    sensitivity: toMicrosoftSensitivity(event.visibility),
-    attendees: event.attendees?.map(toMicrosoftAttendee),
-    ...(event.recurrence
-      ? {
-          recurrence: toMicrosoftRecurrence({
-            recurrence: event.recurrence,
-            start: event.start,
-            recurrenceTimeZone: metadata?.recurrenceTimeZone,
-          }),
-        }
-      : {}),
-  };
-}
-
-interface ToMicrosoftEventPatchOptions {
-  // Resolved master start for recurrence serialization; Graph requires
-  // range.startDate to match the master event's start date, which a sparse
-  // patch does not necessarily carry.
-  startForRecurrence?:
-    | Temporal.PlainDate
-    | Temporal.Instant
-    | Temporal.ZonedDateTime;
-}
-
-function toMicrosoftMetadata(
-  metadata: CreateEventInput["metadata"],
-): MicrosoftEventMetadata {
-  if (!metadata) return {};
-  if ("originalStartTimeZone" in metadata) return metadata;
-  if ("originalEndTimeZone" in metadata) return metadata;
-  if ("onlineMeeting" in metadata) return metadata;
-  if ("recurrenceTimeZone" in metadata) return metadata;
-  return {};
-}
-
-function toMicrosoftRecurrencePatch(
-  recurrence: UpdateEventPatch["recurrence"],
-  start:
-    | Temporal.PlainDate
-    | Temporal.Instant
-    | Temporal.ZonedDateTime
-    | undefined,
-  recurrenceTimeZone?: string,
-) {
-  if (recurrence === undefined) return {};
-  if (recurrence === null) return { recurrence: null };
-
-  if (!start) {
-    throw new RecurrenceConversionError(
-      "a recurrence change requires the event start to anchor range.startDate",
-    );
-  }
-
-  return {
-    recurrence: toMicrosoftRecurrence({
-      recurrence,
-      start,
-      recurrenceTimeZone,
-    }),
-  };
-}
-
-export function toMicrosoftEventPatch(
-  event: UpdateEventPatch,
-  options: ToMicrosoftEventPatchOptions = {},
-): MicrosoftEvent {
-  const metadata = toMicrosoftMetadata(event.metadata);
-
-  const recurrenceStart = options.startForRecurrence ?? event.start;
-
-  return {
-    ...(event.title !== undefined ? { subject: event.title } : {}),
-    ...(event.description !== undefined
-      ? {
-          body: { contentType: "text", content: event.description ?? "" },
-        }
-      : {}),
-    ...(event.start !== undefined
-      ? {
-          start: toMicrosoftDate({
-            value: event.start,
-            originalTimeZone: metadata?.originalStartTimeZone,
-          }),
-        }
-      : {}),
-    ...(event.end !== undefined
-      ? {
-          end: toMicrosoftDate({
-            value: event.end,
-            originalTimeZone: metadata?.originalEndTimeZone,
-          }),
-        }
-      : {}),
-    ...(event.allDay !== undefined ? { isAllDay: event.allDay } : {}),
-    ...(event.location !== undefined
-      ? { location: { displayName: event.location } }
-      : {}),
-    ...(event.availability !== undefined ? { showAs: event.availability } : {}),
-    ...(event.visibility !== undefined
-      ? { sensitivity: toMicrosoftSensitivity(event.visibility) }
-      : {}),
-    ...(event.attendees !== undefined
-      ? { attendees: event.attendees.map(toMicrosoftAttendee) }
-      : {}),
-    // Graph has no conference field to null out: clearing demotes the online
-    // meeting via isOnlineMeeting=false with the provider reset to "unknown".
-    ...(event.conference === null
-      ? { isOnlineMeeting: false, onlineMeetingProvider: "unknown" as const }
-      : event.conference
-        ? toMicrosoftConferenceData(event.conference)
-        : {}),
-    ...toMicrosoftRecurrencePatch(
-      event.recurrence,
-      recurrenceStart,
-      metadata.recurrenceTimeZone,
-    ),
-  };
-}
-
-function parseMicrosoftAttendeeStatus(
-  status: MicrosoftEventAttendeeResponseStatus["response"],
-): AttendeeStatus {
-  if (status === "notResponded" || status === "none") {
-    return "unknown";
-  }
-
-  if (status === "accepted" || status === "organizer") {
-    return "accepted";
-  }
-
-  if (status === "tentativelyAccepted") {
-    return "tentative";
-  }
-
-  if (status === "declined") {
-    return "declined";
-  }
-
-  return "unknown";
-}
-
-export function parseMicrosoftAttendee(
-  attendee: MicrosoftEventAttendee,
-): Attendee {
-  return {
-    email: attendee.emailAddress!.address!,
-    name: attendee.emailAddress?.name ?? undefined,
-    status: parseMicrosoftAttendeeStatus(attendee.status?.response),
-    type: attendee.type!,
-  };
-}
diff --git a/packages/providers/src/calendars/microsoft-calendar/freebusy/index.ts b/packages/providers/src/calendars/microsoft-calendar/freebusy/index.ts
index 9944be26..64bf2220 100644
--- a/packages/providers/src/calendars/microsoft-calendar/freebusy/index.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/freebusy/index.ts
@@ -10,8 +10,8 @@ import type {
   CalendarProviderFreeBusyQueryOptions,
 } from "../../../interfaces/providers";
 import { ProviderError } from "../../../lib/provider-error";
-import { toMicrosoftDate } from "../utils";
-import { parseScheduleItem } from "./utils";
+import { formatDate } from "../events/format";
+import { parseScheduleItem } from "./parse";
 
 const MAX_SCHEDULES_PER_REQUEST = 20;
 
@@ -72,8 +72,8 @@ export class MicrosoftCalendarFreeBusy implements CalendarProviderFreeBusy {
             await this.client.users.calendar.getSchedule({
               userId: "me",
               schedules: batch,
-              startTime: toMicrosoftDate({ value: timeMin }),
-              endTime: toMicrosoftDate({ value: timeMax }),
+              startTime: formatDate({ value: timeMin }),
+              endTime: formatDate({ value: timeMax }),
             }),
           ),
         ),
diff --git a/packages/providers/src/calendars/microsoft-calendar/freebusy/utils.ts b/packages/providers/src/calendars/microsoft-calendar/freebusy/parse.ts
similarity index 77%
rename from packages/providers/src/calendars/microsoft-calendar/freebusy/utils.ts
rename to packages/providers/src/calendars/microsoft-calendar/freebusy/parse.ts
index 4bcd4fa0..1c095ce4 100644
--- a/packages/providers/src/calendars/microsoft-calendar/freebusy/utils.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/freebusy/parse.ts
@@ -17,8 +17,8 @@ export function parseScheduleItemStatus(status: ScheduleItem["status"]) {
 
 export function parseScheduleItem(item: ScheduleItem) {
   return {
-    start: parseDateTime(item.start!.dateTime!, item.start!.timeZone!),
-    end: parseDateTime(item.end!.dateTime!, item.end!.timeZone!),
+    start: parseDateTime(item.start.dateTime, item.start.timeZone),
+    end: parseDateTime(item.end.dateTime, item.end.timeZone),
     status: parseScheduleItemStatus(item.status),
   };
 }
diff --git a/packages/providers/src/calendars/microsoft-calendar/recurrence/format.ts b/packages/providers/src/calendars/microsoft-calendar/recurrence/format.ts
new file mode 100644
index 00000000..d7fd4fa2
--- /dev/null
+++ b/packages/providers/src/calendars/microsoft-calendar/recurrence/format.ts
@@ -0,0 +1,322 @@
+import type {
+  DayOfWeek as MicrosoftDayOfWeek,
+  PatternedRecurrence,
+  RecurrencePattern,
+  RecurrenceRange,
+  WeekIndex,
+} from "@analog/microsoft-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type { UpdateEventPatch } from "@repo/schemas";
+import { toPlainDate, toZonedDateTime } from "@repo/temporal";
+
+import type { Recurrence, Weekday } from "../../../interfaces";
+import { parseTimeZone } from "../utils";
+
+const WEEKDAY_REVERSE_MAP: Record<Weekday, MicrosoftDayOfWeek> = {
+  MO: "monday",
+  TU: "tuesday",
+  WE: "wednesday",
+  TH: "thursday",
+  FR: "friday",
+  SA: "saturday",
+  SU: "sunday",
+};
+
+// ISO dayOfWeek is 1 (Monday) through 7 (Sunday).
+const ISO_DAY_MAP: MicrosoftDayOfWeek[] = [
+  "monday",
+  "tuesday",
+  "wednesday",
+  "thursday",
+  "friday",
+  "saturday",
+  "sunday",
+];
+
+export class RecurrenceConversionError extends Error {
+  constructor(message: string) {
+    super(`Cannot convert recurrence for Microsoft Calendar: ${message}`);
+    this.name = "RecurrenceConversionError";
+  }
+}
+
+function formatWeekIndex(recurrence: Recurrence): WeekIndex {
+  const bySetPos = recurrence.bySetPos;
+
+  if (!bySetPos || bySetPos.length !== 1) {
+    throw new RecurrenceConversionError(
+      "bySetPos must contain exactly one of 1, 2, 3, 4, or -1",
+    );
+  }
+
+  switch (bySetPos[0]) {
+    case 1:
+      return "first";
+    case 2:
+      return "second";
+    case 3:
+      return "third";
+    case 4:
+      return "fourth";
+    case -1:
+      return "last";
+    default:
+      throw new RecurrenceConversionError(
+        `bySetPos value ${bySetPos[0]} has no Microsoft equivalent (supported: 1, 2, 3, 4, -1)`,
+      );
+  }
+}
+
+function formatDaysOfWeek(byDay: Weekday[]): MicrosoftDayOfWeek[] {
+  return byDay.map((day) => WEEKDAY_REVERSE_MAP[day]);
+}
+
+function formatDayOfWeek(dayOfWeek: number): MicrosoftDayOfWeek {
+  const day = ISO_DAY_MAP[dayOfWeek - 1];
+
+  if (!day) {
+    throw new RecurrenceConversionError(`invalid ISO weekday ${dayOfWeek}`);
+  }
+
+  return day;
+}
+
+function assertConvertibleRecurrence(recurrence: Recurrence) {
+  const unsupported: string[] = [];
+
+  if (recurrence.byYearDay?.length) unsupported.push("byYearDay");
+  if (recurrence.byWeekNo?.length) unsupported.push("byWeekNo");
+  if (recurrence.byHour?.length) unsupported.push("byHour");
+  if (recurrence.byMinute?.length) unsupported.push("byMinute");
+  if (recurrence.bySecond?.length) unsupported.push("bySecond");
+  if (recurrence.rDate?.length) unsupported.push("rDate");
+  if (recurrence.exDate?.length) unsupported.push("exDate");
+
+  if (recurrence.rscale && recurrence.rscale !== "GREGORIAN") {
+    unsupported.push(`rscale=${recurrence.rscale}`);
+  }
+
+  if (recurrence.skip && recurrence.skip !== "OMIT") {
+    unsupported.push(`skip=${recurrence.skip}`);
+  }
+
+  if (unsupported.length > 0) {
+    throw new RecurrenceConversionError(
+      `unsupported rule parts: ${unsupported.join(", ")}`,
+    );
+  }
+
+  if (recurrence.count !== undefined && recurrence.until !== undefined) {
+    throw new RecurrenceConversionError(
+      "count and until are mutually exclusive",
+    );
+  }
+
+  if (recurrence.freq === "WEEKLY" && recurrence.bySetPos?.length) {
+    throw new RecurrenceConversionError("bySetPos is not supported for WEEKLY");
+  }
+
+  if (
+    recurrence.until !== undefined &&
+    !(recurrence.until instanceof Temporal.PlainDate)
+  ) {
+    throw new RecurrenceConversionError(
+      "Microsoft recurrence only supports date-valued until",
+    );
+  }
+}
+
+function formatRecurrencePattern(
+  recurrence: Recurrence,
+  start: Temporal.ZonedDateTime,
+): RecurrencePattern {
+  const interval = recurrence.interval ?? 1;
+
+  if (recurrence.byMonth && recurrence.freq !== "YEARLY") {
+    throw new RecurrenceConversionError(
+      `byMonth is only supported for YEARLY, got ${recurrence.freq}`,
+    );
+  }
+
+  if (
+    recurrence.byMonthDay &&
+    recurrence.freq !== "MONTHLY" &&
+    recurrence.freq !== "YEARLY"
+  ) {
+    throw new RecurrenceConversionError(
+      `byMonthDay is only supported for MONTHLY and YEARLY, got ${recurrence.freq}`,
+    );
+  }
+
+  switch (recurrence.freq) {
+    case "DAILY": {
+      if (recurrence.byDay?.length) {
+        throw new RecurrenceConversionError("byDay is not supported for DAILY");
+      }
+
+      return { type: "daily", interval };
+    }
+    case "WEEKLY": {
+      return {
+        type: "weekly",
+        interval,
+        daysOfWeek: recurrence.byDay?.length
+          ? formatDaysOfWeek(recurrence.byDay)
+          : [formatDayOfWeek(start.dayOfWeek)],
+        firstDayOfWeek: WEEKDAY_REVERSE_MAP[recurrence.wkst ?? "MO"],
+      };
+    }
+    case "MONTHLY": {
+      if (recurrence.byDay?.length) {
+        return {
+          type: "relativeMonthly",
+          interval,
+          daysOfWeek: formatDaysOfWeek(recurrence.byDay),
+          index: formatWeekIndex(recurrence),
+        };
+      }
+
+      if (recurrence.byMonthDay && recurrence.byMonthDay.length !== 1) {
+        throw new RecurrenceConversionError(
+          "byMonthDay must contain exactly one day for MONTHLY",
+        );
+      }
+
+      const dayOfMonth = recurrence.byMonthDay?.[0] ?? start.day;
+
+      // RFC 5545 skips months without this day, but Outlook substitutes the
+      // month's last day, silently changing the rule's meaning.
+      if (dayOfMonth > 28) {
+        throw new RecurrenceConversionError(
+          `MONTHLY on day ${dayOfMonth} means "last day" in short months on Outlook, unlike the RFC rule`,
+        );
+      }
+
+      return { type: "absoluteMonthly", interval, dayOfMonth };
+    }
+    case "YEARLY": {
+      if (recurrence.byMonth && recurrence.byMonth.length !== 1) {
+        throw new RecurrenceConversionError(
+          "byMonth must contain exactly one month for YEARLY",
+        );
+      }
+
+      const month = recurrence.byMonth?.[0] ?? start.month;
+
+      if (recurrence.byDay?.length) {
+        return {
+          type: "relativeYearly",
+          interval,
+          month,
+          daysOfWeek: formatDaysOfWeek(recurrence.byDay),
+          index: formatWeekIndex(recurrence),
+        };
+      }
+
+      if (recurrence.byMonthDay && recurrence.byMonthDay.length !== 1) {
+        throw new RecurrenceConversionError(
+          "byMonthDay must contain exactly one day for YEARLY",
+        );
+      }
+
+      const dayOfMonth = recurrence.byMonthDay?.[0] ?? start.day;
+
+      // Same Outlook substitution as MONTHLY: Feb 29 and days beyond a fixed
+      // month's length roll to the month's last day instead of skipping.
+      const stableDays =
+        month === 2 ? 28 : [4, 6, 9, 11].includes(month) ? 30 : 31;
+
+      if (dayOfMonth > stableDays) {
+        throw new RecurrenceConversionError(
+          `YEARLY on month ${month}, day ${dayOfMonth} does not occur every year and rolls to the month's last day on Outlook`,
+        );
+      }
+
+      return { type: "absoluteYearly", interval, month, dayOfMonth };
+    }
+    default: {
+      throw new RecurrenceConversionError(
+        `frequency ${recurrence.freq ?? "(none)"} is not supported`,
+      );
+    }
+  }
+}
+
+interface FormatRecurrenceOptions {
+  recurrence: Recurrence;
+  // The series master's start, never a selected occurrence's: Graph requires
+  // range.startDate to match the master event's start date.
+  start: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime;
+  recurrenceTimeZone?: string;
+}
+
+export function formatRecurrence({
+  recurrence,
+  start,
+  recurrenceTimeZone,
+}: FormatRecurrenceOptions): PatternedRecurrence {
+  assertConvertibleRecurrence(recurrence);
+
+  // Graph gets the zone verbatim (it may be a Windows name); Temporal
+  // conversions need the IANA equivalent.
+  const timeZone =
+    recurrenceTimeZone ??
+    (start instanceof Temporal.ZonedDateTime ? start.timeZoneId : "UTC");
+  const conversionTimeZone = parseTimeZone(timeZone) ?? "UTC";
+
+  // Graph expects range dates and pattern defaults (weekday, day of month)
+  // in recurrenceTimeZone, not the zone the event happened to be parsed in
+  // (events.get parses in the requested Prefer time zone, typically UTC).
+  const startDate = toPlainDate(start, { timeZone: conversionTimeZone });
+
+  const range: RecurrenceRange = {
+    startDate: startDate.toString(),
+    recurrenceTimeZone: timeZone,
+    ...(recurrence.count !== undefined
+      ? { type: "numbered", numberOfOccurrences: recurrence.count }
+      : recurrence.until !== undefined
+        ? {
+            type: "endDate",
+            endDate: toPlainDate(recurrence.until, {
+              timeZone: conversionTimeZone,
+            }).toString(),
+          }
+        : { type: "noEnd" }),
+  };
+
+  return {
+    pattern: formatRecurrencePattern(
+      recurrence,
+      toZonedDateTime(start, { timeZone: conversionTimeZone }),
+    ),
+    range,
+  };
+}
+
+export function formatRecurrencePatch(
+  recurrence: UpdateEventPatch["recurrence"],
+  start:
+    | Temporal.PlainDate
+    | Temporal.Instant
+    | Temporal.ZonedDateTime
+    | undefined,
+  recurrenceTimeZone?: string,
+) {
+  if (recurrence === undefined) return {};
+  if (recurrence === null) return { recurrence: null };
+
+  if (!start) {
+    throw new RecurrenceConversionError(
+      "a recurrence change requires the event start to anchor range.startDate",
+    );
+  }
+
+  return {
+    recurrence: formatRecurrence({
+      recurrence,
+      start,
+      recurrenceTimeZone,
+    }),
+  };
+}
diff --git a/packages/providers/src/calendars/microsoft-calendar/recurrence/parse.ts b/packages/providers/src/calendars/microsoft-calendar/recurrence/parse.ts
new file mode 100644
index 00000000..5001a21b
--- /dev/null
+++ b/packages/providers/src/calendars/microsoft-calendar/recurrence/parse.ts
@@ -0,0 +1,96 @@
+import type {
+  DayOfWeek as MicrosoftDayOfWeek,
+  PatternedRecurrence,
+  WeekIndex,
+} from "@analog/microsoft-calendar";
+import { Temporal } from "temporal-polyfill";
+
+import type { Recurrence, Weekday } from "../../../interfaces";
+
+const WEEKDAY_MAP: Record<MicrosoftDayOfWeek, Weekday> = {
+  monday: "MO",
+  tuesday: "TU",
+  wednesday: "WE",
+  thursday: "TH",
+  friday: "FR",
+  saturday: "SA",
+  sunday: "SU",
+};
+
+const WEEK_INDEX_MAP: Record<WeekIndex, number> = {
+  first: 1,
+  second: 2,
+  third: 3,
+  fourth: 4,
+  last: -1,
+};
+
+export function parseRecurrence(
+  recurrence: PatternedRecurrence,
+): Recurrence | undefined {
+  const { pattern, range } = recurrence;
+
+  const shared: Recurrence = {
+    interval: pattern.interval,
+    ...(range.type === "numbered" && range.numberOfOccurrences !== undefined
+      ? { count: range.numberOfOccurrences }
+      : {}),
+    // Graph's endDate is inclusive, matching RFC 5545 UNTIL for date values.
+    ...(range.type === "endDate" && range.endDate
+      ? { until: Temporal.PlainDate.from(range.endDate) }
+      : {}),
+  };
+
+  const byDay = pattern.daysOfWeek?.map((day) => WEEKDAY_MAP[day]);
+  const wkst = pattern.firstDayOfWeek
+    ? WEEKDAY_MAP[pattern.firstDayOfWeek]
+    : undefined;
+
+  switch (pattern.type) {
+    case "daily":
+      return { ...shared, freq: "DAILY" };
+    case "weekly":
+      return {
+        ...shared,
+        freq: "WEEKLY",
+        ...(byDay?.length ? { byDay } : {}),
+        // Graph defaults firstDayOfWeek to sunday, unlike RFC 5545's implicit
+        // WKST=MO, so a missing field must parse as an explicit SU.
+        wkst: wkst ?? "SU",
+      };
+    case "absoluteMonthly":
+      return {
+        ...shared,
+        freq: "MONTHLY",
+        ...(pattern.dayOfMonth !== undefined
+          ? { byMonthDay: [pattern.dayOfMonth] }
+          : {}),
+      };
+    case "relativeMonthly":
+      return {
+        ...shared,
+        freq: "MONTHLY",
+        ...(byDay?.length ? { byDay } : {}),
+        bySetPos: [WEEK_INDEX_MAP[pattern.index ?? "first"]],
+      };
+    case "absoluteYearly":
+      return {
+        ...shared,
+        freq: "YEARLY",
+        ...(pattern.month !== undefined ? { byMonth: [pattern.month] } : {}),
+        ...(pattern.dayOfMonth !== undefined
+          ? { byMonthDay: [pattern.dayOfMonth] }
+          : {}),
+      };
+    case "relativeYearly":
+      return {
+        ...shared,
+        freq: "YEARLY",
+        ...(pattern.month !== undefined ? { byMonth: [pattern.month] } : {}),
+        ...(byDay?.length ? { byDay } : {}),
+        bySetPos: [WEEK_INDEX_MAP[pattern.index ?? "first"]],
+      };
+    default:
+      return undefined;
+  }
+}
diff --git a/packages/providers/src/calendars/microsoft-calendar/utils.ts b/packages/providers/src/calendars/microsoft-calendar/utils.ts
index ad0655c0..ec57efbd 100644
--- a/packages/providers/src/calendars/microsoft-calendar/utils.ts
+++ b/packages/providers/src/calendars/microsoft-calendar/utils.ts
@@ -3,7 +3,7 @@ import { Temporal } from "temporal-polyfill";
 import { mapWindowsToIanaTimeZone } from "./windows-timezones";
 
 export function isValidTimeZone(timeZone: string) {
-  if (!Intl || !Intl.DateTimeFormat().resolvedOptions().timeZone) {
+  if (!Intl.DateTimeFormat().resolvedOptions().timeZone) {
     throw new Error("Time zones are not available in this environment");
   }
 
@@ -28,44 +28,3 @@ export function parseDateTime(dateTime: string, timeZone: string) {
     parseTimeZone(timeZone) ?? "UTC",
   );
 }
-
-interface ToMicrosoftDateOptions {
-  value: Temporal.PlainDate | Temporal.Instant | Temporal.ZonedDateTime;
-  originalTimeZone?: {
-    raw: string;
-    parsed?: string;
-  };
-}
-
-export function toMicrosoftDate({
-  value,
-  originalTimeZone,
-}: ToMicrosoftDateOptions) {
-  if (value instanceof Temporal.PlainDate) {
-    return {
-      dateTime: value.toPlainDateTime().toString(),
-      timeZone: originalTimeZone?.raw ?? "UTC",
-    };
-  }
-
-  // These events were created using another provider.
-  if (value instanceof Temporal.Instant) {
-    const dateTime = value
-      .toZonedDateTimeISO("UTC")
-      .toPlainDateTime()
-      .toString();
-
-    return {
-      dateTime,
-      timeZone: "UTC",
-    };
-  }
-
-  return {
-    dateTime: value.toPlainDateTime().toString(),
-    timeZone:
-      originalTimeZone?.parsed === value.timeZoneId
-        ? originalTimeZone?.raw
-        : value.timeZoneId,
-  };
-}
diff --git a/packages/providers/src/calendars/utils/meetings.ts b/packages/providers/src/calendars/utils/meetings.ts
deleted file mode 100644
index d32de326..00000000
--- a/packages/providers/src/calendars/utils/meetings.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import type { Attendee, CalendarEvent } from "../../interfaces";
-
-type Meeting = CalendarEvent & { attendees: Attendee[] };
-
-export function isMeeting(event: CalendarEvent): event is Meeting {
-  return !!event.attendees && event.attendees.length > 1;
-}
diff --git a/packages/providers/src/conferencing/google-meet.ts b/packages/providers/src/conferencing/google-meet.ts
index c7a464dc..8c20e355 100644
--- a/packages/providers/src/conferencing/google-meet.ts
+++ b/packages/providers/src/conferencing/google-meet.ts
@@ -1,7 +1,7 @@
 import { GoogleCalendar } from "@analog/google-calendar";
 
-import { parseConferenceData } from "../calendars/google-calendar/events/conferences/utils";
-import { toGoogleCalendarEventInput } from "../calendars/google-calendar/events/utils";
+import { parseConference } from "../calendars/google-calendar/conferences";
+import { formatEventInput } from "../calendars/google-calendar/events/format";
 import type { Conference, ConferencingProvider } from "../interfaces";
 import type { ConferencingProviderCreateConferenceOptions } from "../interfaces/providers";
 import { ProviderError } from "../lib/provider-error";
@@ -38,7 +38,7 @@ export class GoogleMeetProvider implements ConferencingProvider {
       const updatedEvent = await this.client.events.update({
         calendarId,
         eventId,
-        ...toGoogleCalendarEventInput(existingEvent),
+        ...formatEventInput(existingEvent),
         conferenceData: {
           createRequest: {
             requestId: crypto.randomUUID(),
@@ -56,7 +56,7 @@ export class GoogleMeetProvider implements ConferencingProvider {
         throw new Error("Failed to create conference data");
       }
 
-      return parseConferenceData(updatedEvent)!;
+      return parseConference(updatedEvent)!;
     });
   }
 
diff --git a/packages/providers/src/index.ts b/packages/providers/src/index.ts
index 9ee100d2..1ab2f5ed 100644
--- a/packages/providers/src/index.ts
+++ b/packages/providers/src/index.ts
@@ -108,13 +108,6 @@ export function accountToConferencingProvider(
 
   const Provider = supportedConferencingProviders[providerId];
 
-  if (!Provider) {
-    throw new TRPCError({
-      code: "BAD_REQUEST",
-      message: `Conferencing provider not supported: '${providerId}' for account '${activeAccount.providerId}' (providerAccountId: ${activeAccount.accountId})`,
-    });
-  }
-
   return new Provider({
     accessToken: activeAccount.accessToken,
     providerAccountId: activeAccount.accountId,
diff --git a/packages/providers/src/interfaces/events.ts b/packages/providers/src/interfaces/events.ts
index d78bba1d..0a5899ca 100644
--- a/packages/providers/src/interfaces/events.ts
+++ b/packages/providers/src/interfaces/events.ts
@@ -237,3 +237,9 @@ export interface Recurrence {
   rscale?: RScale;
   skip?: "OMIT" | "BACKWARD" | "FORWARD";
 }
+
+// CalendarEvent is a union over the allDay/start/end shapes, which `Omit` would
+// collapse into a single `allDay: boolean` object, so the required `attendees`
+// is intersected onto the union instead.
+export type Meeting = CalendarEvent &
+  Required<Pick<CalendarEvent, "attendees">>;
diff --git a/packages/providers/src/interfaces/providers/calendar.ts b/packages/providers/src/interfaces/providers/calendar.ts
index 1e799b73..1eedb3b6 100644
--- a/packages/providers/src/interfaces/providers/calendar.ts
+++ b/packages/providers/src/interfaces/providers/calendar.ts
@@ -62,7 +62,7 @@ export interface CalendarProviderEventsListOptions {
   calendar: Calendar;
   timeMin: Temporal.ZonedDateTime;
   timeMax: Temporal.ZonedDateTime;
-  timeZone?: string;
+  timeZone: string;
 }
 
 export interface CalendarProviderEventsGetOptions {
diff --git a/packages/providers/src/lib/events.ts b/packages/providers/src/lib/events.ts
new file mode 100644
index 00000000..21ad8406
--- /dev/null
+++ b/packages/providers/src/lib/events.ts
@@ -0,0 +1,5 @@
+import type { CalendarEvent, Meeting } from "../interfaces/events";
+
+export function isMeeting(event: CalendarEvent): event is Meeting {
+  return (event.attendees?.length ?? 0) > 1;
+}
diff --git a/packages/providers/src/lib/index.ts b/packages/providers/src/lib/index.ts
index 4cdba995..48f2138b 100644
--- a/packages/providers/src/lib/index.ts
+++ b/packages/providers/src/lib/index.ts
@@ -1,3 +1,4 @@
 export * from "./recurrences/export";
 export * from "./recurrences/parse";
+export * from "./events";
 export { COLORS } from "../calendars/colors";
diff --git a/packages/providers/src/lib/recurrences/parse.ts b/packages/providers/src/lib/recurrences/parse.ts
index 2d35ce50..939d9ed1 100644
--- a/packages/providers/src/lib/recurrences/parse.ts
+++ b/packages/providers/src/lib/recurrences/parse.ts
@@ -338,7 +338,7 @@ export function parseTextRecurrence({
   const rrule = parseRRule({ lines });
 
   return {
-    ...(rrule ? rrule : {}),
+    ...rrule,
     dtstart,
     exDate,
     rDate,
diff --git a/packages/providers/src/tasks/google-tasks.ts b/packages/providers/src/tasks/google-tasks.ts
index 74e0204d..27096d4d 100644
--- a/packages/providers/src/tasks/google-tasks.ts
+++ b/packages/providers/src/tasks/google-tasks.ts
@@ -83,7 +83,7 @@ class GoogleTasksTasks implements TaskProviderTasks {
       const { items: taskCollections } =
         await this.client.tasks.v1.users.me.lists.list();
 
-      const results = await Promise.all(
+      return Promise.all(
         taskCollections?.map(async (taskCollection) => {
           const { items: tasks } = await this.client.tasks.v1.lists.tasks.list(
             taskCollection.id!,
@@ -104,7 +104,6 @@ class GoogleTasksTasks implements TaskProviderTasks {
           };
         }) ?? [],
       );
-      return results;
     });
   }
 
diff --git a/packages/schemas/src/places.ts b/packages/schemas/src/places.ts
index 2de51e15..3ead35b7 100644
--- a/packages/schemas/src/places.ts
+++ b/packages/schemas/src/places.ts
@@ -2,8 +2,8 @@ import * as z from "zod";
 
 export const autocompleteInputSchema = z.object({
   input: z.string().min(1).max(256),
-  languageCode: z.string().optional().default("en"),
-  limit: z.number().int().min(1).max(10).optional().default(5),
+  languageCode: z.string().default("en"),
+  limit: z.number().int().min(1).max(10).default(5),
 });
 
 export const placeResultSchema = z.object({