fix(outlook): treat date-only bounds as all-day and guard partial all-day updates

Cursor round 2:

- Date-only bounds no longer produce a zero-length window. The param docs invited
  a date like 2025-06-03 for an all-day event, but buildAllDayRange only ran when
  isAllDay was explicitly true, so date-only input built a 00:00->00:00 timed
  window that Graph rejects. A date-only bound carries no time, so the only
  coherent reading is all-day; create/update now promote on that shape and the
  descriptions state it.
- Converting an event to all-day with no bounds now fails with an actionable
  message instead of a Graph 400. Graph requires all-day events to have midnight
  start and end in the same zone, and those cannot be derived from a partial
  PATCH against an event whose existing bounds are timed.

Author: waleedlatif1

apps/docs/content/docs/en/integrations/outlook.mdx

@@ -482,8 +482,8 @@ List Outlook calendar events within a start/end time window
 | Parameter | Type | Required | Description |
 | --------- | ---- | -------- | ----------- |
 | `calendarId` | string | No | ID of the calendar to read. Defaults to the mailbox default calendar. |
-| `startDateTime` | string | Yes | Start of the time window \(ISO 8601, e.g. 2025-06-03T00:00:00-08:00\). Interpreted as UTC if no offset is given. |
-| `endDateTime` | string | Yes | End of the time window \(ISO 8601, e.g. 2025-06-10T00:00:00-08:00\). Interpreted as UTC if no offset is given. |
+| `startDateTime` | string | No | Start of the time window \(ISO 8601, e.g. 2025-06-03T00:00:00-08:00\). Interpreted as UTC if no offset is given. Required unless paging with pageToken. |
+| `endDateTime` | string | No | End of the time window \(ISO 8601, e.g. 2025-06-10T00:00:00-08:00\). Interpreted as UTC if no offset is given. Required unless paging with pageToken. |
 | `maxResults` | number | No | Maximum number of events to return per page \(default: 10, max: 100\) |
 | `orderBy` | string | No | Order of events \(default: start/dateTime\) |
 | `pageToken` | string | No | Full @odata.nextLink URL from a previous page to continue paging |
@@ -567,8 +567,8 @@ Create a new Outlook calendar event
 | --------- | ---- | -------- | ----------- |
 | `calendarId` | string | No | ID of the calendar to create the event in. Defaults to the default calendar. |
 | `subject` | string | Yes | Event subject/title |
-| `startDateTime` | string | Yes | Start time \(ISO 8601, e.g. 2025-06-03T10:00:00-08:00\) or a date \(2025-06-03\) for an all-day event |
-| `endDateTime` | string | Yes | End time \(ISO 8601, e.g. 2025-06-03T11:00:00-08:00\) or a date \(2025-06-04\) for an all-day event |
+| `startDateTime` | string | Yes | Start time \(ISO 8601, e.g. 2025-06-03T10:00:00-08:00\). A date-only value \(2025-06-03\) for both start and end creates an all-day event. |
+| `endDateTime` | string | Yes | End time \(ISO 8601, e.g. 2025-06-03T11:00:00-08:00\). A date-only value \(2025-06-04\) for both start and end creates an all-day event. |
 | `timeZone` | string | No | IANA or Windows time zone name \(e.g. America/Los_Angeles\). Used for datetimes without a UTC offset. Defaults to UTC. |
 | `body` | string | No | Event body content |
 | `contentType` | string | No | Content type for the event body \(text or html\) |
@@ -616,14 +616,14 @@ Update an existing Outlook calendar event
 | --------- | ---- | -------- | ----------- |
 | `eventId` | string | Yes | The ID of the calendar event to update |
 | `subject` | string | No | New event subject/title |
-| `startDateTime` | string | No | New start time \(ISO 8601\) or a date \(2025-06-03\) for an all-day event |
-| `endDateTime` | string | No | New end time \(ISO 8601\) or a date \(2025-06-04\) for an all-day event |
+| `startDateTime` | string | No | New start time \(ISO 8601\). A date-only value \(2025-06-03\) converts the event to all-day. |
+| `endDateTime` | string | No | New end time \(ISO 8601\). A date-only value \(2025-06-04\) converts the event to all-day. |
 | `timeZone` | string | No | IANA or Windows time zone name applied to updated datetimes without a UTC offset. Defaults to UTC. |
 | `body` | string | No | New event body content |
 | `contentType` | string | No | Content type for the event body \(text or html\) |
 | `location` | string | No | New event location display name |
 | `attendees` | string | No | Replacement attendee email addresses \(comma-separated\) |
-| `isAllDay` | boolean | No | Whether the event lasts the entire day |
+| `isAllDay` | boolean | No | Whether the event lasts the entire day. Setting this true requires also sending startDateTime, since Graph needs midnight bounds. |
 | `isOnlineMeeting` | boolean | No | Attach an online meeting to the event. Uses the mailbox default provider \(Teams on work/school accounts\); personal accounts have no supported online-meeting provider. |
 
 #### Output

apps/sim/tools/outlook/calendar-tools.test.ts

@@ -80,6 +80,56 @@ describe('outlook calendar tools', () => {
     )
   })
 
+  it('treats date-only bounds as an all-day event even without the flag', () => {
+    const createBody = outlookCalendarCreateEventTool.request.body as (
+      p: unknown
+    ) => Record<string, unknown>
+    // Date-only carries no time, so this must not become a zero-length 00:00->00:00 window.
+    const created = createBody({
+      accessToken: 't',
+      subject: 'Company holiday',
+      startDateTime: '2025-06-03',
+      endDateTime: '2025-06-03',
+    })
+    expect(created.isAllDay).toBe(true)
+    expect(created.start).toEqual({ dateTime: '2025-06-03T00:00:00', timeZone: 'UTC' })
+    expect(created.end).toEqual({ dateTime: '2025-06-04T00:00:00', timeZone: 'UTC' })
+
+    const updateBody = outlookCalendarUpdateEventTool.request.body as (
+      p: unknown
+    ) => Record<string, unknown>
+    const updated = updateBody({
+      accessToken: 't',
+      eventId: 'e1',
+      startDateTime: '2025-06-03',
+      endDateTime: '2025-06-05',
+    })
+    expect(updated.isAllDay).toBe(true)
+    expect(updated.start).toEqual({ dateTime: '2025-06-03T00:00:00', timeZone: 'UTC' })
+    expect(updated.end).toEqual({ dateTime: '2025-06-05T00:00:00', timeZone: 'UTC' })
+
+    // A timed bound stays timed.
+    const timed = createBody({
+      accessToken: 't',
+      subject: 'Sync',
+      startDateTime: '2025-06-03T10:00:00Z',
+      endDateTime: '2025-06-03T11:00:00Z',
+    })
+    expect(timed.isAllDay).toBeUndefined()
+  })
+
+  it('rejects an all-day conversion that supplies no bounds', () => {
+    const body = outlookCalendarUpdateEventTool.request.body as (
+      p: unknown
+    ) => Record<string, unknown>
+    // Graph needs midnight bounds; they cannot be derived from a partial update.
+    expect(() => body({ accessToken: 't', eventId: 'e1', isAllDay: true })).toThrow(
+      /requires startDateTime/
+    )
+    // Turning all-day off without bounds is still a valid partial update.
+    expect(body({ accessToken: 't', eventId: 'e1', isAllDay: false })).toEqual({ isAllDay: false })
+  })
+
   it('normalizes an all-day update when only one bound is supplied', () => {
     const body = outlookCalendarUpdateEventTool.request.body as (
       p: unknown

apps/sim/tools/outlook/calendar-utils.ts

@@ -105,6 +105,17 @@ export function buildGraphEventDateTime(value: string, timeZone?: string): Graph
   return { dateTime: trimmed, timeZone: timeZone || DEFAULT_OUTLOOK_TIME_ZONE }
 }
 
+/**
+ * True when a bound carries a date but no time (`2025-06-03`).
+ *
+ * A date-only bound has no time component, so the only coherent reading is an all-day
+ * event — the create/update tools promote such a pair rather than emitting a zero-length
+ * midnight-to-midnight timed window, which Graph rejects.
+ */
+export function isDateOnly(value: string | undefined): boolean {
+  return Boolean(value) && !value!.includes('T')
+}
+
 /** Extract the `YYYY-MM-DD` date portion from a date or datetime string. */
 function toDateOnly(value: string): string {
   const trimmed = value.trim()

apps/sim/tools/outlook/calendar_create_event.ts

@@ -5,6 +5,7 @@ import {
   buildGraphEventDateTime,
   CALENDAR_RETRY,
   flattenGraphEvent,
+  isDateOnly,
   normalizeAttendees,
 } from '@/tools/outlook/calendar-utils'
 import type {
@@ -58,14 +59,14 @@ export const outlookCalendarCreateEventTool: ToolConfig<
       required: true,
       visibility: 'user-or-llm',
       description:
-        'Start time (ISO 8601, e.g. 2025-06-03T10:00:00-08:00) or a date (2025-06-03) for an all-day event',
+        'Start time (ISO 8601, e.g. 2025-06-03T10:00:00-08:00). A date-only value (2025-06-03) for both start and end creates an all-day event.',
     },
     endDateTime: {
       type: 'string',
       required: true,
       visibility: 'user-or-llm',
       description:
-        'End time (ISO 8601, e.g. 2025-06-03T11:00:00-08:00) or a date (2025-06-04) for an all-day event',
+        'End time (ISO 8601, e.g. 2025-06-03T11:00:00-08:00). A date-only value (2025-06-04) for both start and end creates an all-day event.',
     },
     timeZone: {
       type: 'string',
@@ -127,7 +128,12 @@ export const outlookCalendarCreateEventTool: ToolConfig<
       }
     },
     body: (params) => {
-      const isAllDay = toBool(params.isAllDay)
+      // Date-only bounds carry no time, so they can only mean an all-day event. Without
+      // this promotion, `2025-06-03` for both bounds would build a zero-length
+      // 00:00->00:00 timed window that Graph rejects, even though the param docs invite
+      // date-only input for all-day events.
+      const bothBoundsDateOnly = isDateOnly(params.startDateTime) && isDateOnly(params.endDateTime)
+      const isAllDay = toBool(params.isAllDay) || bothBoundsDateOnly
       const event: Record<string, unknown> = { subject: params.subject }
 
       if (isAllDay) {

apps/sim/tools/outlook/calendar_update_event.ts

@@ -5,6 +5,7 @@ import {
   buildGraphEventDateTime,
   CALENDAR_RETRY,
   flattenGraphEvent,
+  isDateOnly,
   normalizeAttendees,
 } from '@/tools/outlook/calendar-utils'
 import type {
@@ -57,13 +58,15 @@ export const outlookCalendarUpdateEventTool: ToolConfig<
       type: 'string',
       required: false,
       visibility: 'user-or-llm',
-      description: 'New start time (ISO 8601) or a date (2025-06-03) for an all-day event',
+      description:
+        'New start time (ISO 8601). A date-only value (2025-06-03) converts the event to all-day.',
     },
     endDateTime: {
       type: 'string',
       required: false,
       visibility: 'user-or-llm',
-      description: 'New end time (ISO 8601) or a date (2025-06-04) for an all-day event',
+      description:
+        'New end time (ISO 8601). A date-only value (2025-06-04) converts the event to all-day.',
     },
     timeZone: {
       type: 'string',
@@ -100,7 +103,8 @@ export const outlookCalendarUpdateEventTool: ToolConfig<
       type: 'boolean',
       required: false,
       visibility: 'user-or-llm',
-      description: 'Whether the event lasts the entire day',
+      description:
+        'Whether the event lasts the entire day. Setting this true requires also sending startDateTime, since Graph needs midnight bounds.',
     },
     isOnlineMeeting: {
       type: 'boolean',
@@ -127,17 +131,30 @@ export const outlookCalendarUpdateEventTool: ToolConfig<
     body: (params) => {
       // PATCH is a partial update: only include fields the caller actually provided.
       const event: Record<string, unknown> = {}
-      const settingAllDay = params.isAllDay !== undefined && toBool(params.isAllDay)
+
+      // Date-only bounds carry no time, so they can only mean an all-day event — promote
+      // them even when the caller didn't set the flag (see calendar_create_event).
+      const providedBounds = [params.startDateTime, params.endDateTime].filter(Boolean)
+      const allProvidedBoundsDateOnly =
+        providedBounds.length > 0 && providedBounds.every((bound) => isDateOnly(bound))
+      const settingAllDay =
+        (params.isAllDay !== undefined && toBool(params.isAllDay)) || allProvidedBoundsDateOnly
 
       if (params.subject !== undefined) {
         event.subject = params.subject
       }
 
-      if (settingAllDay && (params.startDateTime || params.endDateTime)) {
-        // Converting to all-day needs midnight bounds with an exclusive end day. Graph
-        // rejects the whole PATCH if either bound is timed or the window is zero-length,
-        // so normalize both together — falling back to the supplied bound when the caller
-        // only gave one, which `buildAllDayRange` then advances to the next day.
+      if (settingAllDay) {
+        // Graph requires an all-day event's start and end to both be midnight in the same
+        // zone, so flipping isAllDay on without bounds would 400 against whatever timed
+        // start/end the event already has. Fail with an actionable message instead.
+        if (providedBounds.length === 0) {
+          throw new Error(
+            'Converting an event to all-day requires startDateTime (and preferably endDateTime): Microsoft Graph requires all-day events to have midnight start and end bounds, which cannot be derived from a partial update.'
+          )
+        }
+        // Normalize both bounds together — falling back to the supplied one when only a
+        // single bound was given, which `buildAllDayRange` then advances to the next day.
         const start = params.startDateTime || params.endDateTime!
         const end = params.endDateTime || params.startDateTime!
         const range = buildAllDayRange(start, end, params.timeZone)
@@ -164,7 +181,9 @@ export const outlookCalendarUpdateEventTool: ToolConfig<
         event.attendees = normalizeAttendees(params.attendees)
       }
 
-      if (params.isAllDay !== undefined) {
+      if (settingAllDay) {
+        event.isAllDay = true
+      } else if (params.isAllDay !== undefined) {
         event.isAllDay = toBool(params.isAllDay)
       }