MCP Apple Calendars

Implementation Reference

• src/index.ts:163-233 (registration)

  Registration of the MCP tool 'updateCalendarEvent' with input schema and handler function that calls the low-level calendars.updateCalendarEvent.
  server.tool( "updateCalendarEvent", { calendarId: z.string(), eventId: z.string(), title: z.string().optional(), startDate: z.string().optional(), endDate: z.string().optional(), location: z.string().optional(), notes: z.string().optional() }, async ({ calendarId, eventId, title, startDate, endDate, location, notes }) => { try { try { const updates = { title, startDate, endDate, location, notes }; // Filter out undefined values Object.keys(updates).forEach(key => { if (updates[key as keyof typeof updates] === undefined) { delete updates[key as keyof typeof updates]; } }); const result = await calendars.updateCalendarEvent(calendarId, eventId, updates); return { content: [{ type: "text", text: JSON.stringify({ success: true, message: "Event updated", event: result }) }] }; } catch (error: any) { // Check if it's a date format error if (error.message && error.message.includes('date')) { return { content: [{ type: "text", text: JSON.stringify({ error: "Failed to update event due to date format issues", message: "The Calendar API requires a specific date format that we couldn't determine. Please try using a different date format or contact the API provider for the correct format.", details: error.message }) }], isError: true }; } // If it's not a date format error, rethrow throw error; } } catch (error) { return { content: [{ type: "text", text: JSON.stringify({ error: "Failed to update event" }) }], isError: true }; } } );
• src/index.ts:165-173 (schema)

  Zod schema defining the input parameters for the updateCalendarEvent tool.
  { calendarId: z.string(), eventId: z.string(), title: z.string().optional(), startDate: z.string().optional(), endDate: z.string().optional(), location: z.string().optional(), notes: z.string().optional() },
• src/calendars.ts:172-216 (handler)

  Low-level handler function that performs the actual API PUT request to update the calendar event, including date formatting using formatDate helper.
  export async function updateCalendarEvent( calendarId: string, eventId: string, updates: { title?: string; startDate?: string; endDate?: string; location?: string; notes?: string; } ): Promise<any> { try { const updatedData: any = { ...updates }; // Format dates if provided if (updatedData.startDate) { const formattedStartDate = formatDate(updatedData.startDate); if (!formattedStartDate) { throw new Error('Invalid start date format provided. Please use one of the supported formats.'); } updatedData.startDate = formattedStartDate; } if (updatedData.endDate) { const formattedEndDate = formatDate(updatedData.endDate); if (!formattedEndDate) { throw new Error('Invalid end date format provided. Please use one of the supported formats.'); } updatedData.endDate = formattedEndDate; } console.error('Updating event with data:', JSON.stringify(updatedData)); // Send the request const response = await axios.put( `${API_BASE_URL}/calendars/${calendarId}/events/${eventId}`, updatedData ); return response.data; } catch (error) { console.error(`Failed to update event "${eventId}" in calendar "${calendarId}":`, error); throw new Error(`Failed to update calendar event: ${error}`); } }
• src/calendars.ts:16-54 (helper)

  Helper function formatDate used by updateCalendarEvent to validate and normalize date strings to ISO8601 format.
  function formatDate(date: Date | string | null): string | null { if (!date) return null; try { // If it's already a Date object, just return ISO string if (date instanceof Date) { if (isNaN(date.getTime())) return null; return date.toISOString(); } // Handle string input const dateStr = date.trim(); // Try parsing the date string as-is first let dateObj = new Date(dateStr); // If the direct parse failed, try alternative formats if (isNaN(dateObj.getTime())) { // Handle forward slash format if (dateStr.includes('/')) { dateObj = new Date(dateStr.replace(/\//g, '-')); } // Handle space instead of T else if (dateStr.includes(' ')) { dateObj = new Date(dateStr.replace(' ', 'T')); } } if (isNaN(dateObj.getTime())) { console.error('Invalid date format:', dateStr); return null; } return dateObj.toISOString(); } catch (error) { console.error('Date formatting error:', error); return null; } }