MCP Time Server Node

Instructions

Implementation Reference

• src/tools/getBusinessDays.ts:27-146 (handler)

  Core implementation of getBusinessDays tool handler. Parses dates, aggregates holidays from calendars and custom lists, categorizes days (business/weekend/holiday), applies weekend exclusion, caches results, and returns counts.
  export function getBusinessDays(params: GetBusinessDaysParams): GetBusinessDaysResult { const { start_date, end_date, holidays = [], holiday_calendar, custom_holidays = [] } = params; // Log entry with all parameters to show what was provided debug.business('getBusinessDays called with params: %O', { start_date, end_date, timezone: params.timezone, exclude_weekends: params.exclude_weekends, holiday_calendar, holidays_count: holidays.length, custom_holidays_count: custom_holidays.length, }); // Important: Log if no country parameter provided but holidays expected if (!holiday_calendar && holidays.length === 0 && custom_holidays.length === 0) { debug.validation('No holiday information provided (no country/calendar, no explicit holidays)'); } // Validate string lengths and array lengths first validateDateString(start_date, 'start_date'); validateDateString(end_date, 'end_date'); validateArrayLength(holidays, LIMITS.MAX_ARRAY_LENGTH, 'holidays'); validateArrayLength(custom_holidays, LIMITS.MAX_ARRAY_LENGTH, 'custom_holidays'); const excludeWeekends = params.exclude_weekends ?? true; const includeObserved = params.include_observed ?? true; const config = getConfig(); const timezone = resolveTimezone(params.timezone, config.defaultTimezone); debug.timezone('Resolved timezone: %s (from: %s)', timezone, params.timezone ?? 'default'); // Build cache key using new utility const cacheKey = buildCacheKey('business', { single: { timezone }, dates: [start_date, end_date], flags: { excludeWeekends, includeObserved }, arrays: { holidays, customHolidays: custom_holidays }, optional: { calendar: holiday_calendar }, }); // Use withCache wrapper return withCache(cacheKey, CacheTTL.BUSINESS_DAYS, () => { // Validate timezone if provided if (timezone && !validateTimezone(timezone)) { debug.error('Invalid timezone: %s', timezone); throw new TimezoneError(`Invalid timezone: ${timezone}`, timezone); } // Validate holiday_calendar if provided if (holiday_calendar) { validateHolidayCalendar(holiday_calendar); } // Parse dates const startDate = parseDateWithTimezone(start_date, timezone, 'start_date'); const endDate = parseDateWithTimezone(end_date, timezone, 'end_date'); // DoS protection: Validate date range validateDateRange(startDate, endDate, start_date, end_date); // Log calculation context debug.business( 'Business days calculation: %s to %s', format(startDate, 'yyyy-MM-dd'), format(endDate, 'yyyy-MM-dd') ); // Use the new holidayAggregator utility debug.holidays('Aggregating holidays for calendar: %s', holiday_calendar ?? 'none'); const allHolidayDates = aggregateHolidays({ calendar: holiday_calendar, includeObserved, dateRange: { start: startDate, end: endDate, }, custom: custom_holidays, legacy: holidays, timezone, }); debug.holidays('Total holidays found: %d', allHolidayDates.size); if (allHolidayDates.size > 0) { debug.holidays('Holiday dates: %O', Array.from(allHolidayDates)); } // Get all days in the interval const days = eachDayOfInterval({ start: startDate, end: endDate, }); debug.timing('Processing %d days from %s to %s', days.length, start_date, end_date); // Categorize days into business, weekend, and holiday const categories = categorizeDays(days, allHolidayDates); // Adjust for weekend inclusion preference const adjustedCategories = adjustForWeekends(categories, excludeWeekends); const { businessDays, weekendDays, holidayCount } = adjustedCategories; // Log summary debug.business( 'Calculated business days: %d of %d total days (%d weekends, %d holidays)', businessDays, days.length, weekendDays, holidayCount ); const result: GetBusinessDaysResult = { total_days: days.length, business_days: businessDays, weekend_days: weekendDays, holiday_count: holidayCount, }; return result; }); }
• src/types/index.ts:95-110 (schema)

  TypeScript interfaces defining input parameters (GetBusinessDaysParams) and output structure (GetBusinessDaysResult) for the get_business_days tool.
  export interface GetBusinessDaysParams { start_date: string; end_date: string; exclude_weekends?: boolean; holidays?: string[]; timezone?: string; holiday_calendar?: string; include_observed?: boolean; custom_holidays?: string[]; } export interface GetBusinessDaysResult { total_days: number; business_days: number; weekend_days: number; holiday_count: number;
• src/index.ts:133-156 (registration)

  MCP tool registration in TOOL_DEFINITIONS array: defines name 'get_business_days', description, and inputSchema for the listTools endpoint.
  name: 'get_business_days', description: 'Calculate business days between dates', inputSchema: { type: 'object' as const, properties: { start_date: { type: 'string' as const, description: 'Start date' }, end_date: { type: 'string' as const, description: 'End date' }, exclude_weekends: { type: 'boolean' as const, description: 'Exclude weekends (default: true)', }, holidays: { type: 'array' as const, items: { type: 'string' as const }, description: 'Array of holiday dates', }, timezone: { type: 'string' as const, description: 'Timezone for calculation (default: system timezone)', }, }, required: ['start_date', 'end_date'], }, },
• src/index.ts:266-267 (registration)

  Mapping in TOOL_FUNCTIONS object that connects the 'get_business_days' tool name to the getBusinessDays handler function for execution.
  get_business_days: (params: unknown) => getBusinessDays(params as Parameters<typeof getBusinessDays>[0]),