MCP Time Server Node

# Time Addition with date-fns (Verified 2025-07-18) **Key Findings**: 1. **Addition Functions**: - Individual functions: `addYears()`, `addMonths()`, `addDays()`, `addHours()`, `addMinutes()`, `addSeconds()` - Generic function: `add()` accepts object with multiple units - All functions are immutable - return new Date objects - Negative values work for subtraction 2. **Month-end Handling**: - Jan 31 + 1 month = Feb 28 (or 29 in leap year) - Intelligently handles month boundaries - Mar 31 + 1 month = Apr 30 (not May 1) 3. **DST Behavior**: - Addition operations work in UTC internally - When displaying in timezone, DST is respected - Example: Adding 2 hours across spring DST shows correct local time jump 4. **Invalid Operations**: - `addDays(date, NaN)` returns Invalid Date - `addDays(date, Infinity)` returns Invalid Date - No exceptions thrown, just Invalid Date returned 5. **Timezone Context**: - Use `toDate(time, { timeZone: tz })` to interpret input in specific timezone - Addition happens in UTC - Use `formatInTimeZone()` to display result in desired timezone 6. **Input Handling**: - Date-only strings are parsed as midnight in system timezone - ISO with offset preserves the absolute time - Unix timestamps work after conversion to Date 7. **Unit Parameter Mapping**: ```typescript // For our API unit parameter: "years" → addYears() or { years: n } "months" → addMonths() or { months: n } "days" → addDays() or { days: n } "hours" → addHours() or { hours: n } "minutes" → addMinutes() or { minutes: n } "seconds" → addSeconds() or { seconds: n } ```