MCP Time Server Node

# Duration Calculation with date-fns (Verified 2025-07-18) **Key Findings**: 1. **Difference Functions**: - `differenceInMilliseconds()`, `differenceInSeconds()`, `differenceInMinutes()`, `differenceInHours()`, `differenceInDays()` - All return integers (truncated, not rounded) - Negative values when end is before start - Order matters: `differenceInX(end, start)` 2. **Truncation Behavior**: - 30 minutes = 0 hours (not 0.5) - 1.5 days = 1 day (not 2) - Always rounds down to nearest integer 3. **Timezone Handling**: - Duration calculations work on absolute time (UTC) - Times with different timezone representations but same absolute time have 0 duration - Use `toDate(time, { timeZone })` to interpret local times in specific timezone 4. **DST Considerations**: - Duration respects actual time elapsed, not wall clock time - Example: 00:00 to 05:00 across spring DST = 4 actual hours (not 5) 5. **Input Parsing**: - Date-only strings parsed as midnight in system timezone - ISO with offset preserves absolute time - No timezone = system timezone interpretation 6. **Human-Readable Formatting**: - `formatDistance()` provides approximate strings ("about 1 year", "1 day") - Options: `includeSeconds`, `addSuffix` - For precise formatting, manual calculation needed 7. **Unix Timestamp Support**: - Convert to Date objects first: `new Date(unix * 1000)` - Then use standard difference functions