Official MCP RegistryListed
Holiday Calendar
U.S. federal holidays with observed dates and business-day math. Example from an open-source kit.
First seen 12 Oct 2026. Evidence as of 22 Oct 2026.
5
Tools
From an anonymous probe
1
Source listings
Each with its own history
2
Recorded changes
Since first seen
Tools
| Tool | Description | Behaviour |
|---|---|---|
| add_business_days | Move a number of U.S. business days forward or backward from a date, skipping weekends and observed federal holidays, for due dates, delivery windows and notice periods. The start date is not counted: 1 business day after a Friday is the next Monday, or Tuesday when that Monday is a holiday. Returns the resulting date and every holiday it skipped. Up to 1,000 business days either way. | Read-only |
| check_business_day | Check whether a date is a U.S. business day (a weekday that is not an observed federal holiday). Returns the weekday, the holiday observed that day if any, and the business days just before and just after it. | Read-only |
| count_business_days | Count the U.S. business days between two dates, both dates included, leaving out weekends and observed federal holidays. Returns the business day count, the weekend days, and each holiday that fell in the span. Spans up to 3,660 calendar days. | Read-only |
| list_federal_holidays | List the eleven U.S. federal holidays for one calendar year (2021 through 2100): each holiday's name, its actual date and weekday, the date it is observed when it falls on a weekend (Saturday moves to the Friday before, Sunday to the Monday after), and the rule that sets it, from 5 U.S.C. 6103. Use it to answer which days federal offices close in a year. | Read-only |
| next_federal_holidays | Find the next one to eleven U.S. federal holidays observed on or after a date, with each one's observed date and how many calendar days away it is. Without from_date it starts from today's date in America/New_York and says which date it used. | Read-only |
Change history
- Repository changed (registry)
- Listed (registry)
| Source | Listing | First seen | Last seen | Versions |
|---|---|---|---|---|
| Official MCP Registry | com.modernmustardseed/holiday-calendar | 12 Oct 2026 | 22 Oct 2026 | 2 |