All servers · Tasks & projects

Holiday Calendar

com.modernmustardseed/holiday-calendar · v1.0.1

Measured by MCP Station

Last check	Reachable
Checked at	—
Check success 7 / 30 days	—
First-try success 30 days	—
Median response	—
Lookups 30 days	—
Authentication	No auth
MCP version	2025-06-18
Rank score	—
Declared risk	Read-only (all tools declare readOnlyHint)
Capabilities declared	tools
Tool definitions	5 tools · with description 100% · input schema is an object 100% · read/destructive hints 100%

U.S. federal holidays with observed dates and business-day math. Example from an open-source kit.

streamable-http · https://starter.modernmustardseed.com/holidays

claude mcp add --transport http holiday-calendar https://starter.modernmustardseed.com/holidays

{
  "mcpServers": {
    "holiday-calendar": {
      "url": "https://starter.modernmustardseed.com/holidays"
    }
  }
}

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
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.
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.
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
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.

Repository · Website · JSON · Text for agents · Registry updated 2026-10-12