Holiday Calendar for Claude.ai

com.modernmustardseed/holiday-calendar

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

client:Claude.ai transport:streamable-http tools:5

Install Holiday Calendar in Claude.ai

Settings → Connectors → Add custom connector

https://starter.modernmustardseed.com/holidays

Claude on the web takes a remote URL and completes OAuth in the browser. For a packaged server use Claude Desktop or Claude Code instead. Claude.ai docs

What Claude.ai can do once it is connected

list_federal_holidays
next_federal_holidays
check_business_day
add_business_days
count_business_days

Holiday Calendar in other clients

Claude Code
Claude Desktop
Cursor
VS Code
Zed
Windsurf
Cline
Gemini CLI
Grok
ChatGPT
LangChain

Holiday Calendar MCP server