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mcp/harbor
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Holiday Calendar MCP

v1.0.0

com.modernmustardseed/holiday-calendar

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

transport:streamable-http tools:5
Website

Target client

run in your project directory 

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

setup guides: Claude Code Claude Desktop Cursor VS Code Zed Windsurf Cline Gemini CLI Grok ChatGPT Claude.ai LangChain

Adds it for this project only. Append --scope user to make it available everywhere. Claude Code docs

list_federal_holidays Read-only

list federal holidays

next_federal_holidays

next federal holidays

check_business_day Read-only

check business day

add_business_days Mutating

add business days

count_business_days Read-only

count business days

All 5 tools, one page each

Mutating and Read-only are read off each tool's name, not its schema — a hint, not a guarantee. Check the server's own documentation before granting access.