Openworkdays

A zero-signup business day calculator you can call directly from Claude or any MCP client. It exposes a single tool that handles three operations: add or subtract working days from a date, count business days between two dates, or check if a date is a business day. You pass your own holiday list as parameters, so it works for any calendar without needing a pre-built database. The entire thing runs as a stateless HTTP endpoint with no authentication, which makes it useful when you need date math in an agent workflow but don't want to deal with API keys or trust an LLM to count weekdays correctly. Self-hostable as two dependency-free Node functions.