How to Build Holiday-Aware Calendars with Claude
Build holiday-aware calendars with Claude and ToolRouter. Accurate working-day calculations for any country.
Tool
Claude builds holiday-aware business calendars with analytical precision, calculating working days per period while accounting for weekends and country-specific holidays. It asks about your fiscal calendar and industry conventions to produce working-day counts matching your actual business operations rather than generic calculations.
Connect ToolRouter to Claude
1Go to Settings → Connectors → Add custom connector
2Enter the details below and click Add
Name
ToolRouterURL
https://api.toolrouter.com/mcp3Done — works on Claude chat, desktop, and mobile
Steps
Once connected (see setup above), use the Public Holidays tool:
- Ask Claude: "Get all public holidays for the US in 2026 using public-holidays"
- Claude returns the complete holiday list
- Ask: "Calculate the number of working days in each month, excluding weekends and these holidays"
- Use the working-day counts in your planning or application
Example Prompt
Try this with Claude using the Public Holidays tool
Get US public holidays for 2026. Then calculate working days per month excluding weekends and holidays. I need this for our project scheduling system.
Tips
- Ask Claude to output the data in a format your scheduling tool can import
- Generate calendars for multiple countries and compare working-day counts
- Update your calendar data annually by re-running the query for the new year