bartosz-kuc/honest-pl-holidays-mcp

Local MCP server for Polish public holidays and business-day arithmetic. Wraps the open Nager.Date holiday database and adds bookkeeping-friendly business-day math on top.
Part of the honest-mcp family of small, auditable, local-first MCP servers.
## Why
Every Polish accountant, JDG owner, or HR person has this problem:
"Payment term is 14 dni roboczych from invoice date — what's the actual due date?"
"Is the client's 'termin płatności 2026-05-01' even a business day? (No — that's Święto Pracy.)"
"Deadline for JPKV7 is the 25th — but 2026-04-25 is a Saturday, does it slip to Monday?"
This server hands both raw holiday data and business-day arithmetic to your AI. No more spreadsheet calendars.
Supports any country Nager.Date covers (200+), but the API defaults to Poland and the bookkeeping angle is Poland-centric.
Weekend caveat: the weekend is always Saturday + Sunday, whatever country you pass — only the holiday list changes per country. Business-day results for countries with a different weekend (e.g. Friday–Saturday in Egypt) will be wrong.
## Features
Six tools:
listholidays — all public holidays in a given year
isholiday — is this specific date a public holiday?
isbusinessday — is this date Mon–Fri and not a holiday? Includes reason (weekend / holiday / businessday)
countbusinessdays — inclusive business-day count between two dates
addbusinessdays — startdate + N business days = ? (N can be negative)
nextholidays — upcoming N holidays from a given date
## Data source
Endpoint: date.nager.at/api/v3
No API key
MIT-licensed holiday data
In-memory cache per year and country — normally one round trip per year and country per session
## Requirements
Python 3.10+
## Setup
bash
git clone https://github.com/bartosz-kuc/honest-pl-holidays-mcp.git
cd honest-pl-holidays-mcp
python3 -m venv venv
./venv/bin/pip install -r requirements.txt
On Windows, use venv\Scripts\pip and venv\Scripts\python instead of venv/bin/pip and venv/bin/python (here and in the configs below).
Register with Claude Code:
bash
claude mcp add pl-holidays /absolute/path/to/venv/bin/python /absolute/path/to/server.py
Claude Desktop claudedesktopconfig.json:
json
"mcpServers": {
"pl-holidays": {
"command": "/absolute/path/to/venv/bin/python",
"args": ["/absolute/path/to/server.py"]
## Example usage
> "Invoice issued today with 14 working-day payment term — when is it due?"
addbusinessdays(startdate="2026-07-22", days=14) → the due date, skipping weekends and Polish public holidays.
> "How many working days between 2026-04-01 and 2026-04-30?"
countbusinessdays(fromdate="2026-04-01", todate="2026-04-30")
> "Is May 1st 2026 a business day in Poland?"