tax-calculator

tax-calculator is a skill for Claude Code from dithiothreitol/jdg-ksiegowy. It costs 140 tokens per session (713 once invoked), scanned A, original, MIT.

A tax calculator for a Polish sole trader using ryczałt, a tax scheme based on revenue rather than profit. It calculates VAT, ryczałt, monthly health insurance for ZUS, and payment deadlines from an invoice or monthly revenue.

In plain words
What is it for?
Use it to estimate tax and ZUS from a net amount, check VAT or ryczałt rates, calculate the monthly total, and find the payment deadlines.
Why use it?
It replaces separate manual calculations for the main amounts due and accounts for the annual-revenue threshold used for the health-insurance estimate. It also separates the usual 20th and 25th payment dates.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python3 skills/tax-calculator/scripts/calculate.py --netto 10500.

Good fit Use it to estimate tax and ZUS from a net amount, check VAT or ryczałt rates, calculate the monthly total, and find the payment deadlines.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/dithiothreitol/jdg-ksiegowy
agentmods
npx agentmods add skills/dithiothreitol/jdg-ksiegowy/tax-calculator

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for tax-calculator

README.md
[![agentmods](https://agentmods.dev/badge/skills/dithiothreitol/jdg-ksiegowy/tax-calculator/github.svg)](https://agentmods.dev/skills/dithiothreitol/jdg-ksiegowy/tax-calculator)
Your own site
<a href="https://agentmods.dev/skills/dithiothreitol/jdg-ksiegowy/tax-calculator"><img src="https://agentmods.dev/badge/skills/dithiothreitol/jdg-ksiegowy/tax-calculator/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for tax-calculator

Your own site · 80×15
<a href="https://agentmods.dev/skills/dithiothreitol/jdg-ksiegowy/tax-calculator"><img src="https://agentmods.dev/badge/skills/dithiothreitol/jdg-ksiegowy/tax-calculator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 140 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 713 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00140 $0.00713
Opus 5 $0.00070 $0.00357
Sonnet 5 $0.00028 $0.00143
Haiku 4.5 $0.00014 $0.00071

Measured 12d ago against content hash b20a19a2de5a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

tax-calculator scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/tax-calculator/SKILL.md · 63 lines

What it actually says

Kalkulator podatkowy JDG (ryczałt)

Liczy podatki z pojedynczej faktury lub z miesięcznego przychodu.

Wymagane dane

  • netto — kwota netto w PLN

Opcjonalnie:

  • vat-rate — domyślnie 23
  • ryczalt-rate — domyślnie 12
  • annual-revenue — szacunkowy roczny przychód (do wyznaczenia progu ZUS); jeśli nie podasz, skrypt zakłada netto * 12
  • month, year — domyślnie bieżący

Wywołanie

python3 skills/tax-calculator/scripts/calculate.py --netto 10500

Z pełnym kontekstem:

python3 skills/tax-calculator/scripts/calculate.py \
  --netto 10500 --vat-rate 23 --ryczalt-rate 12 --annual-revenue 126000

Zwraca JSON na stdout:

{
  "netto": "10500",
  "vat_rate": "23%",
  "vat_amount": "2415.00",
  "brutto": "12915.00",
  "ryczalt_rate": "12%",
  "ryczalt_amount": "1260.00",
  "zus_health_monthly": "...",
  "zus_tier": "...",
  "zus_deductible_monthly": "...",
  "estimated_annual_revenue": "126000",
  "deadlines": {
    "ryczalt_zus": "2026-05-20",
    "vat_jpk": "2026-05-25"
  },
  "total_monthly_tax": "..."
}

Po obliczeniu

Pokaż userowi w czytelnej tabeli (nie surowy JSON): VAT, ryczałt, ZUS zdrowotne, łącznie do zapłaty + dwa terminy. Zaznacz że kwota ZUS to składka zdrowotna (społeczne nie liczone — zakładamy stałą stawkę).

Uwagi

  • Wszystkie kwoty jako Decimal — nigdy float.
  • Próg ZUS jest wyliczany w src/jdg_ksiegowy/tax/zus.py (single source of truth) — nie hardkoduj progów.
  • Stawka ryczałtu 12% jest domyślna dla JDG IT/konsulting; jeśli user ma inną branżę — dopytaj.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 12d ago First seen · 63 lines · 0 tokens per session scan A b20a19a2de5a

Subscribe to this mod's changes

tax-calculator is a skill published in the GitHub repository dithiothreitol/jdg-ksiegowy (5 stars, last pushed 1mo ago), licensed MIT. It adds 140 tokens to every session and 713 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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