grw—lab Studio

Accounting + Free · v0.1.0

VAT worksheet

Sums sales and purchase VAT from a CSV. VAT due is sales VAT minus purchase VAT. A worksheet, not a filed return.

  1. 01

    Add the catalog

    Open Claude Code and paste this line. Do this once. If you already added grw—lab for another skill, skip it.

    $ /plugin marketplace add grw-lab/skills

  2. 02

    Install VAT worksheet

    Paste this second line. It installs VAT worksheet and leaves the other skills out.

    $ /plugin install vat-worksheet@grw-lab

Every skill instead: use /plugin install grw-skills@grw-lab as line 2. On claude.ai, zip the vat-worksheet folder and upload it in Settings, then Capabilities, then Skills. In Cursor, point the agent at vat-worksheet/SKILL.md.

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VAT worksheet

What it does

Adds up sales VAT and purchase VAT from a CSV. VAT due is sales VAT minus purchase VAT. If a row already has a VAT figure, that figure is kept. 15% is used only when VAT is missing.

When to use it

A spreadsheet of invoices that needs one set of VAT totals before an accountant reviews it.

Install

This installs vat-worksheet only. The first line is once per machine.

/plugin marketplace add grw-lab/skills
/plugin install vat-worksheet@grw-lab

To install every grw—lab skill instead, use this as line 2:

/plugin install grw-skills@grw-lab

On claude.ai, zip this folder and add it under Settings, Capabilities, Skills. In Cursor, copy SKILL.md into the project skills folder.

Needs Python 3.9 or newer. No extra packages.

Usage

python scripts/vat_worksheet.py lines.csv --out summary.csv

kind is sale or purchase. Each row needs net or gross. Optional: vat, vat_rate (default 0.15), note.

Example

A sale of net 1000 with VAT 150, a purchase of net 200 with VAT left empty, and a sale whose gross is 115 become sales VAT 165.00, purchase VAT 30.00, and VAT due 135.00.

What's inside

scripts/vat_worksheet.py writes summary.csv with sales, purchases, VAT due, and the line count.

FAQ

Does this file the return? No. It is a worksheet. It is not a ZATCA submission and it is not tax advice.

Why not use the e-invoice skill? zatca-invoice builds one invoice and rounds by VAT category. This skill sums lines you already have.