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Oarsman AI

Agents / Finance & ops / India small business

GST Invoice Sheet

Make GST tax invoices in bulk from a CSV, with automatic CGST, SGST or IGST, round off and amount in words. Includes an Excel/Sheets template. Free forever

Free forever Format: Claude skill + Excel template#Finance & ops#India small business#Claude skill packs

FreeComing soon · get notified

Free 

Free foreverBeing packaged

Coming soon · get notified

Coming soon. Follow Oarsman AI on Gumroad and you'll get an email when it launches. It will sell through Gumroad, with a 14-day refund.

See it work

How GST Invoice Sheet moves through a job, step by step. The run below is an example output, written from what this agent does. It isn't a live run on your data.

Seller + buyerLine itemsGST mathsInvoice sheetYou sendSeller + buyerLine itemsGST mathsInvoice sheetYou send

Sample input

Seller details CSV (name, GSTIN, address, optional bank/UPI/terms)

Example output Illustration

You get:
- invoices/<number>.html, one printable tax invoice each (print to PDF)
- invoice-register.csv and hsn-summary.csv for GSTR-1
- checks.csv and report.md listing errors and warnings
- gst-invoice-template.xlsx for Excel or Google Sheets (in samples/)

What you get

  • Planned contents (not released yet):
  • Skill folders you add to Claude
  • A Python script behind each skill, so numbers are calculated, not guessed
  • Sample data and the test suite, so you can check it yourself

What it does

  • invoices/<number>.html, one printable tax invoice each (print to PDF)
  • invoice-register.csv and hsn-summary.csv for GSTR-1
  • checks.csv and report.md listing errors and warnings
  • gst-invoice-template.xlsx for Excel or Google Sheets (in samples/)

Tools and costs you'll need

  • Claude.ai with code execution, or Claude Code
  • Python 3.10+ (standard library only)
  • Excel, Google Sheets or LibreOffice for the template
  • Any browser to print invoices to PDF

Third-party costs are paid to those providers, not to us.

Test report

40/40 automated checks pass on Python 3.13.5 (standard library only); 15 cases incl. invalid input, duplicates and upstream failures. Not tested: printing from a browser (the invoice HTML is generated and checked in tests, not printed); the template in Apple Numbers; composition-scheme bills of supply.

Known limits

  • Not tested yet: printing from a browser (the invoice HTML is generated and checked in tests, not printed); the template in Apple Numbers; composition-scheme bills of supply.
  • Not on sale yet: it goes on Gumroad once checkout is live. Follow to hear when.

Live demo

  • No live demo yet. We'll add one when it ships.

Demos use fictional businesses and data.

Related paid agents

GST Invoice Sheet stays free forever. If you want to go further, these paid agents do related work.

What's AI here, and what isn't

This is an AI agent: it uses an AI model to read, sort, score or draft. It runs in your own accounts. Anything it would send outside your business waits for your approval unless you choose otherwise, and it never needs your passwords. Our AI disclosure.

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Questions about GST Invoice Sheet

What does GST Invoice Sheet do?

Make GST tax invoices in bulk from a CSV, with automatic CGST, SGST or IGST, round off and amount in words. Includes an Excel/Sheets template. Free forever invoices/<number>.html, one printable tax invoice each (print to PDF). invoice-register.csv and hsn-summary.csv for GSTR-1. checks.csv and report.md listing errors and warnings. gst-invoice-template.xlsx for Excel or Google Sheets (in samples/).

What do I need to run GST Invoice Sheet?

You need: Claude.ai with code execution, or Claude Code; Python 3.10+ (standard library only); Excel, Google Sheets or LibreOffice for the template; Any browser to print invoices to PDF. Third-party costs are paid to those providers, not to us.

Is GST Invoice Sheet tested?

40/40 automated checks pass on Python 3.13.5 (standard library only); 15 cases incl. invalid input, duplicates and upstream failures. Not tested: printing from a browser (the invoice HTML is generated and checked in tests, not printed); the template in Apple Numbers; composition-scheme bills of supply.

How do I get GST Invoice Sheet?

It isn't on sale yet. It's planned at Free on Gumroad, with a 14-day refund. Press "Get notified" to follow us on Gumroad and hear when it launches.

How does it decide CGST + SGST or IGST?

From the state codes: your GSTIN's first two digits versus the place of supply. Same state means CGST + SGST (or UTGST); different means IGST.

Can I use it without Claude or Python?

Yes. Open samples/gst-invoice-template.xlsx in Excel or Google Sheets. The tax split and totals are formulas.

Does it make e-invoices?

No. It makes regular tax invoices. If your turnover requires e-invoicing, generate the IRN on the government portal.

Is it really free?

Yes, free forever, no account and no cap besides 500 invoices per run.

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