UK Accounting — Chameleon AI

Double-Entry Ledger

Every transaction balanced to the penny — debits always equal credits

Date │ Account │ Debit (£) │ Credit (£) │ VAT ────────────┼──────────────────────────┼───────────┼────────────┼──── 2026-04-01 │ 4000 Sales Revenue │ │ 1,200.00 │ S20 2026-04-01 │ 2200 VAT Control │ │ 240.00 │ 2026-04-01 │ 1100 Trade Debtors │ 1,440.00 │ │ ────────────┼──────────────────────────┼───────────┼────────────┼──── 2026-04-05 │ 6100 Office Expenses │ 85.00 │ │ S20 2026-04-05 │ 2200 VAT Control │ 17.00 │ │ 2026-04-05 │ 1200 Bank Current │ │ 102.00 │

📚

UK Chart of Accounts

Standard UK account codes out of the box — assets, liabilities, equity, income and expenses mapped to HMRC categories. Extend with custom accounts as needed.

🗄️

SQLite ledger

All data stored in ~/.chameleon/accounting/<company>/ledger.db. Runs completely offline. Multiple company support — switch between entities with a command flag.

📅

UK tax year

Year-end correctly set to 5 April (UK fiscal year 6 Apr – 5 Apr). P&L and VAT reports automatically span the correct period without manual date adjustment.

🔍

Forensic anomaly scan

Run --forensic to detect unbalanced entries, duplicate references, VAT mismatches and other irregularities. Results printed as structured JSON for AI review.

🤖

AI-readable output

All reports output structured JSON to stdout so the Chameleon AI can parse, summarise and advise on your financial position in natural language.

🌐

WebSocket bridge

The accounting WebSocket bridge (acct_ws_bridge.py) exposes ledger queries to the mobile companion and external dashboards over your Tailscale network.

VAT Codes Supported

S20

Standard rate 20%

Reduced rate 5%

Zero-rated

Exempt

Out of scope

Reports

📈

Profit & Loss

Income vs expenses for the period. Sales, cost of goods, gross profit, operating expenses, net profit — all broken down by account code. Run with --report pl.

⚖️

Balance Sheet

Assets, liabilities and equity at a point in time. Confirms double-entry integrity — assets must equal liabilities plus equity. Run with --report bs.

🧾

VAT Return Summary

Box-by-box VAT figures matching the HMRC MTD VAT return format: Box 1 (output tax), Box 4 (input tax), Box 6 (net sales), Box 7 (net purchases). Run with --report vat.

CLI Quick Reference

Command	Description
`python3 chameleon_accounting.py --report pl`	Profit & Loss for current tax year
`python3 chameleon_accounting.py --report bs`	Balance Sheet as of today
`python3 chameleon_accounting.py --report vat`	VAT return summary (MTD boxes)
`python3 chameleon_accounting.py --forensic`	Anomaly & integrity scan
`python3 chameleon_accounting.py --help`	Full command reference

Streamline your UK bookkeeping

Purpose-built for freelancers and small businesses operating under UK tax rules.

Get in touch ← Back to overview