New from eTail Support

Meet Luca BETA
Your AI Accounts
Department

The free, open-source AI that replaces your accounts department — built on Claude Co-Work. Luca works 24/7, keeping your books reconciled, your VAT return ready to file and your P&L live in real time — so you can focus on running your business. Download from GitHub, or get fully hosted for £20/month. Requires a Claude Co-Work Pro subscription (from $20/month).

Get Hosted Luca — £20/month Free on GitHub
Free
Open source on GitHub
£20
Per month hosted plan
+ Claude Co-Work Pro from $20/mo
£500+
Custom solutions from £500/mo
Tailored to your business
Integrates with amazon eBay Shopify WooCommerce Etsy Magento PayPal
BETA Open Source
What Luca Does

Your AI Accounts Department

Luca handles the bookkeeping work so you can focus on running your business. Free to download and self-host — or let us run it for you.

Automated Bookkeeping

Luca categorizes every transaction using AI and posts double-entry journal entries automatically. No manual data entry. No errors. No backlog.

Bank Reconciliation

Connect your bank and Luca automatically matches every statement line to its ledger entry. 100% reconciled, every day, without you touching it.

VAT Returns

Luca calculates your UK VAT return automatically, quarter by quarter. Always ready to file — no last-minute scrambles, no missed deadlines.

Financial Reporting

Real-time P&L, balance sheet, cashflow and aged debtors/creditors. CFO-level insight available 24/7 — without the CFO salary.

See All Luca Features →
How Luca Works With You

Luca Gets to Know Your Business — Then Keeps Learning

Luca isn't a one-size-fits-all bookkeeping tool. Like a good human accountant, Luca takes the time to understand your business first — then gets more useful the longer he works with you.

Step 1

Researches Your Business

Before Luca posts a single entry, he does the research a new accountant would. Luca reads your website, asks you a few questions about what you sell, who your customers are, where your margin comes from, and how your operations run — so he starts with real context about your business, not a generic template.

Step 2

Learns As He Works

Every invoice Luca processes, every bank line he reconciles, every expense he categorises adds another piece to his picture of your business. He learns your suppliers, your customers, your product mix, your seasonality — just like a long-serving human accountant would build up knowledge over time.

Step 3

Gets More Useful Over Time

As Luca's knowledge of your business deepens, his value grows with it. He spots anomalies faster, answers your questions with business-specific context, and surfaces insights that actually matter to you — not generic commentary. Luca becomes your accountant, not just an accountant.

The human-accountant parallel matters. A good accountant who knows your business for three years is worth far more than one who started last week. Luca works the same way — the longer he's with you, the more he's worth.

Luca BETA Open Source

Meet Luca BETA — Your AI
Accounts Department

Luca is completely free and open-source and built on Claude Co-Work. Download from GitHub, or let us run it for you for just £20/month. Either way, an active Claude Co-Work Pro subscription (from $20/month) is required.

⚠ BETA software — Luca is currently in active development. It is functional and available to use, but is not yet a fully production-ready release. We strongly encourage you to talk to us about customization to make it perfect for your business.

  • Automated bookkeeping and bank reconciliation
  • VAT return preparation and submission
  • Real-time P&L, balance sheet and cashflow
  • CFO-level insight without the CFO salary

⭐ Free download on GitHub · Customization packages from £500 · Talk to us

Open Architecture

How Luca Works Under the Hood

Luca is built on a clean separation of concerns: AI reasoning, accounting logic, and data persistence are three distinct layers. Here is the full stack, from user intent down to cryptographic audit trail.

Read the full source code on GitHub — and ⭐ star if it's useful
Layer 1 — User Interface
Business User
Conversational interaction, document upload, approvals
C
Layer 2 — AI Runtime
Claude Co-Work Pro subscription required — from $20/mo
AI reasoning engine · natural language understanding · tool orchestration · context management
Layer 3 — Skills (Luca's Domain Logic)
lucas-general-ledger
Conversational accounting, insights, orchestration
gl-document-posting
Document ingestion, classification & journal generation
Scheduled Batch Runner
Nightly reconciliation, FX revaluation, VAT prep
Layer 4 — MCP Tool Layer (40+ GL operations exposed to Claude)
gl_post_transaction gl_reconcile_bank_account gl_get_vat_return gl_import_bank_statement gl_get_profit_and_loss gl_get_balance_sheet gl_approve_transaction gl_fx_revaluation gl_get_merkle_proof gl_verify_chain gl_hard_close_period gl_get_aged_debtors gl_get_aged_creditors gl_year_end_close gl_scan_inbox gl_get_trial_balance + 24 more
Layer 5 — Accounting Engine
Double-entry engine · business rule enforcement · VAT calculation · FX revaluation · period management
Layer 6 — Persistence
PostgreSQL
Journal entries · accounts · balances · documents
Audit Trail
Cryptographically linked · tamper-evident · provable integrity
Separation of Concerns

The AI layer and the accounting engine are fully decoupled. The GL REST API enforces accounting rules independently of Claude — a malformed posting is rejected at the API level, not by the AI.

Constrained Tool Access

Claude can only interact with the ledger through the 40+ typed MCP tools. It cannot issue arbitrary SQL or modify the database schema. Every accounting action goes through a defined, auditable interface.

Tamper-Evident Ledger

Every journal entry is cryptographically linked to the previous one via a Merkle Chain. Any modification to historical data — even directly in the database — breaks the chain and is immediately detectable.

The complete source code — GL API, MCP server, Skill definitions — is public and MIT licensed.

⭐ Star Luca on GitHub Read the Full Glossary →

Start Using Luca Today

Three ways to get started — download free from GitHub, go live on the hosted plan for £20/month, or commission a custom build from £500. Note: a Claude Co-Work Pro subscription (from $20/month, billed separately by Anthropic) is required to use Luca.

Free on GitHub Get Hosted — £20/month Custom Build — from £500

Call us: +44 1227 39 0441  ·  Email: luca@etailsupport.com