OpenAccountants MCP Server

Open-source tax skills for AI across 134 countries — VAT/GST, income tax, social contributions. pip install openaccountants-mcp

GitHub

Documentation

OpenAccountants

Open-source accounting skills for AI. 890+ skills across 134 countries + 51 US state packages + 13 Canadian province/territory packages.

11 accounting domains: tax, bookkeeping, e-invoicing, payroll, company formation, financial statements, transfer pricing, tax optimization, crypto tax, cross-border, plus industry verticals and platform integrations.

⚠️ Important — what's in this repo and what isn't

OpenAccountants runs on a two-layer model:

Layer	Where it lives	Quality tier	How to get it
Research drafts (rules, rates, thresholds, workflow bases)	This GitHub repo	Tier 2 — research-verified, AI-drafted, not signed by a credentialed accountant	Clone, fork, audit, contribute. Use freely under the AGPL-3.0 / commercial dual license.
Accountant-verified skills (signed off by a named licensed CPA / CA / EA / Steuerberater / equivalent)	The website + MCP server at openaccountants.com	Tier 1 — corrections applied, audit flash points reviewed, verifier name on every output	Install the MCP connector at openaccountants.com/connect. Your AI loads them automatically with the verifier's name on every answer.

Why split? The skill rules (rates, thresholds, statutes) are public domain restructured — those live here, open. The verified version of record — corrected by a named accountant, with their reputation on it — is served via the MCP so the AI-to-human handoff (request_accountant_review) can route users to a real CPA. That handoff is the product. The repo is the research base.

To USE OpenAccountants: install the MCP connector at openaccountants.com/connect — works with Claude.ai, ChatGPT, Cursor, Windsurf, and any other MCP-aware AI client.

To CONTRIBUTE or AUDIT: you're in the right place. Open issues, submit PRs, verify your jurisdiction.

Website: openaccountants.com · Install: openaccountants.com/connect · Verifiers: openaccountants.com/network

👉 Start here

New to this repo? Read START-HERE.md — it has a table of scenarios ("I'm a freelance developer in California", "I sell on Etsy", "I'm worried about Pillar Two", etc.) and tells you exactly which files to upload and what to say to the AI.

If you just want to dive in, pick your jurisdiction:

You are…	Go to
Freelancer / sole prop in a country	`packages/<country>/` (e.g. `malta`, `germany`, `uk`)
US-based — freelancer or single-member LLC	`packages/us-<state>/` (e.g. `us-ca`, `us-ny`, `us-tx`)
Canada-based — sole prop	`packages/ca-<province>/` (e.g. `ca-on`, `ca-qc`, `ca-bc`) — federal + provincial bundled. If absent, run `python3 scripts/build-packages.py` to (re)generate them.
Cross-border or sector-specific (SaaS, banking, REIT, etc.)	`skills/cross-border/` and `skills/verticals/`

Two ways to use OpenAccountants

Method	What you get	Best for
MCP connector (recommended)	All accountant-verified skills, with named-verifier attribution and the AI-to-human handoff (`request_accountant_review` routes to a real CPA with your worksheet attached). Install at openaccountants.com/connect.	Anyone who actually wants to use OpenAccountants. Claude.ai, ChatGPT (paid Business+), Cursor, Windsurf, Claude Desktop, Claude Code, or any MCP-aware client.
Manual upload from this repo	Only the research-verified drafts in this repo (no verifier name, no handoff). Download a folder, drag `.md` files into your LLM.	Developers / accountants who want to audit, fork, or contribute to the open library before installing.

The MCP path is the canonical product. This repo is the open research base that backs it.

Known limitations

Read this before you trust any output.

LLMs hallucinate and misread. These files steer the model; they do not guarantee correct numbers, classifications, or filings. Always have a qualified professional review before you act.
Tax law changes. Rates, thresholds, and forms go out of date. The repo is a snapshot; openaccountants.com may be ahead of what you cloned.
Verification is in two tiers — see QUALITY-TIERS.md. Accountant-verified (Tier 1) means a licensed practitioner has signed off and put their name on the skill. These are served only via the MCP server at openaccountants.com — not from this repo. Research-verified (Tier 2) means every rate, threshold, and form reference has been drafted from authoritative sources but not yet signed off by a credentialed practitioner. This repo holds the Tier 2 drafts; the Tier 1 signed versions live in the database behind the MCP server.
Coverage is uneven. Thirteen countries ship the full accounting suite (tax + bookkeeping + payroll + formation + financial statements + transfer pricing + tax optimization) in this repo; dozens more have multiple skills without that full stack; many jurisdictions are VAT/GST-only or partial. See Coverage below and each country folder's README.
Newer domains need more eyes. Bookkeeping, payroll, formation, financial statements, transfer pricing, and tax optimization skills are research-verified but have fewer accountant sign-offs than the core tax skills. Help us close that gap.

Honesty is the point: if you know where the gaps are, you can use the project safely. Skeptics welcome.

Quick start (60 seconds)

1. Find your country

Everything you need is in one folder under packages/. Upload every file in that folder.

packages/
├── malta/           ← 23 files (tax + bookkeeping + payroll + formation + financial statements + TP + optimization)
├── uk/              ← ~20 files
├── germany/         ← ~25 files (the fullest)
├── ... 130+ more countries
├── us-ca/           ← Federal + California state skills
├── us-ny/           ← Federal + New York state skills
├── us-tx/           ← Federal + Texas state skills
├── ... 51 US state packages (all 50 states + DC)
├── ca-on/           ← Federal Canadian + Ontario provincial skills
├── ca-qc/           ← Federal Canadian + Quebec provincial skills (incl. QST)
├── ca-bc/           ← Federal Canadian + British Columbia provincial skills
├── ... 13 Canadian province/territory packages (all 10 provinces + 3 territories)
├── canada/          ← Index README only; per-province packages live in ca-<code>/

Canadian packages are generated. If packages/ca-on/, ca-qc/, etc. are missing in your checkout, run python3 scripts/build-packages.py once to materialise them. The script also regenerates the rest of packages/ from source files under skills/.

Also available: _cross-border/ (37 skills), _verticals/ (14 industry skills), _integrations/ (10 platform skills)

International users: pick your country folder (e.g. packages/malta/).

US users: pick packages/us-[your state code]/ (e.g. packages/us-ca/ for California). Each state package bundles federal skills (Schedule C, SE, QBI, estimated tax, etc.) plus your state's income tax, sales tax, and specialty taxes. See the US state index for the full list, or the source coverage matrix for what each state includes.

Canadian users: pick packages/ca-[your province code]/ (e.g. packages/ca-on/ for Ontario, packages/ca-qc/ for Quebec). Each province/territory package bundles the federal Canadian skills (T1, T2125, CPP/EI, GST/HST, T1135, instalments, crypto, bookkeeping, payroll, formation, financial statements, transfer pricing, tax optimization) plus your province/territory's income tax (and QST for Quebec). If the ca-* folders aren't present in your checkout, run python3 scripts/build-packages.py once. See the Canada index for the full list.

For MCP users, US state and Canadian province packages appear as us-ca, us-tx, ca-on, ca-qc, etc. alongside country packages.

Contributors: all packages are generated from source files under skills/ by scripts/build-packages.py. Edit the source, not the package. See CONTRIBUTING.md.

2. Upload to your LLM

Open the folder for your jurisdiction under packages/. Upload all .md files.

Upload to:

Claude.ai → Create a Project, add files as Project Knowledge
ChatGPT → Attach files to a conversation or create a Custom GPT
Any other LLM → Attach or paste the files

3. Attach your bank statement and go

Say any of:

Help me with my 2025 taxes. Here's my bank statement.
Help me set up a company in Malta.
Run my payroll for this month.
Prepare my annual accounts.
Optimize my tax — what deductions am I missing?
Check my invoice compliance for EU e-invoicing.

The AI will ask a few questions, load the right skills, and produce a working paper for your accountant.

Are you an accountant?

These skills need your eye. Most are research-verified — drafted from authoritative sources (tax-authority publications and primary legislation) but awaiting credentialed sign-off. Your review moves them to accountant-verified.

You don't need to use GitHub. Just:

Find your country's folder under packages/
Check the rates against your tax authority's website
Email your corrections to [email protected] — Word doc, Excel, PDF, tracked changes, whatever format works for you

We'll update the skill and credit you publicly as the verified reviewer at openaccountants.com.

Or if you prefer GitHub: fork, fix, PR. Your name goes on the skill either way.

134 countries need accountant reviewers. Pick yours at packages/ and be the first verified professional for your jurisdiction.

What's in each package

Every country folder contains:

File	What it does	Same everywhere?
`foundation.md`	Tells the AI HOW to work — conservative defaults, output format, classification contract	Yes
`intake.md`	Onboarding questions, refusal checks, document inference	Yes (country name filled in)
`[country]-vat.md`	VAT/GST/sales tax rules, supplier pattern library, form mappings	No — country-specific
`[country]-income-tax.md`	Income tax brackets, deductions, transaction patterns	No — country-specific
`[country]-ssc.md`	Social security / pension contributions	No — country-specific
`[country]-bookkeeping.md`	Chart of accounts, P&L/balance sheet format, expense classification	No — 13 countries
`[country]-einvoice.md`	E-invoicing format, mandatory fields, transmission, penalties	No — 15 countries
`[country]-payroll.md`	PAYE withholding, social security, payslips, filing	No — 15 countries
`[country]-formation.md`	Entity types, registration steps, costs, compliance	No — 13 countries
`[country]-financial-statements.md`	Annual accounts, reporting framework, filing, audit	No — 13 countries
`[country]-transfer-pricing.md`	TP documentation, arm's length, CbCR, penalties	No — 15 countries
`[country]-tax-optimization.md`	Legal tax reduction strategies, deductions you're missing, timing	No — 13 countries
`[country]-crypto-tax.md`	Cryptocurrency/digital asset taxation, cost basis, DeFi, staking, NFTs	No — 22 countries
`[country]-guided-intake.md`	Full guided experience with detailed inference (if available)	No — 13 countries have this
`[country]-return-assembly.md`	Cross-checks between VAT, IT, and SSC (if available)	No — 13 countries have this

Special packages:

Package	What it covers
`_cross-border/`	22 skills — multi-jurisdiction coordination, EU SS coordination, OECD treaty defaults, 70+ treaty corridor rates
`_verticals/`	6 industry-specific skills — freelance developer, e-commerce, content creator, consultant, property investor, medical professional
`_integrations/`	10 platform skills — Xero, QuickBooks, Stripe, Wise, PayPal, Revolut, Amazon Seller, Shopify, FreeAgent, Sage

Not every country has every file. Some have only VAT. Some have VAT + income tax + SSC + bookkeeping + e-invoicing. Thirteen countries have the full accounting suite. Check the README inside each country folder.

Coverage

Full accounting suite (13 countries)

Tax + bookkeeping + payroll + formation + financial statements + transfer pricing + tax optimization:

Country	What you get
Malta	VAT + TA24 income tax + Class 2 SSC + provisional tax + rental + crypto
United Kingdom	VAT100 + SA103/SA100 + NIC + student loan + SA105 rental + SA108 CGT + dividends
Germany	UStVA + Einkommensteuer + Sozialversicherung + Gewerbesteuer + rental + crypto
Australia	BAS + ITR + super + Medicare levy + rental + crypto
Canada	GST/HST + T1/T2125 + CPP/EI + 10 provincial returns + crypto
India	GST + ITR-3/4 + advance tax + professional tax + PF/ESI
Spain	IVA + IRPF + RETA + rental + Modelo 111
France	TVA + impot sur le revenu + cotisations sociales + CFE + crypto + rental + capital gains
Japan	Consumption tax + income tax + social insurance + estimated tax + e-Tax
Netherlands	BTW + inkomstenbelasting + ZZP deductions + payroll tax
Portugal	IVA + IRS + contribuições sociais + rental + crypto
Belgium	BTW + personenbelasting + sociale bijdragen + rental
United States (CA)	1040 + Schedule C/SE + CA 540 + crypto

Coverage varies slightly — some countries have all seven domains, others have most. Check each country's README.

Multi-skill countries (~56 countries)

VAT + income tax + social contributions (and sometimes more — formation, payroll, crypto, etc.). No guided intake, but the AI uses the universal intake flow:

Andorra, Argentina, Austria, Belgium, Bermuda, Brazil, Brunei, Bulgaria, BVI, Cayman Islands, Chile, China, Colombia, Croatia, Cyprus, Czech Republic, Denmark, Dominican Republic, Estonia, Finland, Greece, Honduras, Hong Kong, Hungary, Indonesia, Iraq, Ireland, Israel, Kenya, Kuwait, Latvia, Lithuania, Luxembourg, Malaysia, Mexico, Myanmar, New Zealand, Nigeria, Norway, Pakistan, Panama, Peru, Philippines, Poland, Qatar, Romania, Saudi Arabia, Singapore, Slovakia, Slovenia, South Africa, South Korea, Sweden, Switzerland, Taiwan, UAE

Bookkeeping skills (13 countries + all 51 US states + Indonesia)

Chart of accounts, double-entry posting, P&L and balance sheet generation with country-specific formats:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Belgium, Portugal, Sweden, Australia, Canada, Japan, plus Indonesia and every us-<state> package.

E-invoicing compliance (16 countries)

Format validation, mandatory field checks, transmission methods, and penalty regimes:

Italy, France, Germany, Spain, Poland, Portugal, Romania, Belgium, Greece, Hungary, India, Saudi Arabia, Mexico, Brazil, Malaysia, China

Payroll (15 countries + Ireland + Nigeria + ~24 US states)

PAYE/withholding tables, social security computation, payslip generation, employer filing obligations:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Belgium, Portugal, Sweden, Australia, Canada, Japan, India, Brazil, plus Ireland, Nigeria, and the larger US state packages (CA, NY, TX, IL, PA, OH, MI, GA, NC, NJ, VA, WI, MN, MA, MD, MO, IN, KY, CT, AZ, CO, OR, ND, IL — see each us-<state>/ for confirmation).

Company formation (13 countries + China, Indonesia, Ireland, Nigeria, Pakistan, Saudi Arabia + 7 US states)

Entity type comparison, registration steps, capital requirements, costs, post-formation compliance:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Portugal, Australia, Canada, Japan, India, Singapore, plus China, Indonesia, Ireland, Nigeria, Pakistan, Saudi Arabia, and the US incorporation-heavy states (CA, DE, GA, NV, NY, TX, WY).

Financial statements (13 countries)

Annual accounts preparation, reporting framework by entity size, year-end adjustments, filing and audit:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Belgium, Portugal, Australia, Canada, Japan, India

Transfer pricing (15 countries)

TP documentation, arm's length methods, CbCR thresholds, APA, penalties:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Australia, Canada, Japan, India, Brazil, Singapore, South Africa, Mexico

Tax optimization (14 countries)

Legal tax reduction strategies, commonly missed deductions, timing optimizations, entity structure advice:

Malta, UK, Germany, France, Italy, Spain, Netherlands, Australia, Canada, Japan, India, Portugal, Singapore, Indonesia

Crypto tax (21 countries + all 51 US states)

Cryptocurrency and digital asset taxation — capital gains, cost basis, DeFi, staking, mining, airdrops, NFTs, reporting:

Malta, UK, Germany, France, Australia, Canada, Israel, India, Japan, Spain, Netherlands, Portugal, Italy, Singapore, Brazil, Mexico, Sweden, Belgium, Switzerland, South Korea, New Zealand — plus every us-<state> package ships its own <state>-crypto-tax.md.

Cross-border orchestrator (37 skills)

Multi-jurisdiction coordination, EU social security coordination, OECD treaty defaults, and 70+ treaty corridor rates. See packages/_cross-border/ for the full file list.

Industry verticals (14 skills)

Banking, charity / nonprofit, construction, consultant / professional, content creator, e-commerce seller, freelance developer, insurance, investment funds / REITs, medical professional, oil & gas / extractives, property investor, SaaS / digital products, shipping / aviation (tonnage tax).

Platform integrations (10 skills)

Xero, QuickBooks, Stripe, Wise, PayPal, Revolut, Amazon Seller, Shopify, FreeAgent, Sage.

VAT/GST only (65 countries)

Consumption tax classification with country-specific supplier pattern libraries. From Albania to Zimbabwe.

How the skills work

The supplier pattern library

Every country skill contains a lookup table of local vendors. When the AI sees "BANK OF VALLETTA" or "DEUTSCHE TELEKOM" or "STRIPE PAYMENTS UK LTD" on your bank statement, it already knows the classification — no guessing.

Three outcomes per transaction

Outcome	What it means	What happens
Classified	Documents carry enough info	Applied automatically, no flag
Assumed	Data missing, conservative default applied	Flagged for your reviewer with the assumption disclosed
Needs Input	Can't proceed without asking you	One targeted question

Conservative defaults

When uncertain, the system always assumes MORE tax, never less. Your accountant can override a conservative position. They can't easily undo an aggressive one.

Quality tiers

Every skill is in one of two tiers. Check the badge on the file. Full definitions: docs/QUALITY-TIERS.md.

Tier	What it means
Accountant-verified	A licensed practitioner (CPA, EA, CA, Steuerberater, or equivalent) has reviewed the skill, tested it against representative data, and signed off. Name and license number on the skill page.
Research-verified	Every rate, threshold, form, and deadline has been drafted from authoritative sources (tax-authority publications and primary legislation). Follows the accountant-verified format. Awaiting credentialed sign-off.

Most skills are research-verified. Output from any skill must still be reviewed by your accountant before filing.

MCP server

Instead of uploading files by hand, connect your AI client to OpenAccountants via the Model Context Protocol. Install once, configure once — every future conversation can pull the right skills automatically.

How it works

You:    "Help me set up a company in Germany and understand the payroll obligations"
          ↓
Claude: calls list_jurisdictions → sees "germany"
Claude: calls list_files("germany") → germany-formation.md, germany-payroll.md, …
Claude: calls get_file("germany", "germany-formation.md") → full skill loaded
Claude: calls get_file("germany", "germany-payroll.md") → full skill loaded
Claude: loads company-formation-workflow-base.md
          ↓
Claude: walks you through entity types, registration, and employer obligations

Install

git clone https://github.com/openaccountants/openaccountants.git
cd openaccountants
pip install ./mcp          # requires Python 3.10+

Connect

Claude Desktop — add to claude_desktop_config.json:

{
  "mcpServers": {
    "openaccountants": {
      "command": "openaccountants-mcp"
    }
  }
}

Cursor — add to .cursor/mcp.json or via Settings > MCP:

{
  "mcpServers": {
    "openaccountants": {
      "command": "openaccountants-mcp"
    }
  }
}

Full setup details, uv instructions, and environment variables: mcp/README.md.

Claude Code plugin

Using Claude Code? Install the plugin in two commands — it wires up the hosted MCP server (the accountant-verified skills, with named-verifier attribution) and adds a /openaccountants command:

/plugin marketplace add openaccountants/openaccountants
/plugin install openaccountants@openaccountants

Then run /openaccountants <your tax question>, or just ask normally — the connected server pulls the right skills automatically.

For developers

Clone the repo

git clone https://github.com/openaccountants/openaccountants.git

Repo structure

openaccountants/
├── packages/              ← Ready-to-use jurisdiction packages (START HERE)
│   ├── malta/
│   ├── uk/
│   ├── us-ca/
│   ├── us-ny/
│   └── ... 130 countries + 51 US states
├── skills/                ← Source files (for contributors)
│   ├── foundation/        ← 10 workflow bases (universal, VAT, US tax, bookkeeping, payroll, e-invoicing, formation, financial statements, transfer pricing, cross-border)
│   ├── federal/           ← US federal skills
│   ├── international/     ← Country-specific: tax, bookkeeping, payroll, formation, financial statements, TP, optimization
│   ├── orchestrator/      ← Global router, intake flows, return assembly
│   ├── us-states/         ← US state skills
│   ├── cross-border/      ← WHT, PE risk, VAT place of supply, EU rules, treaty corridors
│   ├── verticals/         ← Industry-specific (developer, e-commerce, content creator, etc.)
│   ├── integrations/      ← Platform export formats (Xero, Stripe, PayPal, etc.)
│   ├── intelligence/      ← Deadlines, thresholds
│   └── patterns/          ← Global vendor patterns
├── scripts/               ← Build tools
│   └── build-packages.py  ← Generates packages/ from skills/
└── docs/                  ← Planning docs, architecture, roadmaps

Rebuild packages after editing skills

python3 scripts/build-packages.py

Contribute

We maintain 1,900+ skills across 134 countries, 51 US state packages, and 13 Canadian province/territory packages. Accounting rules change constantly — rates update, thresholds move, forms get revised. Contributions keep this accurate.

Ways to contribute

What	How	Impact
Verify a rate	Check a number against your tax authority's website, open a PR	Strengthens a research-verified skill; with credentialed sign-off, moves it to accountant-verified
Add bank patterns	Add how transactions appear on your local bank statement	Every user in your country gets fewer misclassifications
Fix an error	Find a wrong rate or outdated threshold, submit the correction	Prevents bad working papers
Add a tax skill	Write a new income tax, VAT, or social security skill for your country	Fills a gap for every user in that jurisdiction
Add a bookkeeping skill	Chart of accounts, P&L format, expense classification for your country	Enables full double-entry accounting
Add a payroll skill	PAYE tables, social security, payslip format for your country	Employers in your jurisdiction can run payroll
Add a formation skill	Entity types, registration steps, costs for your country	Entrepreneurs can set up companies
Add a financial statements skill	Annual accounts, reporting framework, audit thresholds	Year-end compliance for your jurisdiction
Add a transfer pricing skill	TP documentation, arm's length methods, CbCR for your country	Multinationals get compliant
Add a tax optimization skill	Legal deductions, timing strategies, entity structure advice	Users stop leaving money on the table
Add an e-invoicing skill	Format, mandatory fields, transmission for your country	Invoices pass validation
Add an industry vertical	Vertical-specific guidance for a profession or business type	Targeted help for that industry
Add a platform integration	Export format mapping for an accounting/payment platform	Users can push data to their tools

How to verify or fix a skill

Find your country under packages/
Compare rates against your tax authority's website
Fork, fix, PR — or email corrections to [email protected] in any format

How to add a new skill

Use any existing skill as a template (e.g., packages/malta/malta-income-tax.md)
Follow the same structure: quick reference table, rate tables, worked example, conservative defaults
Cite your sources (tax authority URL, legislation reference, or open-source repo)
Submit a PR

Credits

Every contributor is credited publicly on the skill file and at openaccountants.com.

See CONTRIBUTING.md for the full guide. Skills published to openaccountants.com require a resolvable jurisdiction — see docs/WEBSITE-SYNC.md.

Pull requests: contributions are accepted under the Contributor License Agreement (CLA.md). You explicitly agree by ticking the CLA box in the pull request template when you open a PR.

Disclaimer

All skills and outputs are for informational and computational purposes only. Not tax advice. Not a replacement for professional judgment. All outputs must be reviewed by a qualified professional before filing.

The most up-to-date, verified version is maintained at openaccountants.com.

Contact

[email protected]

License

Dual-licensed: AGPL-3.0 for open-source use, commercial license for proprietary products.

Contributions are licensed to the project under the Contributor License Agreement; see CONTRIBUTING.md and the PR template for how you opt in.