Tax MCP

The Model Context Protocol server behind the free tax tools at ai2fin.com/tools/compare — so assistants (Claude, ChatGPT, agents) can call them directly.

Stateless and no-auth. It computes over public rate data only and stores nothing. (This is separate from the authenticated app MCP at app.ai2fin.com/mcp, which works on your real financial data behind OAuth.)

Tools

Tool	What it does
tax_rate_lookup	A country's GST/VAT, income and company tax rates
compute_gst_vat	Add or remove a country's GST/VAT on an amount
compare_countries	Compare tax across countries — ai2fin.com/tools/compare as a callable
income_tax_estimate	Income tax estimate over effective-dated brackets (AU, NZ)
company_tax_estimate	Company tax estimate with small-business thresholds (AU, US, GB, IN, CA)
cgt_estimate	Capital-gains tax estimate — losses, discount, marginal stacking (AU resident individuals)

The estimate tools answer only for countries with verified data and degrade to "not available" elsewhere. Every result carries a "general information, not tax advice" note and cites its source authority.

Data = single source

data/rates.json is produced by the website's gen:tax pipeline — the same source behind the calculator and comparison pages — so the MCP, the widgets and the pages never disagree. Don't hand-edit it.

Run / deploy

cd tax-mcp
npm install
npm run dev      # local: POST JSON-RPC to http://localhost:8787
npm run deploy   # to Cloudflare; then map a route e.g. taxmcp.ai2fin.com
npm run bundle   # writes dist/worker.js — a single paste-ready file for the
                 # Cloudflare dashboard editor when the CLI isn't available

Full deploy steps (dashboard copy-paste or CLI): DEPLOY.md.

Abuse protection is via the Cloudflare dashboard (rate limiting + WAF) — not auth.

Connect

Add the deployed URL as a custom MCP connector in Claude (Settings → Connectors) or ChatGPT (developer mode). A GET to the root returns server info; the MCP handshake is POST JSON-RPC (initialize → tools/list → tools/call). It pairs with the live comparison tool at ai2fin.com/tools/compare.

Quick check

curl -s https://taxmcp.ai2fin.com -X POST -H 'content-type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"compute_gst_vat","arguments":{"country":"AU","amount":100,"mode":"add"}}}'