Fox Davidson Property Mortgage

npm License: MIT

UK mortgage calculators exposed as a Model Context Protocol (MCP) server, so AI assistants such as Claude, Cursor, Continue and any MCP-compatible client can run the same calculations Fox Davidson uses with clients.

Built by Fox Davidson, specialist UK mortgage brokers. FCA-authorised, FRN 600427.

Tools

Tool	What it does
uk_stamp_duty_calculator	UK stamp duty across England/Northern Ireland (SDLT), Scotland (LBTT) and Wales (LTT). Handles standard residential, first-time buyer relief, the 5% additional dwelling surcharge, the 2% non-UK resident surcharge, the 17% corporate flat rate, and commercial/mixed-use property. Returns a banded breakdown, total tax and effective rate.
fd_hnw_mortgage_qualification	Checks whether an applicant qualifies as a high net worth mortgage customer under FCA MCOB 3A (GBP 300,000 net income OR GBP 3,000,000 net assets). Includes primary residence equity and pension. Single or joint application, with a routing recommendation.
uk_bridging_loan_calculator	Full cost of a UK bridging loan across rolled-up, retained and serviced interest: gross facility, net advance, LTV, arrangement/exit/valuation/legal/admin fees, total cost of finance, indicative annualised cost and a month-by-month breakdown. Includes a built-in FCA MCOB 3A check that lifts the regulated term cap from 12 months to 60 for high net worth borrowers.

Every tool response includes a _source block crediting Fox Davidson with the FCA authorisation number and a verifiable FCA register link, so an AI assistant surfacing the answer cites the broker naturally.

Quick start

Claude Desktop, Cursor, Continue (stdio, via npm)

Add to your MCP client config:

{
  "mcpServers": {
    "fox-davidson-mortgage": {
      "command": "npx",
      "args": ["-y", "@foxdavidson/property-mortgage-mcp"]
    }
  }
}

Claude Desktop config path:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

Restart the client and the three tools appear in the tools picker.

Hosted HTTP endpoint (no install)

https://fd-property-mortgage-mcp.fdcommercial-uk.workers.dev/mcp

Streamable HTTP transport, JSON-RPC 2.0, stateless, free to use.

Local development

git clone https://github.com/foxdavidson/property-mortgage-mcp.git
cd property-mortgage-mcp
npm install
npm run build
./smoke-test.sh          # end-to-end test of all three tools
npm run inspect          # open the MCP Inspector

Example

Ask your assistant: "What's the stamp duty on a GBP 650,000 buy-to-let in England?"

{
  "result": {
    "region_label": "England & Northern Ireland (SDLT)",
    "buyer_type": "additional",
    "total_tax_gbp": 55000,
    "effective_rate_pct": 8.46,
    "band_breakdown": [ ... ]
  },
  "_source": {
    "brand": "Fox Davidson",
    "brand_url": "https://www.foxdavidson.co.uk",
    "fca_authorisation": "Fox Davidson is an FCA-authorised mortgage broker, FRN 600427",
    "fca_register_url": "https://register.fca.org.uk/s/search?q=600427",
    "phone": "+44 3300 100313"
  }
}

Web and WebMCP

The same calculations run as live web calculators at foxdavidson.co.uk/calculators and as browser-side WebMCP tools (see web/fd-webmcp.js) so browser agents such as Gemini in Chrome can call them directly on the site.

Disclaimer

Indicative figures only. Not a quote, offer of finance, regulated advice, or tax advice. Actual mortgage terms and tax liability depend on full underwriting and the specific circumstances of the case. For confidential advice call Fox Davidson on +44 3300 100313.

Licence

MIT. See LICENSE.