API and MCP tools

Reference tools for professional workflows in England and Wales.

For brokers, conveyancers and letting agents: use the catalogue to inspect input requirements before calling a tool. Results are for reference.

Use the same calculators through REST or MCP. Keep the returned sources, dates, jurisdiction and missing-data notices with each result.

REST example

curl 'https://keysandcosts.co.uk/api/v1/buying_cost?price=350000&nation=england&firstTime=true&date=2026-11-05'

MCP connection

https://keysandcosts.co.uk/mcp

Send a JSON-RPC initialize request, then tools/list and tools/call. No account or API key is needed for the capped free preview.

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-06-18",
    "capabilities": {},
    "clientInfo": {
      "name": "example",
      "version": "1.0"
    }
  }
}