mcp-uk-tools

A small Model Context Protocol (MCP) server that exposes UK public-data tools to any MCP-compatible AI client — Claude Code, Claude Desktop, or your own agent.

It's a clean, dependency-light reference for how I build MCP tool servers: a typed tool schema, a thin request handler, and each tool wrapping a real data source. Every source here is a free, keyless public API, so there are no API keys or secrets anywhere in this repo.

I use this same pattern in production to give an LLM grounded, source-cited access to official registers — this is the open, keyless version of it.

Tools

Related MCP server: Property Price Search MCP Server

Run it

npm ci
node server.js      # speaks MCP over stdio

Use it from Claude Code / Claude Desktop

Add it to your MCP client config:

{
  "mcpServers": {
    "uk-tools": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-uk-tools/server.js"]
    }
  }
}

Then just ask: "What council is SW1A 1AA in?" or "When is the next UK bank holiday?" — the model calls the tools itself.

How it works

• ListToolsRequestSchema → advertises the typed tool schemas

• CallToolRequestSchema → routes a call to the matching handler

• each handler does one fetch to a keyless public API and returns JSON

That's the whole contract. Swap the data sources for your own APIs and you have a grounded tool layer for any agent.

Tests

npm test   # node --test — unit, upstream-response, timeout and stdio integration tests

Every push and PR runs the suite on Node 22 and 24 via GitHub Actions. Node 22+ is required; use a supported LTS release.

License

MIT © Azeem Javed

Reliability contract

Arguments are validated by the server before network access. Nearest-postcode coordinates must be finite numbers within geographic bounds; limit is an integer from 1 to 100. Unknown holiday divisions return an explicit error. Upstream failures and malformed responses do not become successful empty results.

Bank holidays include today in Europe/London, are sorted by date, and return at most eight events. Requests have a 10-second deadline and propagate MCP cancellation. The postcode lookup's historical town field represents an administrative ward/parish, not a verified postal town.

The lockfile and npm ci make dependency resolution repeatable. Tests mock upstream data, cover London date boundaries and exercise a real stdio client/server exchange without contacting public APIs. Dependabot checks npm and Actions dependencies weekly.

npm ci
npm run check
npm test
npm audit --omit=dev

No upstream availability guarantee is implied. Sources: Postcodes.io geolocation contract and GOV.UK bank-holiday data.