APITier MCP server: UK address and verification tools inside Claude

Claude can reason about anything you put in its context. But if you are building a UK agent — a workflow that validates customer addresses, looks up flood risk by postcode, checks VAT registration before an invoice, or verifies a phone number at signup — you need to give Claude live access to UK data, not just pasted JSON.

The APITier MCP server exposes every APITier endpoint as a Claude tool in one configuration block. No middleware, no API glue code, no prompt engineering. This guide shows how to connect it in under ten minutes — and why it changes how you build UK-focused AI workflows.

What is MCP, and why does it matter for UK data workflows?

The Model Context Protocol (MCP) is an open standard for connecting AI models to external tools and data sources. Instead of writing API calls manually, parsing responses, and feeding structured data into prompts, an MCP server defines tools that Claude can call directly — with structured inputs and outputs.

For UK developers, this matters because Claude can now:

• Look up a postcode
• Validate a VAT number
• Check a phone number format
• Enrich addresses with UPRN and LSOA

— all through native tool calls.

The difference is simple:
Claude with pasted JSON = static assistant
Claude with MCP server = active data agent

MCP reached v1.0 in 2025, and tools like Claude Desktop, Claude Code, Cursor, and VS Code Copilot support it natively. That means any MCP server you configure becomes instantly usable across your development stack.

What tools does the APITier MCP server expose?

Before configuring anything, here’s what you actually get.

All tools run on one API key.

Start using APITier MCP tools

• 👉 Explore APIs: https://www.apitier.com/mcp-server
• 👉 Read MCP docs: https://docs.apitier.com/
• 👉 Free tier: 500 calls/month (no card required)

Connecting the APITier MCP server to Claude Desktop

Step 1 — Get your API key

Sign up at https://www.apitier.com and copy your API key.

Step 2 — Install MCP server

npm install -g @apitier/mcp-server

Or run directly:

npx @apitier/mcp-server --api-key YOUR_API_KEY

Step 3 — Configure Claude Desktop

Open config file:

Windows:

notepad %APPDATA%\Claude\claude_desktop_config.json

macOS:

open ~/Library/Application\ Support/Claude/claude_desktop_config.json

Add:

{
  "mcpServers": {
    "apitier": {
      "command": "npx",
      "args": ["@apitier/mcp-server"],
      "env": {
        "APITIER_API_KEY": "your_api_key_here"
      }
    }
  }
}

Step 4 — Restart and verify

Restart Claude Desktop → open new chat → click tools icon.

Test prompt:

What is the flood risk and LSOA for postcode M1 1AE?

If Claude calls a tool → setup is working.

Connecting via Claude Code (CLI)

Create .mcp.json:

{
  "mcpServers": {
    "apitier": {
      "type": "stdio",
      "command": "npx",
      "args": ["@apitier/mcp-server"],
      "env": {
        "APITIER_API_KEY": "${APITIER_API_KEY}"
      }
    }
  }

}

👉 Store API key in .env, not code.

Programmatic usage (Python SDK)

import anthropic

client = anthropic.Anthropic()

response = client.beta.messages.create(
    model="claude-sonnet-4-5",
    max_tokens=1024,
    messages=[{
        "role": "user",
        "content": "Validate VAT GB553557881"
    }],
    mcp_servers=[{
        "type": "url",
        "url": "https://mcp.apitier.com/sse",
        "name": "apitier",
        "authorization_token": "your_api_key_here"
    }],
    tools=[{"type": "mcp_toolset", "mcp_server_name": "apitier"}],
    betas=["mcp-client-2025-11-20"]
)

print(response.content)

Three real workflows you can build today

1. Property risk briefing

Prompt:

Give risk summary for SW1A 2AA

Claude:

• Calls postcode API
• Returns flood risk, IMD, LSOA
• Explains results in plain English

👉 No manual data lookup needed.

2. VAT + address verification

Prompt:

Verify VAT GB553557881 and address SW1A 2AA

Claude:

• Validates VAT
• Confirms company
• Matches address

👉 Perfect for onboarding workflows.

3. Lead enrichment before CRM import

Prompt:

Validate email, phone and postcode for lead

Claude:

• Validates email deliverability
• Confirms phone is active mobile
• Enriches postcode

👉 Outputs ready-to-use CRM data

How tool definitions work (important for developers)

Each MCP tool includes:

• Name → how Claude calls it
• Description → tells Claude when to use it
• Schema → defines input

Example:

{
  "name": "lookup_postcode",
  "description": "Get UK postcode data including address, LSOA, flood risk",
  "inputSchema": {
    "type": "object",
    "properties": {
      "postcode": { "type": "string" }
    },
    "required": ["postcode"]
  }

}

👉 The description is critical — it controls tool usage.

Why developers are adopting MCP for UK data

Traditional API workflow:

• Write request
• Parse response
• Inject into prompt

MCP workflow:

• Claude calls tool directly
• Reads structured result
• Uses it in reasoning

👉 Less code, more capability.

Extend your MCP workflow with these APIs

• Validate properties with UPRN lookup
• Enrich data using postcode geography APIs
• Verify users with phone validation
• Improve lead quality with email validation

Try it yourself (Free)

• Get API key: https://www.apitier.com
• Setup MCP: https://docs.apitier.com/

Free tier: 500 calls/month — no credit card

Frequently asked questions

Does MCP work with Claude Code?

Yes — supports CLI, Desktop, and API integrations.

Does MCP cost extra?

No — same pricing as API usage.

Can I use it with VS Code or Cursor?

Yes — MCP is supported across multiple tools.

Is API key safe?

Use environment variables. Never commit keys.

What if Claude needs unavailable data?

Claude will clearly say the limitation and suggest alternatives.

Final thoughts

The APITier MCP server turns APIs into native AI capabilities.

Instead of writing integrations, you give Claude direct access to:

• Postcodes
• Addresses
• VAT data
• Phone validation
• Email verification

Everything becomes a tool call inside reasoning.

Final CTA

Start building smarter UK AI workflows today

• https://www.apitier.com/api-catalogue
• https://docs.apitier.com/

Free tier available — 500 requests/month
No credit card required.