What is postcode-address-validation?

A local MCP server for validating UK addresses, postcodes, emails, and phone numbers. MCP is a standard way for an AI agent to use external tools; this server runs from an npm package and needs two environment settings.

Use it to check UK contact details, including Royal Mail address data, live email SMTP checks, and HLR phone checks.

It gives an agent a local connection to these validation checks without requiring a separate remote server configuration.

postcode-address-validation — MCP server by postio-uk

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add mcp/postio-uk/postio-integrations/mcp-postcode-address-validation

Clone the repo

git clone --depth 1 https://github.com/postio-uk/postio-integrations

Made for: Claude Code, Codex, Cursor.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

postcode-address-validation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

packages/mcp/server.json · 13 lines

What it actually says

{
  "postcode-address-validation": {
    "command": "npx",
    "args": [
      "-y",
      "@postio/mcp"
    ],
    "env": {
      "POSTIO_API_KEY": "",
      "POSTIO_BASE_URL": ""
    }
  }
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 13 lines scan A 6f1ab23913bb

Subscribe to this mod's changes

postcode-address-validation is an MCP server published in the GitHub repository postio-uk/postio-integrations (0 stars, last pushed 19d ago), licensed MIT. Its token cost is not measured: an MCP server costs its tool schemas, not its config file. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Productivity address address-autocomplete address-finder address-validation mcp monorepo

postcode-address-validation

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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