# PostCode Check (remote · postcodecheck.mike-tusa.workers.dev)

Validate and normalize postal codes offline for 252 countries and territories. Format check only.

- Trust score: 71/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-11-05

## Components

- remote · `postcodecheck.mike-tusa.workers.dev`: 71/100 (this document), [markdown](https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck.md), [page](https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck)

## Channel facts

- Endpoint: `https://postcodecheck.mike-tusa.workers.dev/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.2.3`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-11-05.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 73/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 410 tokens (~205/item across 2 items; 2 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 33/100
  - Stability observed for 10 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 2 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 3 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a current MCP spec version (2026-07-28).

## Install

### How do I install the PostCode Check MCP server?

PostCode Check is a hosted endpoint at https://postcodecheck.mike-tusa.workers.dev/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http dev-workers-mike-tusa-postcodecheck-postcodechec 'https://postcodecheck.mike-tusa.workers.dev/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "dev-workers-mike-tusa-postcodecheck-postcodechec": {
      "url": "https://postcodecheck.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-workers-mike-tusa-postcodecheck-postcodechec": {
      "type": "http",
      "url": "https://postcodecheck.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dev-workers-mike-tusa-postcodecheck-postcodechec]
url = "https://postcodecheck.mike-tusa.workers.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-workers-mike-tusa-postcodecheck-postcodechec": {
      "type": "remote",
      "url": "https://postcodecheck.mike-tusa.workers.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-workers-mike-tusa-postcodecheck-postcodechec --url 'https://postcodecheck.mike-tusa.workers.dev/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-workers-mike-tusa-postcodecheck-postcodechec:
    url: "https://postcodecheck.mike-tusa.workers.dev/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "dev-workers-mike-tusa-postcodecheck-postcodechec": {
      "Transport": "http",
      "Url": "https://postcodecheck.mike-tusa.workers.dev/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-workers-mike-tusa-postcodecheck-postcodechec -t streamable-http -u 'https://postcodecheck.mike-tusa.workers.dev/mcp'
```

### Other

```json
{
  "mcpServers": {
    "dev-workers-mike-tusa-postcodecheck-postcodechec": {
      "type": "http",
      "url": "https://postcodecheck.mike-tusa.workers.dev/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-11-04 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 27 to 30. That category is still filling its 30-day observation window: 8 days of observed history at the previous scan, 9 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-11-02 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-31 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-29 (score 68, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-27 (score 67, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-10-26 (score 66)

First indexed and scored.

## MCP tools (2)

### `validate_postcode` (~186 tokens)

Validate a postal code

Check whether a postal code has a valid format for a country and return its normalized form (uppercase, official space or hyphen), a format example and the country name. Example: country "NL", code "1234ab" → valid true, normalized "1234 AB". Format check only (Google libaddressinput patterns): it does not confirm the code exists or is deliverable. Countries without postal codes return valid false with reason "no_postal_codes". Read-only. Same engine as GET /v1/validate.

Input parameters:

- `code` (string, required): The postal code to check, e.g. "SW1A 1AA", "94103", "10115".
- `country` (string, required): ISO 3166-1 alpha-2 country code, e.g. "US", "GB", "DE" (case-insensitive; "UK" accepted).

Output parameters:

- `country` (string)
- `country_name` (string)
- `format_example`
- `has_postal_codes` (boolean)
- `input` (string)
- `message` (string)
- `normalized`
- `reason` (string)
- `valid` (boolean)
- `version` (string)
- `zip_name` (string)

### `list_countries` (~61 tokens)

List supported countries

List every supported country and territory with its ISO code, English name, whether it uses postal codes, a format example and the local name for the code (zip, eircode, PIN…). Read-only. Same data as GET /v1/countries.

Output parameters:

- `count` (integer)
- `countries` (array)
- `version` (string)
- `with_postal_codes` (integer)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck#diagnostics

## Score history

- 2026-11-05: 71
- 2026-11-04: 71
- 2026-11-03: 70
- 2026-11-02: 70
- 2026-11-01: 69
- 2026-10-31: 69
- 2026-10-30: 68
- 2026-10-29: 68
- 2026-10-28: 67
- 2026-10-27: 67
- 2026-10-26: 66

## Common questions

### What is the PostCode Check MCP server?

PostCode Check is an MCP server listed in the public MCP registry as dev.workers.mike-tusa.postcodecheck/postcodecheck. Validate and normalize postal codes offline for 252 countries and territories. Format check only. This page covers its hosted endpoint (https://postcodecheck.mike-tusa.workers.dev/mcp).

### Is the PostCode Check MCP server safe to use?

PostCode Check scores 71 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the PostCode Check MCP server expose?

PostCode Check exposes 2 tools: validate_postcode, list_countries. Their descriptions and schemas cost roughly 247 tokens of context every time the server is loaded.

### Does the PostCode Check MCP server require authentication?

No. We connected to PostCode Check without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the PostCode Check MCP server still maintained?

PostCode Check is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://postcodecheck.mike-tusa.workers.dev/mcp
- Website: https://postcodecheck.mike-tusa.workers.dev/
- Changelog RSS feed: https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck.json
- HTML version of this page: https://verifymcp.io/servers/dev-workers-mike-tusa-postcodecheck-postcodecheck/postcodecheck