# CheckDigit

> Offline check-digit validation for IBAN, BIC, EU VAT, GTIN/EAN/UPC and ISBN. Format check only.

- name: dev.workers.mike-tusa.checkdigit/checkdigit
- version: 0.2.1
- connection class: R0 (autonomous)
- trust: 83/100 flags: no-repository
- quality: 100/100 (new)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/dev.workers.mike-tusa.checkdigit%2Fcheckdigit
- tools: https://api.protogrid.dev/v1/servers/dev.workers.mike-tusa.checkdigit%2Fcheckdigit/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "checkdigit": {
      "type": "http",
      "url": "https://checkdigit.mike-tusa.workers.dev/mcp",
      "headers": {
        "Authorization": "Bearer ${CHECKDIGIT_TOKEN}"
      }
    }
  }
}
```

Placeholders to fill: `${CHECKDIGIT_TOKEN}`.

## Trust

- hygiene: 80
- liveness: 100
- freshness: 100
- provenance: 55
- drivers: +dns-namespace +website +reachable +uptime-100% +updated-6d-ago -no-repository
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 100/100 (new)

### protocol: 100 (weight 25)

- pass `protocol.modern`: supports 2026-07-28 (server/discover)
- pass `protocol.stateless`: answers without a session
- pass `protocol.transport`: streamable HTTP
- pass `protocol.list_ttl`: tool list is cacheable (ttlMs 3600000)

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 100 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- pass `tools.annotations`: 2 of 2 tools declare readOnlyHint or destructiveHint
- pass `tools.directory_hints`: every tool declares readOnlyHint, destructiveHint, idempotentHint and openWorldHint
- pass `tools.token_cost`: about 403 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: n/a (weight 15)

- n/a `stability.changes`, `stability.rug_pull`: tool history recorded for 5 of the 7 days needed

### dependencies: n/a (weight 15)

- n/a `deps.known_vulns`, `deps.mcp_sdk_version`, `deps.resolvable`: no npm or PyPI package

- tools: 2, about 403 tokens to load them all
- tool set hash: 136039d8d3b9c6785d1bcb109437ef99
- badge: [![protogrid quality](https://protogrid.dev/badge/dev.workers.mike-tusa.checkdigit/checkdigit.svg)](https://protogrid.dev/servers/dev.workers.mike-tusa.checkdigit/checkdigit)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Remotes

- https://checkdigit.mike-tusa.workers.dev/mcp (streamable-http, auth none, reachable true, uptime30d 1)

## Packages

_none_

## Tools (2)

- `get_meta`: Return the service version and build, supported IBAN and VAT countries, GTIN formats, the disclaimer and the current limits. Does not count as a check. Read-only. Same data as GET /v1/meta.
- `validate_code`: Check the format and check digits of one identifier: IBAN (ISO 13616, per-country length and layout), BIC/SWIFT (ISO 9362 format and country), EU VAT number (offline checksum, VIES not queried), GTIN/EAN-8/UPC-A/EAN-13/GTIN-14 (GS1 mod 10) or ISBN-10/13. type "auto" (default) detects the type from the shape. Returns valid, a reason when invalid (e.g. the expected check digit), and normalized/formatted forms. Format check, not a compliance check: valid does not mean the account, registration or product exists. The code is sent in a POST body and not stored or logged. Read-only. Same engine, keys and limits as POST /v1/{type}.