Use case · VerifyDesk

Validate an IBAN via API before a payment goes out

Catch mistyped IBANs before money moves: country length and ISO 7064 mod-97 checksum, with a plain reason when it fails. Runs offline, so the IBAN is not sent to a third party.

The job

Most payment failures caused by bank details are typing errors: a digit swapped, one dropped, a space pasted in the wrong place. The IBAN format carries its own protection against that, a two-digit checksum computed with ISO 7064 mod-97, and a fixed length per country.

Checking both before a payment file is built catches the error while the person who supplied the IBAN is still reachable, rather than days later as a returned transfer.

Why an agent needs a tool for it

An agent reading IBANs out of emails, PDFs and supplier forms will occasionally misread one. validate_iban is a cheap guard to run on every IBAN it extracts, and when it fails it says why in a sentence the agent can pass back to the supplier.

The check runs on our server without calling a bank or a third party, so the IBAN is not shared further than the call itself.

The calls

2 tool calls.

Live production call2026-10-01

Agent calls validate_iban

{
  "name": "validate_iban",
  "arguments": {
    "iban": "DE89 3704 0044 0532 0130 00"
  }
}

VerifyDesk answers

{
  "valid": true,
  "iban": "DE89370400440532013000",
  "country": "DE"
}

Spaces are accepted on the way in and removed on the way out, so the normalized form is ready for a payment file.

Live production call2026-10-01

Agent calls validate_iban

{
  "name": "validate_iban",
  "arguments": {
    "iban": "DE89 3704 0044 0532 0130 01"
  }
}

VerifyDesk answers

{
  "valid": false,
  "iban": "DE89370400440532013001",
  "country": "DE",
  "reason": "Checksum failed (mod-97): digits are mistyped or corrupted."
}

One digit changed at the end. The checksum catches it and the reason is written for whoever has to fix it.

Limits worth knowing

This checks structure, not existence. A well-formed IBAN for a closed account, or for somebody else's account, passes.
It does not confirm that the IBAN belongs to the named payee. That needs a payee verification service at the bank level, which this is not.

Pricing

0.4 credits for the calls on this page.

Tool	Credits per call
validate_iban	0.2

Credits are prepaid and shared across every server. Starter is $10 for 1,000 credits, packs never expire, and 100 credits are free without a card. Full pricing.

Install

Connect VerifyDesk to your agent.

A remote MCP server over Streamable HTTP. Get a free key, swap it in, and the calls above work as written, with answers reflecting the data on the day you call.

EndpointStreamable HTTP

https://verifydesk.agenttoolworks.com/mcp

Connect it, Claude Code

claude mcp add --transport http verifydesk \
  https://verifydesk.agenttoolworks.com/mcp \
  --header "Authorization: Bearer atw_live_your_key"

Setup for Claude Desktop, Cursor and Windsurf is in the docs.