Czech IČO Validation

Check the format and mod-11 checksum of a Czech company identifier (IČO). No external calls.

cz-ico-validate

Example

Input

{
  "ico": "00177041"
}

Answer

{
  "input": "00177041",
  "reason": "IČO passes mod-11 checksum.",
  "is_valid": true,
  "normalized": "00177041",
  "checksum_algorithm": "mod-11 with weights [8,7,6,5,4,3,2] on first 7 digits"
}

Inputs

Field	Type	Required	What it is
`ico`	string	Yes	Czech IČO (1-8 digits; will be left-padded to 8)

Output fields

How reliably each field appears in a successful answer.

Field	Type	Appears
`input`	string	Always (present in every successful answer)
`reason`	string	Always (present in every successful answer)
`is_valid`	boolean	Always (present in every successful answer)
`normalized`	string	Always (present in every successful answer)
`checksum_algorithm`	string	Always (present in every successful answer)

How to call it

The same tool through each route. MCP clients reach it through Strale’s server at https://api.strale.io/mcp; the call below is what the agent sends.

# Needs an API key. max_price_cents caps what this call may cost.
curl -X POST https://api.strale.io/v1/do \
  -H "Authorization: Bearer $STRALE_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "capability_slug": "cz-ico-validate",
    "inputs": {
      "ico": "00177041"
    },
    "max_price_cents": 2
  }'

{
  "tool": "strale_execute",
  "arguments": {
    "slug": "cz-ico-validate",
    "inputs": {
      "ico": "00177041"
    },
    "max_price_cents": 2
  }
}

import { Strale } from "straleio";

const strale = new Strale({ apiKey: process.env.STRALE_API_KEY! });
const result = await strale.do({
  capability_slug: "cz-ico-validate",
  inputs: {
    "ico": "00177041"
  },
  max_price_cents: 2,
});

import os
from straleio import Strale, DoRequest

strale = Strale(api_key=os.environ["STRALE_API_KEY"])
result = strale.do(DoRequest(
    capability_slug="cz-ico-validate",
    inputs={
        "ico": "00177041",
    },
    max_price_cents=2,
))

Limitations

Format and checksum only — does not confirm registration
Validates mathematical format only. A valid checksum does not mean the IČO is registered — use cz-company-data for that.
What to do instead: Chain with cz-company-data for registration check.