# validate_identifier

utilpeek: check the format and check digits of an identifier. For a VIN's vehicle use decode_vin; for phone numbers use parse_phone_number. Returns valid, reason (invalid_checksum, invalid_length, invalid_format, ... when not valid), compact, formatted and a kind-specific detail (an IBAN's country and bank code, an ISBN's ISBN-10/13 forms, ...). An invalid identifier is a normal answer (charged); a malformed request is a 422 (not charged). Checks format and check digits only, offline (python-stdnum): a valid result does not mean the identifier exists or is registered (no registry, bank or VIES call). Payment card numbers are not accepted, not even under luhn. The submitted value is processed in memory only, never logged or stored. Typically under 0.1 s. Price: USD 0.001. Free: 10 utilpeek calls per IP per UTC day. Docs: https://tanod.dev/learn/iban-validation-api.html

Agent View of the PolicyLayer registry record for `validate_identifier`. HTML page: https://policylayer.com/tools/dev-tanod-tanod/validate-identifier

## Facts

- Tool: `validate_identifier`
- Server: Tanod (`https://tanod.dev/mcp`) — https://policylayer.com/tools/dev-tanod-tanod.md
- Homepage: https://github.com/https://tanod.dev/mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 2 (2 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `kind` | string | yes | Identifier kind: iban, bic, vat (EU, format only, no VIES), isbn, issn, ean, isin, lei, imo, luhn (generic mod-10), or a national format (au_abn, br_cnpj, br_cp |
| `value` | string | yes | The identifier (1-64 printable ASCII characters). |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "validate_identifier",
    "arguments": {
      "kind": "<kind>",
      "value": "<value>"
    }
  }
}
```

## Why validate_identifier is rated Low

Even though validate_identifier only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.

## Use case

AI agents call validate_identifier to retrieve information from Tanod without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Tanod:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "validate_identifier": {}
  }
}
```

## Other tools on Tanod (307)

- `audit_token_approvals` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/audit-token-approvals.md
- `aurora_forecast` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/aurora-forecast.md
- `diff_text` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/diff-text.md
- `image_metadata` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/image-metadata.md
- `pdf_pipeline` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-pipeline.md
- `pdf_protect` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-protect.md
- `pdf_remove_pages` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-remove-pages.md
- `pdf_reorder_pages` — Destructive — https://policylayer.com/tools/dev-tanod-tanod/pdf-reorder-pages.md
- `build_ics_event` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-ics-event.md
- `build_pptx_deck` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-pptx-deck.md
- `build_xlsx_workbook` — Execute — https://policylayer.com/tools/dev-tanod-tanod/build-xlsx-workbook.md
- `bulk_agent_index` — Execute — https://policylayer.com/tools/dev-tanod-tanod/bulk-agent-index.md
- `cron_next_runs` — Execute — https://policylayer.com/tools/dev-tanod-tanod/cron-next-runs.md
- `decode_calldata` — Execute — https://policylayer.com/tools/dev-tanod-tanod/decode-calldata.md
- `expand_rrule` — Execute — https://policylayer.com/tools/dev-tanod-tanod/expand-rrule.md
- `html_to_pdf` — Execute — https://policylayer.com/tools/dev-tanod-tanod/html-to-pdf.md
- `image_crop` — Execute — https://policylayer.com/tools/dev-tanod-tanod/image-crop.md
- `parse_ics` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-ics.md
- `parse_phone_number` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-phone-number.md
- `parse_rss_feed` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-rss-feed.md
- `parse_sitemap` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-sitemap.md
- `parse_url` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-url.md
- `parse_user_agent` — Execute — https://policylayer.com/tools/dev-tanod-tanod/parse-user-agent.md
- `render_mermaid` — Execute — https://policylayer.com/tools/dev-tanod-tanod/render-mermaid.md
- `satellite_passes` — Execute — https://policylayer.com/tools/dev-tanod-tanod/satellite-passes.md
- `sec_financials` — Execute — https://policylayer.com/tools/dev-tanod-tanod/sec-financials.md
- `transcribe_audio` — Execute — https://policylayer.com/tools/dev-tanod-tanod/transcribe-audio.md
- `x402_well_known_file` — Execute — https://policylayer.com/tools/dev-tanod-tanod/x402-well-known-file.md
- `compare_stablecoin_transfer_fees` — Financial — https://policylayer.com/tools/dev-tanod-tanod/compare-stablecoin-transfer-fees.md
- `transfer_preflight` — Financial — https://policylayer.com/tools/dev-tanod-tanod/transfer-preflight.md
- …and 277 more: https://policylayer.com/tools/dev-tanod-tanod.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=dev-tanod-tanod · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/dev-tanod-tanod