Punycode Converter Skill

Overview

Conversion follows the Punycode algorithm from RFC 3492. When `text` contains a dot it is treated as a domain: it is split into labels, and in `encode` mode only labels with non-ASCII characters are converted and given the `xn--` prefix, while plain labels such as `de` are left alone. In `decode` mode only labels starting with `xn--` are decoded. Without a dot the whole string is converted as a single label. The input is not lower-cased or normalised first, so `München` and `münchen` encode differently; normalise input before calling if you need registry-style results.

Invalid Punycode in `decode` mode, such as digits outside the alphabet, a truncated sequence or a value that is not a character, returns a 400 that names `text`. `isDomain` is true when the input contains a dot.

`isIDN` is true when the Unicode form contains a non-ASCII character or the ASCII form contains an `xn--` label, so `example.com` returns false. `scripts` lists the writing systems found in labels that contain non-ASCII letters, with digits, hyphens and combining accents ignored. `mixedScript` is true when any label mixes scripts outside the combinations used by real languages (Japanese Han with Hiragana, Katakana and Latin; Korean Han with Hangul and Latin; Chinese Han with Bopomofo and Latin). It catches Latin-and-Cyrillic style spoofs, not same-script look-alikes such as `rn` for `m`. On the Free plan `isIDN` and `mixedScript` are null.

Live Test Punycode Converter Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as PunycodeConverterSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call

{
  "name": "PunycodeConverterSkill",
  "arguments": {
    "text": "münchen.de"
  }
}

You do not name the tool yourself; the model picks it. Asking about münchen.de in the terms this skill covers is enough for it to reach for PunycodeConverterSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

Argument	Type	Description
`text`Required	string	Unicode text or domain to encode (max 1000 characters) length 0–1000
`mode`Optional	string	Conversion mode `encodedecode` default encode

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "input": "münchen.de",
    "output": "xn--mnchen-3ya.de",
    "mode": "encode",
    "isIDN": true,
    "isDomain": true,
    "scripts": [
      "Latin"
    ],
    "mixedScript": false
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`input`	string	`münchen.de`	Original Punycode text provided for decoding conversion
`output`	string	`xn--mnchen-3ya.de`	Decoded Unicode text converted from Punycode format
`mode`	string	`encode`	Conversion mode used for the transformation operation
`isIDN`Premium	boolean	`true`	Indicates if result is valid internationalized domain name
`isDomain`	boolean	`true`	Whether the input was treated as a domain name (that is, it contained a dot) rather than a single label.
`scripts`	array	`["Latin"]`	Writing systems (Latin, Cyrillic, Greek, Han, etc.) detected in the domain's non-ASCII labels. Empty for a plain ASCII domain; a single entry for a legitimate international domain
`mixedScript`Premium	boolean	`false`	True when a single domain label mixes writing systems in a way no real language does (e.g. Latin combined with Cyrillic) — the signature of a homograph / look-alike phishing domain. Legitimate combinations such as Japanese (Han + Hiragana/Katakana) are not flagged. Detects cross-script spoofs, not same-script look-alikes

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

Status	What it means
`400` / `422`	The arguments did not validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Blocked by a key restriction or an IP allow-list. Never a bad identity.
`404`	This skill is not part of VerveKit. Check the catalog.
`429`	Out of credits, or a brief rate limit. The message tells them apart.

A call costs 1 credit each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Domain Registration: Verify and convert international domain names
Web Development: Handle IDN domains in applications
Email Systems: Process internationalized email addresses
Security: Detect homograph attacks using similar-looking Unicode characters

Other ways to use Punycode Converter Skill

Set up Punycode Converter Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →