Shoe Size Converter Skill

Overview

Shoe Size Converter turns the input into a length in centimetres, then derives every other system from that length with linear formulas. US, UK and Australian sizes step 0.847 cm per size from a gender-specific offset. For US sizing, men's sizes start from 21.5 cm, women's from 20.2 cm, unisex from 21 cm and children's from 9.5 cm; UK and Australian sizes use slightly higher offsets of 22.3, 21, 21.7 and 10.3 cm. An Australian input with `gender=child` falls back to the unisex offset.

The other systems ignore gender. EU size is centimetres divided by 0.667. Japanese size equals the centimetre value. Mexican size uses the 0.847 step from a 17.5 cm offset. Korean size is the length in millimetres, so `kr` is ten times `cm`.

`from` accepts `us`, `uk`, `eu`, `cm`, `jp`, `au`, `mx` or `kr`; `gender` accepts `men`, `women`, `unisex` or `child` and defaults to `unisex`. `size` is parsed as a decimal number. Every value in `conversions` is rounded to one decimal place and is not snapped to a half size, so a US men's 9 becomes UK 8.1 rather than 8 or 8.5. `input_region` is the source system in upper case, and `input_size` and `gender` echo what was used.

Because the formulas are linear, very small or very large inputs extrapolate rather than fail, which can produce sizes no manufacturer makes. On the Free plan `eu`, `cm` and `jp` are removed from `conversions`.

Live Test Shoe Size Converter Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as ShoeSizeConverterSkill. 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.

{
  "name": "ShoeSizeConverterSkill",
  "arguments": {
    "size": "9",
    "from": "us"
  }
}

You do not name the tool yourself; the model picks it. Asking about 9 in the terms this skill covers is enough for it to reach for ShoeSizeConverterSkill 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"
    }
  }
}

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.

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.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

{
  "status": "ok",
  "error": null,
  "data": {
    "input_size": 9,
    "input_region": "US",
    "gender": "men",
    "conversions": {
      "cm": 29.1,
      "jp": 29.1,
      "us": 9,
      "uk": 8.1,
      "au": 8.1,
      "eu": 43.7,
      "mx": 13.7,
      "kr": 43.7
    },
    "note": "Sizes are approximate and may vary by manufacturer"
  }
}

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.

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.

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

E-commerce

Help international customers find their correct shoe size when shopping from different countries

Travel Planning

Convert shoe sizes when shopping abroad or purchasing from international retailers

Size Charts

Generate comprehensive size charts for footwear products with multiple regional standards

Retail Apps

Integrate size conversion features into shopping apps to improve customer experience

Other ways to use Shoe Size Converter Skill

Set up Shoe Size 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.

Related

More in Reference Data: