Word Ladder Skill

Overview

Ladders are found with breadth-first search: from the start word the API tries every single-letter substitution at every position, keeps the results that are in its word list, and expands level by level until it reaches the end word. The first path found is therefore a shortest one; when several shortest ladders exist, only one is returned.

Random puzzles take word length from `difficulty`: 3 letters for `easy`, 4 for `medium` and 5 for `hard`. Pairs are drawn from a common-word list and kept only when a ladder exists with 2-3 intermediate words (easy), 3-5 (medium) or 4-7 (hard). The pair search is bounded, so a call can return fewer puzzles than `count` asked for; read `count` in the response.

When you send both `start` and `end`, each must be 3-6 letters. Same-length words must appear in the common list or a full English pronouncing dictionary, otherwise the call returns 404 naming the missing word. The search tries common words first and falls back to the full dictionary only if no common-word ladder exists, which keeps solutions familiar where possible. Words of different lengths come back with `solvable: false`. For your own words `difficulty` is derived from the ladder length (up to 4 words easy, up to 6 medium, longer hard), or `unknown` when there is no ladder.

`steps` counts the intermediate words, not the letter changes: COLD to WARM through CORD, CARD and WARD has `steps: 3` and four changes. `solution` lists every word including both ends, uppercased. On the Free plan `solution`, `html` and `image` are null.

Live Test Word Ladder Skill Skill →

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as WordLadderSkill. 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": "WordLadderSkill",
  "arguments": {}
}

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.

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{
  "status": "ok",
  "error": null,
  "data": {
    "puzzles": [
      {
        "startWord": "ANIL",
        "endWord": "CUED",
        "steps": 5,
        "solution": [
          "ANIL",
          "ARIL",
          "ARID",
          "IRID",
          "IRED",
          "CRED",
          "CUED"
        ],
        "solvable": true,
        "difficulty": "medium"
      }
    ],
    "count": 1,
    "difficulty": "medium",
    "html": "<html><head><title>Word Ladder</title><style>body {font-family: Arial, sans-serif; padding: 20px; max-width: 600px; margin: 0 auto;}h1 {text-align: center; color: #4CAF50;}.puzzle {background: #f5f5f5; padding: 25px; margin: 20px 0; border-radius: 10px;}.words {display: flex; justify-content: space-between; align-items: center; margin: 20px 0;}.word {font-size: 28px; font-weight: bold; letter-spacing: 3px; padding: 15px 25px; border-radius: 10px;}.start {background: #4CAF50; color: white;}.end {background: #2196F3; color: white;}.arrow {font-size: 30px; color: #999;}.steps {text-align: center; font-size: 14px; color: #666; margin-bottom: 15px;}.ladder {display: flex; flex-direction: column; align-items: center; gap: 10px; margin: 20px 0;}.rung {width: 150px; height: 40px; border: 2px dashed #ccc; border-radius: 5px; display: flex; align-items: center; justify-content: center; font-size: 18px; letter-spacing: 5px;}.hint {font-size: 13px; color: #888; font-style: italic; margin-top: 10px;}</style></head><body><h1>Word Ladder</h1><p style='text-align:center;'>Change one letter at a time to get from the first word to the last</p><div class='puzzle'><div class='steps'>Puzzle #1 - 5 steps</div><div class='words'><span class='word start'>ANIL</span><span class='arrow'>→</span><span class='word end'>CUED</span></div><div class='ladder'><div class='rung'>_ _ _ _</div><div class='rung'>_ _ _ _</div><div class='rung'>_ _ _ _</div><div class='rung'>_ _ _ _</div><div class='rung'>_ _ _ _</div></div></div></body></html>",
    "image": {
      "imageName": "6f0f9e5e-ce0d-4570-a706-8fc5ccbfc948_wordladder.png",
      "format": ".png",
      "downloadURL": "https://storage.googleapis.com/apiverve/APIData/wordladder/6f0f9e5e-ce0d-4570-a706-8fc5ccbfc948_wordladder.png?GoogleAccessId=635500398038-compute%40developer.gserviceaccount.com&Expires=1766010731&Signature=FQwH%2FqXC0eYHgHqGKfBoEETrcXALoIpkf2z7HCkmYcFu2IgL2uMbCBi22tEsrlY3yOkksRuZ56C2685lLi98CWvgCF1J9UrYaAWjFtLesnHZ0i%2B0SWYIy5wZLWnVq4UrJDLZVrvSe8lh21mQJrduVY8QqV%2FI0sViUlnlndLMFUfhEQedKYAGRtmXjJlpl1YA9A9%2BtJoqRvMm4YStfJyLJmExPQKnPiRoP6EB6%2B8%2F1WUq5vH3%2BWglijVroxaJ%2BJy6kgQ8qTuVX9%2FzFi8R0DDHZtd0IpcTL8EBvNvHnjRPS4lZB%2Bm3k9GCxqGCnsj8pssu6ymtzGNEqA%2BBqAthODekWw%3D%3D",
      "expires": 1766010731681
    }
  }
}

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 2 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Word Games

Create word ladder challenges for puzzle apps

Education

Teach vocabulary and word relationships

Brain Training

Develop problem-solving and word skills

Competitions

Generate puzzles for word game tournaments

Other ways to use Word Ladder Skill

Set up Word Ladder 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.

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