Koskamo

Zovo Cross Sum Puzzles MCP

Generates printable cross-sum number puzzles with answer keys for ChatGPT and Claude. Supports grid sizes from 6x6 to 12x12 with easy, medium, and hard difficulties. Includes a solver to ensure unique solutions and allows seeding for reproducible puzzles.

Visit Zovo

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Zovo Cross Sum Puzzles MCP logo, by ZovoCommunity listingStreamable HTTPNo sign-inEndpoint checked 2026-11-08Published by Zovo
MCP endpoint (Streamable HTTP)
https://cross-sums.zovo.one/mcp
Vendor documentation

What its tools do

1 tool, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.

Read-only (1)

1 of 1 have a description · 1 of 1 declare behavior hints · 1 of 1 with parameters document them all

Checks and signals

Each line is separate evidence, not a trust score.

  • Passed Endpoint answered the live check ·
  • Availability 1 of 1 checks passed in 30 days

What you can do with it

  • Generate printable cross-sum puzzles for teachers and students
  • Solve puzzles on screen using the chat card with a Check button
  • Create seeded puzzles for reproducible output
  • Export puzzles as PDFs with answer keys

Source and maintenance

Community listingRegistry 1.0.0
mcp-registry: io.github.theluckystrike/cross-sums@1.0.0Project website

Protocol and capabilities

Server
cross-sums 1.0.0
MCP protocol negotiated in check
2025-11-25
Tools
1 advertised
Resources
1 advertised
Resource templates
1 advertised
Prompts
Not advertised
Server-advertised capabilities
{
  "tools": {
    "listChanged": true
  },
  "resources": {
    "listChanged": true
  }
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

Zovo Cross Sum Puzzles makes printable cross-sum number puzzles (a grid of white squares and clue squares; each run of white squares adds up to its clue with no repeated digit) as a PDF with an answer key, and the widget lets the user solve them on screen. Call generate_cross_sums with one object per puzzle in puzzles[] when they differ, or count plus size and difficulty for a set. Each puzzle is checked by a solver to have one solution. Do not print the answers in chat unless asked; they are on the answer pages.

Tools

1 advertised

generate_cross_sums — Generate cross sum puzzles
Advertised by the server during the last successful anonymous check.
Advertised read-only

Use this when the user wants printable cross-sum puzzles (cross sums, number crossword puzzles with sums, addition logic puzzles) as a PDF with an answer key, or wants to solve one on screen. Each grid from 6 x 6 to 12 x 12 (counting the clue row and column) has white squares for the digits 1 to 9 and clue squares with sums; each run of white squares adds up to its clue with no repeated digit. Put one object per puzzle in puzzles[] when they differ (size, difficulty, seed); for a set of the same kind, set count with size and difficulty. A solver checks each puzzle for one solution. The PDF has 1, 2 or 4 puzzles per page on Letter or A4, an optional title and name line, and answer pages; the card lets the user fill in digits and check them. Defaults: 1 medium 8 x 8 puzzle, Letter, 1 per page, name line and answer key on. Does not solve a puzzle from a photo or make grids larger than 12 x 12.

generate_cross_sums input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "properties": {
    "seed": {
      "type": [
        "number",
        "string",
        "null"
      ],
      "description": "Starting seed; puzzle N uses seed + N - 1. Reuse it to reprint the same puzzles. Example: 2026"
    },
    "size": {
      "type": [
        "number",
        "string",
        "null"
      ],
      "description": "Grid size for all puzzles, 6 to 12 (default 8), counting the clue row and column. Example: 10"
    },
    "count": {
      "type": [
        "number",
        "string",
        "null"
      ],
      "description": "How many puzzles when they are all the same kind (1 to 12, default 1). Example: 4"
    },
    "paper": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 30
        },
        {
          "type": "null"
        }
      ],
      "description": "letter (default, US 8.5 x 11 in) or a4. Example: a4"
    },
    "title": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 200
        },
        {
          "type": "null"
        }
      ],
      "description": "Title printed at the top of each page. Example: Weekend Cross Sums"
    },
    "puzzles": {
      "anyOf": [
        {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "seed": {
                "type": [
                  "number",
                  "string",
                  "null"
                ],
                "description": "Seed for this puzzle (same seed and settings give the same puzzle). Example: 4821"
              },
              "size": {
                "type": [
                  "number",
                  "string",
                  "null"
                ],
                "description": "Grid size from 6 to 12, counting the clue row and column (8 means an 8 x 8 grid). Example: 8"
              },
              "difficulty": {
                "anyOf": [
                  {
                    "type": "string",
                    "maxLength": 40
                  },
                  {
                    "type": "null"
                  }
                ],
                "description": "easy, medium (default) or hard. Harder puzzles have longer runs and fewer clue squares. Example: hard"
              }
            },
            "additionalProperties": {}
          },
          "maxItems": 12
        },
        {
          "type": "null"
        }
      ],
      "description": "One object per puzzle when the puzzles differ, e.g. [{\"size\":6,\"difficulty\":\"easy\"},{\"size\":10,\"difficulty\":\"hard\"}]. Leave out and use count for a set of the same kind. Up to 12."
    },
    "per_page": {
      "type": [
        "number",
        "string",
        "null"
      ],
      "description": "Puzzles per printed page: 1 (default), 2 or 4. Example: 2"
    },
    "name_line": {
      "type": [
        "boolean",
        "string",
        "number",
        "null"
      ],
      "description": "Print a Name and Date line on the puzzle pages (default true). Example: false"
    },
    "answer_key": {
      "type": [
        "boolean",
        "string",
        "number",
        "null"
      ],
      "description": "Add answer pages with the solved grids (default true). Example: true"
    },
    "difficulty": {
      "anyOf": [
        {
          "type": "string",
          "maxLength": 40
        },
        {
          "type": "null"
        }
      ],
      "description": "Difficulty for all puzzles: easy, medium (default) or hard. Example: easy"
    }
  }
}
generate_cross_sums output schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "title",
    "count",
    "per_page",
    "paper",
    "pages",
    "answer_key",
    "name_line",
    "all_one_solution",
    "puzzles",
    "notes",
    "downloads"
  ],
  "properties": {
    "count": {
      "type": "number"
    },
    "notes": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "pages": {
      "type": "number"
    },
    "paper": {
      "type": "string"
    },
    "title": {
      "type": "string"
    },
    "puzzles": {
      "type": "array",
      "items": {
        "type": "object",
        "required": [
          "number",
          "size",
          "difficulty",
          "white_squares",
          "clues",
          "longest_run",
          "one_solution",
          "logic_only",
          "solver_steps",
          "seed"
        ],
        "properties": {
          "seed": {
            "type": "number"
          },
          "size": {
            "type": "string"
          },
          "clues": {
            "type": "number"
          },
          "number": {
            "type": "number"
          },
          "difficulty": {
            "type": "string"
          },
          "logic_only": {
            "type": "boolean"
          },
          "longest_run": {
            "type": "number"
          },
          "one_solution": {
            "type": "boolean"
          },
          "solver_steps": {
            "type": "number"
          },
          "white_squares": {
            "type": "number"
          }
        },
        "additionalProperties": false
      }
    },
    "per_page": {
      "type": "number"
    },
    "downloads": {
      "type": "object",
      "required": [
        "pdf"
      ],
      "properties": {
        "pdf": {
          "type": "string"
        }
      },
      "additionalProperties": false
    },
    "name_line": {
      "type": "boolean"
    },
    "answer_key": {
      "type": "boolean"
    },
    "puzzle_count": {
      "type": "object",
      "required": [
        "shown",
        "total"
      ],
      "properties": {
        "shown": {
          "type": "number"
        },
        "total": {
          "type": "number"
        }
      },
      "additionalProperties": false
    },
    "all_one_solution": {
      "type": "boolean"
    }
  },
  "additionalProperties": false
}
generate_cross_sums annotations
{
  "title": "Generate cross sum puzzles",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

Not advertised

No prompt definitions available.

Resources

1 advertised

cross-sums-widget — Zovo Cross Sum Puzzles view

Advertised by the server during the last successful anonymous check.

Interactive view for Zovo Cross Sum Puzzles.

cross-sums-widget URI
ui://widget/cross-sums-v1-1.0.0-3e12440215174ef8f1a1c40f9bd8e0596d75a6235221138abbb6bcdb94546855.html

MIME type: text/html;profile=mcp-app

cross-sums-widget-legacy — Zovo Cross Sum Puzzles view (previous versions)

Advertised by the server during the last successful anonymous check.

cross-sums-widget-legacy URI template
ui://widget/cross-sums-{version}.html

MIME type: text/html;profile=mcp-app

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
1189 ms
95th percentile latency
1189 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 1189 ms · metadata changed · 1 tool(s), 1 resource(s), 1 resource template(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http zovo-cross-sum-puzzles-mcp https://cross-sums.zovo.one/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add zovo-cross-sum-puzzles-mcp --url https://cross-sums.zovo.one/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable zovo-cross-sum-puzzles-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "zovo-cross-sum-puzzles-mcp": {
      "url": "https://cross-sums.zovo.one/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "zovo-cross-sum-puzzles-mcp": {
      "type": "streamableHttp",
      "url": "https://cross-sums.zovo.one/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start zovo-cross-sum-puzzles-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "zovo-cross-sum-puzzles-mcp": {
      "type": "http",
      "url": "https://cross-sums.zovo.one/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http zovo-cross-sum-puzzles-mcp https://cross-sums.zovo.one/mcp

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.
Claude Desktop configuration
https://cross-sums.zovo.one/mcp

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "zovo-cross-sum-puzzles-mcp": {
      "serverUrl": "https://cross-sums.zovo.one/mcp"
    }
  }
}

Let your agent find its tools

Find servers like Zovo Cross Sum Puzzles MCP from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.

Connect Koskamo Explore workflows
See all 6,071