Prime Check

Calculators REST API MCP

Check whether an integer is prime. For composite numbers, returns the prime factorisation. Supports inputs up to 2^53-1 but is only fast for n ≲ 10^12.

This page documents the MCP tool findutils:prime_check. See the REST reference →

View as Markdown

Call it over MCP

Tool name findutils:prime_check · no API keys · 120 requests/min per IP

Claude Code

claude mcp add findutils --transport http https://mcp.findutils.com/

Claude Desktop — claude_desktop_config.json

{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}

Raw JSON-RPC (any MCP client) — verified example

curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "prime_check",
      "arguments": {
        "n": 97
      }
    }
  }'

Input schema

Argument	Type	Required	Description
n	integer	yes	Integer to test. Must be ≥ 2.

Example arguments (verified)

{
  "n": 97
}

Also a REST endpoint

The same tool answers plain HTTP at POST /api/tools/prime-check/execute — no key, 60 requests/min.

Open the REST reference for Prime Check →

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