Polymath Megablaster MCP server

Polymath MegaBlaster MCP

Local and open-weight models (Llama, Qwen, Mistral, etc.) are consistently bad at exact math, date arithmetic, unit conversion, and a dozen other deterministic tasks. (Frontier hosted models like Claude and GPT-4 handle most of this correctly unaided already — this tool is aimed at closing the gap for smaller/local models, not replacing what those already do well.)

This is a local toolkit of 15 free tools that give AI agents a way to offload the kinds of computations reasoning models generally do not perform very well, computations are offloaded onto a calculator that uses classical deterministic methods to ascertain needed values. Fully offline, deterministic and 100% local, no network calls, no telemetry, no API keys. Fully open source and built lean.

Useful things it does:

• Does exact math on huge numbers without rounding errors
• Figures out dates correctly, including leap years and "the last day of the month" edge cases
• Converts between units (km/miles, C/F, kg/lb) without approximating
• Works out subnet math for networking
• Computes distance between two coordinates (great-circle)

More technical things it does:

• Arbitrary-precision arithmetic, factorials, permutations, combinations (avoids float64 overflow)
• Statistics (mean, median, stdev, variance, percentiles) on a list of numbers
• Base conversion (decimal, hex, binary, octal)
• Levenshtein edit distance and similarity ratio (deterministic fuzzy matching)
• Time zone conversion (IANA zone aware)
• Token counting (GPT tokenizer) so an agent can manage its own context budget

Why local

Most AI dev tool MCP servers either charge a subscription or call out to a remote API. This one never touches the network. Every tool is pure local computation, verifiable in the source: read src/tools.js, there is no fetch or http import anywhere in it.

Setup

1. Install Node.js (v18 or newer) if you don't have it: https://nodejs.org

2. Clone this repo and install dependencies:

git clone https://github.com/headlessherm-creator/polymath-megablaster-mcp.git
cd polymath-megablaster-mcp
npm install

3. Point your MCP client at the local path:

{
  "mcpServers": {
    "polymath": {
      "command": "node",
      "args": ["/absolute/path/to/polymath-megablaster-mcp/src/index.js"]
    }
  }
}

Add that to your MCP client's config and restart it. Setup docs for common clients:

• Claude Desktop: https://modelcontextprotocol.io/quickstart/user
• Cursor: https://docs.cursor.com/context/model-context-protocol
• Claude Code: https://docs.claude.com/en/docs/claude-code/mcp

Tools (15, all free)

factorial, permutations, combinations (all arbitrary-precision, avoid float64 overflow), compute_statistics (mean, median, stdev, variance, percentiles)

• Deterministic math: calculate (arbitrary-precision expression evaluator),

days handled correctly), convert_timezone

• Date and time: dateadd, datediff (leap years, month boundaries, business

(decimal, hex, binary, octal)

• Conversion: convertunit (length, weight, volume, temperature), convertbase

lookup)

• Networking: calcsubnet (CIDR math), checkip_type (private/reserved range

a large prompt)

• Text: levenshtein_distance (exact edit distance and similarity ratio)
• Geo: haversine_distance (exact great-circle distance between coordinates)
• Agent utility: count_tokens (GPT tokenizer, for managing context budget before

Dependencies

• @modelcontextprotocol/sdk: the MCP protocol implementation
• zod: input schema validation
• mathjs: arbitrary-precision math evaluation
• gpt-tokenizer: GPT tokenizer for count_tokens

Shortened. The full README is on GitHub.