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Calcupedia

by calcupedia.io · remote · no sign-in to list tools · v1.0.1 · published by io.calcupedia

2,400+ calculators and unit converters with exact results and a live calculator card in the chat.

Changes · 2
CompareRegistry entry

4 tools: 2 change things and 2 only read.

Scanned Oct 21, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http calcupedia https://calcupedia.io/api/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnrun_calculator

    The server marks "run_calculator" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "run_calculator" says "run": a word for a change.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

4 tools

Changes things 2Claude Code: ask
  • calculateRecalculates a calculator card after the user changes a value.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Recalculates a calculator card after the user changes a value. Used by the card itself, not by the assistant.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • title: Recalculate
  • run_calculatorRuns one Calcupedia calculator with its verified formulas.1 finding

    Why it is in this group

    • The name "run_calculator" says "run": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "run_calculator" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "run_calculator" says "run": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Runs one Calcupedia calculator with its verified formulas. Returns every result, a link that opens the calculator with the same values, and the inputs it accepts with their current values. Use it for finance, health, math, date and unit-conversion questions that need exact figures the user can check. Input keys differ per calculator and are listed by search_calculators; omitted inputs use the calculator's defaults.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • title: Run a calculator
Only reads 2Claude Code: allow
  • search_calculatorsSearches Calcupedia's 2,400+ calculators and unit converters by keyword (for example "mortgage", "bmi", "kg to lbs").No findings

    Why it is in this group

    • The name "search_calculators" says "search": a word for reading.
    Description, as the server wrote it
    Searches Calcupedia's 2,400+ calculators and unit converters by keyword (for example "mortgage", "bmi", "kg to lbs"). Returns matching calculators with their slug, category and page link; the top 3 also list their input keys, defaults and allowed values. Use it when the user wants a number worked out (a loan or mortgage payment, interest, savings, tax, salary, BMI, calories, a date or age, a percentage or a unit conversion) or asks for a calculator, then pass the slug to run_calculator.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • title: Search calculators

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 1.0.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http calcupedia https://calcupedia.io/api/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__calcupedia__search_calculators",
      "mcp__calcupedia__get_embed_link"
    ],
    "ask": [
      "mcp__calcupedia__calculate",
      "mcp__calcupedia__run_calculator"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as calcupedia. Review it before you use it.