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Jackpot Calculator

by jiankn · remote · no sign-in to list tools · v0.1.0 · published by GitHub user jiankn

Estimate US lottery taxes, compare cash and annuity, split pool prizes and calculate jackpot odds.

Final · 1Changes · 2
CompareRegistry entry

4 tools: 1 do something that can't be undone, 2 change things and 1 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 jackpot-calculator https://jackpot-calculator-mcp.jiankn.workers.dev/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warncalculate_lottery_payout

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

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "calculate_lottery_payout" says "payout": a word that usually means money moves, which cannot be taken back.

    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

Can't be undone 1Claude Code: ask
  • calculate_lottery_payoutEstimate taxes and withholding on a known lottery cash prize.1 finding

    Why it is in this group

    • The name "calculate_lottery_payout" says "payout": a word that usually means money moves, which cannot be taken back.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

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

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "calculate_lottery_payout" says "payout": a word that usually means money moves, which cannot be taken back.

      What this check looks for
    Description, as the server wrote it
    Estimate taxes and withholding on a known lottery cash prize. Input dollars; result integer cents. Bundled 2026 rules.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Changes things 2Claude Code: ask
  • calculate_lottery_oddsCalculate jackpot coverage for distinct combinations in one drawing and optional before-tax expected ticket return.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
    Calculate jackpot coverage for distinct combinations in one drawing and optional before-tax expected ticket return.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • calculate_pool_shareEstimate one equal member’s cash prize, taxes and withholding.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
    Estimate one equal member’s cash prize, taxes and withholding. Each member is assumed to have the specified tax profile.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Only reads 1Claude Code: allow
  • compare_lump_sum_annuityCompare a published cash option with 30 growing annuity payments after taxes, including present value and break-even rate.No findings

    Why it is in this group

    • The name "compare_lump_sum_annuity" says "compare": a word for reading.
    Description, as the server wrote it
    Compare a published cash option with 30 growing annuity payments after taxes, including present value and break-even rate.

    Annotations the server declares

    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

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 0.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http jackpot-calculator https://jackpot-calculator-mcp.jiankn.workers.dev/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__jackpot-calculator__compare_lump_sum_annuity"
    ],
    "ask": [
      "mcp__jackpot-calculator__calculate_lottery_payout",
      "mcp__jackpot-calculator__calculate_pool_share",
      "mcp__jackpot-calculator__calculate_lottery_odds"
    ],
    "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 jackpot-calculator. Review it before you use it.