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Frankfurter

by lineofflight · remote · no sign-in to list tools · v0.5.1 · published by GitHub user lineofflight

Convert currencies and fetch blended FX rates from 50+ institutional sources.

Final · 1
CompareRegistry entry

4 tools: 1 do something that can't be undone and 3 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 frankfurter https://mcp.frankfurter.dev/

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnconvert

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

    Matched text

    annotations: {"readOnlyHint":true,"openWorldHint":true}; The name "convert" says "convert": 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

Can't be undone 1Claude Code: ask
  • convertConvert an amount from one currency to another.1 finding

    Why it is in this group

    • The name "convert" says "convert": a word for a change.
    • The input addresses people (input.to): what it sends cannot be taken back.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

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

      Matched text

      annotations: {"readOnlyHint":true,"openWorldHint":true}; The name "convert" says "convert": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Convert an amount from one currency to another. Returns {amount, currency} rounded to the target's minor units. Upstream rounds rates per direction; for low-value sources, flip via `get_rates` for more precision. Pass `provider` to use one institution's published rate, e.g. UST for a U.S. Treasury reporting rate.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: true
Only reads 3Claude Code: allow
  • get_ratesLatest or a single day's exchange rates.No findings

    Why it is in this group

    • The name "get_rates" says "get": a word for reading.
    Description, as the server wrote it
    Latest or a single day's exchange rates. The raw-rate companion to `convert`. With `provider`, published rates from one or more institutions: on its own base the digits are as published, with the date they took effect.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: true
  • list_currenciesList all supported ISO 4217 currency codes and their full names (e.g.No findings

    Why it is in this group

    • The name "list_currencies" says "list": a word for reading.
    Description, as the server wrote it
    List all supported ISO 4217 currency codes and their full names (e.g. { 'USD': 'United States Dollar' }).

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: true
  • list_providersList the institutions whose rates Frankfurter relays, with key, rate type, frequency (daily, monthly or quarterly) and coverage dates.No findings

    Why it is in this group

    • The name "list_providers" says "list": a word for reading.
    Description, as the server wrote it
    List the institutions whose rates Frankfurter relays, with key, rate type, frequency (daily, monthly or quarterly) and coverage dates. Use a key as `provider` in `convert` or `get_rates` for that institution's published rates instead of the blend.

    Annotations the server declares

    • readOnlyHint: true
    • openWorldHint: true

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

claude mcp add --transport http frankfurter https://mcp.frankfurter.dev/

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__frankfurter__get_rates",
      "mcp__frankfurter__list_currencies",
      "mcp__frankfurter__list_providers"
    ],
    "ask": [
      "mcp__frankfurter__convert"
    ],
    "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 frankfurter. Review it before you use it.