mcp-currency

mcp-currency

Ask your assistant what something is worth in another currency and get a real answer with a date on it. It reads the European Central Bank's daily euro foreign exchange reference rates -- the same published series banks, tax authorities and accountants use -- converts amounts between any of the currencies the ECB quotes, and shows how a pair has moved over time. There is no API key, no account and no rate limit, because the ECB publishes the file openly. Both files are cached on your own machine, so after the first download every answer is instant and the server keeps working on a plane. Every answer states which rate date it used, because ECB rates are published once a day and a Sunday carries Friday's rate.

Built by theluckystrike.

Real ECB exchange rates in your chat -- no API key, cached locally, works offline.

60-second install

npm publish for @theluckystrike/mcp-currency is pending. Until then, the .mcpb one-click bundle or a clone+buildis the working path -- both are verified below.

One-click (.mcpb): download currency.mcpb from the latest release and double-click it in Claude Desktop:https://github.com/theluckystrike/mcp-servers/releases/latest

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "currency": {
      "command": "npx",
      "args": ["-y", "@theluckystrike/mcp-currency"]
    }
  }
}

Claude Code:

claude mcp add currency -- npx -y @theluckystrike/mcp-currency

Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "currency": {
      "command": "npx",
      "args": ["-y", "@theluckystrike/mcp-currency"]
    }
  }
}

The npx form above starts working the moment the package is published. Until then, use the .mcpb bundle above, orbuild from source with exactly these three commands:

git clone https://github.com/theluckystrike/mcp-servers.git && cd mcp-servers
npm install
npm run build -w packages/mcp-license -w servers/currency

Then point your client's command at node with one arg: the absolute path to servers/currency/dist/index.js.

To run in Pro mode set MCP_LICENSE_KEY in the same config block, or call license_activate once with your key.

Tools

Resource fx://latest exposes the cached rates as JSON. Prompt convert_invoice_lines walks the wholeexpense-tracker -> currency -> invoice chain in one step.

Free vs Pro

A refused history window returns the reason and the exact narrower call to make; it never silently truncatesa table and it never returns a transport error.

Get Pro: https://mcp.zovo.one/buy/currency (or $39 for the whole bundle: https://mcp.zovo.one/buy/bundle)

Pairs with

• expense-tracker -- expense_to_invoice takes target_currency plus an fx_ratesobject and folds a multi-currency expense set into one invoice currency, but it will not fetch or invent a rate.fx_rates_for {target, currencies} here returns exactly that object. "Rebill Nova in USD" then works end to endwithout the user typing a single exchange rate.
• invoice -- one invoice carries one currency. Convert first, issue second, and put the returnedinvoice_note ("Converted at ECB reference rates of 2026-09-02") on the document so the client can check it.

expense_to_invoice {project, from, to}          -> which currencies are actually present
fx_rates_for {target: "USD", currencies: [...]} -> {"EUR": 1.0812, "GBP": 1.2717}, rate date
expense_to_invoice {..., target_currency: "USD", fx_rates: {...}} -> one currency, every line annotated
invoice_create {currency: "USD", items: [...]}  -> the document

How the rates work

• Source: the ECB euro foreign exchange reference rates, eurofxref-daily.xml and eurofxref-hist.xml.
• Published around 16:00 CET on TARGET business days. There is no rate for a weekend, 1 January, Good Friday,Easter Monday, 1 May, or 25 and 26 December.
• Asking for a date with no rate returns the last rate published on or before it -- the convention every bankuses -- and the answer says which date it landed on and why. A date inside the cached range with no rate isa weekend or a TARGET holiday and is named as one; a date after the newest day in the cache is reported asnot published yet, with the cache's latest date and whether this call went to the ECB to look for it.
• The ECB quotes everything against the euro, so a USD/PLN rate is a cross rate: the ratio is formed andmultiplied at full precision, and the only rounding in the path is the last one, to the target currency'sminor units. The answer carries both numbers: rate_exact is the multiplier, rate is the same rate roundedto 6 decimals for reading. Recomputing by hand from the 6-decimal rate can differ by a minor unit or two;it is far out for pairs whose rate is nowhere near 1 (1,000,000 VND is KWD 11.667, not KWD 12.000).
• Results are rounded to the target currency's own ISO 4217 minor units: JPY comes back whole, BHD to three places.
• These are reference rates for accounting and reporting. They are not dealing rates; your bank's rate will differ.

Privacy

All data stays local. The only network request this server makes is to www.ecb.europa.eu for the two public ratefiles, and only when the local copy is older than 6 hours (daily) or 24 hours (history). Nothing about your amounts,your currencies or your machine is sent anywhere. The cache lives in${XDG_DATA_HOME:-~/.local/share}/mcp-servers/currency/; delete that directory to reset the server. SetECB_BASE_URL to point at your own mirror if outbound access is restricted.

MIT licensed. Support: [email protected]. Built by theluckystrike.