FX Rates MCP Server

A production-shaped Model Context Protocol server that gives AI agents (Claude, ChatGPT, Cursor, and any MCP client) live and historical foreign-exchange rates. Built by 7Block Labs as a public reference for how we ship MCP servers for companies that sell data and APIs.

It runs on the free Frankfurter API (European Central Bank reference rates, no key required), so you can clone it and have a working MCP server in under a minute.

Why this repo exists

Most "MCP servers" are an OpenAPI spec auto-converted into one tool per endpoint — which agents use badly. This one is deliberately built the way a data/API company should ship theirs:

• Task-shaped tools, not endpoint dumps. Five tools that answer real questions (convert_amount, latest_rates, historical_rate, timeseries, list_currencies) instead of a raw mirror of the HTTP API.
• Precise tool descriptions + read-only annotations (readOnlyHint) so the model knows when and which tool to call — the difference between a demo and something agents use reliably.
• Streamable HTTP transport (MCP spec 2025-06-18 and later), ready to deploy as a remote server.
• A clean seam for auth + plan entitlements. For a paid data API this is where per-user OAuth 2.1, plan → scope mapping, rate limits, and usage metering attach. See docs/PRODUCTION.md.

Quickstart

python -m venv .venv && source .venv/bin/activate
pip install -e .

# Local (stdio) — for Claude Desktop / Cursor:
python -m fx_mcp.server

# Remote (Streamable HTTP) — for hosting:
TRANSPORT=http PORT=8000 python -m fx_mcp.server

Use it in Claude Code

claude mcp add --transport http fx-rates http://localhost:8000/mcp

Use it in Claude Desktop / Cursor (stdio)

{
  "mcpServers": {
    "fx-rates": { "command": "python", "args": ["-m", "fx_mcp.server"] }
  }
}

Tools

Tool	What it answers
convert_amount	"How much is 100 USD in EUR?" (latest or on a date)
latest_rates	Today's ECB rates for a base against some/all currencies
historical_rate	Rates on a specific past date
timeseries	A daily series over a range (for trends / charts)
list_currencies	All supported currency codes + names

From reference to your production server

This is the free-data version. For a company selling a paid data API, the same architecture extends to: account linking (OAuth 2.1 into your existing logins), plan-aware entitlements and rate limits, usage metering into your billing, an in-chat UI, and listing in the Claude and ChatGPT directories.

That's what we do. 7Block Labs builds and launches MCP servers for data and API companies — get in touch.

License

MIT — see LICENSE.