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MCP Currency Converter in Windsurf

ECB reference rates with the rate date on every answer. It caches the European Central Bank's daily and historical euro reference rates, converts between any currencies the ECB quotes through EUR cross rates, and emits the exact fx_rates object the expense tracker needs to rebill a project in one currency.

Ten tools out of the 100 Cascade can hold, and one outbound host: www.ecb.europa.eu, only when the local cache is older than 6 hours. It is the cheapest server in this collection to leave enabled.

What you get in Windsurf

You say	Tool
What is 4,500 EUR in USD today?	`convert`
What was the GBP rate on 30 August?	`rate_on`
Rebill Nova in USD using today's rates.	`fx_rates_for then expense_to_invoice`

Counted from the published history file: the ECB series runs 1999-01-04 to 2026-09-02, 10,104 calendar days holding 7,084 dates, so 29.9% of dates carry no rate. Every answer names the rate date it actually used.

Install it in Windsurf

The file is mcp_config.json, and the key inside it is mcpServers.

Scope	Path
macOS, Windows and Linux	`~/.codeium/windsurf/mcp_config.json`

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

Save and reopen the MCP Servers list; Cascade picks it up without restarting the editor.

The npm publish of @theluckystrike/mcp-currency is pending; until then use the .mcpb bundle or a clone and build from the latest release.

No install: the hosted endpoint

There is no hosted endpoint for this one yet. MCP Currency Converter runs locally over stdio with the config above, which is also the only form in which it reads and writes files on your own disk. Three of the servers in this collection are served at https://mcp.zovo.one/mcp/<name> over MCP streamable HTTP: time-tracker, price-tracker and invoice.

Windsurf notes worth knowing first

Read this first: mcp_config.json applies to the legacy Cascade agent only. The Devin Local agent, the default for new tabs, takes its servers from the Devin CLI config files, so a correct entry here can still be invisible in a fresh tab. The other hard number is a cap: Cascade reaches at most 100 tools at once, and every enabled server spends from it.

Free: latest rates, convert, convert_many, fx_rates_for, history windows up to 90 days. Pro is $19 once, verified offline.

Questions

Where does Windsurf keep its MCP config?

~/.codeium/windsurf/mcp_config.json, under mcpServers. Reach it from the MCPs icon at the top right of the Cascade panel, or Devin Settings, Cascade, MCP Servers.

I edited the file and a new tab still cannot see MCP Currency Converter.

That file applies to the legacy Cascade agent only. The Devin Local agent, the default for new tabs, reads its servers from the Devin CLI config files instead. Check which agent the tab runs.

How many servers can I load at once?

Cascade reaches at most 100 tools at any one time, and every enabled server spends from that single budget. MCP Currency Converter contributes 10 tools, so keep the enabled list short rather than counting servers.

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