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MCP Per Diem in Windsurf

Statutory travel allowances on the rate tables the tax authorities publish, and the trips you priced with them. It prices one business trip against a bundled rate table and shows the arithmetic that produced the number: the allowance per day, the partial-day fraction the scheme's own ladder gave, every deduction for a meal somebody else paid for, and the total in the scheme's own currency. Three schemes ship with it, the Polish delegation regulation at home and per country, the HMRC benchmark scale rates for travel inside the UK, and the US GSA CONUS standard M&IE with the lodging cap. Start and end are instants rather than wall clocks, so a trip across a clock change is 23 or 25 hours, and the Polish 24-hour period and the US calendar day give different and equally correct answers to the same trip. Trips can be saved under a name with a TRIP-YYYY-NNNN id, listed with a total per currency, reported per scheme and per month, and handed to the expense tracker as ready-made expense_add arguments. The tables are files inside the package rather than a feed, so the same trip priced twice gives the same answer, and every rate carries its authority, instrument, source URL and effective date.

Eight tools against Cascade's ceiling of 100, and this one pairs naturally with mcp-expense-tracker and mcp-timezone, so budget the three at roughly 30 tools when you decide what else fits alongside them.

What you get in Windsurf

You sayTool
What is the per diem for 58 hours in Krakow, leaving Tuesday at 8am, with breakfast provided on the first day and two hotel nights?perdiem_calc
Price the same trip under the HMRC benchmark rates instead.perdiem_calc
Save that as the Krakow audit trip and show me what I have claimed this quarter.trip_record

A destination that is not in the bundled table is refused by name rather than priced at a neighbour's rate. Measured through a real client on 2026-09-05: asked for a Polish per diem for Oman, the model called perdiem_calc, got back the server's own refusal (Poland domestic plus 34 countries abroad are bundled, so a missing country means not verified here rather than no rate exists), called perdiem_rates to check the coverage for itself, and then said plainly that it would not guess a number. An earlier build of this server answered that same trip with Romania's EUR 42.00 diet, because "romania".includes("oman") is true; the fallback is a prefix match now. In the same session a 58-hour Krakow trip came back at PLN 258.75, PLN 123.75 of diets plus PLN 135.00 of lodging ryczalt, with the arguments assembled from the prose unprompted.

Install it in Windsurf

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

ScopePath
macOS, Windows and Linux~/.codeium/windsurf/mcp_config.json
{
  "mcpServers": {
    "per-diem": {
      "command": "npx",
      "args": ["-y", "@theluckystrike/mcp-per-diem"]
    }
  }
}

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

The npm publish of @theluckystrike/mcp-per-diem 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 Per Diem 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: Rate lookups and calculations are unlimited on every tier, on all three schemes: the tables are public regulation, and metering the reading of a regulation would be charging for the tax authority's work rather than for this server's. 5 trips saved a calendar month, counted by start date, and unlimited trip lists. 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 Per Diem.

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 Per Diem contributes 8 tools, so keep the enabled list short rather than counting servers.

Related

MCP Per Diem in detail · The same server in VS Code and Cline · Every server in Windsurf · Guides · Windsurf docs · Buy Pro