MCP Server GSA DSSR DTMO

Allowances API MCP Server

Official GSA, DSSR and DTMO per diem and allowance rates inside Claude, Cursor, VS Code, Codex and any other MCP client.

Connect once, then ask your assistant for a rate. Every Allowances API endpoint is a tool.

Endpoint

https://mcp.allowancesapi.com/mcp

Streamable HTTP. Send your key in the X-API-Key header on every request.

Connect with Claude Get a free API key

Connect in Cursor

Connect with Codex

Connect in VS Code

One command for Claude Code, one config block for Claude Desktop. The Cursor link installs the server with a YOUR_KEY placeholder to replace in Cursor's MCP settings.

What you can ask

Travel budgets

"What is the GSA per diem for San Diego in March 2027?"

Overseas proposals

"Give me the DSSR COLA and hardship rates for Nairobi, Kenya."

Expense checks

"Calculate the mileage reimbursement for a 240-mile drive on 2026-10-01."

How it works

✓ Every public /v1/ endpoint is exposed as an MCP tool: per diem lookups, DSSR allowances, the GSA mileage and trip calculators, metadata and your usage.
✓ Your API key, plan, effective-date and quota rules apply exactly as they do on the REST API. A tool call costs one request; discovery calls are free.
✓ Works on every plan, including the free Sandbox. No OAuth, no extra setup: one header, any client that supports custom HTTP headers.
✓ Stateless and refreshed daily with the official rate tables, so your assistant always answers with current data.

Set up your client

Replace YOUR_KEY with your API key. Each snippet is complete; nothing else is required.

Claude Code

One command registers the server for the current project. Add --scope user to make it available everywhere.

claude mcp add --transport http allowances https://mcp.allowancesapi.com/mcp \
  --header "X-API-Key: YOUR_KEY"

Claude Code: share with your team

Commit a .mcp.json at the repository root and keep the key in an environment variable.

{
  "mcpServers": {
    "allowances": {
      "type": "http",
      "url": "https://mcp.allowancesapi.com/mcp",
      "headers": { "X-API-Key": "${ALLOWANCES_API_KEY}" }
    }
  }
}

Cursor

Use the Connect in Cursor button above, or add this to ~/.cursor/mcp.json (global) or .cursor/mcp.json (project).

{
  "mcpServers": {
    "allowances": {
      "url": "https://mcp.allowancesapi.com/mcp",
      "headers": { "X-API-Key": "YOUR_KEY" }
    }
  }
}

VS Code / GitHub Copilot

Add this to .vscode/mcp.json in your workspace. VS Code prompts for the key on first use and never writes it to the file.

{
  "inputs": [
    { "type": "promptString", "id": "allowances-key", "description": "Allowances API key", "password": true }
  ],
  "servers": {
    "allowances": {
      "type": "http",
      "url": "https://mcp.allowancesapi.com/mcp",
      "headers": { "X-API-Key": "${input:allowances-key}" }
    }
  }
}

Claude Desktop

Claude Desktop cannot send custom headers to remote servers, so it connects through the mcp-remote bridge (needs Node.js). Open Settings, Developer, Edit Config and add this, then restart the app.

{
  "mcpServers": {
    "allowances": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.allowancesapi.com/mcp", "--header", "X-API-Key:${ALLOWANCES_API_KEY}"],
      "env": { "ALLOWANCES_API_KEY": "YOUR_KEY" }
    }
  }
}

Codex CLI

Register the URL, then add the header to ~/.codex/config.toml. env_http_headers reads the key from an environment variable instead.

codex mcp add allowances --url https://mcp.allowancesapi.com/mcp

# ~/.codex/config.toml
[mcp_servers.allowances]
url = "https://mcp.allowancesapi.com/mcp"
http_headers = { "X-API-Key" = "YOUR_KEY" }

Check it with curl

Lists the available tools. Without the header the server answers 401.

curl https://mcp.allowancesapi.com/mcp \
  -H "X-API-Key: YOUR_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

Every tool is documented

The MCP tools mirror the REST endpoints and are documented next to them. The API reference lists them in its MCP section, with the input schema of every tool, and the OpenAPI document publishes the full catalogue in its x-mcp extension, so agents can discover the server from the schema alone.

Connect with Claude Get a free API key

Connect in Cursor

Connect with Codex

Connect in VS Code

Data sourced from official public per diem and allowances tables. Not affiliated with any government agency.

Claude, Cursor, Visual Studio Code, GitHub Copilot and Codex are trademarks of their respective owners.