# cityparity MCP server

Cost-of-living and quality-of-life comparison tools that AI agents can call. Point an agent at two cities and it returns take-home pay, a full cost breakdown, the equivalent salary you'd need in the target city, and the non-cash deltas people actually move for: vacation, parental leave, universal healthcare.

Hosted at **`https://mcp.cityparity.com/mcp`**. Free, no API key, rate-limited at the edge. Built on the [Model Context Protocol](https://modelcontextprotocol.io/) (spec `2025-06-18`, Streamable HTTP).

- Site: <https://cityparity.com>
- Install docs (every client): <https://cityparity.com/mcp>
- Machine-readable docs: <https://mcp.cityparity.com/llms.txt>
- OpenAPI (REST mirror): <https://mcp.cityparity.com/openapi.json>

## What it covers

About 165 cities across 69 countries. Most calculators stop at salary and rent. cityparity prices the social safety net (childcare subsidies, parental leave, statutory vacation, universal healthcare), so "the lower-salary city actually pays more" stops being a hand-wave and becomes a number.

## Tools

| Tool | What it does |
|------|--------------|
| `compare_cities` | Full scenario comparison between two cities: take-home, cost breakdown, equivalent target salary, lifestyle deltas, quality score. |
| `list_cities` | Discover supported city slugs, grouped by country. |
| `get_city_summary` | One-city profile: tax shape, headline costs, safety-net values. |
| `rank_cities` | Top N cities by composite quality score, with custom weights and region/country filters. |
| `get_safety_net` | Parental leave, universal-healthcare flag, vacation, public holidays for 1 to 20 cities. |
| `get_inbound_tax_regime` | Inbound-worker regimes: Italy impatriati, Portugal IFICI, Belgium expat, Poland B2B ryczałt, Greece inbound. |

City slugs are kebab-case (`san-francisco`, `hong-kong`). Call `list_cities` first if you're unsure.

## Connect

Most modern clients speak Streamable HTTP and need no install. Just point them at the URL.

### Claude Code

```bash
claude mcp add --transport http cityparity https://mcp.cityparity.com/mcp
```

### Claude Desktop / ChatGPT Desktop

```json
{
  "mcpServers": {
    "cityparity": {
      "url": "https://mcp.cityparity.com/mcp"
    }
  }
}
```

Claude Desktop config lives at `~/Library/Application Support/Claude/claude_desktop_config.json` (macOS) or `%APPDATA%\Claude\claude_desktop_config.json` (Windows). ChatGPT Desktop uses `…/OpenAI/ChatGPT/mcp.json`. Restart the app after editing.

### Cursor

```json
{
  "name": "cityparity",
  "url": "https://mcp.cityparity.com/mcp"
}
```

### Codex CLI

```yaml
mcpServers:
  cityparity:
    url: https://mcp.cityparity.com/mcp
```

### Stdio-only clients (this package)

If your client can't do HTTP MCP yet, the npm package in this repo bridges stdio → HTTP:

```json
{
  "mcpServers": {
    "cityparity": {
      "command": "npx",
      "args": ["-y", "cityparity-mcp"]
    }
  }
}
```

## The bridge (this package)

`cityparity-mcp` is a ~150-line stdio→HTTP forwarder. It reads line-delimited JSON-RPC from stdin, POSTs each line to the MCP endpoint, and writes the responses back to stdout (streaming SSE line by line). That's the whole job: no data, no calc engine, no secrets. Read [`bin/cityparity-mcp.mjs`](bin/cityparity-mcp.mjs) if you want to verify.

```bash
npm install -g cityparity-mcp   # or use npx, as above
```

| Env var | Default | Purpose |
|---------|---------|---------|
| `CITYPARITY_MCP_URL` | `https://mcp.cityparity.com/mcp` | Override the upstream endpoint (local dev) |
| `CITYPARITY_MCP_DEBUG` | unset | Log request/response framing to stderr |

Run the tests (zero dependencies, Node ≥ 20):

```bash
npm test
```

## Methodology

The full methodology (how taxes, costs, childcare subsidies, and safety-net scoring work) is on the [homepage](https://cityparity.com/#methodology). One thing worth flagging: **RSU income is not an input.** Grants are treated as source-only because they usually don't follow you across employers. If you're keeping a US employer remotely, treat the result as directional in that direction.

## Privacy

Queries reach `mcp.cityparity.com` and nothing else. No accounts, no client-side telemetry, nothing personally identifiable logged beyond standard HTTP server logs.

## License

MIT. cityparity's underlying data and calculation engine are not part of this package. This repo is the public MCP surface plus the open-source stdio bridge.

---

Found a bug or want a city added? <https://cityparity.com/contact/>