The WattChop MCP server gives an AI agent direct access to the WattChop API: the certified tariff catalog, load synthesis, and battery + PV sizing. Connect in three lines, with or without an API key.

The server address is:

https://mcp.wattchop.com/mcp

Claude Code

claude mcp add --transport http wattchop https://mcp.wattchop.com/mcp

With a key:

claude mcp add --transport http wattchop https://mcp.wattchop.com/mcp \
    --header "X-Api-Key: $WC_API_KEY"

Cursor

Add the server to .cursor/mcp.json. The key goes in a headers object — Cursor has no header flag.

{
  "mcpServers": {
    "wattchop": {
      "url": "https://mcp.wattchop.com/mcp",
      "headers": { "X-Api-Key": "wc_org_..." }
    }
  }
}

Omit headers entirely to connect in sandbox.

Claude Desktop and claude.ai on the web

Both reach a remote server through Settings → Connectors → Add custom connector. Paste the URL and leave the OAuth fields empty.

claude_desktop_config.json is not the right place — that file configures local servers that run on your own machine, and this one is remote.

The connector dialog has nowhere to put a header, so these two clients connect in sandbox mode only. If you need keyed access from Claude Desktop today, use Claude Code or Cursor alongside it.

Confirm it worked

You should see ten tools. Ask your agent to run docs_search with no arguments — it lists this documentation, needs no key, and costs nothing.

If the tool list looks stale after an upgrade, remove the connector and add it again. Tool lists are cached per registration.

Keep your key out of your repository

Put it in an environment variable and reference it. A key belongs in the X-Api-Key header and nowhere else — never in a request body, a prompt, a commit, or a screenshot.

Where the payloads are documented

These tools wrap the same endpoints the Partner API exposes over plain HTTPS. For field-by-field payload detail — request shapes, the savings envelope, the diminishing-returns curve, and the interval-data formats — see WattChop Partner API — Sizing Engine →.