Gauge

Gauge is an MCP server for people running a small website. It lets an AI assistant read your site's analytics and send email, from one install.

It is a bundle: one server made of modules. You switch on the modules you use. New modules arrive switched off, so an update never changes what your assistant can do until you choose to.

Gauge works with any MCP client: Claude Desktop, Claude Code, Cursor, VS Code, Sonique, Hermes, OpenClaw and others. It runs on your computer and stores nothing; your data stays in Umami and Resend.

Install

Gauge needs Python 3.11 or newer. With uv you don't install anything ahead of time:

uvx gauge-mcp --version

Or with pip:

pip install gauge-mcp

Settings

Set these as environment variables in your MCP client's config, or put them in a config file (see below). You only need the settings for the modules you use. Gauge starts without any of them and tells you what's missing when you call a tool.

Config file (optional). Gauge also reads ~/.config/gauge/config.toml, or the file named by GAUGE_CONFIG. Environment variables win over the file.

[umami]
url = "https://analytics.example.com"
username = "viewer"
password = "change-me"

[resend]
enabled = false

Add it to your MCP client

Most clients use the same JSON shape. Put it where your client keeps MCP servers:

{
  "mcpServers": {
    "gauge": {
      "command": "uvx",
      "args": ["gauge-mcp"],
      "env": {
        "GAUGE_UMAMI_URL": "https://analytics.example.com",
        "GAUGE_UMAMI_USERNAME": "viewer",
        "GAUGE_UMAMI_PASSWORD": "change-me",
        "GAUGE_RESEND_API_KEY": "re_your_key",
        "GAUGE_RESEND_FROM": "hello@example.com"
      }
    }
  }
}

Over HTTP. For clients that connect to a URL instead of launching a process:

gauge-mcp --transport http --port 8765

It serves streamable HTTP at http://127.0.0.1:8765/mcp. It listens only on your own machine by default. Put authentication in front of it before exposing it anywhere else.

Tools

Every tool returns structured data with a published schema, so an assistant can write code against the results instead of reading text. Date ranges take days (default 7) or ISO 8601 start and end. Errors always look like gauge.<module>.<code>: <message> Fix: <hint>.

Safety

• Gauge only calls the services you configure. It sends nothing anywhere else and keeps no data.
• resend_send sends real email, so you approve each one, not the assistant. When the assistant asks to send, Gauge asks you directly through your MCP client (MCP elicitation) and shows the sender, recipients and subject. The assistant can't answer that question for you.
• Some MCP clients can't ask you questions yet. In those, Gauge refuses to send unless you've pre-approved the recipients with GAUGE_RESEND_ALLOWED_RECIPIENTS, or turned approval off with GAUGE_RESEND_REQUIRE_CONFIRM=false.
• Give Gauge the least access it needs: a view-only Umami user, and a Resend key limited to sending if you don't need the other email tools.

Develop

uv venv && uv pip install -e '.[dev]'
.venv/bin/pytest

License

MIT. Published by Seaynic Labs.