FitbitMcp 0.1.29

fitbit-mcp

A .NET-based Model Context Protocol (MCP) server for the Google Health API, installable as a .NET tool from nuget.org — the data a Fitbit tracker or scale ends up in once it syncs through Google.

This is an independent, community-built project - not an official Fitbit, Google, or Google Health product. It is not affiliated with, endorsed by, or supported by Google or Fitbit. It works against the public Google Health API using your own OAuth client credentials, registered separately in your own Google Cloud project. "Fitbit" and "Google Health" are trademarks of their respective owners, used here only to describe API compatibility.

Purpose

A Fitbit tracker or scale quietly builds up years of weight, activity, heart rate, and sleep data — but it all sits behind Google's own app, disconnected from everything else. This project connects that data to an LLM directly, so you can ask about it in plain language instead of scrolling through graphs.

A couple of examples of what that looks like once the tools are connected (illustrative - your own numbers will differ):

You: How did I sleep this week compared to last?

Claude: This week you averaged 6h 42m asleep per night across 6 nights logged, up from 6h 10m the week before. Wednesday was your most restless night (58 minutes awake); Sunday was your best, at 7h 15m asleep with only 12 minutes awake.

You: How's my weight trending against body fat this year?

Claude: They're moving together - weight climbed from 97.4kg to a peak of 103.3kg through Q1 into mid-April while body fat rose from 27.8% to 31.4% over the same stretch, then both eased back through Q2. That kind of matched movement points to real recomposition rather than day-to-day water-weight noise.

Requirements

• .NET 8 or .NET 10 runtime - to install and run the tool (see Install below)
• An MCP-capable LLM client - Claude Code, Claude Desktop, or LM Studio (see Configure Claude Code, Claude Desktop, or LM Studio below)
• A Google account and a Google Cloud project - with the Google Health API enabled and an OAuth 2.0 client of your own; see docs/google-cloud-setup.md for the full walkthrough

Status

Working prototype, verified against a real account.

See open issues for the current roadmap.

Security

The HTTP transport has no authentication or authorization layer yet - anyone who can reach the endpoint can call any tool, including the ones reading your real Google Health data. This is fine for local use (stdio, or --http left on localhost), but it means this must not be exposed publicly - no public Docker hosting, no binding to 0.0.0.0 on an open network - until that gap is closed. See docs/cloud-deployment.md for the auth work that's needed first and the reasoning behind deferring hosted/multi-user use.

Available tools

Install

Requires the .NET 8 or .NET 10 SDK - the package multi-targets both, so dotnet tool install picks whichever one matches your installed SDK automatically.

dotnet tool install --global FitbitMcp

This installs a fitbit-mcp command. Confirm it's on your PATH with fitbit-mcp --version (the .NET tools directory, ~/.dotnet/tools, needs to be there - the installer usually adds it automatically).

You'll also need a Google Cloud project with the Google Health API enabled and an OAuth 2.0 client of your own - see docs/google-cloud-setup.md for the full, step-by-step walkthrough (it covers the OAuth consent screen, scopes, and client type in detail, which is easy to get wrong on a first pass).

Configure credentials

Credentials are passed as environment variables - GoogleHealth:ClientId etc. become GoogleHealth__ClientId (double underscore in place of :), which is how .NET's config system maps env vars automatically.

That's the only credential input needed - unlike some MCP servers, you don't manage access or refresh tokens by hand. The one-time authorization below captures and stores them for you, and they refresh automatically after that.

One-time authorization

This grants the server access to your own Google Health data. It's interactive - a browser opens for you to sign in and approve access - and finishes automatically, no code to copy by hand:

export GoogleHealth__ClientId="<your client id>"
export GoogleHealth__ClientSecret="<your client secret>"
fitbit-mcp auth login

You only need to do this again if access is revoked, or roughly every 7 days if your Google Cloud project's OAuth consent screen is still in "Testing" status - see docs/google-cloud-setup.md for why, and what it means in practice.

Run it

The server supports two transports, chosen at startup - stdio by default, or HTTP via a flag:

fitbit-mcp                                       # stdio - for MCP clients that spawn the process directly
fitbit-mcp --http --urls http://localhost:5230    # HTTP - a long-running server on a port

In HTTP mode the MCP endpoint is at <url>/mcp (Streamable HTTP), e.g. http://localhost:5230/mcp.

Configure Claude Code, Claude Desktop, or LM Studio

Do the credentials + one-time authorization steps above first - that part is always interactive and can't happen from inside a client's spawned process.

Can these clients start fitbit-mcp automatically? Yes - all three spawn a local stdio process directly from their own config, no server to keep running yourself.

Find the installed binary's absolute path

GUI-launched apps often don't inherit the PATH your terminal has, so the bare fitbit-mcp command name may not resolve even though it works in a shell. Use the absolute path instead:

• macOS/Linux: ~/.dotnet/tools/fitbit-mcp
• Windows: %USERPROFILE%\.dotnet\tools\fitbit-mcp.exe

Claude Code

claude mcp add fitbit-mcp -- ~/.dotnet/tools/fitbit-mcp

Restart or reconnect your Claude Code session - new MCP registrations aren't picked up mid-session.

Claude Desktop

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/claude_desktop_config.json; Windows: %APPDATA%\Claude\claude_desktop_config.json):

{
  "mcpServers": {
    "fitbit-mcp": {
      "command": "/Users/you/.dotnet/tools/fitbit-mcp",
      "args": [],
      "env": {
        "GoogleHealth__ClientId": "<your client id>",
        "GoogleHealth__ClientSecret": "<your client secret>"
      }
    }
  }
}

Restart Claude Desktop to pick it up.

LM Studio

LM Studio's MCP config (mcp.json) follows the same command/args/env shape as Claude Desktop above. Its documented path is ~/.lmstudio/mcp.json (macOS/Linux) / %USERPROFILE%\.lmstudio\mcp.json (Windows), but there are user reports of the real path differing by version/OS - rather than guessing, use the in-app editor: Program tab → Install → Edit mcp.json, which opens whichever file is actually authoritative for your install, and paste in the same JSON shown for Claude Desktop above (just the inner object works too, since LM Studio also uses an mcpServers map).

Building from source / contributing

Not needed just to use the tool - see docs/DEVELOPER.md in the repo for running from a clone, architecture notes, and how NuGet publishing works.

License

MIT — see LICENSE.