loseit-mcp

An MCP server and CLI for logging food to Lose It!.

⚠️ Unofficial. Lose It! publishes no public API. This talks to the private GWT-RPC endpoint used by the Lose It! web app, so it can break whenever they ship a new web build.

Tools

log_custom_food exists because updateFoodLogEntry carries the food's name, brand, and nutrient map inline — so an entry can describe a food the database has never heard of. Use it for restaurant meals, homemade dishes, or any portion where forcing a database match would distort the numbers.

Related MCP server: nutrition-mcp

Setup

uv sync
cp .env.example .env   # then fill in your credentials

Configuration

Settings resolve in priority order: CLI flags → environment → .env → JSON config file → defaults.

* Not required if LOSEIT_TOKEN is set.

.env is gitignored. The session token is cached at ~/.config/loseit-mcp/session.json with owner-only permissions and refreshes automatically when it expires.

Running the server

loseit-mcp serve                                  # stdio (default)
loseit-mcp serve --transport streamable-http --port 8000

Register the stdio server with an MCP client:

{
  "mcpServers": {
    "loseit": {
      "command": "uv",
      "args": ["run", "loseit-mcp", "serve"],
      "cwd": "/absolute/path/to/loseit-mcp"
    }
  }
}

CLI

The same operations are available directly, which is the easiest way to test:

loseit-mcp search "greek yogurt" -n 5
loseit-mcp describe <food_id>
loseit-mcp diary 2026-07-25
loseit-mcp log <food_id> -m lunch -a 120 -u g
loseit-mcp log-custom "Caesar Salad" 620 -m lunch -b "Gastrohub" -p 46 -c 18 -f 40
loseit-mcp weigh 199.2
loseit-mcp delete <entry_id> -d 2026-07-25

Add --dry-run to either log command to preview the math without writing, and --json for machine-readable output.

Notes

• Deleting writes a recoverable copy to local trash before the wire call.

• Weights carry no unit over the wire; the number is interpreted in whatever unit the account displays (lb or kg).

• Fractional portions of database foods can display a misleading unit (half a banana rendering as "1/4 Each") because the server's canonical serving count differs from the food's native unit. Calories stay correct, but log-custom is the more predictable route for odd portions.

Architecture

The GWT-RPC wire format is handled by the phitoduck/lose-it SDK. This project adds email/password authentication (the SDK expects you to supply a JWT yourself, and its browser-cookie import does not support Windows), the custom-food logging path, weight recording via saveRecordedWeight (captured from the web app's weigh-in widget), and the MCP server and CLI layers.