Single tool server with a reasonably clear naming convention and action-verb prefix ('get_'). Description is present and adequately detailed (137 chars), addressing what the tool does and its purpose. However, the input schema lacks descriptions for the parameter, which is a critical gap. Output schema is not visible in the provided code, making it impossible to verify proper field documentation. The tool appears functional but falls short of production-grade standards due to missing parameter descriptions and undocumented output structure.

• Add a non-empty description to the 'date_str' parameter in the input schema. Example: 'Date for which to retrieve the summary, in YYYY-MM-DD format (e.g., 2024-01-15). If omitted, defaults to today.'
• Document the output schema with explicit field names, types, and descriptions. E.g., { steps: number, calories: number, distance_km: number, activities: [ { name: string, duration_minutes: number, ... } ], ... }
• Add error handling documentation to the tool description. Example: 'Returns an error if the date is invalid, the user is not authenticated, or no data is available for that date. Call with valid YYYY-MM-DD dates only.'
• Consider adding optional parameters: 'limit' (default 20, max 100) to cap the number of activities returned, and 'include_raw_timeseries' (boolean, default false) to let agents opt into detailed time-series data when needed.
• Verify that Garmin API credentials are injected server-side (environment variables or secure vault), not exposed as tool parameters. If visible in the code, refactor to pattern:secret-injection.