Garmin Coach MCP

get_weight_data

Fetch weight and body composition data for a specific date from Garmin Connect. Enter a YYYY-MM-DD date to retrieve that day's metrics; defaults to today.

Instructions

Get weight and body composition data for a specific date

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_weight_data"
  }
}

Input Schema

Name	Required	Description	Default
`date`	No	Date in YYYY-MM-DD format (defaults to today)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.0Oct 1, 2026

TDQS

A3.5/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden. It indicates a read operation (Get) but does not disclose behavioral details such as handling of missing dates, multiple records, or error cases. The default behavior is only hinted in the parameter schema, not the description.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence with no redundant words, efficiently conveying the tool's purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite simplicity and no output schema, the description leaves the agent unaware of the return structure (e.g., which body composition fields). For a tool retrieving multiple metrics, this is incomplete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Parameter schema coverage is 100% with a clear description for the date parameter. The main description adds no extra meaning beyond what the schema already provides, so score is at baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Get' and the resource 'weight and body composition data', and specifies the scope 'for a specific date'. This uniquely identifies the tool among siblings like get_heart_rate_data or get_hydration_data.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives. The description does not mention any conditions, prerequisites, or comparisons to sibling tools like get_health_metrics or get_daily_overview.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.