garminconnect-js

get_max_metrics_range

Read-only

Fetch maximum VO2 max and related fitness metrics over a chosen date range from Garmin Connect, enabling trend analysis and progress tracking.

Instructions

Max metrics (VO2 max and related values) over a date range. Throws GarminError if start > end.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "start": "<start>",
      "end": "<end>"
    },
    "name": "get_max_metrics_range"
  }
}

Input Schema

Name	Required	Description	Default
`end`	Yes	Calendar date, YYYY-MM-DD (UTC)
`start`	Yes	Calendar date, YYYY-MM-DD (UTC)

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 15, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely new behavior beyond the annotations by disclosing the validation contract: it throws GarminError when start > end, telling the agent this is an error rather than an empty result. It still says nothing about pagination or return shape, keeping it short of a 5.

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?

Two short sentences, zero filler. The resource and range are front-loaded and the failure condition follows immediately.

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

Completeness4/5

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

For a two-parameter read-only tool with a fully documented schema and no output schema, the description covers what is returned (max metrics such as VO2 max) and the one failure mode. Only the return structure/pagination is left unspecified, which is a minor gap for a read tool whose annotations already cover safety.

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?

Schema description coverage is 100% and both date parameters carry format and UTC guidance in the schema, so the baseline is 3. The description's only added parameter meaning is the start > end ordering constraint, which is useful but minimal.

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

Purpose4/5

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

States a specific verb+resource (max metrics / VO2 max values) plus scope ('over a date range'), which implicitly distinguishes it from the sibling get_max_metrics for a single point in time. It never names that sibling explicitly, so the differentiation is inferable rather than stated.

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

Usage Guidelines3/5

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

The date-range scope implies when to reach for this tool versus a single-day variant, but there is no explicit when-to-use, when-not-to-use, or named alternative. An agent must infer the routing decision from the phrase 'over a date range' alone.

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

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