get_fitness_ageRetrieves Garmin fitness age for a specified date, defaulting to today, so you can track changes in fitness age over time.
Garmin's fitness age for a date.
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | Calendar date, YYYY-MM-DD. Defaults to today. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and open-world behavior, so the description adds essentially nothing beyond that. It does not say what the fitness age represents (units, derivation, whether it is Garmin-computed only), nor what happens when no data exists for the date.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single front-loaded sentence with no filler. It is efficient, though its brevity borders on under-specification rather than true conciseness.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, the description should say what is returned (a numeric age in years? an object with chronological age comparison?); it does not. For a metric tool whose only parameter is already documented, this leaves the agent guessing about the response shape.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and the single optional 'date' parameter is fully documented with format and today-default in the schema. The description adds no additional semantics, so baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names the resource ('fitness age') and the source ('Garmin's') plus the temporal scope ('for a date'), so the agent can tell it returns a wellness metric. However, the verb is only implied and there is no explicit differentiation from the many metric siblings (get_hrv, get_body_battery, get_steps). It is identifiable but not sharply distinguished.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this versus other metric tools, no exclusions, and no alternatives named. Usage is only inferable from the tool name and the sibling list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.