Get Fitness Stats

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

The annotations already establish read-only and open-world intent, and the description adds useful aggregation and date-range scoping. However, it does not explain what shape the returned aggregated statistics take, whether the date range is inclusive, or how the grouping defaults behave beyond the schema documentation.

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?

The description is a single clear, front-loaded sentence that communicates the primary action and scope without filler. Every word earns its place, and the structure makes the tool easy to scan.

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?

The schema covers the invocation parameters, and the readOnly annotation covers safety, but there is no output schema and the description does not explain what the aggregated response contains beyond the vague phrase 'fitness statistics'. This makes it minimally usable, but somewhat incomplete in a large sibling-tool context.

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?

The input schema covers all parameters well: startDate, endDate, metric, and groupByActivities all have descriptions, including formats and defaults. The description adds little beyond the word 'aggregated', so it neither hurts nor meaningfully compensates beyond the schema coverage.

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 clearly states that the tool gets aggregate fitness statistics over a date range, using a specific verb ('Get') and resource ('aggregated fitness statistics'). It does not fully differentiate its output from broad sibling tools like get_health_metrics or get_daily_summary, but the 'aggregated' + 'between two dates' framing provides meaningful scope.

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?

The description implies the tool is appropriate when date-bounded aggregate fitness stats are needed, but it does not provide explicit when-to-use or when-not-to-use guidance, nor does it name alternatives. It hints at context through 'aggregated' and 'between two dates' but does not give a clear usage policy.

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