get_fitness_age

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

No annotations are provided, so the description carries the burden of revealing behavior. It correctly signals a read-only 'get' operation and discloses the default date behavior. It does not describe what happens when no fitness age data exists for the date, error cases, or the shape of the returned value.

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 compact and front-loaded with the purpose. The parameter documentation is minimal, precise, and useful. Every sentence earns its place, with no filler or redundant restatement.

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?

Given the tool's low complexity and single optional parameter, the description is nearly complete. It lacks an explicit return type or error behavior, but for a simple dated getter this is a minor gap, especially since the purpose and parameter semantics are clear.

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 description coverage is 0%, so the description must fully clarify the parameter. It does: 'date_str: Date as YYYY-MM-DD. Defaults to today.' This adds format and default semantics that the input schema alone does not provide.

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 uses a specific verb and resource: 'Get the athlete's Garmin Fitness Age' for a date. This clearly distinguishes it from the sibling tools, none of which are explicitly dedicated to fitness age. The resource and date context are unambiguous.

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 when to use the tool: whenever the athlete's fitness age is needed for a given date. It also clarifies that omitting the date defaults to today. However, it does not explicitly discuss alternatives, exclusions, or situations where another sibling tool would be preferred.

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