get_fitness_age

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

With no annotations, the description should disclose read-only behavior, permissions, or side effects. It only lists output components and the default date behavior; it does not explicitly confirm the operation is safe or describe rate/usage limits.

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 brief and front-loaded with the core resource, but the first sentence is a fragment without an explicit action verb. The Args block is clean and contributes value.

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 an output schema available and only one well-documented parameter, the tool is easy to invoke. It could be improved by adding a brief note about its relationship to fitness metrics tools, but it is not severely incomplete for a simple getter.

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 single date parameter is fully explained with format (YYYY-MM-DD) and default behavior (today), compensating for the 0% schema description coverage. This is exactly the semantic information an agent needs.

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 identifies the resource (Garmin fitness age) and enumerates its components, which distinguishes it from generic metrics tools. However, it is a noun phrase rather than a verb+resource sentence, and it does not explicitly contrast with sibling tools like get_fitness_metrics.

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?

No guidance on when to choose this tool over siblings is provided. There is no mention of alternatives, exclusions, or prerequisites, leaving the agent to infer usage from the name alone.

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