get_fitnessage_data

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds useful context that data comes from Garmin Connect and is scoped to the current user, but it does not discuss return behavior, latency, or auth requirements beyond the annotations.

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 two compact sentences with the tool purpose front-loaded. The Garmin source, read-only nature, and date format are all relevant, and there is no wasted text.

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?

This is a simple one-parameter retrieval tool, an output schema exists, and annotations cover the safety profile. The description sufficiently covers the current-user scope and date format, though it could do slightly more to explain what the required cdate represents.

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 compensate for the single required parameter. It adds the useful format constraint 'Dates are YYYY-MM-DD,' but the parameter name 'cdate' is still somewhat opaque and the description does not clarify whether it is a target date, range start, or snapshot date.

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 states a specific verb and resource: 'Return Fitness Age data for current user.' It clearly distinguishes the resource from sibling metric tools like get_training_readiness or get_max_metrics, though it does not explicitly differentiate when this metric is preferred over related ones.

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 provides no explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. Usage is only implied by the tool name and the phrase 'for current user.'

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