VO2 max and fitness age

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

Annotations already provide readOnlyHint=trueable, so the read-only nature is covered without contradiction. The description adds only the metric list and temporal scoping, but does not disclose behavioral details such as data freshness, null-date handling, or whether all metrics are always present.

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 concise fragment with no filler words. It front-loads the main metric names and the date context, making it 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?

With only one optional parameter, no required fields, annotations covering read-only behavior, and an output schema present, the description provides enough context for basic invocation. The main gap is missing date format/null semantics, but the default null in the schema and output schema mitigate this.

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 parameter meaning. 'As of a date' does clarify that the optional date parameter sets the temporal reference point, but it does not specify date format, what null means, or whether partial dates are accepted.

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 identifies the specific resource (VO2 max, fitness age, heat/altitude acclimation) and adds a temporal scope ('as of a date'), which distinguishes it by topic from sibling tools. It lacks an explicit verb like 'retrieve' or 'get,' but the intent is still clear.

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 phrase 'as of a date' implies the tool is used to fetch these metrics for a particular date, providing some usage context. However, there is no explicit guidance on when to choose this over related siblings such as daily_summary or training_status, and no mention of what omitting the date means.

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