get_hrv

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does explain the date-range semantics ('period=days, up to end, YYYY-MM-DD'), which goes beyond the raw schema. However, it does not state that this is a read-only operation, what the response contains, or how the default end/days behave at runtime, leaving notable gaps.

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 front-loaded sentence that states the core purpose first and keeps all content relevant. The parenthetical is compact and information-dense, though slightly cryptic. No words are wasted, but the cryptic phrasing prevents a top score.

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 low complexity (2 optional params, output schema present), the description covers the basic purpose and some parameter meaning. However, it lacks explicit usage guidance and fully transparent parameter behavior (e.g., defaults, null end). It is minimally viable but has clear gaps for an agent needing to select and invoke it confidently.

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 undeclared parameters. It partially does by mapping 'days' to 'period' and 'end' to 'up to end, YYYY-MM-DD'. But the phrasing 'period=days' is ambiguous because 'period' is not a schema parameter, and it does not clarify that both parameters are optional or their default behaviors, so compensation is incomplete.

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 the resource ('HRV history') and the time scope ('last N days'), which clearly identifies what the tool returns. It is distinguishable from sibling tools like get_resting_heart_rate or get_body_battery because HRV is a specific metric. However, it does not elaborate on whether the history is daily averages, raw values, or another form, so it is not fully explicit.

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 guidance on when to use this tool versus siblings such as get_daily_heart_rate or get_body_battery. There is no mention of alternatives, exclusions, or conditions that would select this tool. The only implicit cue is the name and 'HRV history,' which is insufficient explicit routing guidance.

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