get_hrv_trend

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

With no annotations provided, the description carries the full behavioral burden. It discloses the output shape (daily values and weekly rolling averages), explains why the tool exists, and provides an actionable interpretation threshold. It does not discuss authentication, timezone behavior, or edge cases, but for a read-only trend tool this is reasonably transparent.

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 front-loaded with the core purpose, followed by return-value summary, practical usage reasoning, range guidance, and parameter documentation. Each sentence earns its place, and the actionable threshold adds value without bloating the 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?

For a simple two-parameter read-only tool with an output schema present, the description is complete enough. It covers what the tool does, what it returns, how to interpret the result, and the acceptable date range, so an agent can invoke it correctly without additional inference.

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, and it does. It documents both start_date and end_date with explicit YYYY-MM-DD format and reinforces the date-range intent through the recommended and maximum range guidance. It could add inclusivity/exclusivity semantics, but the added value over the bare schema is meaningful.

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: 'Get HRV trend over a date range,' and clarifies it returns daily HRV values plus weekly rolling averages. It clearly distinguishes this trend-focused tool from raw single-day HRV accessors by emphasizing that single-day HRV is too noisy to act on.

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 clear when-to-use guidance: use it to identify baseline shifts indicating fatigue or recovery, and states the recommended range of 7-21 days with a maximum of 30 days. It implicitly discourages single-day use but does not explicitly name an alternative sibling tool such as get_hrv_data, so exclusion guidance is slightly incomplete.

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