get_hrv_data

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe, externally-sourced read. The description adds that the result covers both readings and a status for a single calendar day, but discloses nothing about data availability, empty days, or return shape. With annotations carrying the safety profile, this is adequate.

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?

A single front-loaded sentence with no waste; the resource is named first and the scope constraint follows. It is tight, though 'readings and status' remains slightly abstract about what is actually returned.

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 one-parameter read tool with no output schema, the description covers what is fetched and for which day, which is the minimum viable. It does not describe the shape or contents of 'readings and status', and there is no output schema to compensate, so a gap remains.

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?

There is a single required parameter documented at 100% schema coverage, with format and timezone ('YYYY-MM-DD (UTC)') spelled out in the schema itself. The description's 'one date' reinforces, but does not extend, what the schema already provides. Baseline 3 applies when the schema does the heavy lifting.

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?

States a specific resource (heart-rate variability readings and status) and narrows scope to 'one date', which implicitly distinguishes it from the sibling get_hrv_data_range. It never names that sibling explicitly, so the differentiation requires a small inference.

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 'for one date' implies this is the single-date tool as opposed to the range variant, but there is no explicit when-to-use rule, prerequisite, or named alternative. Usage is inferred rather than stated.

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