get_hrv_trend

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

With no annotations, the description must disclose behavior. It states that it 'Returns daily HRV values and weekly rolling averages', revealing the output shape. However, it does not explicitly confirm that the operation is read-only or describe any potential side effects, though 'Get' implies no mutation.

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 well-structured with a purpose statement, return details, usage guidance, and parameter descriptions. It is slightly longer than necessary due to the clinical interpretation note ('A drop of >10ms...'), but this information is relevant and not redundant, so it earns a high 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?

For a simple two-parameter getter, the description fully covers the tool's purpose, usage, return content, and parameter formats. The existence of an output schema further fills in structural details, making the description complete for a caller to use the tool correctly.

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?

The input schema has no descriptions for either parameter, so the description's statement of 'Start date in YYYY-MM-DD format' and 'End date in YYYY-MM-DD format' adds essential format information. It does not specify inclusivity of dates or ordering, but the phrase 'over a date range' implies inclusive bounds, and ordering is conventionally understood.

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 clearly states the verb 'Get' and the specific resource 'HRV trend over a date range'. It further distinguishes this from a simple data fetch by mentioning weekly rolling averages, making the purpose unambiguous even without comparing to sibling tools.

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?

It explicitly explains when to use this tool: 'Single-day HRV is too noisy to act on — use this tool to identify baseline shifts'. It also provides practical usage constraints with 'Recommended range: 7-21 days. Maximum: 30 days.', guiding the caller on appropriate date ranges.

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