Summarize wellness trends

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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond that: it discloses that only per-period averages are returned, enumerates which metrics, notes min-max ranges and day counts where data is missing, caps range at 366 days, and says aggregation happens server-side. That is exactly the context an agent needs to set expectations and avoid misinterpreting output.

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?

Front-loaded with the 'best tool for X' claim and example queries, then the return contract, then the special group_by case, then constraints. Dense but every clause carries information; the parenthetical example queries make it longer than strictly minimal but they earn their place by disambiguating use cases.

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?

There is no output schema, so the description carries the full burden of describing return values — and it does, listing the metric set, averaging semantics, ranges, and missing-data day counts. For a 5-parameter aggregation tool with no required params, nothing an agent needs in order to call it correctly is absent.

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 coverage is 80% so the baseline is 3, but the description adds real meaning: it explains what group_by='weekday' is for, enforces the 366-day range limit, and clarifies the period-vs-start_date/end_date relationship. It does not explain the 'total' group_by option or the include-array tradeoff beyond what the schema says.

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 verb+resource (summarize wellness trends) and pins scope to 'over weeks or months', with concrete example queries ('has my sleep improved', 'resting HR trend this year'). The per-period-average framing plus the metric list clearly separates it from single-metric siblings like get_steps, get_hrv, or get_sleep.

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?

Gives strong when-to-use signal via example phrasings and explicitly routes 'which days do I sleep worst / most stressed' to group_by='weekday'. Missing an explicit exclusion such as 'for a single day use get_daily_summaries instead', so the boundary with the raw-fetch siblings is implied rather than stated.

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