Body measurements (scale)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds genuinely useful behavior: units are decoded, metrics the scale didn't measure return null, and range is capped at 366 days. These details are not derivable from the annotations and prevent misinterpretation of nulls as zeros.

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-loads the resource and date-range scope, then the metric inventory, and closes with defaults. The metric list is long but each item earns its place as return-value content; otherwise no wasted prose.

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 read-only, no-output-schema tool, it covers the essentials an agent needs: what rows represent (one per step-on), what fields appear, null semantics, and date-range defaults/limits. Only the manual-entry parameter behavior is left unaddressed.

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 100%, so both date parameters are already documented, and the description's default/limit note largely reinforces 'Default: 29 days before end_date.' It adds nothing about include_manual (manual vs device entries), so it does not meaningfully exceed the schema baseline.

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 ('Weigh-ins in a date range') and enumerates the exact metric fields returned, including cardio-scale-only extras. An agent can immediately distinguish this from get_blood_pressure or get_daily_activity without opening the schema.

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 clear operating context: default window of last 30 days and a hard ceiling of 366 days, which guides how to call it. It does not explicitly name when to prefer a sibling (e.g., a blood-pressure readout) or state exclusions, so it falls short of the top band.

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