Weight

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

Annotations only declare it as a safe idempotent read. The description adds material behavior: raw gram units, the 92-day-per-call ceiling, the likelihood of empty results, and the previousDateWeight fallback that must be date-checked before being treated as current. That is precisely the kind of trap the annotations cannot convey.

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 what is returned and the unit convention, then the emptiness caveat, then the range mechanics. Dense but each sentence carries weight; the period examples are slightly redundant given the enum is fully enumerated in the schema.

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?

No output schema exists, so the description must explain the return shape, and it does: measurements as Garmin sends them, grams, plus the previousDateWeight edge case. Combined with the range limits, an agent has everything needed to call and interpret it.

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% and already documents the period enum, the 92-day max span, and 'use instead of start_date/end_date.' The description's period examples and 92-day note largely restate the schema, adding only the practical instruction to split long ranges into multiple calls.

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 exactly what is returned (weight and body composition measurements over a range), the data source (Garmin smart scale or manual Garmin Connect entries), and the unit convention (grams, 74000 = 74 kg). An agent can distinguish this from get_weight_goals or wellness siblings 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 explicit selection rules between period and start_date/end_date, tells the agent to make several calls for histories beyond 92 days, and warns that results are often empty. It does not name a sibling tool as an alternative, so it stops short of full when/when-not routing.

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