garmin_body_composition

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

No annotations are provided, so the description carries the full behavioral burden, and it adds almost nothing: it doesn't say what time window is returned, whether data requires a synced device or account, or how freshness is handled. The presence of an output schema offsets the need to describe return values, but behavioral context is otherwise missing.

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 filler, which is appropriately sized for a no-arg reader. It is a noun phrase rather than a full clause, so it reads slightly as a label than an instruction.

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?

With no parameters and an output schema, the description needn't explain the return payload, so it is close to sufficient. However, for a 'history' tool with no parameters, the agent has no idea what period or granularity is covered, which is a meaningful omission.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The only missed opportunity is that a param-less history tool could clarify its default range.

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 names the specific resource — weight, BMI, and body composition history — plus trend analysis, so an agent knows what data comes back. It does not state an explicit verb or differentiate itself from overlapping siblings such as garmin_trends, garmin_health_summary, or garmin_wellness_activity, which all plausibly surface similar longitudinal data.

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?

There is no guidance on when to call this versus garmin_trends, garmin_health_summary, or the other metric-specific tools. With ~50 siblings in the namespace, the absence of a routing hint is a real gap.

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