garmin_body_battery

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

With no annotations, the description carries the full behavioral disclosure burden, but it only lists output categories. It does not describe read-only safety, how date defaults are applied, or behavior on days without data. The 'per day' clause gives some granularity, but most behavioral traits are absent.

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 a single, telegraphic sentence with no filler, and it front-loads the metric and the key aggregates. It is compact for a simple date-range tool, though slightly noun-phrase-like rather than an explicit 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?

For a simple read-only metric tool, the schema covers parameters and the output schema covers return shape, so the description is mostly sufficient for invocation. However, missing usage guidance and behavioral context prevent it from being fully self-contained.

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 description coverage is 100%, and both date parameters are already documented with format and default behavior in the schema. The description adds no new parameter-level meaning, so the baseline of 3 is appropriate.

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, Body Battery, and enumerates the reported metrics: charged/drained plus high/low/latest per day. This clearly distinguishes it from sibling tools that cover other metrics like sleep, HRV, or stress. It lacks an explicit verb such as 'retrieve', but the meaning is unambiguous.

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?

No guidance is provided about when to use this tool versus the many garmin_* siblings. The only cue is the tool name and metric name, forcing the agent to infer use cases. There is no when-not, alternative mention, or selection condition.

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