Body Battery

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description usefully states which values come back, but says nothing about external-API auth, rate limits, or data-availability behaviour (openWorldHint implies an external Garmin service where those matter).

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 sentence with the resource and returned fields front-loaded; every clause (metrics, scope) carries information and there is no filler.

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 3 fully documented, all-optional parameters and no output schema, the description gives enough to call the tool and know what it returns. Minor gaps remain: no hint about default behaviour or whether a missing day yields an empty result.

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%, so date formats, inclusivity and the include_series summary/fallback behaviour are all documented in the schema. The description's 'one day or a range' adds only a light framing of how start_date/end_date interact, which is baseline value.

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 concrete resource (Garmin Body Battery) and enumerates the exact metrics returned (charged, drained, highest, lowest), plus the temporal scope (one day or a range). The metric name alone distinguishes it from siblings like get_stress or get_hrv, though it never explicitly says so.

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?

The phrase 'for one day or a range' implies the two calling modes, but there is no explicit when-to-use guidance, no mention of prerequisites (e.g. a paired Garmin device), and no routing away from or toward related tools such as get_daily_overview.

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