Body battery

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context by explaining the semantics (rises with rest, falls with activity/stress) and the return fields (high/low, charge/drain totals), which helps the agent interpret results without contradicting the annotations.

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?

Two concise, front-loaded sentences. The first sentence states what the tool does; the second adds useful interpretive context. No redundant phrases or filler, every clause earns its place.

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 tool with no output schema, the description tells the agent what to expect (daily high/low, charge/drain totals) and why it matters (trending vs recovery). Combined with the rich parameter schema and safety annotations, the tool is fully described with no obvious gaps.

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 input schema covers all three parameters with detailed descriptions (date formats, relative values, and the summary/full detail distinction), so schema coverage is 100%. The description only refers generically to 'a date range' and doesn't add parameter-specific details beyond what the schema provides, landing at the 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?

The description uses a specific verb ('Get') and names the exact resource ('body battery energy levels') plus the date-range scope. It lists the specific data returned (daily high/low, charge/drain totals), which clearly distinguishes it from sibling tools like garmin_get_stress or garmin_get_hrv.

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 description gives a clear use case: analyzing multi-day energy trends, with the explanatory note about how body battery rises with rest and falls with activity/stress. It doesn't explicitly mention alternatives or exclusions, but the context is sufficient to infer when this tool is appropriate.

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