get_body_battery

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds useful scope context (default 7-day window, per-day granularity) but says nothing about missing-day handling, timezone/date interpretation, or how the summary relates to the raw JSON. Note a soft conflict: the description promises a 7-day default while the schema declares start and end each default to today.

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 where the resource leads and the default range is parenthetical. It earns its place, though it is telegraphic to the point of under-specification for a data-returning tool with an output 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?

With an output schema present, return-value detail is legitimately omitted, and annotations cover the read-only profile. What remains missing is disambiguation from the crowded sibling set and a coherent statement of the default date window, which the schema and description currently describe differently.

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 start/end formats and the raw flag are already documented, anchoring this at a 3 baseline. The description's 'defaults to the last 7 days' arguably adds range semantics, but it sits in tension with the schema's per-parameter 'defaults to today', leaving the actual default window ambiguous rather than clarified.

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?

Names a specific resource (Body Battery) and the exact metrics returned (charged/drained/high/low) at a per-day granularity, which is enough to tell it apart from generic siblings like get_daily_summary. The verb 'get' is implied rather than stated, and no sibling is named for contrast, keeping it short of a 5.

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 only usage context is the implicit 'defaults to the last 7 days' range; there is no statement of when to prefer this over the many related siblings (get_daily_summary, get_stress, get_hrv, get_health_range), nor any exclusions. An agent must infer the choice from the tool name alone.

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