get_body_battery

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

There are no annotations, so the description carries the behavioral burden. The wording 'readings for a day' suggests a read-only lookup and the date format is useful, but it does not disclose what happens when the optional day parameter is null, timezone assumptions, or limitations. For a simple getter this is minimally acceptable but not richly transparent.

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 zero redundancy: it states the resource, the scope, and the date format. The key information is front-loaded and every word 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 single-parameter read tool with an output schema present, the description covers the essential call contract—what to request and the date format. The main omissions, null default behavior and sibling selection guidance, are modest given the tool's low complexity.

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 schema offers only a title and null default, while the description adds the crucial YYYY-MM-DD format—valuable since schema description coverage is 0%. However, it does not clarify the meaning of the null default or the expected result when day is omitted, leaving a partial but non-trivial contribution.

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 clearly identifies the resource (Body Battery readings) and the temporal scope (a single day), with an explicit date format. It does not explicitly contrast with sibling tools such as get_body_battery_stress, but the target resource is distinct enough that an agent can infer what the tool returns.

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 implies a single-day use case but provides no guidance on when to prefer this tool over get_body_battery_stress or get_body_battery_stress_history, and no exclusions or context are given. With many sibling tools, the omission of any selection criteria is a notable gap.

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