getBodyBattery

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

With no annotations, the description carries the full burden. It discloses the maximum date range (14 days) and the types of events included, but omits behavioral traits such as whether the operation is read-only, authentication requirements, rate limits, or error handling. This is a read tool, but the description does not explicitly confirm that.

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, front-loaded sentence that efficiently conveys the tool's purpose and output content. It is dense but not overly verbose, though it could be slightly more structured with bullet points.

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?

Given the simple two-parameter schema and no output schema, the description adequately explains what data is returned per day, including charge/drain, readings, and events. It covers the essential information an agent needs to call the tool correctly, though it could mention output format or error conditions.

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 the schema already documents both parameters. The description only reiterates the date format (yyyy-MM-dd) and the 14-day limit, adding no new meaning beyond what the schema provides.

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 states a specific verb (get) and resource (Body Battery) and details the data returned per day, including charge/drain, readings, and events. It clearly distinguishes this tool as focused on Body Battery data, though it does not explicitly name sibling tools for differentiation.

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 usage by specifying a date range up to 14 days and listing the data returned, but it offers no explicit guidance on when to choose this tool over alternatives like getDailySummary or getSleep. No exclusions or prerequisites are mentioned.

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