Compare periods

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

Annotations already declare the tool as read-only, open-world, idempotent, and non-destructive, so the description's main contribution is the input constraint of 'up to 366 days each' and the specific metric ('average calories and macros'). It does not disclose return format, date handling details, or any other behavioral traits, but the annotations lower the bar.

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 with no filler. Every word adds value: the action, the metrics, and the range limit. It is concise and well-structured.

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 tool with 4 undocumented parameters and no usage guidance, the description could do more. It states what the tool does and the range limit, but omits any mention of the output structure (though an output schema exists), assumptions about date inclusivity, or guidance on when to use this tool. The annotations and output schema fill some gaps, but the description alone is not fully complete for decision-making.

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 0%, so the description must compensate. It adds meaning by explaining that the four date parameters define two ranges and that each range is limited to 366 days. However, it does not explicitly describe each parameter (e.g., the relationship between start and end dates) or the expected date format, relying on the self-explanatory parameter names.

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 states the tool's function with a specific verb ('compares'), resource ('average calories and macros'), and scope ('two ranges of up to 366 days each'). This differentiates it from siblings like get_nutrition_trends, which likely show trends rather than direct period-to-period comparisons.

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 the tool is for comparing two date ranges, but it provides no explicit guidance on when to choose it over alternatives (e.g., get_nutrition_trends, get_daily_summary). No when-not-to-use or alternative tool names are mentioned, so the usage context is only implied.

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