Nutrition diary

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

Annotations already declare read-only, idempotent, and non-destructive behavior, which the description does not contradict. The description adds valuable behavioral detail: the aggregation is performed locally and is limited to 31 days. It does not cover error cases or response format, but this is mitigated by the presence of an output schema and annotations cover the safety profile.

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, tightly written sentence that packs in essential info: what it returns, single vs range, the 31-day cap, and a caveat about the API. There is no redundant wording, and the semicolon separates two related thoughts effectively without bloating the description.

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 low complexity of the tool and the presence of a detailed output schema, the description covers the core behavior (single date or range) and the local aggregation constraint. It does not explicitly state what happens if no parameters are supplied, but all params are optional, which could be ambiguous. Still, the description is largely complete for the typical use cases.

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 has no descriptions and 0% coverage, so the description carries the burden for parameter semantics. It clarifies that 'date' is for a single day and 'start_date'/'end_date' define a range, but it does not specify date formats, whether parameters are mutually exclusive, or behavior when no parameters are provided. This is a partial but insufficient compensation for the schema gap.

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 returns the diary for a specific date or a locally aggregated range up to 31 days. It uses a specific verb 'returns' and identifies the resource 'diary', effectively distinguishing it from sibling tools like get_daily_summary or get_nutrition_trends. The note about YAZIO lacking a confirmed range endpoint also clarifies the tool's unique role.

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 provides clear usage context: use this tool to retrieve diary data for a single date or a range. It implies that for ranges, this tool is necessary due to the lack of a native endpoint. However, it does not explicitly mention when to use alternative tools, such as getting daily summaries separately, or when not to use this tool.

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