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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description adds value beyond that by disclosing the return structure (meals with foods, amounts, nutrition, and per-day totals), which matters because there is no output schema. It does not mention the 31-day cap or pagination, but the schema itself carries the cap.

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, front-loaded with the verb and resource, then expanding into scope and return content. No filler, no repetition of the title.

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 three optional parameters, no output schema and full annotation coverage, the definition supplies the one thing structured data lacks: what the response contains (meals, foods, amounts, nutrition, totals). The only minor gap is that it does not distinguish the 'totals' scope behavior in the prose, though the schema covers that.

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 date, dates and scope are already fully documented in the schema, including formats, defaults and the 31-day limit. The description's 'one day or a range of days' only restates that capability and adds no format, precedence or default semantics beyond what the schema provides. Baseline 3 applies.

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 gives a specific verb (reads) plus the exact resource (the person's food diary) and scope (one day or a range of days), then enumerates the payload: meals, foods, amounts, nutrition values and daily totals. An agent can distinguish this from edit_diary and log_meal purely from the verb and the 'reads' framing without opening any schema.

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?

Usage is implied by 'for one day or a range of days', which tells the agent this covers both single-day and multi-day reads, but there is no explicit statement of when to prefer a sibling tool (e.g., use list_foods for catalog lookups, log_meal to add entries) or any exclusion. Guidance is present only indirectly.

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