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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial value beyond them: the return structure (entries in meal-scheme order), the fields per entry, day-level totals, and a required Cotlet API key with app access. That auth and shape disclosure is real context the annotations do not carry.

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 opening line is front-loaded with the core concept (logged food grouped by meal with calories/macros), and every sentence about entries, totals, and the delete workflow is relevant. The first two sentences overlap somewhat in describing meal grouping, a minor redundancy.

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?

There is no output schema, so the description correctly carries the burden of describing return values (entries, item_id, macros, day totals) and even discloses the auth prerequisite. What remains unstated is behavior for future/empty days, but overall it is complete enough to call the tool correctly.

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?

With a single optional parameter and 100% schema description coverage, the schema already documents the date format and 'Default: today.' The description only restates 'one day,' adding no syntax or constraint beyond the schema, so the 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 states a specific verb and resource: 'Returns the food diary for one day, meal by meal,' and details the granularity (grouped by meal, per-entry macros, day totals). It is clearly distinct from logging tools like fitatu_log_food, though it does not explicitly contrast itself with close-sounding siblings such as fitatu_get_nutrition_summary.

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 context is implied by the read nature of the tool and the downstream hint 'Use item_id with delete_diary_item,' which links to the deletion workflow. However, there is no explicit routing against the overlapping sibling fitatu_get_nutrition_summary, and no stated when-not conditions.

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