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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it performs a fuzzy 'best match' search (so results may not be the exact food requested) and it discloses the returned fields (nutrients, data type, date). It still doesn't say whether multiple matches are surfaced or how a miss is reported.

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 dense sentence that front-loads the resource, then the two input modes, then the return payload. 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?

For a zero-required-parameter read tool with no output schema, the description covers inputs, resolution strategy and returned fields, which is close to sufficient. Remaining gaps are minor: units/precision of nutrient values and no-match behavior, but nothing blocks correct invocation.

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 coverage is 100%, and the schema descriptions already explain query, fdc_id ('skips the search') and the dataType values, so the description mostly restates structured data. The parenthetical '(or takes an fdc_id)' mirrors the schema rather than adding new semantics such as precedence when both are supplied.

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?

States a specific verb and resource ('Nutrient composition of a food from USDA FoodData Central') plus the two resolution paths (query match or fdc_id) and what is returned. The sibling tools (checks/regulations) occupy an entirely different domain, so no differentiation is required, and an agent can tell immediately what this returns.

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 rather than stated: the agent can infer that a query triggers a search while fdc_id 'skips the search', and that dataType narrows the source. There is no explicit when-to-use guidance, no mention of when this tool is preferable to other lookups, and no note on what happens when nothing matches.

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