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

No annotations exist, so the description carries the full burden and largely meets it: it discloses batch limits, that absence in "nutrients" means unknown rather than zero, the caveat that empty "missing" only covers core label nutrients, per-100g/ml/serving basis, and merged-id redirection with a "merged" map. It does not state auth/permission needs, rate limits, or error behavior for invalid or unknown ids.

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?

It is front-loaded with the core purpose, then immediately sequences the important caveats (unknown ≠ zero, empty "missing" limits, basis, merged ids). It is dense and clause-heavy, but no sentence is filler; a light bulleted structure would read better without adding content.

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 no output schema and no annotations, the description does the heavy lifting for a 3-parameter batch-read tool: it explains the card's shape, unit basis, missing-data semantics, and id merging. What remains thin is error handling for bad or unknown ids and the meaning of the "regime" parameter.

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 67%, and the description adds some genuine meaning: the batch cap and the unknown-vs-zero rule for nutrient values, plus the merged-id citation behavior. It says nothing about the "fields" projection semantics or "regime" derivations beyond what the schema already documents, so it neither compensates fully nor adds much for those two parameters.

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 names a specific verb+resource: fetching full entity cards by id in batches up to 100, and enumerates the payload (facts with unit/basis/proof rank/source, portions, identifiers, serving, quality hints). It is clearly distinguishable from siblings like search or compare, though it never explicitly names an alternative such as describe or nutrition to contrast against.

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: you call it when you already have an id and want a complete card. There is no explicit when-to-use/when-not or pointer to the sibling (describe, nutrition, lookup_barcode) that resolves an id first. The merged-id note and the source-id alias in the schema do give practical entry conditions.

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