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

Annotations already declare read-only, idempotent, non-destructive behavior, but the description adds genuinely new traits: the not-found fallback (found=false plus the list of available foods instead of an error) and that each value ships with a source article URL for citation. Both materially change how an agent handles a miss. It stops short of describing output shape beyond those fields.

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?

Front-loaded with the action and resource, then coverage, then sibling routing, then the fallback behavior — a sensible order with no repeated content. It is a dense single paragraph, but nearly every clause carries a fact an agent needs.

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 present, the description still conveys return content (four nutrients, per-100g and per-serving values, source URLs) and the miss path (found=false with available foods). Combined with clean annotations and a fully documented 2-parameter schema, an agent has everything needed to call and interpret it.

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%, including the enum for nutrient and an example-laden description for food, so the schema already carries parameter meaning. The description adds only the per-100g vs per-katori framing, which is output-side rather than input-side nuance, 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?

Specific verb ('Get nutrition facts') plus a precisely scoped resource ('ONE Indian food'), with the nutrient set and per-100g/per-katori breakdown named. It also names the coverage corpus (60 foods, ICMR-NIN tables), so an agent can tell exactly what domain this serves.

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?

Explicitly routes the agent: 'Use compare_foods for several foods at once, search_guides for topics rather than single foods.' Both the when and the when-not are stated with named siblings, leaving nothing to inference.

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