usda_food_nutrition

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

With no annotations provided, the description fully discloses the payment mechanism: it requires a signed x402 v2 authorization via the '_payment' parameter to unlock the paid response, and without it returns a 402 accept-list. The description also states it returns a clean macro block plus alternates, giving clear behavioral expectations.

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 description is about five sentences and front-loads the purpose ('USDA FoodData Central nutrition lookup'). It is efficient and all sentences add value, briefly covering input, output, and payment. However, it could be slightly more structured (e.g., bullet points) for easier scanning.

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?

The description explains the return of a 'clean per_100g macro block' and alternates but does not detail the full return format (e.g., food name, description, or how alternates are structured). There is no output schema to compensate. Error handling and edge cases (e.g., invalid query) are not addressed. For a paid tool, this is adequate but not complete.

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% with all three parameters described in the schema. The description adds value for the '_payment' parameter by explaining the x402 v2 authorization format and that it unlocks the paid response. For 'query' and 'limit', the schema descriptions suffice, but the extra payment context raises the score above baseline 3.

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 clearly states the tool performs a 'USDA FoodData Central nutrition lookup' and specifies what it returns: 'best-matching record with a clean per_100g macro block' plus alternates. This distinguishes it from sibling tools which are unrelated (e.g., solana_wallet_scan, pubmed_medical_search).

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?

The description says 'Query any food (brand or generic)' and explains the payment workflow, but does not provide when to use this tool versus alternatives or any conditions to avoid using it. It implicitly assumes the user wants nutrition data but offers no comparative guidance.

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