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

No annotations are provided, so the description carries the full burden. It discloses the expert-reviewed nature, non-binding guidance caveat, and the $0.50 per-call cost paid via x402 micropayment. These are meaningful behavioral traits beyond the basic operation, though it does not cover every possible limitation.

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 moderately long but front-loaded with the core purpose and output. The cost and payment details are relevant for the agent's decision-making, and the caveat about non-binding advice is important. Each sentence contributes, though some marketing language could be trimmed.

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, the description sufficiently explains what the tool returns: the applicable rule of origin and proof method (EUR.1, statement on origin, or REX). It also covers cost, language options via schema, and the non-binding nature. This is adequate for an agent to call it 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?

Schema coverage is 100%, so the baseline is 3. The description adds value by giving concrete examples for the 'q' parameter ('olive oil' or 'EU-South Korea EUR.1') and clarifying that it accepts a product or an agreement, which aids the agent in forming correct queries.

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's function: providing expert-verified preferential rules of origin for EU trade agreements, including the applicable rule and proof documentation. It explicitly says to use it to determine whether goods qualify for reduced/zero preferential duty, which distinguishes it from sibling tools focused on tariffs, classification, or procedures.

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 gives a clear use case: determining origin qualification and required documentation. It does not explicitly mention when not to use it or name alternatives among the siblings, so it stops short of full exclusion guidance.

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