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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the data source, the exact scope of returned measures, the customs-duties-only limitation, the legal caveat, and precise pricing behavior: $0.002 in USDC per successful call via x402 on Base, Solana, or Arc, with failed calls not charged. These are important behavioral facts an agent cannot infer from the annotations.

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 front-loaded with purpose and covered measures, then adds the customs-duty-only caveat and pricing in compact sentences. Despite being dense, every clause carries useful information for deciding whether and how to call the tool.

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 tool is a read-only, open-world tariff lookup with an output schema, so the description need not explain return values. It covers source, scope, exclusions, legal caveat, and payment behavior, leaving no material gap for 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?

The input schema has 100% description coverage, including format examples and the default destination of DE. The description reinforces that code is a goods code and origin is a country, but it does not add format or edge-case guidance beyond the schema. A baseline 3 is appropriate because the schema already carries the parameter semantics.

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 states a specific verb and resource: consult EU import measures (TARIC) for a goods code from an origin country into an EU member state. It names the authoritative source (European Commission Access2Markets) and enumerates the measure types covered, which clearly distinguishes it from sibling customs tools such as logistics_china_customs_tariffs or logistics_uk_trade_tariff.

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 clear context for use: EU import duties, preferences, anti-dumping, suspensions, and conditions, with the explicit scope limitation 'Customs duties only (no VAT).' It also warns to check TARIC for legally binding detail. It does not explicitly name alternative sibling tools such as logistics_customs_duty_calc, so a 4 rather than a 5.

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