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

Annotations already establish readOnlyHint=true and openWorldHint=true. The description adds important behavioral context beyond annotations: pricing ($0.002 USDC per successful call), payment via x402, and that failed calls are not charged. It also indicates the tool returns dated CBP rules and presidential documents with links.

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 the core check and limits, followed by output contents and pricing. Every sentence earns its place: one covers the checks, one covers returned documents, and one covers payment terms.

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?

An output schema exists, so return values need not be fully explained. The description covers purpose, key limits, suspension status, output document types, and payment behavior, making it complete enough for an agent to invoke 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 description coverage is 100% for the single optional valueUsd parameter, and the schema already explains it is the shipment fair retail value to check against the $800 limit. The description reinforces the $800 check but does not add format, edge-case, or validation guidance beyond the schema.

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 a specific resource and check: US de minimis (Section 321), including the $800/$100/$200 limits, suspension status, and duty-free eligibility. It does not explicitly name or differentiate itself from sibling customs tools such as logistics_customs_duty_calc, so it falls short of the top score.

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 provides clear contextual triggers: checking a shipment value against the $800 limit, determining whether de minimis is currently suspended, and whether a shipment can enter duty-free today. It does not explicitly say when not to use the tool or name alternative siblings.

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