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

Annotations already declare readOnlyHint and openWorldHint, but the description goes materially further: it discloses the payment protocol and cost ($0.002 USDC per successful call via x402 on Base, Solana or Arc) plus the important billing nuance that failed calls are not charged. This is exactly the kind of operational context an agent needs before invoking a paid, open-world lookup.

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 resource and scope, then field coverage, filter, caveat, and price — four tight clauses with no filler. Minor redundancy in restating the name-filter behavior already present in the schema keeps it from a 5.

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 an output schema present, the description needn't explain return values, and annotations cover the read-only safety profile. The remaining agent-critical unknowns — data source, cost model, and the licence caveat — are all addressed, so nothing important is missing 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?

Schema description coverage is 100%, so all three parameters (q, limit, country) are already documented in the schema, including the country format example and the 1–200 limit range. The description's only added parameter detail is the name-substring filter, which restates the schema's own wording for q, 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?

States a specific verb+resource (FIATA member freight forwarders by country from FIATA's public members directory) and enumerates the returned fields: postal address, phone, e-mail, website and named managers. This is clearly distinguishable from siblings like logistics_customs_broker_verify or logistics_customs_broker_verify-adjacent licence tools, which a reader can infer from the explicit 'national associations and individual member companies' scoping.

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?

'Filter by part of the company name' names the narrowing condition, and 'FIATA membership is not a government licence; it lists members of the international federation only' is an explicit when-NOT-to-rely-on-this caveat for compliance workflows. It stops short of naming a specific alternative sibling for licence verification, so it falls just below a 5.

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