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

With no annotations, the description carries the full burden and does disclose meaningful behavior: a metered cost ($0.001 per call via x402/USDC on Base) and that responses carry a provenance chain plus an Ed25519 attestation, which signals verifiability/trust properties. It omits edge behavior (invalid/unknown ISO code handling, rate limits, payment failure modes), so it falls short of a 5.

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?

Two dense sentences with zero filler, and the purpose is front-loaded ahead of the payment/provenance caveats. The payment and attestation clauses are compressed but each still carries distinct information, so it stops just short of ideal structure.

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 and no annotations, the description must carry the response contract, and while it names the top-level fields and the attestation, it does not describe structure, error behavior, or what a 'free quote' response contains. For a paid tool where callers need to reason about cost and payment failure, this leaves real gaps.

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 only 50%: the required 'id' parameter has no schema description (only maxLength 8), and the description compensates by specifying it is an ISO code, resolving an otherwise opaque key. The optional 'payment' parameter is explained in the schema, not the description, so the description does not fully cover both parameters.

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 and the lookup key: 'World Bank country record by ISO code.' It also enumerates the returned fields (region, income group, lending category, capital, coordinates), so an agent knows exactly what this retrieves. No sibling covers World Bank country data, so no differentiation is required.

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?

There is no when-to-use guidance, no mention of alternatives, and no stated preconditions or exclusions. Usage is only inferable from the name and the 'by ISO code' phrasing. This matches the calibration's 2 for 'no when-to-use, no prerequisites.'

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