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

The description adds substantial context beyond the readOnly/openWorld annotations: annual frequency, the caveat that recent years may be missing or revised, the exact price ($0.002 USDC per successful call), the payment rail (x402 on Base, Solana or Arc), and that failed calls are free. This cost and failure-semantics disclosure is genuinely useful for an agent deciding whether to call. Return format is not covered, but an output schema exists.

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?

Three tight sentences: purpose and example first, then data caveats, then pricing. Each sentence carries distinct, decision-relevant information with no repetition of the schema.

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, full parameter coverage and useful annotations, the description fills the remaining gaps an agent needs: source identity, data recency caveats, and payment mechanics. A brief note on response shape or typical latency would round it out, but nothing essential for correct invocation is missing.

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 are documented in the schema, and the description's example indicator code duplicates what the schema already provides. The description adds only the 'annual data' framing, which reinforces the meaning of the years parameter but does not extend it. Baseline 3 is appropriate.

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 the specific resource (World Bank indicator values), the scope (one country, by year) and gives a concrete example indicator code, so an agent can identify the tool immediately. The named data source (World Bank) implicitly separates it from siblings like finance_asian_dev_bank_data or finance_bank_of_england_iadb, but no explicit sibling routing statement is made.

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?

Usage is implied by the scope and the 'annual data' framing, giving an agent enough context to know this is for yearly country-level macro indicators. However, there is no explicit when-to-use guidance, no mention of when to prefer an alternative source, and no statement of prerequisites beyond payment.

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