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

Annotations only cover readOnlyHint and openWorldHint; the description adds genuinely useful behavior — no point cost, no URL fetching, and a privacy_consent_required response mode. That last clause is muddled, though: it talks about 'fields' when the schema sets additionalProperties=false and has no such parameter, leaving the trigger condition ambiguous.

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 core capability and exclusions are front-loaded and efficient, but the privacy-consent sentences consume roughly half the text and describe a condition that appears unreachable given the schema, which dilutes the signal.

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?

For a simple two-parameter read tool this covers purpose, constraints, and cost, but it omits what the response actually contains (value only? value plus reference year?) and is vague about the consent flow, so an agent still has open questions.

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 0%, so the description must compensate. It does map the two indicator codes to human meanings (GDP in current US$, total population), but says nothing about the country parameter's required ISO two-letter uppercase format, leaving half the inputs unexplained.

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 and resource ('Read the latest value of two published World Bank indicators') and enumerates exactly which two, so the agent knows the domain. It doesn't name a specific sibling (e.g., hub_wikidata or hub_fx) as the alternative for other country statistics, which keeps it short of a 5.

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?

Gives concrete exclusions: only the two listed indicator codes are accepted, no URL input, and no point spend. That is real when-not guidance, but it never routes the agent to a sibling tool for other indicators or other country data, so the alternatives half of the rubric is missing.

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