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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavior: a $0.010 cost, that the response includes payment instructions for the Saylor endpoint, and that no provider account is required — billing and auth context an agent would otherwise have to discover by calling.

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?

Four short sentences, front-loaded with what is returned, followed by cost and payment mechanics. No filler, though the payment sentence could be trimmed slightly without losing meaning.

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?

No output schema, but the description compensates by enumerating return contents (years, units, source links, missing values) as well as the payment-instruction payload. For a single-parameter read tool, the only real gap is differentiation from the near-identical sibling get_country_report.

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?

Only one parameter exists and schema coverage is 100%, with the country property already documenting the two-letter World Bank code and the exclusion of aggregates. The description adds nothing about the parameter, 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 and resource plus the exact fields returned (population, GDP in current US dollars, CPI inflation) and the observation limit of five recent annual points. It does not distinguish itself from the sibling get_country_report, which plausibly overlaps, so an agent cannot fully disambiguate from the text alone.

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?

Scope is implied through 'up to five recent annual observations' and the World Bank country-code requirement in the schema, which hints at the use case. However, it never states when to prefer this over get_country_report, get_sdg_indicators or get_fx_report, and gives no exclusions or prerequisites beyond the payment note.

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