get_country_metric

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

With no annotations, the description carries the burden and does so well: it discloses that year='latest' walks back past null years, that fx_date defaults to year-end of a pinned year with a last-trading-day fallback, and that the response reports the actual year and FX rate used. It omits any auth, rate-limit, or error behavior, keeping it out of 5 territory.

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 one-line purpose followed by a tight per-parameter bullet list; every line conveys format, allowed values, or default behavior. No filler.

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 parameter-heavy read tool with no output schema and no annotations, the description covers defaults, fallback behavior, and the shape of the response (year used, FX rate and date, flags, sources). It is nearly self-sufficient, though edge cases like invalid country codes or missing data are not addressed.

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, and it documents all five parameters: accepted country code formats with examples, the metric enum values with a definition of gdp_per_capita, year formats plus 'latest' semantics, accepted currencies, and the fx_date format/default. This adds substantial meaning beyond the bare schema titles.

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 combination ("One country's gdp, population, or gdp_per_capita for a year") and enumerates the metric dimension, which implicitly separates it from aggregate siblings like region_total and rank_countries. It does not explicitly name or contrast a sibling, so it stops 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?

Usage is implied by the bullets rather than stated: an agent can infer this is for a single country's metric, but the description never says when to pick it over region_total, rank_countries, or convert_currency. No exclusions or prerequisites are given.

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