Compare Countries

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 still earns credit for disclosing the non-obvious data semantics: only the latest available value per country is returned, which rules out time-series interpretation. It omits anything about missing/stale data for lagging reporters, so it stops 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 tight sentences, zero filler, with the core scope statement (one indicator, several countries) front-loaded ahead of the softer benefit claim. Nothing needs trimming.

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 present, return values need no explanation, and annotations cover the read-only profile. For a 2-parameter read-only tool the description is sufficient, though it could note behavior when a country lacks data for the requested indicator.

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% and the enum list of indicator keys plus country-code example already live in the schema. The description's 'one indicator' wording reinforces cardinality but adds no format or validation detail beyond what is structured. Baseline 3 is correct when the schema does the heavy lifting.

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 (Compare) and resource (one indicator across several countries), plus the temporal scope (latest available value each). It contrasts implicitly with country_profile by scoping to a single indicator, but never names a sibling, so an agent must infer the boundary from sibling names 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?

The clause 'Good for ranking or benchmarking economies' points at intended use cases, so usage is implied rather than stated as a rule. There is no explicit when-not guidance and no named alternative (e.g. country_indicator for single-country time series), leaving the agent to work out the routing itself.

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