country.lookup

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

With no annotations provided, the description carries the full burden. It comprehensively lists return fields (names, ISO codes, region, capital, etc.), indicating a read-only, safe operation. No contradictory statements observed.

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 description is two sentences, no extraneous words. First sentence defines the tool and parameters, second lists return fields. Perfectly front-loaded and efficient.

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?

Given the tool's complexity (4 parameters, no output schema), the description covers all necessary aspects: input parameters, usage, and return fields. It adequately compensates for missing annotations and schema coverage.

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 explains the semantics of each parameter: alpha2 and alpha3 as ISO 3166-1 codes, and fullText for exact match. This adds meaningful context beyond the schema's property names.

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 clearly states it is for country metadata lookup using specific identifiers (alpha2, alpha3, name) and mentions optional fullText exact match. It effectively distinguishes itself from sibling tools, none of which are country-specific.

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 description specifies the lookup keys (alpha2, alpha3, name) and the fullText option, which implies usage, but it provides no explicit when-to-use guidance or comparisons to alternatives. The sibling list is large but lacks a directly competing tool, reducing the need for exclusion guidance.

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