country_by_code

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

Annotations already declare readOnly, idempotent, non-destructive, and open-world behavior, so safety is covered. The only additional detail the description offers is the upstream source ('REST Countries'), and it says nothing about what happens with an invalid or ambiguous code (empty result vs. error) or what subset of country data is returned.

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?

One short sentence, front-loaded with the verb and resource; nothing is padded. It is efficient, though the extreme brevity is what leaves the gaps noted above.

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 one-parameter lookup with no output schema and no parameter documentation, the description needs to at least pin down the accepted code format and expected response shape. It does neither, leaving the agent to guess on the single required input.

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% and the single parameter 'code' is undocumented in both schema and description. The critical ambiguity — ISO alpha-2 vs. alpha-3, case sensitivity, or numeric codes — is not resolved anywhere, so the description fails to compensate for the coverage gap.

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 names a specific verb and resource ('Get a country') and adds the lookup key ('by code'), so an agent knows exactly what it retrieves. It does not explicitly distinguish itself from siblings like country_by_name or country_by_region, but the code-based scope is implied clearly enough.

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?

There is no guidance on when to choose this over country_by_name, country_all, country_info_detail, or country_by_ip, all of which live in the same family. The agent must infer selection purely from the tool name.

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