list_countries

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

No annotations exist, so the description should clarify behavioral traits. It states it lists data, implying a read-only operation, but does not explicitly mention that it is non-destructive or safe. For a simple listing tool, the minimal description is borderline, but the lack of explicit safety disclosure holds it back.

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 a single, concise sentence that front-loads the core action. Every character earns its place; no unnecessary words.

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 simplicity of the tool (listing countries), the output schema exists, and parameters are fully documented, the description is nearly complete. It lacks a brief note on typical use cases (e.g., populating a dropdown) but is sufficient for agents.

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%, meaning the schema already fully documents all parameters. The description adds no additional parameter semantics beyond what is in the schema, so baseline 3 is appropriate.

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 the verb 'List' and the resource 'countries', and specifies the return values (ISO codes, names). It distinguishes from other list_* tools in the sibling list by naming a unique entity. However, it could be more explicit about the purpose (e.g., for reference dropdowns).

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?

No guidance on when to use this tool versus alternatives. The description lacks context on typical scenarios or prerequisites. Agents are left to infer from the tool name alone.

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