country_by_region

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

No annotations are provided, and the description does not convey behavioral traits such as data source details, response format, rate limits, or that it is a read-only operation. The brief statement adds no behavioral context beyond the obvious.

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?

At 7 words, the description is concise but overly terse. It could include essential details without becoming verbose. The structure is a single sentence, which is acceptable for such a simple tool.

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 low complexity (one parameter, no output schema), the description should at least specify valid region values and response behavior. It fails to provide this, making the tool usage unreliable without external knowledge.

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?

The input schema has a single string parameter 'region' with 0% schema description coverage and no enums. The description does not clarify what constitutes a valid region (e.g., continent names, country names? ), leaving the agent with no guidance on parameter values.

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 'Get', resource 'countries', and filter 'by region'. This distinguishes it from sibling tools like country_by_code, country_by_name, etc., which filter by different criteria.

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 provides no guidance on when to use this tool versus alternatives. It does not specify when to use 'by region' vs other country endpoints, nor any prerequisites or limitations.

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